Appendix B. Pesticides in Oregon Groundwater

Transcription

1 Appendix B Pesticides in Oregon Groundwater Jeffrey J. Jenkins and Wade R. Trevathan Department of Environmental and Molecular Toxicology Oregon State University August,

2 Pesticides in Oregon Groundwater Jeffrey J. Jenkins and Wade R. Trevathan Department of Environmental and Molecular Toxicology Oregon State University Introduction As part of the Oregon Department of Agriculture s (ODA) participation in the U. S. Environmental Protection Agency s (EPA) Pesticides and Groundwater Strategy, a cooperative agreement between ODA and the Agricultural Chemistry Research and Extension program, Department of Environmental and Molecular Toxicology, Oregon State University (OSU) was established in FY96 and continued through FY2003. The aim, in part, was to develop a pesticides and groundwater database as a part of Oregon s Generic State Pesticide Management Plan (PMP). The data reported here supplement that previously provided in the report Pesticides and Groundwater Quality in Oregon, New groundwater monitoring data was obtained from the following sources: the U.S. Geological Survey (USGS), and Oregon Department of Human Services (DHS) Drinking Water Program, and Oregon Department of Environmental Quality (DEQ.) In developing the Pesticides in Oregon Groundwater ( ) database, the U. S. Environmental Protection Agency (EPA) STORET database was queried for pesticides sampled in Oregon groundwater. The STORET system has undergone significant updating in structure and access and is now available via the internet [ Data retrieval is less arduous; however, the data still require significant formatting to make them applicable to current scientific and regulatory efforts related to watershed and drainage basin organization and to keep them compatible with the existing Oregon database. Data uploaded to STORET include groundwater (wells, aquifers) and surface water (lakes, streams, runoff, reservoirs) pesticide, plus a large amount of data on a variety of water quality parameters such as ph, dissolved oxygen, temperature, conductivity, and non-pesticide chemical. Data in STORET are generated for a variety of reasons. Virtually any agency or group collecting data can upload its data to STORET. Therefore, the Clean Water Act (CWA), Safe Drinking Water Act (SDWA), and other programs are likely catalysts for conducting monitoring and sampling, but such data are not required to be uploaded to STORET. The following entities are identified by STORET as contributing some type of environmental sampling data: Oregon Department of Environmental Quality U.S. Environmental Protection Agency U.S. Geological Survey U.S. Bureau of Reclamation U.S. Forest Service National Marine Fisheries Service U.S. Fish & Wildlife Service U.S. Army Corp. of Engineers National Oceanic and Atmospheric Administration 2

3 Figure 1. Major Drainage Basins in Oregon. 1 North Coast 2a Upper Willamette 2b Middle Willamette 2c er Willamette 3 Sandy 4 Hood 5 Deschutes 6 John Day 7 Umatilla 8 Grande Ronde 9 Powder 10 Malheur 11 Owyhee 12 Malheur Lake 13 Goose and Summer Lakes 14 Klamath 15 Rogue 16 Umpqua 17 South Coast 18 Mid Coast 3

