Centre d expertise en analyse environnementale du Québec BOOKLET 3

Transcription

1 Cente d expetise en analyse envionnementale du Québec Sampling Guide fo Envionmental Analysis BOOKLET 3 SAMPLING OF GROUNDWATER EDITION : May 2007 Revised : Apil 24, 2009

2 Note to the eade: The infomation petaining to egisteed tademaks o commecial poducts is used only as a guide and can be substituted fo any equivalent poducts. Fo additional infomation: Cente d expetise en analyse envionnementale du Québec o to access ou documents on ou Web site at the following addess : o to contact us at : Cente d expetise en analyse envionnementale du Québec 2700, ue Einstein, bueau E Québec (Québec) G1P 3W8 Telephone: Fax: ceaeq@mddep.gouv.qc.ca Bibliogaphic efeence: MINISTÈRE DU DÉVELOPPEMENT DURABLE, DE L ENVIRONNEMENT ET DES PARCS DU QUÉBEC, 2009, Sampling Guide fo Envionmental Analysis, Booklet 3 Sampling of Goundwate, Cente d expetise en analyse envionnementale du Québec, 86 p. Legal Deposit Bibliothèque et Achives nationales du Québec, 2009 ISBN Guide d échantillonnage à des fins d analyse envionnementale ISBN Guide d échantillonnage à des fins d analyse envionnementale (English Vesion) ISBN (PDF) REV. Apil 24, 2009 ISBN (PDF) (Edition: May 2007) ISBN (PDF) (Fench Edition: Apil 24, 2009) ISBN (peviously published in Fench by Les éditions le Giffon d agile, ISBN X, 1 st Edition, 1994) Gouvenement du Québec, 2009

3 FOREWORD This Sampling Guide fo Envionmental Analyses details a seies of codes of pactice to plan and conduct sampling activities. The pupose of the guide is to ensue the quality of samples collected and the validity of scientific infomation aising fom these samples. The ceation of this document was an initiative of the Ministèe du Développement duable, de l Envionnement et des Pacs, moe specifically the Cente d expetise en analyse envionnementale du Québec, afte infomation came to light evealing that samples did not have the tools necessay to gain an immediate knowledge of sampling pactices in Québec. This desciptive efeence guide was developed to seve as an infomation tool fo individuals to who cay out activities that ae pat of an envionment chaacteization pogam. Fom the outset, samples have expessed a keen inteest in having this type of efeence document available. Not because all of the infomation in the guide is unpublished wok; but because it was of inteest and useful to include a summay of infomation contained in technical efeences o infomation based on pactical sampling expeience in Québec. The Sampling Guide fo Envionmental Analysis consists of a seies of booklets dealing specifically with sampling in diffeent envionments. Cahie 1 - Généalités (in Fench only), must accompany each booklet in the seies. It povides a geneal famewok fo implementing a sampling pogam and discusses technical pocedues elating to quality, legality, health and safety issues. It also ecommends pocedues to optimize sampling pogams. This thid booklet, entitled Sampling of Goundwate, descibes the types of equipment that ae equied to install wells, conduct sampling pocedues and peseve samples. Apil 2009 Booklet 3 - Sampling of Goundwate Page 3 of 86

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5 TABLE OF CONTENTS LIST OF TABLES...8 LIST OF ILLUSTRATIONS INTRODUCTION LOCATING SAMPLING POINTS LAYOUT AND INSTALLATION OF MONITORING INSTRUMENTS IN THE SATURATED ZONE Types of wells Open well Taditional well Multilevel well Monitoing well nest Dilling equipment Hollow and solid stem auges Rotay dills Cable dills Diamond dills Potable dills Dilling pecautions Mateial fo constuction of monitoing wells Tubing and staine Filteing sand Sealing mateial Seals Potective casing and cove Dimensions of sampling wells Installing mateial Tube and staine Filteing sand Annula space sealing mateial Development of monitoing wells SAMPLING PROCEDURES Development of a sampling pogam Detemining which paametes to analyze Sampling fequency...40 Page Booklet 3 - Sampling of Goundwate Page 5 of 86

6 Ode of sampling Wate level analyses and hydaulic testing Well puging Sampling equipment Diect sampling methods Suction methods Positive displacement methods Destuctive methods Special samples Choice of mateials Sample filtation Method of cleaning equipment Identifying samples Safety pecautions PRESERVING, STORING AND TRANSPORTING SAMPLES PARAMETERS MEASURED IN THE FIELD Tempeatue ph Electical conductivity Oganic vapous explosive gases Keeping a field log book SAMPLING IN AN UNSATURATED ZONE Sampling intestitial wate Sampling of the gaseous phase QUALITY CONTROL SAMPLING SPRING WATER AND WELLS FOR DRINKING WATER Sping wate Sampling a dinking wate well SAMPLING AND MEASUREMENT OF THE THICKNESS OF NON-MISCIBLE LIQUIDS Light non-miscible liquids Dense non-miscible liquids CONCLUSION...78 Page 6 of 86 Booklet 3 - Sampling of Goundwate

7 REFERENCES...79 BIBLIOGRAPHY...85 Booklet 3 - Sampling of Goundwate Page 7 of 86

8 LIST OF TABLES TABLE 1 - FACTORS THAT AFFECT HORIZONTAL SPACING BETWEEN WELLS...12 TABLE 2 - ADVANTAGES AND DISAVANTAGES OF OPEN WELLS...14 TABLE 3 - ADVANTAGES AND DISADVANTAGES OF TRADITIONAL WELLS...16 TABLE 4 - ADVANTAGES AND DISADVANTAGES OF SINGLE MULTILEVEL WELLS 17 TABLE 5 - ADVANTAGES AND DISADVANTAGES OF MONITORING WELL NESTS...21 TABLE 6 - TYPES OF TRACERS AND THEIR PROPERTIES...27 TABLE 7 - ADVANTAGES AND DISADVANTAGES OF A BAILER...44 TABLE 8 - ADVANTAGES AND DISADVANTAGES OF SYRINGE SYSTEMS...46 TABLE 9 - ADVANTAGES AND DISADVANTAGES OF MANUAL INERTIA PUMPS...47 TABLE 10 - ADVANTAGES AND DISADVANTAGES OF SUCTION METHODS...50 TABLE 11 - ADVANTAGES AND DISADVANTAGES OF POSITIVE DISPLACEMENT METHODS...54 TABLE 12 - ADVANTAGES AND DISADVANTAGES OF DESTRUCTIVE METHODS...55 TABLE 13 - RELIABILITY OF SAMPLING METHODS...56 TABLE 14 - ADSORPTION AND RELEASE OF ORGANIC COMPOUNDS...61 TABLE 15 - RELIABILITY ON THE BASIS OF THE TYPES OF PARAMETERS...63 Page Page 8 of 86 Booklet 3 - Sampling of Goundwate

9 LIST OF ILLUSTRATIONS FIGURE 1 - DIAGRAM OF AN OPEN WELL...15 FIGURE 2 - DIAGRAMS OF A MULTILEVEL WELL...18 FIGURE 3 - DIAGRAM OF A MONITORING WELL NEST...22 FIGURE 4 - MONITORING WELL...30 FIGURE 5 - DIMENSION OF COMPONENTS OF A MONITORING WELL...32 FIGURE 6 - BAILER...43 FIGURE 7 - SYRINGE SAMPLING SYSTEM...45 FIGURE 8 - SUCTION SAMPLING METHOD...49 FIGURE 9 - GAS DISPLACEMENT SAMPLING METHOD...52 FIGURE 10 - POSITIVE DISPLACEMENT SAMPLING METHOD BLADDER...53 FIGURE 11 - DIAMETER OF PORES OF MATERIAL AND SIZES OF PARTICLES, ORGANISMS AND CHEMICAL COMPOUNDS THAT MAY BE PRESENT IN GROUNDWATER...67 FIGURE 12 - DIAGRAM OF A LYSIMETER...72 FIGURE 13 - STANDARD CONSTRUCTION OF A BIOGAS SAMPLING WELL...74 Page Booklet 3 - Sampling of Goundwate Page 9 of 86

10 1. INTRODUCTION Demand fo chaacteization studies of goundwate quality is gowing because management of this esouce has been deemed one of the pioity actions of the envionmental potection and consevation stategy. The success of chaacteization studies ests lagely on the validity of goundwate samples collected. Steps that ae pat of the sample collection pocedue, fom location and constuction of monitoing equipment, to delivey of samples to the laboatoy, ae potential souces of sample deteioation and contamination. Enomous stides ae cuently being made in goundwate sampling techniques as an examination of official ecods fom confeences and symposiums, and aticles in scientific jounals shows. Pogess and development in new sampling techniques makes the need fo implementing stict standads unnecessay. What s moe, methods cannot apply to all goundwate contamination studies due to the wide vaiety of geological and hydogeological conditions that exist. Thee is, howeve, a need fo guidelines to help detemine which methods should be chosen, based on field conditions and objectives Ideally, each sampling point should have its own sampling equipment. Monitoing wells should be dilled using hollow-stem auge dills and should be constucted of inet mateial such as stainless steel and Teflon. If accuate vetical definition is equied, monitoing wells should be set up in individual boeholes. Fo pactical and cost easons, howeve, this ecommendation cannot always be enfoced. The degee of pecision of a sampling pogam also depends on how much contamination is pesent. This guide is theefoe not an exhaustive oveview of all possible techniques. The hydogeologist in chage of a poject is esponsible fo implementing a goundwate monitoing pogam. Adheence to the methods detailed heein does not guaantee the success of opeations in all possible types of hydogeological conditions. A seies of steps must be followed when collecting goundwate samples. They usually consist of the following sequence: dilling, setting up monitoing instuments, sampling, stoage and tanspotation of samples. Each of these steps is a potential souce of chemical o physical alteation of a sample. The pincipal souces of alteation include physical distubances (wate mixing) due to dilling opeations, chemical and bacteial contamination due to dilling opeations, chemical contamination and adsoption due to contact with monitoing equipment, sampling equipment and containes, and coss contamination fom one sampling site to anothe due to contaminated equipment. Sample integity theefoe equies the following safeguads: - the chemical composition of goundwate must not change significantly duing its migation fom the geological fomation to the monitoing well; Booklet 3 - Sampling of Goundwate Page 10 of 86

11 - dilling methods and monitoing systems must not affect the chemical composition of goundwate; - sampling equipment and sampling methods must not contibute to the alteation o contamination of wate samples; - pesevation methods and the method of tanspotation must not alte the wate s physical o chemical popeties, which have an impact on the analyses conducted. 2. LOCATING SAMPLING POINTS The decision of whee to locate sampling points is the fist step of implementing a sampling pogam. The choice should be based on whee a contamination souce is located, the aea s hydogeological chaacteistics and the physical and chemical popeties of contaminants. If measuing points ae not coectly positioned, the esult will be a flawed intepetation of the extent and type of contamination. A study of existing geological and hydogeological infomation at the site is theefoe cucial befoe implementing a sampling pogam. Knowledge of goundwate flow diections, in elation to whee a contamination souce is located is the most impotant facto when selecting a sampling point. If a monitoing well is set up in a hydaulic location upsteam fom a contamination souce, you can detemine natual and egional concentations (natual levels) in the suounding aea. Ideally, one well should be selected to detemine natual levels in each statigaphic unit. The well should be located upsteam and outside of the aea that is deemed potentially contaminated. Othe monitoing wells should be located in a hydaulic location downsteam fom the contamination souce. Some should be located nea the souce to chaacteize contamination, and othes futhe downsteam will help detemine the extent of contamination. Factos that affect the hoizontal spacing between monitoing wells ae listed in Table 1 (next page). The numbe of monitoing wells equied and thei exact location will be specified as the sampling pogam poceeds. Booklet 3 - Sampling of Goundwate Page 11 of 86

12 Table 1 - FACTORS THAT AFFECT HORIZONTAL SPACING BETWEEN WELLS WELLS POSITIONED CLOSELY TOGETHER Liquid wastes ae pesent; the site unde study is a small aea; thee is pemeable fill mateial nea possible souces of contamination; thee ae undedains, tench dains o othe undegound lines; the geology is complex (factued fomations close to one anothe, faults, folds, discontinued stuctues); the statigaphic geology is polymictic; the site is located nea a efill zone; a high hydaulic gadient; the topogaphy has shap contasts; slight dispesivity at the site; high infiltation ate. WELLS POSITIONED WELL APART The geology is egula (no factued fomations, no faults, no folds, continuous stuctues); unifom statigaphic geology; low hydaulic gadient; high dispesivity at the site; low infiltation ates. Page 12 of 86 Booklet 3 - Sampling of Goundwate

