APPENDIX A: General Sampling Technique

Transcription

1 APPENDIX A: General Sampling Technique Sample collection is an important aspect of outfall monitoring, and correct sampling procedure ensures sampling contamination does not occur. If a discharge is identified discharging from the end of the pipe, the sample is collected by putting the sample collection cup under the discharge to collect an adequate sample volume. Investigators should always wear nitrile gloves when collecting samples and conducting field tests. When the discharge is at grade and discharging into a stream, a sample is collected by reaching into the pipe, this ensures that the sample being collected is not being affected by flow from the stream the outfall may be discharging to. Care should be taken by investigators to avoid disturbing sediment or introducing potential contamination from other sources. In the event of sampling through drop inlets or manholes, a sample will be collected using a GeoTech peristaltic pump. Tubing may need to be weighted to make contact with water. Tubing should be thoroughly flushed with storm drain water before collecting sample. A flow chart outlining outfall screening procedure is illustrated in Figure A1.

2 Figure A1. Schematic illustrating the procedure to be followed in the field for screening outfalls.

3 To avoid contamination and certain health risks it is recommended that protective gloves be worn during sample collection and analysis. Never collect a sample by hand in any situation where you must enter an area in which toxic gasses could pool, or where you must bring your face near an outfall pipe that could be emitting hazardous or toxic gasses!! Water Quality staff are not permitted to enter confined spaces under any circumstance. Contaminant Chemetric Testing a. Ammonia analysis: 1. Rinse the sample cup as follows: a) Fill the sample cup with the liquid from the sample bottle. b) Swish the liquid in the sample cup so that all of the interior area has been covered. c) Discard the rinse liquid downstream of the sampling site. d) Repeat steps a- c three times 2. Fill sample cup to the 25 ml mark with the liquid from the outfall. 3. Add 2 drops of the A Stabilizer Solution to the sample liquid in the sample cup. 4. Stir the liquid with the tip of the ampoule. 5. Snap the tip of the ampoule by placing the ampoule tip into one of the depressions in the bottom of the sample cup, and pressing the ampoule toward the side of the cup. (The sample will fill the ampoule, leaving a small bubble to facilitate mixing.) 6. Remove the fluid filled CHEMet ampoule from the sample cup. 7. Invert the ampoule 3-4 times (or until contents of ampoule appears mixed), allowing the bubble to travel from end to end each time. 8. Wipe all liquid from the exterior of the ampoule with a paper towel and wait 1 minute. 9. Compare ampoule color to the appropriate color, using either the low concentration tube comparer, or the mid- to- high range comparer. Identify the comparer concentration color that most closely matches the ampoule.

4 10. Discard of the used ampoule in the waste CHEMets bottle (white top) marked Ammonia or NH3. b. Chlorine analysis: 1. Rinse the sample cup as follows: a) Fill the sample cup with the liquid from the sample bottle. b) Swish the liquid in the sample cup so that all of the interior area has been covered. c) Discard the rinse liquid downstream of the sampling site. d) Repeat steps a- c three times 2. Fill sample cup to the 25 ml mark with the liquid from the outfall. 3. Add 5 drops of the A Stabilizer Solution to the sample liquid in the sample cup. 4. Stir the liquid with the tip of the ampoule. 5. Snap the tip of the ampoule by placing the ampoule tip into one of the depressions in the bottom of the sample cup, and pressing the ampoule toward the side of the cup. (The sample will fill the ampoule, leaving a small bubble to facilitate mixing.) 6. Remove the fluid filled CHEMet ampoule from the sample cup. 7. Invert the ampoule 3-4 times (or until contents of ampoule appears mixed), allowing the bubble to travel from end to end each time. 8. Wipe all liquid from the exterior of the ampoule with a paper towel and wait 1 minute. 9. Compare ampoule color to the appropriate color, using either the low concentration tube comparer, or the mid- to- high range comparer. Identify the comparer concentration color that most closely matches the ampoule. 10. Discard of the used ampoule in the waste CHEMets bottle (white top) marked Chlorine or Cl. c. Phenols and Copper analysis: (procedure is the same for both indicators; use appropriate ampoule where appropriate) 1. Rinse the sample cup as follows: a) Fill the sample cup with the liquid from the sample bottle. b) Swish the liquid in the sample cup so that all of the interior area has been covered. c) Discard the rinse liquid downstream of the sampling site.