4 For the purposes of updating the Pesticides in Oregon Groundwater database, STORET was queried for pesticide groundwater monitoring data from 1997 to No groundwater monitoring data was submitted to STORET by any state or federal agency during that period. However, pesticide monitoring data from 1997 to 2003 not submitted to STORET was obtained from DEQ directly. Groundwater samples collected by DEQ were analyzed by the Oregon Department of Agriculture (ODA) Laboratory Services. In accordance with amendments to the Safe Drinking Water Act (SDWA), DHS has expanded requirements for sampling and analysis of community drinking water systems for organic chemicals, including pesticides. Currently, there are approximately 1,200 systems in the DHS database. The DHS drinking water monitoring program is conducted under requirements of the SDWA and includes 86 contaminants, approximately 25 of which are pesticides. Water systems serving >3,300 population require two consecutive quarterly samples during one year of the compliance period (the current 3-yr period runs Jan to Dec. 2004). Sampling may be less frequent if the system has a Drinking Water Protection program in place. Data are obtained directly from DHS and provided in database format. Monitoring for pesticides in groundwater has been a part of the USGS National Water Quality Assessment (NAWQA) Program. In 1993, USGS monitored pesticides in Willamette Basin groundwater. The USGS has conducted only a limited amount of groundwater sampling for pesticides since 1998, including re-sampling of 29 sites previously sampled in Consistent with the original report, the supplemental data have been segregated into 18 drainage basins, as defined by Oregon Department of Water Resources. The Willamette Basin is further subdivided into three sub-basins, to give a total of 20 geographic areas (See Figure 1.) Data is further subdivided by agency to address differences in sampling and analytical capabilities. The most notable difference between agencies is the limit of detection of the analytical methods used. USGS and ODA detection limits are often orders of magnitude lower than those employed by DHS. This difference reflects monitoring strategies of the agencies, as the cost of analysis at lower levels is significant. The cost of further decreasing detection limits orders of magnitude below health based standards or guidelines may not be warranted if the goal is to assure all Oregonians safe drinking water. However, the cost may be warranted if the goal is to better understand the relationship between pesticide use practices and groundwater quality, or to establish trends that allow researchers to predict future impacts. The EPA Office of Water has established Health Advisories (HAs), which are non-enforceable guidelines for chemical residues in drinking water, for approximately 200 chemicals, including about 50 pesticides. These include 1-day and 10-day HAs for children and adults and lifetime HAs for adults. The HA is the concentration of a chemical in drinking water that is not expected to cause adverse non-carcinogenic effects over the period of exposure. EPA has also established HAs for some pesticides classified as carcinogens. In addition, as a part of rulemaking under the Safe Drinking Water Act, the agency has established the Maximum Contaminant Level (MCL) and Maximum Contaminant Level Goal (MCLG) for about 25 pesticides in drinking water. The MCL, an enforceable standard, is the maximum allowable level of a contaminant in water delivered by a public water system. The MCLG is the concentration of a drinking water 4

5 contaminant that is thought to be protective of adverse human health effects. In almost all cases, the MCL and MCLG are the same. In a few instances, the MCLG has been set at zero. Pesticides looked for in Oregon groundwater with zero MCLGs are these: acifluorfen, alachlor, chlordane, HCB, heptachlor, heptachlor epoxide, and pentachlorophenol (PCP). In determining the lifetime HAs and MCLGs, the estimated dose is based on a 70 Kg person consuming 2 liters per day. For non-carcinogens, lifetime HAs and MCLs are derived from the drinking water equivalent to the Reference Dose (RfD). The RfD is an estimate of total human daily exposure to contaminants that is unlikely to result in adverse health effects over a lifetime. For carcinogens, the excess cancer risk associated with lifetime ingestion of drinking water is estimated. The target for the lifetime HA or MCLG is a concentration in drinking water that results in less than 1 in 10,000 (1 x 10-4 ) excess lifetime cancer risk. In determining the risk of consuming contaminated drinking water, other routes of exposure, such as diet, are considered so that the risk associated with the total daily exposure from all sources does not exceed the drinking water equivalent to the RFD for non-carcinogens or the 1 in 1,000,000 (1 x 10-6 ) excess lifetime cancer risk for carcinogens. In the absence of actual data, it is generally assumed that drinking water comprises 20% of all routes of exposure. The World Health Organization (WHO) also publishes drinking water quality guidelines that are intended to be used as a basis for the development of national standards. See WHO Guidelines for Drinking Water Quality, Volume 2 (1996). Listed in order of preference are the MCLs, followed by HAs. If these values are not available, the WHO drinking water guideline is given. If MCL, HA, or WHO data are not available, then a HA was calculated from the DWEL (Drinking Water Equivalence Level, EPA, 1989). The DWEL is determined from the RfD assuming a 70 Kg person consumes 2 liters per day for a lifetime. To determine the HA, the DWEL is adjusted assuming that drinking water comprises 20% of the allowable daily intake of a given chemical. Use a HA determined from the DWEL assumes that there is no non-threshold lifetime cancer risk, or the HA calculated for cancer risk would be greater than that calculated using the DWEL. Also see Appendix A. Raw data was obtained from the Oregon Department of Human Services, Drinking Water Program as a Microsoft Access database; Oregon Department of Environmental Quality as a Microsoft Excel spreadsheet; and the U.S. Geological Survey as a text delimited file downloaded from their web site. All data was converted into Excel and combined into a 'normalized' set of data fields. These data fields are agency, drainage basin, site number, sample date, parameter name, result, units, and detection limit. The normalized database also includes unit conversion to standardize concentration as micrograms per liter (ug/l.) Using Excel SQL functions, the normalized data was sorted into basins and separated by and non-. Simple statistics (high, low, mean, median, standard deviation) were performed in Excel. Raw data and the normalized database are contained on a separate CD. The normalized database is presented in basin format in Appendix B. Results The results of our inquiry regarding pesticides monitored in Oregon groundwater from 1997 to 2003 found the following: between 1997 and 2003 the DHS Drinking Water Program reported 5