13 The vetical distibution of sampling points is based on the statigaphic geology. Ideally, thee should be one sampling point fo each hydostatigaphic unit that is tavesed. If samples ae collected fo the pupose of detemining if goundwate has been contaminated by a ecent contamination souce located nea the suface, at least the fist pemeable zone that is come acoss fom the contamination souce must be sampled. Setting up a sampling point in this aea will seve as a waning of the migation of the contamination zone. Knowledge about the physical popeties of contaminants, paticulaly solubility and density, will help guide the sampling pogam. Non-miscible liquids, which ae lighte than wate, emain at the top of the wate table. The distibution of dense liquids, howeve, is moe complex, so they ae found at geate depths. 3. LAYOUT AND INSTALLATION OF MONITORING INSTRUMENTS IN THE SATURATED ZONE Befoe beginning this section, which explains how monitoing instuments ae set up and laid out, the distinction should be made between a monitoing well and a piezomete. Monitoing wells ae used to collect wate samples, to detect and sample non-miscible liquids and to measue wate levels. A piezomete is used gauge wate levels fo the pupose of detemining the diection of goundwate flow and velocity 1. In a goundwate sampling pogam, monitoing wells ae used Types of wells The fou most common types of monitoing wells include: open wells, taditional wells, multilevel wells in a boehole and well nests. The advantages and disadvantages of each type ae discussed below Open well This method of monitoing consists of sampling goundwate fom an open well that contains no piping (Figue 1). It is the simplest monitoing method, but can only be used in consolidated ock fomations whee walls can emain vetical without suppot. Open wells do not help to detemine the vetical distibution of contaminants, but can lead to an initial detection of contamination. Thee ae a few wods of caution egading the intepetation of esults of analyses fom this type of well because usually only wate fom the top of the suface is collected duing sampling. Unfotunately, howeve, dense nonmiscible liquids and extemely contaminated wate sink to the bottom of wells. Whee this is the case, wate samples should be collected fom the bottom of wells. Also, since wate can filte in along the entie length of a boehole, in most cases thee is a majo dilution effect. Booklet 3 - Sampling of Goundwate Page 13 of 86

14 Table 2 - ADVANTAGES AND DISAVANTAGES OF OPEN WELLS ADVANTAGES: They ae inexpensive; thee is no contact between well mateial and goundwate; a wide ange of dilling techniques can be used. DISADVANTAGES: They povide no infomation about the vetical distibution of contaminants; because it is a composite sample, contaminants may be diluted; because the entie length of the boehole is open, contaminants can migate vetically. Page 14 of 86 Booklet 3 - Sampling of Goundwate

15 FIGURE 1 - DIAGRAM OF AN OPEN WELL Booklet 3 - Sampling of Goundwate Page 15 of 86

16 Taditional well The taditional well method consists of installing a staine at a given depth to measue the degees of contamination. The staine zone is isolated fom othe hoizons by a tight-fitting cap of bentonite. Installation of this type of cap equies an annula space between the tube and boehole wall. The usual constuction of this type of installation is descibed in detail in section 2.3. Table 3 - ADVANTAGES AND DISADVANTAGES OF TRADITIONAL WELLS ADVANTAGES: It minimizes vetical migation of contaminants; can be set up quickly and inexpensively; hydaulic conductivity tests can be conducted on site. DISADVANTAGES: Only one level can be sampled; can contibute to vetical migation of contaminants if the cap is not tightfitting Multilevel well Anothe type of setup is to intoduce tubes fitted with staines into diffeent levels of a boehole (Figue 2a). Each level of sampling is sepaated by tightfitting bentonite caps and each staine is suounded by a sand filte. The ai tightness between each level is an impotant facto. Positioning aitight caps and sand lantens may be difficult if the wate table is nea the gound suface. Fo pactical puposes, usually no moe than thee to fou monitoing wells can be inseted in each boehole. In sand fomations, anothe type of setup uses piezomete bundles (seies of small tubes fitted with an open, sceened o poous end point, attached to a igid tube (Figue 2b). These systems do not equie the installation of tightfitting caps o sand lantens because sandy mateial will enclose itself aound the equipment. These types of installations involve use of moe sophisticated systems. They systems consist of sampling gates distibuted along the length of the igid tube (Figue 2c). Sampling gates ae sepaated fom one anothe by plugs. Each sampling gate is connected to a tube that allows sampling at the suface, using a suction technique if the wate table is less than 8 metes deep, o using a gas displacement pump o manual piston pump. Page 16 of 86 Booklet 3 - Sampling of Goundwate

17 Most sampling gate systems ae sold commecially. The most commonly used ae Westbay and Solinst systems. These systems ae paticulaly useful in factued fomations (one gate pe intecepted factue when factues ae popely located). These types of installations ae commonly used when deep boeholes ae equied and dilling a seies of boeholes is not possible due to costs. Hydaulic conductivity tests must be pefomed befoe the devices ae installed because of the small diamete of monitoing wells. The advantages and disadvantages of single multilevel boeholes ae shown in Table 4, on the page that follows. Table 4 - ADVANTAGES AND DISADVANTAGES OF SINGLE MULTILEVEL WELLS ADVANTAGES: They povide infomation about the vetical distibution of contaminants; they can be installed quickly. DISADVANTAGES: They ae usually expensive; sampling depths must be detemined in advance; bentonite caps ae had to install; thee is a isk of inteconnection between one level and anothe duing dilling and sampling; tubes can become plugged ove time; some tube mateials can wap and make wate sampling difficult. Booklet 3 - Sampling of Goundwate Page 17 of 86

18 FIGURE 2 - DIAGRAMS OF A MULTILEVEL WELL A - SAMPLING LEVELS SEPARATED BY SEAL PLUGS Souce adapted fom efeence 7 Page 18 of 86 Booklet 3 - Sampling of Goundwate

19 B - PIEZOMETER CLUSTER Booklet 3 - Sampling of Goundwate Page 19 of 86

20 C - SAMPLING GATE SYSTEM Souce: adapted fom efeence 7 Page 20 of 86 Booklet 3 - Sampling of Goundwate

21 Monitoing well nest Of all the diffeent types of monitoing wells, the most eliable is the monitoing well nest if concentation pofiles have to be detemined accoding to depth (Figue 3). This involves a seies of taditional monitoing wells dilled to diffeent depths in individual boeholes that ae in close poximity to one anothe. This type of setup povides effective vetical definition and minimizes the isk of coss contamination. This monitoing system should be favoued ove othes. Each well should be constucted accoding to the installation technique descibed in section Table 5 - ADVANTAGES AND DISADVANTAGES OF MONITORING WELL NESTS ADVANTAGES: They povide effective vetical definition of contamination; thee is no isk of coss contamination; simple hydaulic tests can be caied out. DISADVANTAGES: They ae long to install; they ae elatively expensive. Booklet 3 - Sampling of Goundwate Page 21 of 86

22 FIGURE 3 - DIAGRAM OF A MONITORING WELL NEST NB: A monitoing well should be built accoding to Figues 4a and 5 Souce: adapted fom efeence 7 Page 22 of 86 Booklet 3 - Sampling of Goundwate

23 3.2. Dilling equipment All dilling equipment, without exception, distubs hydogeological conditions in neighbouing suoundings 2. The degee of distubance depends on two main factos: the type of dilling equipment used and the type of geological fomation. Given the vast aay of dilling equipment and geological conditions available, all of the possible scenaios cannot be discussed in this document. Details fo each item of equipment ae pesented in Discoll (1986) 3 and Davis et al. (1991) 4. The five main types of dilling equipment to install monitoing wells include: - hollow and solid stem auges; - otay dills (mud, ai and wate); - cable dills; - diamond dills; - potable dills. In some cases, well constuction may equie use of moe than one type of dilling equipment. The following factos detemine which type of dilling equipment should be used: - type of geological mateial; - depth of boeholes; - position of boeholes (access); - availability of equipment; - paametes to be analyzed Hollow and solid stem auges A dilling method that uses auge dills is least likely to contaminate goundwate because it does not equie use of dilling mud o liquid. This method should theefoe be pefeed ove othe methods. Auge dills, howeve, can only be used in loose mateial and maximum dilling depths vay fom 6 to 45 m, depending on the equipment and type of geological mateials pesent. As auges penetate the soil, dilling esidues ise to the suface. Residues must be completely emoved fom the boehole because they can contaminate goundwate in uncontaminated aeas. Booklet 3 - Sampling of Goundwate Page 23 of 86

24 All dilling esidues must be stoed in containes until soil analysis esults become available. If esults eveal that esidues ae not contaminated, accoding to the A-B-C citeia chat in the Politique de éhabilitation des teains contaminés [Rehabilitation of Contaminated Sites Policy 5 ], they can be left at the site without teatment. If dilling esidues ae contaminated, they must emain at the site in containes until they can be ehabilitated, using an appoved method, at the site. Residues must be managed in the same manne as contaminated soil 5. Thee ae two types of auge dills: hollow-stem auges and full-stem auges. The main advantage of hollow-stem auges ove full-stem auges is the fact that monitoing wells can be installed without the need to emove auges fom the gound. Full-stem auges can only be used in solid mateial because the walls of the boehole must emain vetical long enough to allow monitoing wells, a sand lanten and seal plug to be installed. Auge dilling is fast, inexpensive and the dilling machine can be put into sevice quickly. Duing dilling opeations, thee may be upwad and downwad movement of goundwate alongside the auge. This vetical wate movement, which shifts in the diection of hydaulic gadients, can cause an uncontaminated zone to appea contaminated and vice vesa. Movement of contaminated soil to a highe level can also poduce the same effect Rotay dills In unconsolidated deposits, taditional otay dills use dilling fluids. The pupose of fluids is to cool the dill, bing dilling esidue to the suface and suppot the walls of the boehole. The fluids may be wate, a mixtue of wate and bentonite, activated sludge o a mixtue of wate and synthetic oganic polymes. The main diffeence between bentonite and oganic sludge is the addition of oganic polymes to change consistency, viscosity and liquid suface tension if necessay. These polymes include polyacylamides, caboxymethyl cellulose, sodium acylate, lignosulfonates and lignins. These poducts ae a potential souce of contamination of goundwate samples and thei use is ecommended only whee auge dilling is not possible. The advantage of otay dills is that they can be used in all types of geological mateial and at exteme depths. Use of wate as a dilling fluid causes it to spead to pemeable zones, which subsequently dilutes the wate that may initially be contaminated. Wate used duing the dilling pocess must be emoved fom the well befoe sampling begins. A detailed discussion about dilling fluids and pocedues to develop and empty monitoing wells appeas in sections 2.2.6, 2.5 and 3.3. Page 24 of 86 Booklet 3 - Sampling of Goundwate

25 Use of a wate/bentonite and wate/oganic polymes mixtue is a moe seious poblem because it is difficult to emove all these mateials. Bentonite has the disadvantage of holding positively chaged contaminants, which educes the aqueous concentations of these compounds. Oganic polymebased muds elease lage amounts of oganic compounds into goundwate and encouage adsoption o oganic and metal contaminants. Dilling methods that equie use of dilling fluids ae theefoe not ecommended. If use of a dilling fluid is absolutely necessay, use puified wate. Rotay dills equie use of ai athe than wate o dilling mud. Contamination can occu if wate comes into contact with ai because volatile oganic compounds can be caied fom extaneous mateial (dust, lubicating oil) and oxidize some chemical compounds such as nitites, sulfides, etc. Special filtes can theefoe be installed on ai compessos. Ai contact with wate can also cause volatile oganic compounds to be eleased fom the aqueous phase to the gaseous phase. A foaming agent is often mixed with ai to help ecove dilling esidues. The foam, howeve, can ente the fomation and contaminate goundwate. This dilling technique is not ecommended in situations whee oganic compounds ae analyzed Cable dills Opeation of cable dills consists of diving casings in unde the weight of a hamme suspended fom a steel cable. In unsatuated zones, wate must be used to allow the casing to descend. Because this wate is not pessuized, as it is with otay dills, thee is little isk of contamination. Small amounts of lubicating oil can be used to extend the life of the hamme. This type of dill can opeate in all types of geological mateial to geat depths and causes only a small edistibution of mateial along the walls. Dilling time is elatively long compaed to othe methods descibed above. A monitoing well is installed when tempoay steel casings ae emoved. The installation and withdawal of tempoay casings does not significantly affect wate quality and does not pomote contamination between zones. The cable dilling method should be used only whee auge dilling cannot be used Diamond dills Diamond dills ae used mainly in cystalline ocks to enable coe tests of ock and the installation of piezometes. A casing is diven in with the help of a diamond bit dill that must be cooled by wate. Intoduction of dill wate into goundwate can cause contamination o can dilute the contaminants pesent. Booklet 3 - Sampling of Goundwate Page 25 of 86