6 15,653 analyses of groundwater samples for pesticides, DEQ reported 1,538 analyses performed by ODA, and USGS reported 4,523 analyses. Of these 21,714 analyses there were 97 pesticide, or less than 0.5% of analyses. Pesticides detected in Oregon groundwater from 1997 to 2003 are given in Table 1. Results are shown by basin. Six of Oregon s 20 basins and subbasins had pesticides detected in groundwater. The Middle Willamette sub-basin had the most pesticides detected with 10. Table 2 shows for each detected pesticide the frequency of detection by basin. DCPA (dacthal) showed the widest geographic distribution with in four basins: Malheur, Owyhee, Powder, and Umatilla (Table 3.) Tables 1-3 also include human health standards and guidelines. The values shown in bold are greater than one-half the drinking water standard or guideline. Only DCPA exceeded this threshold. Five analyses from the Malheur basin and 2 analyses from the Powder basin exceeded 35 ppb, one-half of the EPA Health Advisory for DCPA. The highest level measured was 110 ppb. A total of 13 pesticides were detected in Oregon groundwater between 1997 and For these pesticides Table 3 compares basins with, number of, number of analyses, and percent of analyses with. For 8 of the 13 pesticides the percent was 5% or less. However, desethyl-atrazine, an atrazine metabolite, was detected in 59% of analyses and DCPA was detected in 45% of samples analyzed. Tables 4 and 5 summarize monitoring results for pesticides in Oregon groundwater between 1984 and During this period 29 pesticides were detected in 12 of Oregon s basins or subbasins. Similar to the results reported for the 1997 to 2003 monitoring period, between 1984 and 1996 DCPA and atrazine were the most frequently detected pesticides in Oregon groundwater. DCPA was the most frequently detected; found in 5 basins at a frequency of 65%. However, for 13 of the 29 pesticides the percent was 5% or less. For the 1984 to 1996 monitoring period 9 pesticide exceeded one-half the human health standard or guideline. Comparing the and monitoring periods shows an overall reduction in the number of pesticides detected in Oregon groundwater from 29 to 13, a reduction in the number of basins with from 12 to 6, and a reduction in the number of pesticide exceeding the human health standard or guideline from 9 to 1. These general trends suggest that the frequency and concentration and pesticides detected in Oregon groundwater is decreasing. 6

7 Table 1. Pesticides Detected in Oregon Groundwater by Basin ( ). Pesticide Data Source 1 of analyses Detection limit Hood Basin Standard Guideline Source 2 Alachlor DHS MCL Malheur Basin Atrazine DHS MCL DCPA (Dacthal) ODA HA 3,4-Dichloroaniline (diuron metabolite) Middle Willamette Basin ODA HA from DWEL 5 4,4`-DDT ODA WHO Atrazine ODA MCL Atrazine DHS Atrazine USGS Atrazine-desethyl (atrazine metabolite) ODA Bromacil ODA HA Malathion ODA HA Metolachlor ODA Metribuzin ODA HA from DWEL MCL HA Simazine ODA MCL Simazine DHS Simazine USGS Terbacil ODA HA Owyhee Basin DCPA (Dacthal) ODA HA Powder Basin DCPA (Dacthal) ODA HA Umatilla Basin Atrazine ODA MCL Atrazine DHS Atrazine-desethyl (atrazine metabolite) ODA Chlorpyrifos ODA HA DCPA (Dacthal) ODA HA from DWEL HA Simazine ODA MCL Simazine DHS Terbacil ODA HA DHS: Oregon Department of Human Services, Drinking Water Program (15,653 analyses) ODA: Oregon Department of Agriculture (1,538 analyses of samples collected by DEQ) USGS: United States Geological Survey (4,523 analyses) MCL:Maximum Contaminant Level, an enforceable drinking water standard. WHO: World Health Organization drinking water guideline. HA: Health Advisory, a non-enforceable drinking water guideline for lifetime exposure. DWEL: The Drinking Water Equivalent Level (DWEL) is based on the Reference dose (RfD) and assumes a 70 Kg person drinks 2 liters per day over a lifetime. The HA is determined from the DWEL by assuming that drinking water comprises 20% of the allowable daily intake. Also assumed; there is no lifetime cancer risk, or the HA calculated for cancer risk would be greater than that calculated using the DWEL. The method detection limit (MDL) was not reported for this data point. The value listed indicates the minimum reporting level (regulatory standard). No method detection limit (MDL) was reported for positive. The MDL listed reflects that reported for non-detects. The HA for the metabolite 3,4-dichloroaniline is based on the DWEL for its parent compound; diuron/linuron. 7

8 Table 2. Pesticides Detected in Oregon Groundwater ( ) Pesticide Data Source 1 Basins with % analyses with Detection limit Standard Guideline Source 2 3,4-Dichloroaniline (diuron/metabolite) ODA % HA from DWEL 3 4,4`-DDT ODA 1 1 5% WHO Alachlor Atrazine Atrazine-desethyl (atrazine metabolite) Bromacil Chlorpyrifos DCPA (Dacthal) Malathion Metolachlor Metribuzin Simazine Terbacil DHS 1 1 <1% MCL ODA 0 0 0% USGS 0 0 0% ODA % MCL DHS 1 1 <1% MCL USGS 0 0 0% ODA % ODA % HA USGS 0 0 0% ODA 1 2 5% USGS 0 0 0% ODA % USGS 0 0 0% HA from DWEL HA HA ODA % HA USGS 0 0 0% ODA 1 2 5% USGS 0 0 0% ODA 1 1 2% USGS 0 0 0% ODA % DHS 0 0 0% 4.0 USGS 0 0 0% MCL HA MCL ODA 2 3 7% HA USGS 0 0 0% DHS: Oregon Department of Human Services, Drinking Water Program (15,653 analyses) ODA: Oregon Department of Agriculture (1,538 analyses of samples collected by DEQ) USGS: United States Geological Survey (4,523 analyses) 2 MCL:Maximum Contaminant Level, an enforceable drinking water standard. WHO: World Health Organization drinking water guideline. HA: Health Advisory, a non-enforceable drinking water guideline for lifetime exposure. DWEL: The Drinking Water Equivalent Level (DWEL) is based on the Reference dose (RfD) and assumes a 70 Kg person drinks 2 liters per day over a lifetime. The HA is determined from the DWEL by assuming that drinking water comprises 20% of the allowable daily intake. Also assumed; there is no lifetime cancer risk, or the HA calculated for cancer risk would be greater than that calculated using the DWEL. 3 The HA for the metabolite 3,4-dichloroaniline is based on the DWEL for its parent compound; diuron/linuron. 4 s in bold exceed 1/2 the standard or guideline. 8

9 Table 3. Geographic Distribution of Pesticides Detected in Oregon Groundwater ( ). Pesticide and Drainage Basin Data Source 1 analyses Detection limit 3,4-Dichloroaniline (diuron metabolite) Standard or guideline 14 ug/l (HA from DWEL 2, 3 ) Middle Willamette ODA ,4`-DDT Standard or guideline 2 ug/l (WHO 2 ) Middle Willamette ODA Alachlor Standard or guideline 2 ug/l (MCL 2 ) Hood DHS Atrazine Standard or guideline 3 ug/l (MCL) Malheur DHS Middle Willamette ODA, (DHS, USGS) Umatilla ODA, (DHS) Atrazine-desethyl (atrazine metabolite) Standard or guideline 70 ug/l (HA from DWEL) Middle Willamette ODA Umatilla ODA Bromacil Standard or guideline 90 ug/l (HA 2 ) Middle Willamette ODA Chlorpyrifos Standard or guideline 20 ug/l (HA from DWEL) Umatilla ODA DCPA (Dacthal) Standard or guideline 20 ug/l (HA) Malheur ODA Owyhee ODA Powder ODA Umatilla ODA Malathion Standard or guideline 100 ug/l (HA) Middle Willamette ODA Metolachlor Standard or guideline 70 ug/l (MCL) Middle Willamette ODA Metribuzin Standard or guideline 200 ug/l (HA) Middle Willamette ODA Simazine Middle Willamette Standard or guideline 4 ug/l (MCL) ODA, (DHS, USGS) Umatilla ODA, (DHS)