26 The pincipal advantage of this technique is that is allows the degee of ock factuing to be assessed on the basis of coe samples that ae taken. The isk of alteation of the chemical integity of wate samples is the same as isks associated with cable dill and otay dill methods Potable dills If dilling points cannot be accessed using dills mounted on tucks o catepilla tactos, use of potable dills will be equied. They ae, howeve, limited to small depths. The most common ae hand-held gas-poweed dills (vibation-pecussion dills and solid stem auges). These methods do not equie use of dilling fluids and thee is minimal contamination isk. Use of petoleum lubicants, howeve, equies special pecautionay measues to ensue that lubicants do not come into contact with wate. The motos of these dills can be easily conveted to natual gas Dilling pecautions Duing dilling opeations, pecautionay measues must be taken, egadless of which dilling method is in use. These include: Caeful supevision The dilling supeviso assigned to installation of wate quality monitoing instuments must closely monito each phase and must neve leave the site duing the time dills ae in opeation. The supeviso must always bea in mind that an individual who has expeience with wate supply dilling methods, may not necessaily be familia with contaminant hydogeology methods. Lubicating oils Lubicating oils outinely used by dill opeatos to educe coosion and wea of equipment ae a potential souce of contamination because they can mix with wate. In the case of some oganic compounds, contamination and potability ae measued in µg/l. Theefoe, a vey minute amount of oil is all that is equied fo these types of concentations to be found in wate. Remembe also that lubicating oils contain high levels of heavy metals. Lubicants can also contain cadmium, cobalt, chomium, coppe, ion, molybdenum, nickel, lead, zinc and othe metals including baium, calcium, magnesium, potassium and sodium. Page 26 of 86 Booklet 3 - Sampling of Goundwate

27 It is difficult to completely avoid use of lubicating oils and geases duing dilling opeations. It is possible, howeve, to uge opeatos to use these poducts spaingly to minimize the isk of contamination, paticulaly if heavy metals, oganic compounds and majo ions have to be analyzed. Use of plantbased hydaulic oils and geases (Raisio Biosafe type) educes the isk of wate sample contamination. Dilling fluids To minimize isks elated to use of wate duing cetain dilling pocedues, dill opeatos must use wate that is as clean as possible and enquie about its souce. If the wate composition is not known, it should be sampled fo analysis. Remembe that, egadless of its composition, wate that is used duing opeations will inevitably cause a dilution of the concentation of cetain paametes. Taces can be added to the dilling wate to veify if the effects attibuted to the wate have been completely mitigated. A list of taces and thei pincipal popeties appeas in Table 6. Table 6 - TYPES OF TRACERS AND THEIR PROPERTIES DYES: uanin, hodamine WT, sulfohodamine G ADVANTAGES: easy to use; safe; concentations can be measued at the site. DISADVANTAGES: Some dyes ae affected by the ph level and tempeatue o ae adsobed by clay paticles and oganic matte. ELECTROLYTES: sodium chloide, potassium chloide, ammonium chloide and lithium chloide ADVANTAGES: Concentations can be measued at the site; DISADVANTAGES: they equie a lage amount of electolyte. Adapted fom Discoll, G., (1986) 3. Booklet 3 - Sampling of Goundwate Page 27 of 86

28 Cleanliness of equipment Dilling instuments should be checked fo cleanliness befoe beginning a dilling pogam. It is impotant to ensue that ods and auges have been cleaned thooughly because they may have been used peviously at a contaminated site. Thoughout the dilling pogam, equipment pats must be stoed in locations that do not contain potential souces of contamination. Dilling should be caied out fom the least contaminated aea, to the most contaminated aea, if the contamination souce is known. Equipment may have to be decontaminated between two dilling sites, paticulaly if the last dilling opeation was caied out in a visibly contaminated aea. In these cases, decontamination using a steam-jet cleane, o using the method descibed in section 2.3.1, is ecommended. Inteception of a laye of non-miscible liquid Dilling though layes of non-miscible liquids that have a highe density than wate is usually not ecommended to pevent the isk of speading contamination. If, in ode to potect public health and the envionment, concentations of a contaminant in the aqueous phase of wate-beaing fomations must be detemined, dilling should take place downsteam fom the diection of goundwate flow and outside of the aea whee non-miscible liquids ae located. To develop site ehabilitation pogams, the thickness and popeties of these poducts must be detemined. To detemine this infomation, a staine should be positioned in the non-miscible phase and should extend slightly on eithe side of it. If non-miscible phases ae dense than wate, they migate vetically until they encounte an impevious baie. Thei migation is govened mainly by the topogaphy of this laye and to a lesse degee by the diection of goundwate flow. Infomation to sample and measue the density of these liquids is discussed in section 9. If dilling is caied out though a zone contaminated by non-miscible liquids, a small amount of contaminants will adhee to auges and will contaminate wate and soil that comes into contact with auges. The small amounts of contaminants that ae caied in the boehole wate along with auges will contibute to deteioation of goundwate quality. Page 28 of 86 Booklet 3 - Sampling of Goundwate

29 3.3. Mateial fo constuction of monitoing wells A monitoing well consists of a numbe if components, which ae shown in Figue 4a. A staine attached to a tube is placed below the wate level. An envelope of silica sand is placed aound the staine up to a slightly highe level (1 mete) to encouage the flow of wate to this zone. A seal plug, moe than one mete thick, consisting of bentonite (ganula o powde) is then placed ove the filteing mateial to isolate the stained wate aea fom ovelying layes and suface wate. The space emaining between the tube and boehole wall must be filled with a cement/bentonite mixtue o bentonite sluy. Dilling esidues must neve fill the annula space. A cap of expansive cement sluy, extending fom the suface to the fostline (at least 2 m), pevents unoff wate fom filteing in. To pevent ain wate fom accumulating, the cement sluy will fom a small mound at the suface and cove only the diamete of the boehole (Figue 4a). A potective cove fitted with a padlock is anchoed in the cement suface to potect the monitoing well fom beakage o vandalism. Like the tube, the potective casing must be ventilated to pevent a potential accumulation of explosive gases and to allow the wate level in the well to be subject to vaiations in atmospheic and hydaulic pessues. A dain hole must be installed in the potective casing at gound level (Figue 4a) to daw off wate that might accumulate in this space. In some cases (steets, paking lots, sevice stations, etc.), the potective stuctue must installed below gound level and must be watetight (Figue 4b). This will equie placing an O-ing o thick seal between the cove and potective casing. The monitoing well must be popely identified to avoid confusion with othe undegound installations. The poposed dimensions fo components of a well ae shown in Figue 5. Booklet 3 - Sampling of Goundwate Page 29 of 86

30 FIGURE 4 - MONITORING WELL A - COMPONENTS OF A MONITORING WELL Souce: adapted fom efeence 7 Page 30 of 86 Booklet 3 - Sampling of Goundwate

31 B - PROTECTIVE STRUCTURE BELOW GROUND LEVEL Souce: adapted fom efeence 7 Booklet 3 - Sampling of Goundwate Page 31 of 86

32 FIGURE 5 - DIMENSION OF COMPONENTS OF A MONITORING WELL Page 32 of 86 Booklet 3 - Sampling of Goundwate

33 Thee ae two ways to ensue that mateial has been installed coectly: by measuing the depth of mateial afte each phase and by detemining how much mateial will be equied in advance. If thee is a significant diffeence between the amount of mateial used and the oiginal volume calculated, o if the depth of mateial is not consistent with calculations, this infomation must be noted. These diffeences may distot the epesentativeness of wate samples and wate levels. Each monitoing well component must be caefully selected to minimize the isk of alteation of the chemical integity of goundwate. Types of mateial and the effects they can have on the physical and chemical popeties of wate ae discussed in the sections that follow Tubing and staine Tubing and staines ae most often manufactued fom stainless steel and polyvinyl chloide (PVC). If stainless steel is used, it must be gade 304 and 316 6,7,8,9. The high cost of stainless steel tubing and staines, howeve, limits the degee to which stainless steel is used. Polyvinyl chloides elease taces of compounds, including phtalates and metals. In most cases, PVC is an adequate substitute fo stainless steel to constuct a well fo goundwate sampling puposes. When it comes to analysis of volatile oganic compounds, thee is not a significant diffeence between PVC and stainless steel fo detection of contaminants in wate at concentations on the ode of micogam pe lite (see Tables 15a and 15b). Homemade staines made of othe mateial such as galvanized steel and acylonitile-butadiene styene copolyme (ABS) ae not ecommended. Manufactue staines ae pefeed because they have less suface contact with wate. Using a saw to make homemade staines dislodges fine paticles of mateial that incease the specific aea of the staine and encouage inteaction with wate. Obviously, paticula cae must be taken to ensue that the tubing and staine emain clean. If they ae not cleaned and wapped sepaately, they should be cleaned accoding to the method descibed in Cahie 1 Généalités (in Fench only). These pats should also not be left unpotected in locations whee thee ae potential contamination isks (the back of a dilling tuck, fouled gound suface, etc.). A potective box o plastic sheeting should be available fo tempoay stoage at the dill site. Booklet 3 - Sampling of Goundwate Page 33 of 86

34 Filteing sand Use of filteing sand will not be equied if unconsolidated deposits ae pemeable. In a geological fomation whee thee is poo pemeability, the pesence of a silica sand lanten aound the aea of the staine is necessay and encouages a hydaulic connection between the geological fomation and the staine. Duing sampling, wate migates though the sand ing. Filteing sand can theefoe alte the chemical composition of wate by adsoption/desoption. The contibution of filteing sand to the alteation of the chemical composition of wate is geate in mateials with little pemeability because the flow is slowe and wate is in contact with sand fo a longe peiod. The effect of filteing sand on wate s chemical composition will be minimal if the pope paticle size of clean silica sand is distibuted aound the opening of the staine. Use of ounded o sub-ounded sand is ecommended and use of silica chips is not ecommended Sealing mateial The pupose of a bentonite chips o ganules plug is to pevent the cement/bentonite mixtue o bentonite sluy, that is placed highe in the annula space, fom intuding. If bentonite sluy is placed diectly above filteing sand, a seconday filteing sand must be added between the filteing sand and bentonite sluy. Sodium bentonite has a high ion exchange capability. The pincipal outcome of these eactions is the elease of sodium into wate and the extaction of calcium. In cabonatized soil, use of calcium bentonite is ecommended. Due to the alkaline popeties of bentonite, it also causes the wate s ph level to ise slightly 10. Despite these inconveniences, use of a bentonite chips o ganules plug is ecommended because contamination due to bentonite has been established, wheeas contamination due to infiltation of suface wate has not. The pupose of the cement/bentonite mixtue is to minimize the inflow of suface wate o the uppe layes of the seal plug. The mixtue should be pepaed using clean wate in a high-speed mixe. The amount of bentonite to be added to the cement must be appoximately 3 to 8% of the weight of the cement 7. The effectiveness of how well a monitoing well has been sealed can be tested using the method poposed by Chapuis (l987) 11. Page 34 of 86 Booklet 3 - Sampling of Goundwate

35 Seals Special attention must be given to connecting seals between sections of casing. The ideal connection is made using casing theaded accoding to standad ASTM F480. A theaded joint fitted with an O-ing povides a bette seal than a simple theaded joint, to minimize the isk of wate infiltation fom layes above the staine zone. Use of plastic (PVC) glues should be avoided. These glues contain compounds that can leach into wate and intefee with analyses of oganic compounds. Most glues contain two o thee of the following solvents 6 : - methyl ethyl ketone; - tetahydofuan; - methyl butyl ketone; - dimethyl fomamide. - cyclohexanone; These solvents ae not outinely analyzed but thei pesence in wate intefees with main pioity oganic contaminants. Even a small amount of plastic glue can elease solvents into goundwate at concentations on the ode of 100 µg/l, even afte wells have been puged 6. It is also impotant to emembe that metal seals ae often coated with a laye of oil that can also affect oganic compound analyses Potective casing and cove Technically, the cove and potective casing do not come into contact with wate to be sampled. They do not theefoe affect the wate s chemical composition. The only estiction when selecting the ight type of cove is when the casing head is installed at gound level. The cove must be tightlysealed and igid enough to pevent infiltation of gound wate. The head of the monitoing well should be fitted with a potective casing that is padlocked to pevent vandalism Dimensions of sampling wells The length of the staine zone that is chosen may affect wate composition. A staine zone ove too long a section can ceate a connection between two layes, which will esult in a dilution of wate fom the contaminated zone. Staines between 60 cm and 3 m ae adequate in most cases. Regadless of the length of the staine section, goundwate will oiginate mainly fom moe pemeable layes and will vey aely epesent the quality of wate ove the entie staine section. In a factued fomation, the staine zone should cove a longe section, which impoves the chances of intecepting factues, but can also cause a dilution effect. Booklet 3 - Sampling of Goundwate Page 35 of 86

36 Paticula attention must be given to the staine position in the case of non-miscible liquids. If hydocabons lighte than wate ae pesent, it is impotant to ensue that the staine zone extends above the wate table in ode to intecept the supenatant phase. In the case of non-miscible liquids that ae dense than wate, the staine must be long enough to each the uppe limit of the fist impevious zone encounteed below the non-miscible liquid phase. If multilevel wells ae installed, openings should be located in the lowe pat of the sand filte 12. Fo pactical easons, a monitoing well fo goundwate sampling is usually 3.75 cm o 5.0 cm in diamete. Most of the usual sampling techniques can be caied out with these diametes. In less pemeable mateial, lage diamete wells esult in longe stabilization times. The lage the diamete of a well, the lage the volume of wate that has to be puged pio to sampling. The time and costs of sampling pocedues will be highe fo lage wells. If mateial has to be added (filteing sand, seal plugs, expansive cement), the annula space between the boehole wall and tubing must be at least 5 cm. In pemeable geological fomations consisting of unconsolidated deposits, natually developed wells ae ecommended. The staine opening should coespond to d 20 (diamete of paticles coesponding to 20% of the weight of the sample passing though the sieve duing a gadation test) fo the finest sample taken ove the length of the staine zone. In geological fomations with low pemeability, filteing sand is equied. The gadation cuve fo filteing sand is chosen by multiplying the d 30 of the finest sample taken ove the length of the staine zone by thee o fou. The unifomity coefficient (d 60 /d 10 ) fo filtes can vay between 2 and 3 3. Whee this is the case, the opening of the appopiate staine should coespond to d 10 of the filteing sand. In both cases, the staine opening should allow almost the entie natual fomation and filteing sand to be held because a small diamete monitoing well (3.75 to 5.0 cm) is difficult to develop. The eade can efe to the ecommendations of Discoll (1986, Chapte 13) 3 fo wate supply wells when selecting the opening of staines fo lage diamete monitoing wells Installing mateial Tube and staine It is impotant to cente the tube and staine in the boehole to ensue that sealing mateial and filteing sand (whee necessay) ae distibuted evenly aound the tube and staine. Page 36 of 86 Booklet 3 - Sampling of Goundwate

37 Adjustable diamete centalizes (polyvinyl chloide and stainless steel) can be secued pio to o when installing tubes in the well. Centalizes ae placed on the tube at 3 to 6 mete intevals. If semi-cicula centalizes ae used, depth is easie to measue when filteing sand and sealing mateial ae installed. Centalizes must have a smalle diamete than the boehole o tempoay casing Filteing sand Use of the hoppe tube method is ecommended when installing filteing sand. Filteing sand is intoduced by gavity though a igid hose o semiflexible tube between the boehole wall and staine. The annula space is filled while dy o simultaneously with clean wate, fom the bottom to the top of the staine. The hoppe should be at least 3.75 cm in diamete. If filling is caied out in the pesence of tempoay casing (hollow auge, cable dilling) and in loose unconsolidated deposits, the casing must be emoved gadually (30 to 60 cm at a time) as the filteing sand is being added. In solid unconsolidated deposits (silt and clay), ock o had fomations, tempoay casing o a hollow auge can be emoved up to the sand s pojected top level, befoe filteing sand is intoduced. The level of filteing sand must be measued as it is being added to ensue that it eaches the desied height Annula space sealing mateial A) Bentonite cap (above the filteing sand): Bentonite chips can be added by pouing, when a well is no moe than 15 m deep and the annula space is at least 7.5 cm. Chips should be packed togethe with a od. In wells that ae deepe than 15 m, bentonite chips can be mixed with clean wate and poued in though a hoppe in the annula space. If bentonite sluy is used diectly on top of filteing sand, a seconday filteing sand must be poued in to pevent the sluy fom migating to the fist filte and into the staine section 7. The coasest faction fo the seconday sand should be equal to d 10 of the filteing sand. The d 10 fo the seconday filteing sand should be between one-thid and one-fifth of the d 10 fo the filteing sand, to ensue that fine mateial fom seconday filteing sand does not engulf the filteing sand. The finest paticles should be no bigge than 0.7 mm and no smalle than 0.1 mm in diamete. Booklet 3 - Sampling of Goundwate Page 37 of 86

38 This type of paticle-size distibution is fine enough to pevent sluy fom penetating the seconday filteing sand, but coase enough to be intoduced in a easonable time. The hydaulic conductivity of the seconday filteing sand should be geate than o equal to the hydaulic conductivity of the laye of the geological fomation with which it is in contact. To pevent eosion of seconday filteing sand duing filling, the hoppe should be placed against the tube at an angle. B) Above the bentonite cap: The cement-bentonite mixtue o bentonite sluy is intoduced using a hoppe hose at least 3.75 cm in diamete. A positive displacement pump should be used to continuously fill the annula space fom the bottom to the top. The bottom of the hoppe should emain immesed in the mixtue at all times duing filling. The hoppe, howeve, should be emoved as soon as filling is complete Development of monitoing wells The pupose of developing a monitoing well is to emove fine paticles that wee intoduced duing dilling opeations to estoe the natual hydaulic conductivity of the wate-beaing fomation and to obtain wate samples that have as little tubidity as possible. The five main methods of developing monitoing wells ae by plunge, pumping/ovepumping, baile, steam of wate, steam of ai. The fist thee methods can be used in combination. The last two ae not ecommended because intoducing ai o wate into a geological fomation can alte the chemical integity of wate samples collected. Plunge The plunge tavels down as fa as the top of the staine and moves fom top to bottom ove a length of one mete. Fine paticles and sand that move to the staine must be pumped out peiodically. The plunge is then gadually loweed towads the bottom of the staine. The plunge should be slowly agitated at the beginning, then agitation should gadually incease duing development. Too much agitation can cause the staine o tube to beak. This method is effective with a cable dill fo a stainless steel monitoing well. If mateial othe than steel is used, the tube and staine may beak. Page 38 of 86 Booklet 3 - Sampling of Goundwate

39 Pumping/ovepumping The pumping/ovepumping method consists of pumping wate fom a well faste than it can ente, until it is almost dy. The pump is then stopped and wate ises to its initial level in the well. This cycle is epeated seveal times, until wate is fee of sediments. A siphon effect can also be poduced inside the staine if the pump does not have a one-way check valve. This can be poduced by tuning the pump on and off peiodically. Baile Development of a monitoing well using a baile is caied out by allowing the baile to fall into the well, which aises the wate level to dislodge fine paticles aound the staine. As the baile fills with wate, a dawdown effect is ceated and fine paticles ae dawn into the well. This opeation should be epeated until the wate is fee of suspended paticles. To speed up the pocess, the baile can be shaken quickly nea the base of the well. These methods can usually be caied out in pemeable mateial. In mateial with low pemeability, none of these methods poduces satisfactoy esults. Clean wate should be ciculated though the tube to the staine and filteing sand befoe a seal plug is installed. The wate flow should be contolled to pevent filteing sand fom moving to the suface. Once a seal plug has been installed, the well should be pumped to emove the small amount of wate intoduced into the fomation duing the development pocess. The pumped wate should be disposed of in accodance with the disposal citeia poposed in section 3.3. Fo moe infomation about development of monitoing wells, the eade can efe to Alle et al. (1988) SAMPLING PROCEDURES 4.1. Development of a sampling pogam Detemining which paametes to analyze The pupose of goundwate sampling is to detemine if thee has been contamination and what type of contamination is pesent. The paametes to be analyzed and the degee of the desied pecision, must be detemined on the basis of established policies, guidelines and egulations. Booklet 3 - Sampling of Goundwate Page 39 of 86

40 A eview of the histoy and type of activities at the contaminated site o on neighbouing sites will sometimes povide clues about which contaminants might be pesent. A eview of this infomation may also seve as a guide to planning the sampling pogam. Sometimes, howeve, the infomation available does not povide enough clues about the pesence of cetain contaminants when they ae pesent. A sceening analyses pocedue should be used to detect as many paametes as possible duing the fist sampling session. The list of paametes can be significantly educed duing subsequent samplings Sampling fequency A sampling pogam to chaacteize, estoe o monito goundwate quality afte a contaminated site has been ehabilitated, should consist of at least fou sampling sessions each yea. One detailed session and thee patial sessions should enable tends to be defined. Duing a detailed session, a scan is caied out fo all suspected contaminants and only those paametes that ae detected duing this session ae analyzed duing a patial session. Ideally, monitoing wells should be sampled thoughout the entie yea, including at least one session pe season to detemine seasonal fluctuations in wate quality Ode of sampling Duing a sampling pogam, monitoing wells that ae located the futhest away fom a souce of contamination must be sampled fist because they have a lowe isk of being highly contaminated. This ode of sampling minimizes the isk of coss contamination. Sometimes, the exact location of a contamination souce is unknown. It theefoe becomes difficult to detemine an ode of sampling. The fist session will help detemine which monitoing wells ae most contaminated and seve to establish the ode of sampling. Sampling ode is not impotant if a dedicated sampling system is in use. Dedicated systems consist of pemanently setting up cetain pieces of equipment fo sampling at each monitoing well Wate level analyses and hydaulic testing Wate sampling sessions often include wate level analyses and occasionally hydaulic testing. Hydaulic tests should be intepeted accoding to the Hvoslev 14 method o an equivalent method. Testing should not be conducted if the wate level is dopping o if wate o a foeign object has to be added. Testing should be caied out when the wate level is ising (puging). Wate level pobes, pefeably made of stainless steel, should be cleaned accoding to pocedues ecommended in section 3.6. If non-miscible phases ae detected o if the density of a wate column is >1 (ex. salt wate), an equivalent load in wate depth should be calculated. Page 40 of 86 Booklet 3 - Sampling of Goundwate

41 4.3. Well puging All wells, without exception, that ae scheduled fo sampling to veify goundwate quality must be puged befoe samples ae collected. Puging is caied out to emove stagnant wate in ode to obtain a sample that is epesentative of the undegound fomation. Stagnant wate in a well can be affected by the following pocesses: contact with well constuction mateial, contact with the atmosphee, outgassing and biological activity. Well puging must allow enough wate to be dained fom the well. Too lage an amount will intefee with the hydogeological system. Ideally monitoing wells should be puged until the wate s physical and chemical popeties (tempeatue, electical conductivity and ph) ae stable. 15,16,17,18 Fo pemeable mateial, a volume of wate equivalent to 3 to 5 times the total volume of wate in the monitoing well and in the filteing sand (depending on its poosity) should be emoved. It is impotant to pevent dawdowns by avoiding ovepumping when wells ae puged. Excessive pumping will dawn wate fom ovelying and undelying layes to the zone you would like to sample. Daining wate fom the staine and filteing sand should be avoided because it may contibute to volatilization of volatile oganic compounds. In the case of mateial with low pemeability, whee lage volumes of wate cannot be puged ove a easonable peiod, stagnant wate should be puged fom the well at least once. Sampling must be caied out as soon as enough goundwate has eenteed the well. Puging should be caied out fom the top of the wate column to the bottom, to avoid distubing the wate unnecessaily 19. Wate that is puged must be collected and stoed in containes, until the esults of analysis ae available. The wate can then be emptied at the site if concentations ae below citeion B of the Politique de éhabilitation des teains contaminés [Rehabilitation of Contaminated Sites Policy 5 ] o dained into the sewe system if concentations comply with the sewe dainage standads of the municipality o wate can be teated at the site, as the case may be Sampling equipment A vaiety of equipment is available fo goundwate sampling. Equipment anges fom simple to sophisticated. New instuments ae constantly being developed and gadually intoduced onto the maket. The type of manufactuing mateial and opeating methods fo the instument in question ae the pincipal citeia to conside when selecting equipment. These two impotants factos can affect a sample s chemical composition. This pat of the guide contains a bief desciption of equipment and discusses advantages and disadvantages. The types of mateial that go into constucting sampling systems ae discussed in section Booklet 3 - Sampling of Goundwate Page 41 of 86

42 Of all the diffeent types of sampling systems, thee ae fou lage goups of systems that can be classified accoding to thei opeating pocedue: diect sampling methods, suction methods, positive displacement methods and destuctive methods Diect sampling methods Diect sampling methods include sampling devices that ae loweed into a well. This categoy includes bailes, syinges and hand piston pumps. Baile A diagam of a baile is shown in Figue 6. It consists of a tube fitted with a check valve at the bottom. A baile is loweed and aised by hand fom the suface using a cable. The tube fills when it is loweed and wate is tapped in the tube by the check valve when it is aised. Because of its simple design, a baile can be manufactued at a easonable cost using a vaiety of mateial. It is also easy to clean. Baile s, howeve, can only daw small volumes of wate (maximum 1 L) and may theefoe not be suitable fo use in some instances. In some deep wells with a high wate level, sampling can become labou-intensive. When a sample in a tube is decanted to a containe, it is exposed to ai. Bailes that allow a sample to be decanted fom the bottom at a educed capacity ae now on the maket. Use of this type of baile is ecommended whee tace amounts of volatile oganic compounds have to be sampled. Page 42 of 86 Booklet 3 - Sampling of Goundwate