10 Table 3 continued. Terbacil Standard or guideline 90 ug/l (HA) Middle Willamette ODA Umatilla ODA Abbreviations in parentheses ( ) indicate the chemical was analyzed for and not found. DHS: Oregon Department of Human Services, Drinking Water Program (15,653 analyses) ODA: Oregon Department of Agriculture (1,538 analyses of samples collected by DEQ) USGS: United States Geological Survey (4,523 analyses) 2 MCL:Maximum Contaminant Level, an enforceable drinking water standard. WHO: World Health Organization drinking water guideline. HA: Health Advisory, a non-enforceable drinking water guideline for lifetime exposure. DWEL: The Drinking Water Equivalent Level (DWEL) is based on the Reference dose (RfD) and assumes a 70 Kg person drinks 2 liters per day over a lifetime. The HA is determined from the DWEL by assuming that drinking water comprises 20% of the allowable daily intake. Also assumed; there is no lifetime cancer risk, or the HA calculated for cancer risk would be greater than that calculated using the DWEL. 3 The HA for the metabolite 3,4-dichloroaniline is based on the DWEL for its parent compound; diuron/linuron. 4 s in bold exceed 1/2 the standard or guideline. 10

11 Table 4. Pesticides Detected in Oregon Groundwater by Basin ( ) Pesticide wells analyses Detection limit Deschutes Basin (DEQ) Standard/ guideline Source 2 atrazine MCL dicamba (Banvel) HA BHC, alpha BHC, beta Goose and Summer Lakes Basin (DEQ) MCPA HA 2,4-D MCL 2,4,5-T HA 2,4-DB WHO dinoseb MCL Dicamba (Banvel) HA picloram MCL er Willamette Basin (DEQ) BHC, gamma MCL DCPA (Dacthal) HA dieldrin HA methoxychlor MCL er Willamette Basin (USGS) atrazine MCL atrazine, desethyl DCPA (Dacthal) HA metolachlor HA propachlor HA propanil WHO simazine MCL triallate DWEL Malheur Basin (DEQ) DCPA (Dacthal) HA atrazine MCL Middle Willamette Basin (USGS) atrazine MCL atrazine, desethyl metolachlor HA simazine MCL propanil WHO diuron HA DCPA (Dacthal) HA dinoseb MCL 11

12 Table 4. (continued). Pesticide wells analyses Detection limit North Coast Basin (DEQ) Standard/ guideline Source 2 atrazine MCL heptachlor MCL PCP MCL Owyhee Basin (DEQ) DCPA (Dacthal) HA Rogue Basin (DEQ) PCP MCL heptachlor MCL DCPA (Dacthal) HA dieldrin HA Umatilla Basin (DEQ) DCPA (Dacthal) HA atrazine MCL dicamba (Banvel) HA PCP MCL endosulfan DWEL Upper Willamette Basin (DEQ) atrazine MCL heptachlor MCL Upper Willamette Basin (USGS) atrazine MCL atrazine, desethyl bromacil HA prometon HA simazine MCL tebuthiuron HA terbacil HA 1 s in bold exceed 1/2 the standard or guideline. 2 MCL: Maximum Contaminant Level, an enforceable drinking water standard. WHO: World Health Organization drinking water guideline. HA: Health Advisory, a non-enforceable drinking water guideline for lifetime exposure. DWEL: Drinking Water Equivalent Level, based on the RfD and assuming 70 Kg person drinks 2 liters per day over a lifetime. The DWEL has been adjusted assuming that drinking water comprises 20% of the allowable daily intake. Use of the adjusted DWEL assumes that there is no non-threshold lifetime cancer risk, or the HA calculated for cancer risk would be greater than that calculated using the adjusted DWEL. 3 Pesticide metabolite from degradation in soil or water. 4 No longer used in Oregon. 12