43 FIGURE 6 - BAILER The most likely souce of contamination duing use of a baile is the cable. Caution should be taken to pevent the cable fom coming into contact with the gound o othe possible souces of contamination. Pio to sampling, the cable should be insed with well wate and the potion of the cable that was immeged should be cleaned, accoding to the pocedue in section 3.6. Use of a new cable fo each monitoing well pevents the isk of coss contamination. Booklet 3 - Sampling of Goundwate Page 43 of 86

44 Duing handling, the sample should be exposed to as little ai as possible and the wate should be agitated as little as possible. The advantages and disadvantages of bailes ae detailed in Table 7. TABLE 7 - ADVANTAGES AND DISADVANTAGES OF A BAILER ADVANTAGES: It can be used as a dedicated sampling system; it is potable; no souce of enegy is equied; it is made of a vaiety of mateial; easy to clean; it is inexpensive; it enables non-miscible liquids to be sampled; it is easy to use; it enables hydaulic conductivity testing and can be used to develop and puge wells. DISADVANTAGES: It has a small volume; it does not pefom well in deep wells with high wate levels; contact with ai and degassing of the sample can occu when it is decanted to a containe; valves can become blocked by suspended solids. Syinges Syinge systems have ecently been developed fo goundwate sampling pocedues 2. Figue 7 shows the pincipal components of this type of system. A wate sample is taken at a desied depth fom the suface. Page 44 of 86 Booklet 3 - Sampling of Goundwate

45 FIGURE 7 - SYRINGE SAMPLING SYSTEM Booklet 3 - Sampling of Goundwate Page 45 of 86

46 To take samples at appoximately 4 metes in depth, ai pessue must be applied to pevent the plunge fom ising. Pessue in the syinge is eleased when it eaches the desied depth. The main advantage of a syinge system is that wate samples can be potected fom exposue to ai because the syinge seves as the sampling containe. A filte can be added to the lowe end of the syinge. The advantages and disadvantages of syinges ae detailed in Table 8. TABLE 8 - ADVANTAGES AND DISADVANTAGES OF SYRINGE SYSTEMS ADVANTAGES: Samples do not come into contact with ai; the souce of the sample is known; they ae made of inet mateial; they can be used as a containe; they ae potable, inexpensive and easy to use. DISADVANTAGES: They have a small volume; they cannot be used to puge wells; thei use is limited to samples that have few suspended solids; a souce of compessed gas is equied. Inetia pump Watea type An inetia pump opeates accoding to the same pinciple as a baile. When it is loweed, wate entes the tubing and is tapped by a one-way check valve when pulled up. By continuously oscillating the tubing in an up-and-down motion connected, wate ises to the suface. Tubing often consists of a flexible polyethylene hose, which can also be made of Teflon o aluminium. High-density polyethylene tubing is pefeable to low-density tubing because low-density tubing is too flexible and tends cack easily. Inetia pumps ae available in a vaiety of mateials and diametes. They can use tubes with a diamete as small as 2 cm and have a numbe of advantages. They ae easy to use, eliable, potable and equie no paticula maintenance. They can be used manually to a depth of 40 metes. Page 46 of 86 Booklet 3 - Sampling of Goundwate

47 Because they ae inexpensive, they can be used as a dedicated system to puge wells and fo sampling. To minimize the distubance of wate when sampling volatile oganic compounds, a smalle diamete device can be adjusted to fit the plastic tubing. The main disadvantages of an inetia pump ae the tubulence that is ceated when a pump is agitated in a well and weaing of the pump against a walls. If a well has not been developed coectly, valves may block. The advantages and disadvantages of inetia pumps ae detailed in Table 9. TABLE 9 - ADVANTAGES AND DISADVANTAGES OF MANUAL INERTIA PUMPS ADVANTAGES: They have a simple design; ae lightweight and potable; ae easy to opeate; equie little maintenance; ae inexpensive; can be used in small diamete wells; ae suited to sampling volatile oganic compounds 20 ; can be used fo puging and fo sampling; can be used manually to a depth of 40 metes and with a moto, to a depth of 60 metes; can be used as a dedicated system. DISADVANTAGES: They ae difficult to use in deep monitoing wells o lage-diamete wells because they equie a moto; the automated system is not potable; weaing of the pump occus following polonged use on a metal tube; they can cause tubulence in a well. Booklet 3 - Sampling of Goundwate Page 47 of 86

48 Suction methods Suction sampling methods use negative pessue to daw wate fom a sampling well. These methods usually consist of loweing, a tube connected to a suface pump, to the desied depth. A vacuum can be applied at the suface using vaious methods: a manual vacuum pump o peistaltic pump. They ae connected to an Elenmeye flask to limit potential contamination fom flexible ubbe tubing (ex. Tygon ), which ae commonly used in combination with peistaltic pumps. The suction method pinciple is illustated in Figue 8. Theoetically, suction methods cannot be used to collect samples at depths in excess of 9.7 m. In pactice, howeve, samples cannot be collected at depths in excess of 7.5 m because thee will not be enough vacuum pessue. These methods ae theefoe esticted to instances whee the wate level is less than 7 to 8 m fom the gound suface. The staine, howeve, can be positioned at much geate depths. The vacuum can be applied to eithe the liquid phase o gaseous phase. These methods ae usually not ecommended fo collecting samples that ae submitted fo analyses of volatile oganic compounds. Whee vacuum pessue is applied to wate, degassing poblems ae less seious, but do still exist. Page 48 of 86 Booklet 3 - Sampling of Goundwate

49 FIGURE 8 - SUCTION SAMPLING METHOD Booklet 3 - Sampling of Goundwate Page 49 of 86

50 Table 10 lists the advantages and disadvantages of suction methods. TABLE 10 - ADVANTAGES AND DISADVANTAGES OF SUCTION METHODS ADVANTAGES: They ae easy to manufactue; ae inexpensive; ae potable; have a vaiable output capacity; components can be made of inet mateial. DISADVANTAGES: Thee is a chance of chemical alteation due to vacuum pessue; depth is limited Positive displacement methods Positive displacement methods ae based on mechanisms that exet diect pessue on wate by using a gas, piston, tubine o bladde movement, to dive wate. These methods allow samples to be collected at depths of 1,000 metes. The chance of chemical alteation of wate due to exposue to positive pessue is small compaed to the chance of chemical alteation due to use of suction methods 2. Positive displacement methods ae used when the wate level is too deep and diect sampling methods ae impactical. A sample undegoes significant changes in pessue as it is aised to the suface fom exteme depths. A sample taken seveal hunded metes below the suface can undego pessue changes equal to seveal thousand kilopascals, which changes steady-state conditions. Gas-diven systems ae included in positive displacement methods. They consist of applying pessuized gas to a wate column, which foces wate to ise in a collecto tube up to the suface 21. The details of these types of systems ae shown in Figue 9. In the case of gas-diven systems, contact of the wate with gases may alte the wate s chemical composition. Nitogen is the gas that is ecommended duing use of these methods because it is elatively inet. Page 50 of 86 Booklet 3 - Sampling of Goundwate

51 Positive displacement devices also include submesible piston pumps and bladde systems (bladde pump), shown in Figue 10. Although expensive, bladde pumps povide samples that ae moe epesentative than gas-diven systems because the gases that ae used do not come into contact with wate. Unlike submesible pumps (piston o tubine), bladde pumps agitate wate less, which makes them moe eliable fo sampling volatile compounds. Of all positive displacement sampling methods, a bladde pump is the ecommended system. Booklet 3 - Sampling of Goundwate Page 51 of 86

52 FIGURE 9 - GAS DISPLACEMENT SAMPLING METHOD Page 52 of 86 Booklet 3 - Sampling of Goundwate

53 FIGURE 10 - POSITIVE DISPLACEMENT SAMPLING METHOD BLADDER Booklet 3 - Sampling of Goundwate Page 53 of 86

54 TABLE 11 - ADVANTAGES AND DISADVANTAGES OF POSITIVE DISPLACEMENT METHODS ADVANTAGES: Reduced chance of degassing and volatilization; the piezomete puges quickly; can be used at exteme depths; they accommodate a vaiable flow. DISADVANTAGES: They ae expensive; equie a powe supply; ae difficult to clean; equie a lage diamete; wate comes into contact with pump components Destuctive methods Destuctive sampling techniques ae methods that equie a vey diffeent appoach than the methods discussed ealie in this guide. Destuctive methods do not equie use of pemanently installed monitoing instuments. They theefoe cannot be used fo long-tem monitoing of goundwate quality. The most common method consists of extacting wate fom soil samples collected duing dilling opeations. Destuctive methods ae used in clay deposits with low pemeability o whee the inlet of wate into piezometes is vey slow and whee, as a esult, taditional methods do not poduce satisfactoy esults. Wate can be extacted fom soil samples by centifugation o compessing the sample. Since only vey small amounts of wate can be extacted using these methods, it is impotant to caefully choose which paametes ae analyzed. Page 54 of 86 Booklet 3 - Sampling of Goundwate

55 TABLE 12 - ADVANTAGES AND DISADVANTAGES OF DESTRUCTIVE METHODS ADVANTAGES: Sampling can be caied out in mateial with low pemeability. DISADVANTAGES: Only small volumes of wate ae extacted; they do not allow long-tem monitoing Special samples Resins An altenative to goundwate sampling fo analysis of volatile oganic compounds is the use of tubes containing an adsobent esin. The sample is foced though the tube by a pump. Oganic compounds ae tapped and esins ae taken to the laboatoy fo desoption and analysis. Lage volume samples ae equied to detect vey small levels of oganic compounds. Resins help minimize the amount of space equied to cay egula samples. They also pevent a sample fom coming into contact ai because it emains in the collecto tube. Well point HydoPunch type Well points ae samples that can be diven into unconsolidated deposits (fine gavel, sand, silt and clay), to a depth of 5 to 8 metes, using a dilling machine hydaulic system o penetomete. Points ae made of stainless steel and Teflon and can be ecoveed afte wate sampling and left at the site, depending on the model. Use of a dilling fluid (wate, mud, ai, etc.) is not equied. The point must penetate at least 2 metes below the wate table to enable goundwate sampling. A device has also been developed fo sampling light non-miscible liquids. Tables 13a to 13d, show a summay of the types of samples that can be used, depending on which paametes ae analyzed. Booklet 3 - Sampling of Goundwate Page 55 of 86

56 TABLE 13 - RELIABILITY OF SAMPLING METHODS A - DIRECT SAMPLING METHOD 2 PARAMETRE BAILER SYRINGE INERTIA PUMP INORGANIC CHEMISTRY Ammonium () Silve () Asenic () Baium () Cadmium () Calcium Chloides Chomium () Conductivity Ion () Fluoides Magnesium Manganese () Mecuy () Nitates ph () Lead () Redox potential (E h ) () Selenium () Sodium Sulfates () ORGANIC CHEMISTRY Phenolic compounds () Volatile compounds () Pesticides () RADIOACTIVITY Alpha and beta () Radium MICROBIOLOGY Heteotophic plate count Total and fecal colifoms Fecal steptococcus : eliable (): limited eliability n: uneliable Page 56 of 86 Booklet 3 - Sampling of Goundwate

57 B - SUCTION SAMPLING METHOD ON THE BASIS OF PARAMETERS 2 PARAMETRES INORGANIC CHEMISTRY Ammonium Silve Asenic Baium Cadmium Calcium Chloides Chomium Conductivity Ion Fluoides Magnesium Manganese Mecuy Nitates ph Lead Redox potential (E h ) Selenium Sodium Sulfates SUCTION LIFT APPLIED TO WATER () () () () () () () () () () () () SUCTION LIFT APPLIED TO GAS n n n n n () n n () n n n n n n () ORGANIC CHEMISTRY Phenolic compounds Volatile compounds Pesticides n n n n () RADIOACTIVITY Alpha and beta Radium () n () MICROBIOLOGY Heteotophic plate count Total and fecal colifoms Fecal steptococcus : eliable (): limited eliability n: uneliable () () () Booklet 3 - Sampling of Goundwate Page 57 of 86