13 Table 5. Pesticides Detected in Oregon Groundwater ( ). Pesticide Basins with % of analyses with Detection limit Standard/ Guideline Source 1 2,4-D MCL 2,4-DB WHO 2,4,5-T HA atrazine MCL atrazine, desethyl DWEL BHC, alpha BHC, beta BHC, gamma MCL bromacil HA dicamba (Banvel) HA DCPA (Dacthal) HA dieldrin HA dinoseb MCL diuron HA endosulfan DWEL ethylene dibromide MCL heptachlor MCL MCPA HA methoxychlor MCL metolachlor MCL pentachlorophenol MCL picloram HA prometon HA propachlor HA propanil WHO simazine MCL tebuthiuron HA terbacil HA triallate DWEL 1 MCL: Maximum Contaminant Level, an enforceable drinking water standard. WHO: World Health Organization drinking water guideline. HA: Health Advisory, a non-enforceable drinking water guideline for lifetime exposure. DWEL: Drinking Water Equivalent Level, based on the RfD and assuming 70 Kg person drinks 2 liters per day over a lifetime. The DWEL has been adjusted assuming that drinking water comprises 20% of the allowable daily intake. Use of the adjusted DWEL assumes that there is no non- threshold lifetime cancer risk or the HA calculated for cancer risk would be greater than that calculated using the adjusted DWEL. 2 Goose and Summer Lakes Basin disposal site at Alkali Lake. 3 No longer used in Oregon. 4 Pesticide metabolite from degradation in soil or water. 5 Oregon Health Division drinking water program. 6 s in bold exceed 1/2 the standard or guideline. 13

14 Pesticide Groundwater Monitoring in Oregon by Basin 1 Pesticide Deschutes Basin analyses Detection limit None Non- 2,4,5-TP (SILVEX) ,4-D Alachlor Atrazine BHC-gamma (lindane) Carbofuran Chlordane Dalapon Dibromochloropropane (DBCP) Dicamba 1 5 not reported 0 Dinoseb Diquat Endothall Endrin Ethylene dibromide (EDB) Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene Combined monitoring data from Oregon Department of Human Services, Oregon Department of Environmental Quality/Oregon Department of Agriculture, and the U.S. Geological Survey. 14

15 Goose and Summer Lakes Basin Pesticide analyses Detection limit None Non- 2,4,5-TP (silvex) ,4-D Alachlor Atrazine BHC-gamma (lindane) Carbofuran Chlordane Dalapon Dibromochloropropane (DBCP) Dinoseb Diquat Endothall Endrin Ethylene dibromide (EDB) Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

16 Grande Ronde Basin Pesticide analyses Detection limit None Non- 2,4,5-TP (silvex) ,4-D Alachlor Atrazine BHC-gamma (lindane) Carbofuran Chlordane Dalapon Dibromochloropropane (DBCP) Dinoseb Diquat Endothall Endrin Ethylene dibromide (EDB) Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

17 Pesticide Hood Basin of analyses Detection limit Alachlor Non- 2,4,5-TP (silvex) ,4-D Atrazine Carbofuran Chlordane Dalapon Dibromochloropropane (DBCP) Dinoseb Diquat Endothall Endrin Ethylene dibromide (EDB) BHC-gamma (lindane) Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

18 Pesticide John Day Basin of Detection analyses limit None Non- 2,4,5-TP (silvex) ,4-D Alachlor Atrazine BHC-gamma (lindane) Carbofuran Chlordane Dalapon Dibromochloropropane (DBCP) Dinoseb Diquat Endothall Endrin Ethylene dibromide (EDB) Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

19 Klamath Basin Pesticide analyses Detection limit None Non- 2,4,5-TP (silvex) ,4-D Alachlor Atrazine BHC-gamma (lindane) Carbofuran Chlordane Dalapon Dibromochloropropane (DBCP) Dinoseb Diquat Endothall Endrin Ethylene dibromide (EDB) Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

20 er Willamette Basin Pesticide analyses Detection limit None Non- 1,2-Dichloroethane ,4-Dichlorobenzene ,4,5-TP (silvex) ,4-D ,4-D methyl ester ,4-DB ,6-Diethylaniline (alachlor metabolite) Acetochlor Acifluorfen Acrolein Alachlor Aldicarb Aldicarb sulfone Aldicarb sulfoxide Atrazine Azinphos-methyl Bendiocarb Benfluralin Benomyl Bensulfuron Bentazon Bromacil Bromomethane Bromoxynil Butylate Carbaryl Carbofuran Chloramben methyl ester Chlordane Chlorimuron Chlorothalonil Chlorpyrifos cis-1,3-dichloropropene cis-permethrin Clopyralid Cyanazine Cycloate Dacthal monoacid Dalapon

21 Pesticide er Willamette Basin (continued) Detection analyses limit DCPA (Dacthal) Diazinon Dibromochloropropane DBCP Dicamba Dichlorprop Dieldrin Dinoseb Diphenamid Diquat Disulfoton (Di-Syston) Diuron Endothall Endrin EPTC (Eptam) Ethalfluralin Ethoprop Ethylene dibromide EDB Fenuron Flumetsulam Fluometuron Fonofos gamma-bhc (Lindane) Glufosinate Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorobutadiene Hexachlorocyclopentadiene (cyclodiene impurity) Hexachloroethane Imazaquin Imazethapyr Imidacloprid Iodomethane Lindane Linuron Malathion MCPA MCPB Metalaxyl Methiocarb Methomyl Methoxychlor Methyl parathion Metolachlor Metribuzin

22 Pesticide er Willamette Basin (continued) Detection analyses limit Metsulfuron Molinate N-(4-Chlorophenyl)-N'-methylurea (monuron) Naphthalene Napropamide Neburon Nicosulfuron Norflurazon Oryzalin Oxamyl Parathion Pebulate Pendimethalin Pentachlorophenol Phorate (Thimet) Picloram Prometon Pronamide Propachlor Propanil Propargite Propham Propiconazole Propoxur Siduron Simazine Sulfometuron Tebuthiuron Terbacil Terbufos Thiobencarb Toxaphene trans-1,3-dichloropropene Triallate Triclopyr Trifluralin

23 Malheur Basin Pesticide analyses Detection limit Atrazine DCPA (Dacthal) Non- 2,4,5-TP (Silvex) ,4-D Alachlor BHC-GAMMA (Lindane) Carbofuran Chlordane Dalapon Dibromochloropropane DBCP Dinoseb Diquat Endothall Endrin Ethylene Dibromide EDB Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

24 Pesticide Malheur Lake Basin of Detection analyses limit None Non- 2,4,5-TP (silvex) ,4-D Alachlor Atrazine BHC-gamma (lindane) Carbofuran Chlordane Dalapon Dibromochloropropane (DBCP) Dinoseb Diquat Endothall Endrin Ethylene dibromide (EDB) Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

25 Middle Willamette Basin Pesticide analyses Detection limit 3,4-Dichloroaniline diuron ,4`-DDT Atrazine Atrazine-desethyl Bromacil Malathion Metolachlor Metribuzin Simazine Terbacil Non- 2,4,5-TP (silvex) ,4-D ,4-D methyl ester ,4-DB ,4-Dichlorophenol (2,4-D metabolite) ,6-Diethylaniline (alachlor metabolite) ,4`-DDD ,4`-DDE Acetochlor Acifluorfen Alachlor Aldicarb Aldicarb sulfone Aldicarb sulfoxide Azinphos-methyl Bendiocarb Benfluralin Benomyl Bensulfuron Bentazon Bromoxynil Butylate Carbaryl Carbofuran Chloramben methyl ester Chlordane Chlorimuron Chlorothalonil Chlorpyrifos cis-permethrin

26 Pesticide Middle Willamette Basin (continued) Detection analyses limit Clopyralid Cyanazine Cycloate Dacthal monoacid Dalapon DCPA (Dacthal) Diazinon Dibromochloropropane DBCP Dicamba Dichlorprop Dieldrin Dinoseb Diphenamid Diquat Disulfoton (Di-Syston) Diuron Endothall Endrin EPTC (Eptam) Ethalfluralin Ethoprop Ethylene dibromide EDB Fenuron Flumetsulam Fluometuron Fonofos gamma-bhc (Lindane) Glufosinate Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Imazaquin Imazethapyr Imidacloprid Lindane Linuron MCPA MCPB Metalaxyl Methiocarb Methomyl Methoxychlor Methyl parathion Metsulfuron

27 Pesticide Middle Willamette Basin (continued) Detection analyses limit Molinate N-(4-Chlorophenyl)-N'-methylurea (monuron) Napropamide Neburon Nicosulfuron Norflurazon Oryzalin Oxamyl (Vydate) Parathion Pebulate Pendimethalin Pentachlorophenol Phorate (Thimet) Picloram Prometon Pronamide Propachlor Propanil Propargite Propham Propiconazole Propoxur Siduron Sulfometuron Tebuthiuron Terbufos Thiobencarb Toxaphene Triallate Tribenuron Triclopyr Trifluralin

28 Pesticide North Coast Basin of analyses Detection limit None Non- 2,4,5-TP (silvex) ,4-D Alachlor Atrazine BHC-gamma (lindane) Carbofuran Chlordane Dalapon Dibromochloropropane (DBCP) Dinoseb Diquat Endothall Endrin Ethylene dibromide (EDB) Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