58 C - POSITIVE DISPLACEMENT SAMPLING METHOD 2 PARAMETRE CENTRIFUGAL PUMP PISTON PUMP BLADDER PUMP GAS DISPLACE MENT INORGANIC CHEMISTRY Ammonium Silve () Asenic () Baium () Cadmium () Calcium Chloides Chomium () Conductivity Ion () Fluoides Magnesium Manganese () Mecuy () Nitates ph () Lead () Redox potential(e h ) () () Selenium () Sodium Sulfates () ORGANIC CHEMISTRY Phenolic compounds () () () Volatile compounds () () () Pesticides () RADIOACTIVITY Alpha and beta Radium MICROBIOLOGY Heteotophic plate count () () () Total and fecal colifoms () () () Fecal steptococcus () () () : eliable (): limited eliability n: uneliable Page 58 of 86 Booklet 3 - Sampling of Goundwate

59 D - DESTRUCTIVE SAMPLING METHOD 2 PARAMETER INORGANIC CHEMISTRY Ammonium Silve Asenic Baium Cadmium Calcium Chloides Chomium Conductivity Ion Fluoides Magnesium Manganese Mecuy Nitates ph Lead Redox potential(e h ) Selenium Sodium Sulfates EXTRACTION OF INTERSTITIAL WATER FROM SOIL SAMPLES () () () () () () () () () () () () () n () () ORGANIC CHEMISTRY Phenolic compounds Volatile compounds Pesticides n n RADIOACTIVITY Alpha and beta Radium () MICROBIOLOGY Heteotophic plate count Total and fecal colifoms Fecal steptococcus : eliable (): limited eliability n: uneliable Booklet 3 - Sampling of Goundwate Page 59 of 86

60 Choice of mateials Chemical contamination as a esult of samples coming into contact with cetain mateials can have negative consequences. Sampling system components (tubing, pumps, valves, sampling containes, etc.) ae manufactued of a vaiety of mateials that can contibute, to vaying degees, to the chemical alteation of a sample. Metals, plastics, glass and ubbe ae the most common mateials in use. Two eactions, which ae the esult of wate coming into contact with these mateials, can affect the wate s chemical composition: the elease of compounds into wate and adsoption of contaminants on the suface of mateials. If small concentations of metals o oganic compounds ae anticipated in goundwate, pecautions should be taken when choosing the mateial that will come into contact with wate. Plastics The most common plastics fo sampling goundwate include 22 : - Teflon - PVC = polyvinyl chloide - PE = high-density and low-density polyethylene (HDPE and LDPE) - PP = polypopylene - ABS = acylonitile-butadiene-styene copolyme - SR = styene ubbe Some of these plastics elease consideable amounts of compounds into wate. Fo example, PVC, commonly used in well constuction, eleases compounds such as phtalates, otho-cesol, naphtalene, butyloctylfumaate and butylchloacetate 2. The elements that ae most affected by adsoption on PVC, PE and PP ae lead and oganic compounds. The pocesses of adsoption and elease of oganic compounds occu quickly in the case of PE, modeately slowly in the case of PP and slowly in the case of PVC. Adsoption of oganic compounds in wate on PVC is significant (ove 10%) if compounds ae hydophobic (solubility < 1 millimole/cubic mete), and not significant whee solubility is less than 10 millimoles pe cubic mete 23. Of all the plastics mentioned at the beginning of this section, ABS and SR ae those that have pose the highest isk fo alteation of a wate chemical composition. Teflon poses the smallest isk. Teflon is cuently the highest ecommended plastic fo sampling tace amounts of oganic compounds because it is the most inet. Use of Teflon should theefoe be favoued ove othe plastics. Tables 14a to 14c, show the adsoption and desoption isks of six oganic compounds commonly detected in goundwate that comes into contact with PVC, PE and PP sufaces 2. Page 60 of 86 Booklet 3 - Sampling of Goundwate

61 Some plastics allow gas to diffuse though thei walls. The loss of gas (volatile oganic compounds) as a esult of this pocess, howeve, is not well documented. Plastics that ae elatively gas-pemeable (fom most pemeable to least pemeable) include: LDPE, Teflon, PP, HDPE and PVC. Fo long-tem sampling pogams, a plastic s degee of esistance and duability on contact with chemical compounds pesent in wate should be veified with manufactues. TABLE 14 - ADSORPTION AND RELEASE OF ORGANIC COMPOUNDS A - BY PVC (adapted fom efeence 2 ) COMPOUND ADSORPTION RELEASE Bomofom Tetachlooethylene 1,1,1-Tichlooethane 1,1,2-Tichlooethane Tichlooethylene Tichloofluoomethane None Modeate None None None None None Maginal None None None None B - BY PE (adapted fom efeence 2 ) COMPOUND ADSORPTION RELEASE Bomofom Tetachlooethylene 1,1,1-Tichlooethane 1,1,2-Tichlooethane Tichlooethylene Tichloofluoomethane Modeate Vey stong Substantial Modeate Substantial Substantial Modeate None Maginal Maginal None Maginal C - BY PP (adapted fom efeence 2 ) COMPOUND ADSORPTION RELEASE Bomofom Tetachlooethylene 1,1,1-Tichlooethane 1,1,2-Tichlooethane Tichlooethylene Tichloofluoomethane Maginal Vey stong Modeate Maginal Substantial Modeate Vey stong None Maginal Maginal Maginal Maginal Metals Metals ae esistant, igid and unaffected by changes in tempeatue. A numbe of alloys, howeve, can elease metals into wate. Cases of wate contamination by zinc and coppe fom bass have been documented. Oxidization poducts and coosion of metal components can also find thei way into wate. Booklet 3 - Sampling of Goundwate Page 61 of 86

62 Metal components ae usually made of ion, aluminum and coppe. In addition to the elease of metal ions in wate, metal components act as adsobent sufaces on which a vaiety of oganic compounds can become tapped. Of all the metal components that might be used, only those made of 304 and 306 gade stainless steel show the least degee of isk of contamination. Accoding to Discoll (1986) 3, howeve, use of these steels is not ecommended to detect heavy metals in goundwate because they can elease chomium and othe metals. Galvanized steel can elease ion, manganese, zinc and cadmium in wate. It is also impotant to note that metal pats that have not been washed ae often coated with a potective film of oil that can elease oganic compounds into wate. Glass Like Teflon and stainless steel, glass is consideed a elatively inet mateial. Fo oganic compounds, glass is the pefeed mateial. Glass sufaces, howeve, can adsob positive ions such as metals and elease negative ions such as silicates and boates. Rubbe Rubbe is sometimes used to manufactue a vaiety of sampling system components (sealing ings, tubing). Rubbe, howeve, is able to adsob a wide vaiety of oganic compounds. Rubbe is also a majo souce of oganic and inoganic compounds that can find thei way into wate. The use of ubbe should theefoe be avoided, egadless of which paamete is analyzed. Recommended mateial Mateials that ae ecommended fo sampling oganic compounds include, in ode of pefeence: - glass; - Teflon ; - stainless steel; - polyvinyl chloide; - polyethylene; - polypopylene. Tables 15a to 15c, on the pages that follow, seve as a guide to selecting constuction mateial on the basis of which paametes ae analyzed. Page 62 of 86 Booklet 3 - Sampling of Goundwate

63 TABLE 15 - RELIABILITY ON THE BASIS OF THE TYPES OF PARAMETERS TO BE ANALYZED 2 A - RELIABILITY OF PLASTICS PARAMETER TEFLON PVC SR PE PP ABS INORGANIC CHEMISTRY Ammonium Silve Asenic Baium Cadmium Calcium Chloides Chomium Conductivity Ion Fluoides Magnesium Manganese Mecuy Nitates ph Lead Redox potential(e h ) Selenium Sodium Sulfates n n () n ORGANIC CHEMISTRY Phenolic compounds Volatile compounds Pesticides () () () n n n () () () n n n n n n RADIOACTIVITY Alpha and beta Radium MICROBIOLOGY Heteotophic plate count Total and fecal colifoms Fecal steptococcus () () () () () () () () () () () () () () () : eliable (): limited eliability n: uneliable Booklet 3 - Sampling of Goundwate Page 63 of 86

64 B - RELIABILITY OF METALS PARAMETER INORGANIC CHEMISTRY Ammonium Silve Asenic Baium Cadmium Calcium Chloides Chomium Conductivity Ion Fluoides Magnesium Manganese Mecuy Nitates ph Lead Redox potential(e h ) Selenium Sodium Sulfates STAINLESS STEEL () () () () () () () () GALVANIZED STEEL () () () () () () () () COPPER BRASS () () () () () () () () ALUMINIUM () () () () () () () () ORGANIC CHEMISTRY Phenolic compounds Volatile compounds Pesticides () () () () () () () () () RADIOACTIVITY Alpha and beta Radium MICROBIOLOGY Heteotophic plate count Total and fecal colifoms Fecal steptococcus () () () () () () () () () : eliable (): limited eliability n: uneliable Page 64 of 86 Booklet 3 - Sampling of Goundwate

65 C - RELIABILITY OF GLASS AND RUBBER PARAMETER GLASS RUBBER INORGANIC CHEMISTRY Ammonium Silve Asenic Baium Cadmium Calcium Chloides Chomium Conductivity Ion Fluoides Magnesium Manganese Mecuy Nitates ph Lead Redox potential(e h ) Selenium Sodium Sulfates () () () () () () () () ORGANIC CHEMISTRY Phenolic compounds Volatile compounds Pesticides RADIOACTIVITY Alpha and beta Radium MICROBIOLOGY Heteotophic plate count Total and fecal colifoms Fecal steptococcus () () n n n () () () : eliable (): limited eliability n: uneliable Booklet 3 - Sampling of Goundwate Page 65 of 86

66 4.5. Sample filtation Despite best effots to obtain wate samples with as little tubidity as possible, they usually contain some suspended silty/agillaceous paticles. The eaction between suspended paticles in wate and pesevative agents can alte the wate s composition, paticulaly the content of metals. Filteing at the sampling site is ecommended fo wate samples that ae scheduled to be analyzed fo dissolved metals 24,25. Filteing should be caied out immediately afte sample collection to pevent pecipitation and adsoption of metals. Pesevatives ae added afte filteing. Filteing should be caied out using 0.45 micon filtes. These types of filtes tap all silt paticles, most agillaceous paticles, most bacteia and a potion of ion and manganese hydoxides. Viuses and oganic macomolecules (humic and fulvic acids) will not be tapped (see Figue 11). Samples that ae to be submitted to analyses fo volatile and non-volatile oganic compounds, negative ions and total metals (dissolved and suspended) must not be filteed. The two most common types of filtes ae oganic filtes (cellulose nitate) and inoganic filtes (polycabonate membane). Cellulose nitate filtes can adsob some oganic constituents and elease nitogen, phosphous, zinc and molybdenum; wheeas polycabonate filtes do not appea to cause contamination. Filtes should be handled using stainless steel o Teflon tongs to pevent contamination. Cae should be taken to pevent damage to filtes. Page 66 of 86 Booklet 3 - Sampling of Goundwate

67 FIGURE 11 - DIAMETER OF PORES OF MATERIAL AND SIZES OF PARTICLES, ORGANISMS AND CHEMICAL COMPOUNDS THAT MAY BE PRESENT IN GROUNDWATER Lage-diamete filtes speed up filteing because filtes have to be eplaced less often. Howeve, only one filte can be used to filte one wate sample. Filteing equipment should be washed thooughly afte each sample, accoding to the method descibed in section 3.6. If the pupose of sampling is to detemine if wate fom a well is potable, samples should not be filteed. If goundwate quality is being analyzed to detemine the how effective dainage to a sewe system is, samples should not be filteed. If wate is tubid and samples ae submitted to oganic chemical analyses, it may be appopiate to analyze oganic compounds that have high distibution constants (watesuspended solids) in a filteed sample and in an unfilteed sample. Majo diffeences may occu in some instances. Booklet 3 - Sampling of Goundwate Page 67 of 86

68 4.6. Method of cleaning equipment Coss contamination between sampling points depends on the type of sampling method that is used and cleaning pocedues. The epesentativeness of samples collected using sophisticated methods may be jeopadized if pope cleaning pocedues ae not followed. The eade should efe to Cahie 1 Généalités (in Fench only) fo infomation about the fundamental pinciples of washing sampling equipment. Specific details petaining to goundwate ae listed below. All paametes (oganic and inoganic) Fo this section, efe to Cahie 1 Généalités (in Fench only). Oganic paametes only Fo this section, efe to Cahie 1 Généalités (in Fench only). Inoganic paametes only Fo this section, efe to Cahie 1 Généalités (in Fench only). If samples ae submitted to analysis of nitates, nitic acid (HNO 3 ) should be eplaced by 10% hydochloic acid (HCl) Identifying samples The details fo identification of goundwate samples ae the same as those fo othe sectos of activity. The eade should theefoe efe to Cahie 1 Généalités (in Fench only) Safety pecautions The safety pecautions that must be obseved duing goundwate sampling ae detailed in the Cahie 1 Généalités (in Fench only). It is impotant to ead this section befoe beginning any sampling wok. Page 68 of 86 Booklet 3 - Sampling of Goundwate