29 Pesticide Owyhee Basin of Detection analyses limit DCPA (Dacthal) Non- 2,4,5-TP (Silvex) ,4-D Alachlor Atrazine BHC-GAMMA (Lindane) Carbofuran Chlordane Dalapon Dibromochloropropane DBCP Dinoseb Diquat Endothall Endrin Ethylene Dibromide EDB Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

30 Pesticide wells Powder Basin of analyses Detection limit DCPA (Dacthal) Non- 2,4,5-TP (Silvex) ,4-D Alachlor Atrazine BHC-GAMMA (Lindane) Carbofuran Chlordane Dalapon Dibromochloropropane DBCP Dinoseb Diquat Endothall Endrin Ethylene Dibromide EDB Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

31 Pesticide Mid Coast Basin of Detection analyses limit None Non- 2,4,5-TP (Silvex) ,4-D Alachlor Atrazine BHC-GAMMA (Lindane) Carbofuran Chlordane Dalapon Dibromochloropropane DBCP Dinoseb Diquat Endothall Endrin Ethylene Dibromide EDB Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

32 Pesticide Rogue Basin of Detection analyses limit None Non- 2,4,5-TP (Silvex) ,4-D Alachlor Atrazine BHC-GAMMA (Lindane) Carbofuran Chlordane Dalapon Dibromochloropropane DBCP Dinoseb Diquat Endothall Endrin Ethylene Dibromide EDB Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

33 Pesticide Sandy Basin of Detection analyses limit None Non- 2,4,5-TP (Silvex) ,4-D Alachlor Atrazine BHC-GAMMA (Lindane) Carbofuran Chlordane Dalapon Dibromochloropropane DBCP DICAMBA 1 3 nr 0 Dinoseb Diquat Endothall Endrin Ethylene Dibromide EDB glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

34 South Coast Basin Pesticide of analyses Detection limit None Non- 2,4,5-TP (Silvex) ,4-D Alachlor Atrazine BHC-GAMMA (Lindane) Carbofuran Chlordane Dalapon Dibromochloropropane DBCP Dinoseb Diquat Endothall Endrin Ethylene Dibromide EDB Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

35 Pesticide Umatilla Basin of Detection analyses limit Atrazine Atrazine-desethyl Chlorpyrifos DCPA (Dacthal) Simazine Terbacil Non- 2,4,5-TP (silvex) ,4-D ,6-Diethylaniline (alachlor metabolite) ,4`-DDE Alachlor alpha-bhc azinphos-methyl Benfluralin Butachlor Butylate Carbaryl Carbofuran Carboxin Chlordane Cyanazine Cycloate Dalapon Diazinon Dibromochloropropane DBCP Dicamba Dieldrin Dimethoate Dinoseb Diphenamid Diquat Disulfoton (Di-Syston) Endothall Endrin EPTC (Eptam) Ethalfluralin Ethoprop Ethylene dibromide EDB Fonophos

36 Pesticide Umatilla Basin (continued) Detection analyses limit gamma-bhc (Lindane) Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Hexazinone Linuron Malathion Methoxychlor Metolachlor Metribuzin Molinate Napropamide Oxamyl (Vydate) Parathion (ethyl) Parathion (methyl) Pebulate Pendimethalin Pentachlorophenol Permethrin cis Phorate (Thimet) Phosdrin (Mevinphos) Picloram Prometon Pronamide Propachlor Propanil Propargite Tebuthiuron Terbufos Toxaphene Triallate Trifluralin

37 Pesticide Umpqua Basin of Detection analyses limit None Non- 2,4,5-TP (Silvex) ,4-D Alachlor Atrazine BHC-GAMMA (Lindane) Carbofuran Chlordane Dalapon Dibromochloropropane DBCP Dinoseb Diquat Endothall Endrin Ethylene Dibromide EDB Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol Picloram Simazine Toxaphene

38 Upper Willamette Basin Pesticide of analyses Detection limit None Non- 2,4,5-TP (Silvex) ,4-D Alachlor Atrazine BHC-GAMMA (Lindane) Carbofuran Chlordane Dalapon Dibromochloropropane DBCP Dinoseb Diquat Endothall Endrin Ethylene Dibromide EDB Glyphosate Heptachlor Heptachlor epoxide Hexachlorobenzene Hexachlorocyclopentadiene (cyclodiene impurity) Methoxychlor Oxamyl (Vydate) Pentachlorophenol picloram Simazine Toxaphene