69 5. PRESERVING, STORING AND TRANSPORTING SAMPLES The eade should efe to Cahie 1 Généalités (in Fench only) to lean the fundamentals fo pesevation, stoage and tanspot of samples. Details elating specifically to goundwate ae found in the document DR Modes de consevation pou l échantillonnage des eaux souteaines (in Fench only). 26,27,28 6. PARAMETERS MEASURED IN THE FIELD Some paametes must be measued as soon as possible at the sample collection site (on samples o diectly in wells) because they ae sensitive to changes in tempeatue and pessue. These include tempeatue, ph and electical conductivity 16. Although not outine, on-site measuement of oganic vapous also has obvious advantages Tempeatue 6.2. ph Tempeatue should pefeably be measued in the well o as soon as a sample is collected in a containe, othe than containes sent to the laboatoy. Measuements ae taken ideally with a tempeatue pobe o themomete that is pecise to within ± 0.2 C. ph is one of the paametes that is most sensitive to changes in tempeatue and pessue. ph diffeences of up to two units can be obseved between values measued in the field and those measued in the laboatoy. A wide vaiety of pobes ae designed specifically to measue the ph of wate, depending on the degee of pecision equied. Electodes that povide a pecision of ± 0.1 ph unit ae adequate fo most applications. Geate pecision is equied when geochemical models must be used. These instuments consist essentially of an electode bathing in a solution of KCl, accompanied by solutions that ae equied fo calibation. The ecommendations that follow ae geneal in natue and apply to all types of instuments that ae sold commecially: egadless of model, the electode must be calibated befoe measuements ae taken. Calibation must be checked egulaly with ph 4, 7 and 10 buffe solutions; - goundwate and the electode should be appoximately the same tempeatue, ideally the tempeatue of goundwate. This can be accomplished with the help of a closed cell; - the electode must be insed in puified wate pio to and afte each time it is immesed in a wate sample; Booklet 3 - Sampling of Goundwate Page 69 of 86

70 - samples that have been used fo ph measuements cannot be eused fo analysis of electical conductivity, potassium (K + ) o chloide (Cl - ), due to the possible tansfe of KC1 fom the electode to the sample; - the ph-mete must be stoed is a dy location away fom souces of moistue. It should also not be exposed to diect sunlight. It must emain at a constant tempeatue when measuements ae taken; - the level of the KCI solution in which the electode is bathed must be monitoed constantly. The electode must always bath in this solution when it is not in use Electical conductivity Electical conductivity is an indicato of the chage of ions in a solution. Fo a site whee conductivity is monitoed, an incease in conductivity may indicate contamination. Electical conductivity in the field ae used to gauge, although only a vey geneal assessment, the degee of contamination and, if necessay, to change the dilling pogam to adapt it to conditions at the site. Electical conductivity is elatively easy to gauge in the field. Conductivity is measued using a conductivity mete. The value obtained must be multiplied by a constant fo each cell to obtain the eal conductivity of the calibation solution and samples. Calibation can be caied out using a KCl 0.01 M solution, which has an electical conductivity of 1,400 µmhos/cm (µs/cm) at 25 C. Some conductivity metes have a 2% compensato pe degee Celsius, which bings values to 25 C. If a compensato is not pesent, the calculation must be caied out manually accoding to method 2510 B of the Standad Method fo the Examination of Wate and Wastewate Oganic vapous explosive gases As a safety pecaution and to guide dilling opeations, estimates of concentations of explosive gases (methane), hydogen sulfide and oganic vapous can be made as wok pogesses. Mixtues of explosive gases can be detected with the use of explosimetes (see Cahie 1 Généalités (in Fench only)). Concentations of total oganic vapous can also be measued using Hnu and OVA (Oganic Vapo Analyze) instuments. Field measuements of oganic compounds equie use of a potable gaseous phase chomatogaph 29. These instuments ae extemely sensitive and difficult to calibate. They must be used by skilled individuals to poduce conclusive esults Keeping a field log book In addition to infomation descibed in Cahie 1 Généalités (in Fench only), a goundwate sample field log book should detail the volume of wate puged, methods of sample collection and the washing agents used. Page 70 of 86 Booklet 3 - Sampling of Goundwate

71 7. SAMPLING IN AN UNSATURATED ZONE An unsatuated zone is that potion of the subsuface that is located above the satuation line. This potion of the gound consists of solid, liquid and gas phases. The liquid phase is found in conditions of negative pessue and theefoe cannot be sampled using taditional monitoing methods (monitoing wells). Thee ae, howeve, sampling methods to collect wate and gases in the unsatuated zone. These methods ae often moe complicated and expensive than sampling techniques in the satuated zone. The paagaphs that follow discuss the most common methods fo sampling intestitial wate and gases in the unsatuated zone Sampling intestitial wate By sampling intestitial wate in an unsatuated zone, you can follow the advancement of a peiphey of contamination that oiginated fom a point-specific souce o had to pinpoint souce on the suface, in ode to pedict when it will aive at the wate table. Intestitial wate in an unsatuated zone can be sampled using devices called lysimetes. A lysimete is a small poous ceamic containe fastened to a PVC pipe that is capable of maintaining a vacuum (Figue 12). The vacuum is applied fom the suface and foces wate into the poous containe. A vacuum must be maintained between samples. Duing a sampling session, the vacuum is inceased using a suction device to ecove wate in the cup at the suface. Booklet 3 - Sampling of Goundwate Page 71 of 86

72 FIGURE 12 - DIAGRAM OF A LYSIMETER Page 72 of 86 Booklet 3 - Sampling of Goundwate

73 Befoe a lysimete is installed, it must be checked to ensue that is it completely watetight. The hole in which the lysimete is installed must have a minimum diamete to enable the neighbouing soil to enclose aound the cup. A bentonite cap nea the suface minimizes infiltation of suface wate. The ability of this instument to opeate coectly, depends on its ability to maintain a vacuum. Only a small volume of wate can be ecoveed, which limits the numbe of analyses that can be pefomed. The choice of which paametes to measue must be made caefully. By adding a laye of silica powde aound the ceamic cup, this will pevent the cup fom becoming clogged by colloidal paticles Sampling of the gaseous phase Sampling of the gaseous phase that is pat of the unsatuated zone can seve as an indicato of goundwate and soil contamination. Theefoe, setting up monitoing wells and establishing soil sampling points can be optimized. Peventive decontamination measues can be taken if gas is detected using special sensos. These methods have applications that ae paticulaly inteesting fo detection of volatile oganic compounds due to leaks fom undegound tanks. Only volatile compounds can be measued fo this type of analysis; the most common include benzene, toluene, xylene, ethylbenzene, tichlooethylene, chloofom, tetachlooethylene and tichlooethanes. The most effective way to sample these gases is to install a biogas well and to collect samples using tubes that contain an absobent substance o an expandable bag. Details fo installing a biogas well ae listed in Figue 13. Constuction is vey simila to that of a monitoing well, except fo the staine, which is positioned above the wate table and the sampling spout that is hemetically secued to the PVC cove. Samples of gases that have accumulated in the biogas well ae collected by means of a manual pump. Booklet 3 - Sampling of Goundwate Page 73 of 86

74 FIGURE 13 - STANDARD CONSTRUCTION OF A BIOGAS SAMPLING WELL Page 74 of 86 Booklet 3 - Sampling of Goundwate

75 The two main tubes that contain an adsobent substance ae tubes of activated cabon and Dage tubes. Activated cabon tubes tap oganic compounds and ae taken to the laboatoy fo desoption and analysis. Dage tubes enable a semi-quantitative on-site assessment of gas concentations. As gas ciculates though the tube, the adsobent substance loses colou. The length that has lost coloation indicates the concentation of the compound. A manual pump ciculates gas in the tube. Dage tubes ae available fo a wide vaiety of oganic compounds and fo gases such as cabon dioxide, hydogen sulfide and methane. Dage tubes ae of paticula inteest fo aeas that neighbou sanitay landfill sites. These tubes ae available on the maket fo a numbe of othe compounds and fo a wide ange of concentations. 8. QUALITY CONTROL In addition to the quality contols listed in Cahie 1 Généalités (in Fench only), a goundwate sampling pogam should include inte-laboatoy inspections, such as those descibed in the quality assuance and contol pocedues document entitled: Pocédues d'assuance et de contôle de la qualité pou les tavaux analytiques contactuels SAMPLING SPRING WATER AND WELLS FOR DRINKING WATER 9.1. Sping wate The sampling of points whee wate esufaces (sping) is less tedious than sampling monitoing wells because no pumping o puging is equied, and no special sampling equipment is necessay. To sample a sping, simply place a containe as close as possible to the goundwate dischage point. The type of containe, type of pesevatives and volumes to collect ae identical to those ecommended fo monitoing wells in the document DR Modes de consevation pou l échantillonnage des eaux souteaines (in Fench only) Sampling a dinking wate well Testing the quality of dinking wate in a ual community is caied out by collecting samples fom domestic wells. It is impotant to emembe that dinking wate wells ae designed fo the pupose of wate supply, not fo sampling the quality of goundwate. Results must theefoe be intepeted with caution. Results should be intepeted on the basis of dinkability of the wate. The following ecommendations ae suggested: - obtain all possible infomation about the well s constuction (depth, type of pump, teatment unit), type of piping system and potential souces of contamination aound the well; - if thee is no teatment unit, wate can be sampled fom the tap. If thee is a teatment unit (filte, wate softene, evese osmosis system), samples should be collected at the intake of the teatment unit; Booklet 3 - Sampling of Goundwate Page 75 of 86

76 - simila to sampling a monitoing well, a dinking wate well must be puged befoe sampling can begin. Puging can be caied out by allowing the tap to un until the wate s physical and chemical popeties ae stable. If a well is used outinely, the stabilization peiod is 5 to 10 minutes. Since the stabilization peiod will vay fom one well to anothe, depending on diamete and depth, indicato paametes such as conductivity and tempeatue should be measued befoe samples ae collected; - containes, pesevatives and the volumes equied should be detemined accoding to the document DR Modes de consevation pou l échantillonnage des eaux souteaines (in Fench only); - if volatile compounds ae being sampled, wate should be allowed to flow slowly into containes and bottles must be tilted slightly to minimize agitation. A sample must be collected once indicato paametes ae stable. 10. SAMPLING AND MEASUREMENT OF THE THICKNESS OF NON-MISCIBLE LIQUIDS Non-miscible liquids ae liquids that do not mix togethe. Depending on thei density compaed to wate, lighte liquids float on the suface of the wate table and dense liquids move though the wate table until they each an impenetable baie. Sampling of nonmiscible liquids should be caied out befoe wells ae puged, because sampling afte puging may esult in fluid mixing. The thickness of petoleum poducts in a monitoing well can be estimated using a tanspaent baile, a stip coated with an indicato compound and an inteface pobe. An inteface pobe, which is vey simila to a wate level pobe, changes esonance when it moves fom the floating laye to the undelying wate aea. The thickness measued in the well always exceeds the actual thickness of the non-miscible liquid in a wate-beaing fomation 31,32,33. Thee is no simple elationship to connect the thickness of non-miscible liquids measued in a well to the actual thickness of non-miscible liquids in a wate-beaing fomation 34,35. Page 76 of 86 Booklet 3 - Sampling of Goundwate

77 Howeve, the thickness of light non-miscible liquids in a wate-beaing fomation can be linked appoximately using the CONCAWE 36 equation: h» H ( wate - LNML ) whee h = H = wate = LNML = LNML aveage thickness of light non-miscible liquid in the wate-beaing fomation nea a well thickness of light non-miscible liquid measued in a well wate density density of light non-miscible liquid Light non-miscible liquids This categoy of contaminants includes a vaiety of petoleum poducts, in paticula gasoline, diesel, oils and ta. Soil and goundwate contamination by these liquids is usually attibuted to undegound tanks containing petoleum poducts. These poducts ae elatively easy to find and sample because thei migation duing the non-miscible phase is limited to the top of the wate table. The two systems used to collect a floating phase sample in a well ae bailes and check valve hand pumps. Ideally, dedicated systems should be used because sampling instuments will not be able to be decontaminated at the site. The same equipment should not be used to sample the aqueous phase Dense non-miscible liquids Dense non-miscible liquids include chloinated oganic solvents, such as tichlooethylene, tetachlooethylene, tichlooethanes and dichloomethane o a mixtue of petoleum poducts such as ceosotes and tas, polychloinated biphenyls (PCB) and some pesticides. If these poducts ae accidentally intoduced into the subsuface, they migate vetically though the wate table until they come acoss an impemeable baie. They become extemely difficult to tace in complex geological fomations, paticulaly in factued fomations. Sampling of the dense liquid phase is caied out in the same manne as the floating phase, using a baile and a check valve hand pump connected to a polyethylene tube. These two systems have the advantage of being able to be dedicated. Booklet 3 - Sampling of Goundwate Page 77 of 86

78 11. CONCLUSION Success of a goundwate sampling pogam depends on the epesentativeness of the samples collected. Poject manages and sample collectos must make decisions when a sampling pogam is dawn up and when it is in opeation. Each decision may alte the chemical and micobiological integity of samples. The selection of sampling points, dilling method, well dimensions, sampling method, selection of well constuction mateials and sampling equipment ae all factos that equie caeful decisions. An undestanding of the factos and pocesses that can alte the chemical composition of wate when samples ae collected, equies knowledge and effots that ae devoted to chemical analyses and intepetation of esults. An accuate definition of which objectives ae tageted in the chaacteization study will detemine the pecision that will be equied and the safety pecautions that be equied duing the sampling pogam. Pecautions that esult in cost oveuns may not be justified if they ae pat of a peliminay chaacteization study, but may become essential as chaacteization wok takes shape o ehabilitation wok pogesses. We hope that this booklet will help uses who ae involved in implementing sampling pogams and that it will guide thei wok. Page 78 of 86 Booklet 3 - Sampling of Goundwate

79 REFERENCES 1- LIARD, A, et al. Caactéisation envionnementale des sites contaminés, École Polytechnique de Montéal en collaboation avec l'association of Engineeing Geologists, Section de Montéal, avil GILHAM, R.W., M.J.L. ROBIN, J.F. BARKER and J.A. CHERRY. Goundwate Monitoing and Sample Bias, Depatment of Eath Sciences, Univesity of Wateloo, Wateloo, Ontaio, June 1983, 206 p. 3- DRISCOLL, F.G., Goundwate and Wells, 1986, Second edition, Johnson Division Publishes, 1089 p. 4- DAVIS, H., J.L. JEHN and S. SMITH. Monitoing Well Dilling Soil Sampling, Rock Coing and Boehole Logging, in Pactical Handbook of Goundwate Monitoing, 1991, Lewis Publishes, p MINISTÈRE DE L'ENVIRONNEMENT DU QUÉBEC, Diection des substances dangeeuses, Gestion des lieux contaminés. Politique de éhabilitation des teains contaminés, févie 1988, SD BARCELONA, M.J., J.P. GIBB and R.A. MILLER. A Guide to the Selection of Mateials fo Monitoing Well Constuction and Goundwate Sampling, Illinois State Wate Suvey, Champaign, Illinois, 1983, 78 p. 7- NIELSON, D.M. and R. SCHALLA. Design and Installation of Gound Wate Monitoing Wells, in Pactical Handbook of Goundwate Monitoing, 1991, Lewis Publishes, p PARKER, L.V., A.D. HEWITT and T.F. JENKINS. «Influence of Casing Mateials on Tace-Level Chemicals in Well Wate», Goundwate Monitoing Review, Sping 1990, p Booklet 3 - Sampling of Goundwate Page 79 of 86

80 9- RIGGS, C.O. and A.W. HATEWAY. Goundwate Monitoing Field Pactice-An Oveview, dans: Goundwate Contamination: Field Methods, ASTM STP 963, A.G. Collins and A.I. Johnson, Eds., Ameican Society fo Testing and Mateials, Philadelphia, 1988, p GIBB, J.P. «How Dilling Fluids and Gouting Mateials Affect the Integity of Goundwate Samples fom Monitoing Wells», Goundwate Monitoing Review, Winte 1987, p CHAPUIS, R.P. Piézomète hydaulique et isques d'eeu associés, Séminaie su les baièes géologiques pou le contôle de la contamination des eaux aux sites d'enfouissement, mas 1987, 165 p. 12- GARRETT, P. How to Sample Goundwate and Soils, National Wate Well Association Publishes, 1988, 37 p. 13- ALLER, L., T.W. BENNETT, G. HACKETT, R.J. PETTY, J.H. LEHR, H. SEDORIS, D.M. NIELSEN and J.E. DENNE. Monitoing Well Developpement, in: Handbook of Suggested Pactices fo the Design and Installation of Goundwate Monitoing Wells, 1988, p HVORSLEV, M.J. «Time lag and soil pemeability in goundwate obsevations», in U.S. Amy Cops Engs. Wateways Exp. Sta. Bull. 36, Vicksbug, Miss. 15- BARCELONA, M.J., J.A. HELFRICH, and E.E. GARSKE. Veification of Sampling Methods and Selection of Mateials fo Goundwate Contamination Studies, in Goundwate Contamination: Field Methods, ASTM STP 963, A.G. Collins and A.I. Johnson, Eds., Ameican Society fo Testing and Mateials, Philadelphia, 1988, p CHERRY, J.A. et al. Field Guide fo Sampling and Chemical Analysis of Goundwate, Field couse, Depatment of Eath Sciences, Univesity of Wateloo, Wateloo, Ontaio, HERZOG, B.L., J.D. PENNINO, and G.L. NIELSON. Goundwate Sampling, in Pactical Handbook of Goundwate Monitoing, 1991, Lewis Publishes, p Page 80 of 86 Booklet 3 - Sampling of Goundwate

81 18- PANKO, A.W. and P. BARTH. Chemical Stability Pio to Gound Wate Sampling: A Review of Cuent Well Puging Methods, in Goundwate Contamination: Field Methods, ASTM STP 963, A.G. Collins and A.I. Johnson, Eds., Ameican Society fo Testing and Mateials, Philadelphia, 1988, p ROBIN, M.J.L. and R.W. GILHAM. «Field Evaluation of Well Puging Pocedues», Goundwate Monitoing Review, Fall 1987, p BARKER, J.F. and R. DICKOUT. «An Evaluation of Some Systems fo Sampling Gas- Chaged Goundwate fo Volatile Oganic Analysis», Goundwate Monitoing Review, Fall 1988, p ROBIN, M.J.L., D.J. DYTYNYSHYN, and S.J. SWEENEY. «Two Gas-Dive Sampling Devices», Goundwate Monitoing Review, Winte 1982, p JONES, J.N. and G.D. MILLER. Adsoption of Selected Oganic Contaminants onto Possible Well Casing Mateials, in Goundwate Contamination: Field Methods, ASTM STP 963, A.G. Collins and A.I.Johnson Eds., Ameican Society fo Testing and Mateials, Philadelphia, 1988, p BARKER, J.F., R.V. NICHOLSON, D. SMYTH, D.L. RUDOLPH, J.P. GREENHOUSE, P. GUDJURGIS, J. MOLSON, E.O. FRIND, E.A. SUDICKY. Subsuface assessment fo contaminated sites - Handbook, DRAFT, Fo eview, Wateloo Cente fo Goundwate Reseach, Univesity of Wateloo, Ontaio, Canada, Octobe BARCELONA, M.J. and J.P. GIBB. Development of Effective Goundwate Sampling Potocols, in Goundwate Contamination: Field Methods, ASTM STP 963, A.G. Collins and A.I. Johnson Eds., Ameican Society fo Testing and Mateials, Philadelphia, 1988, p STUART Gane, P.E. «Making the Most of Field-Measuable Goundwate Quality Paametes», Goundwate Monitoing Review, Summe 1988, p AMERICAN PUBLIC HEALTH ASSOCIATION, Ameican Wate Woks Association and Wate Pollution Contol Fedeation. Standad Method fo the Examination of Wate and Wastewate, 17 th edition Method 2510B. Booklet 3 - Sampling of Goundwate Page 81 of 86

82 27. U.S. ENVIRONMENTAL PROTECTION AGENCY. Handbook fo Sampling and Sample Pesevation of Wate and Wastewate, U.S. Govenment Pinting Office, Washington, DC, 1982, EPA-600/ MINISTRY OF THE ENVIRONNEMENT OF THE ONTARIO. Potocol fo the Sampling and Analysis of Industial/Municipal Wastewate, Municipal and Industial System fo Abattement, June BUCHMILLER, R.C. «Sceening of Goundwate Samples fo Volatile Oganic Compounds Using a Potable Gas Chomatogaph», Goundwate Monitoing Review, Sping 1990, p MINISTÈRE DE L'ENVIRONNEMENT DU QUÉBEC, Diection des laboatoies, Pocédue d'assuance et de contôle de la qualité pou les tavaux analytiques contactuels, avil HAMPTON, D.R. Laboatoy investigation of the elationship between actual and appaent poduct thickness in sands, in Envionmental concens in the petoleum industy, S.M. testa (ED), Pacific section, AAPG, HAMPTON, D.R. et al. «A New Tool to Measue Petoleum Thickness in Shallow Aquifes», in Poceedings of the fouth national outdoo action confeence on aquife estoation, gound wate monitoing and geophysical methods, Las Vegas, Nv, May 14-17, HUGHES, John P., et al. «Two Techniques fo Detemining the Tue Hydocabon Thickness in an Unconfined Sandy Aquife» in Poceedings of the Confeence on Petoleum Hydocabons and Oganic Chemicals in Gound Wate: Pevention, Detection and Restoation, Houston, Tx, Novembe 9-11, LENHARD, R.J., J.C. PARKER. «Estimation of fee hydocabon volume fom fluid levels in obsevation wells» in Gound Wate, 1990, vol. 28, p MERCER, J.W., R.M. COHEN. «Review of non-miscible fluids in the subsuface: Popeties models chaacteization and emediation» in Jounal of contaminant hydogeology, 1990, 6, p Page 82 of 86 Booklet 3 - Sampling of Goundwate

83 36. de PASTROVICH, T.L., Y. BARADAT, R. BARTHEL, A. CHIARELLI, D.R. FUSSELL. Potection of goundwate fom oil pollution, The Hague, Nethelands, CONCAWE, epot, 3/79, BALLASTERO, T., B.L. HERZOG and O.D. EVANS. Monitoing and Sampling the Vadose Zone, in Pactical Handbook of Goundwate Monitoing, 1991, Lewis Publishes, p O'LEARY, P. and P. WALSH. 1991, Lesson 3, Landfill Gas Movement, Contol and Uses, Waste Age, June 1991, p Booklet 3 - Sampling of Goundwate Page 83 of 86

84

85 BIBLIOGRAPHY BARCELONA, M.J., J.P. GIBB, J.A. HELFRICH and E.E. GARSKE. Pactical Guide fo Goundwate Sampling, Illinois State Wate Suvey, Champaign, Illinois, 1985, ISWS Contact Repot 374. BARCELONA, M.J., J.F. KEELY, W.A. PETTYJOHN and A. WEHRMANN. Handbook of Goundwate Potection, Hemisphee Publishing Copoation, 1988, 212 p. FETTER, C.W. «Potential Souces of Contamination in Goundwate Monitoing», Goundwate Monitoing Review, Sping 1983, p GÉLINAS, P.J., J. LOCAT, P. THERRIEN, et A. MASSON. Hydogéologie des contaminants; Instumentation et suveillance, Dépatement de Géologie, Faculté des Sciences et de Génie, Univesité Laval, GGL-A0406, GIBB, J.P. and M.J.BARCELONA. «Sampling fo Oganic Contaminants in Goundwate», Jounal AWW, May 1984, p GIBB, J.P., R.M. SCHULLER, and R.A. GRIFFIN. Pocedues fo the Collection of Repesentative Wate Quality Data fom Monitoing Wells, Illinois State Wate Suvey, Champaign, Illinois 61820, 1981, 61 p. KEELY, J.F. and K. BOATENG. Monitoing Well Installation, Puging and Sampling Techniques-Pat I: Conceptualization, Goundwate, vol. 25, no. 3, May-June 1987, p PETTYJOHN, W.A. et al., «Sampling Goundwate fo Oganic Contaminants», Goundwate, 19:2:180, 1981, p PICKENS, J.F., R.M. CHERRY, R.M. COUPLAND, G.E. GRISAK, W.F. MERRITT and B.A. RISTO, «A Multiple Device fo Goundwate Sampling», Goundwate Monitoing Review, Sping 1981, p Booklet 3 - Sampling of Goundwate Page 85 of 86

86 RCRA. Goundwate Monitoing Technical Enfocement Guidance Document, NWWA-EPA Seies, Septembe REYNOLDS, Glenn W. et al. Envion. Sci. Technol. 1990, 24(1), 135. SCALF, M.R., J.F. McNABB, W.J. DUNLAP, R.L. COSBY and J.S. FRYBERGER. Manual of Goundwate Quality Sampling Pocedues, Robet S. Ke Envionmental Reseach Laboatoy, Office of Reseach and Developpement, U.S. Envionmental Potection Agency, Oklahoma, 1981, 93 p. SWANSON, Gloia J. Well Wate Jounal 1989, May, 76. Page 86 of 86 Booklet 3 - Sampling of Goundwate

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