5 d) Repeat steps a- c three times 2. Fill sample cup to the 25 ml mark with the liquid from the outfall. 3. Stir the liquid with the tip of the ampoule. 4. Snap the tip of the ampoule by placing the ampoule tip into one of the depressions in the bottom of the sample cup, and pressing the ampoule toward the side of the cup. (The sample will fill the ampoule, leaving a small bubble to facilitate mixing.) 5. Remove the fluid filled CHEMet ampoule from the sample cup. 6. Invert the ampoule 3-4 times (or until contents of ampoule appears mixed), allowing the bubble to travel from end to end each time. 7. Wipe all liquid from the exterior of the ampoule with a paper towel and wait 1 minute. 9. Compare ampoule color to the appropriate color, using either the low concentration tube comparer, or the mid- to- high range comparer. Identify the comparer concentration color that most closely matches the ampoule. 10. Discard of the used ampoule in the waste CHEMets bottle (white top) marked Phenols, Copper, or Cu. d. Detergent Analysis: 1. Rinse the reaction tube with sample, and then fill it to the 5 ml mark with sample. 2. While holding the double tipped ampoule in a vertical position, snap the upper tip using the tip breaking tool. 3. Invert the ampoule and position the open end over the reaction tube. Snap the upper tip and allow the contents to drain into the reaction tube. 4. Cap the reaction tube and shake it vigorously for 30 seconds. Allow the tube to stand undisturbed for about one (1) minute. 2. Make sure the flexible tubing is firmly attached to the CHEMet ampoule tip. 6. Insert the CHEMet ampoule into the reaction tube making sure that the end of the flexible tubing is at the bottom of the tube. Break the tip by pressing against the side of the tube. The ampoule should draw in fluid only from the organic phase (bottom layer). 7. When filling is complete, remove the assembly from the reaction.

6 8. Wipe all liquid from the exterior of the ampoule. Place ampoule cap firmly onto the tip. Invert the ampoule several times, allowing the bubble to travel from end to end each time. 9. Place the ampoule, flat end downward into the center of the comparator. Direct the comparator up toward a source of bright light. Rotate the comparator until you find the color standard that shows the closest match. If the color is between two color standards an estimate can be made. 10. Discard of the used ampoule and liquid waste in the waste CHEMets bottle marked detergents. Interpreting Chemet Results and Physical Measurements a. Ammonia (nitrogen) Low- level ammonia nitrogen may be present in water naturally as a result of the biological decay of plant and animal matter. Higher concentrations may be found in raw sewage and industrial effluents, particularly from petroleum refineries where ammonia is a by- product of the refining process. Ammonia is a major component of fertilizers. High concentrations in surface waters can indicate contamination from waste treatment facilities, industrial effluents, or fertilizer run off. Excessive ammonia concentrations are toxic to aquatic life. Ammonia measurements in streams of 1 to 2 mg/l indicate possible contamination by sewage, while measurements of greater than 2 mg/l indicate increasing certainty of sewage contamination. Durham s stormwater runoff typically averages 0.1 mg/l to 0.6 mg/l of ammonia (individual measurements below 1.5 mg/l). b. Chlorine (free & total) Because of its strong oxidizing properties, chlorine in aqueous solution is an excellent biocide used to treat potable waters, municipal wastes and swimming pools. Durham s treated water typically has between 0.8 and about 1.5 mg/llof chlorine, although the concentration will vary throughout the water distribution system. During most of the year, the City uses chloramines as the form of distribution system disinfectant. Measuring total chlorine will measure either form. Concentrations of chlorine over about 0.75 mg/l are strong indications of potable water discharge. Chlorine must be measured at the time of sample collection; therefore laboratory confirmation is not

7 reliable. Measurements that range from 0.25 mg/l to 0.4 mg/l, indicate a possible potable water source. (Lab measurements of fluoride have been used to confirm the source to be potable water. Fluoride measurements greater than 0.4 mg/l can be used to give a confirmation). c. Detergents (anionic surfactants) Industrial facilities that use detergents to clean machinery can discharge anionic detergents into the water supply. Soap manufacturers may also discharge detergents. Other sources are household cleaners, personal care products and sanitary sewer discharges. Due to false positive readings values of 0.25 mg/l or lower should not be considered. d. Copper (total soluble) Copper is found naturally in the earth's crust and in seawater. Copper is also an important component of fungicides and insecticides. Copper- containing fungicides are used to control biological growth in the water supply. The Maximum Contaminant Level Goal for copper is 1.3 mg/l in drinking water. The measurement of copper is an important means of monitoring the corrosion of condensate systems and heat exchangers. e. Phenols Phenol (hydroxy- benzene) is the simplest of a group of similar organic chemicals which includes: cresols, xylenols and catechols. Many of these "phenolics" are used as raw materials in the manufacture of polymers, plasticizers, hydraulic fluids and various industrial chemicals. Phenol itself is a common ingredient of disinfectants. In drinking water, low- level phenolic concentrations impart a foul taste and odor, especially upon chlorination. High phenol concentrations can indicate contamination from industrial effluents or waste discharge. f. ph

8 ph is a very important water quality indicator. Under normal conditions it is rarely outside the range of 6 to 9 specified in North Carolina Water Quality Standards. However, ph outside this range can be very harmful to aquatic life, and elevated ph in the range of 8.5 to 9 significantly increases the toxicity of ammonia. g. Specific Conductivity Specific conductivity is a measure of the ability of water to conduct an electrical current. It is highly dependent on the amount of dissolved solids in the water. Specific conductivity is an important water- quality measurement because it gives an idea of the amount of dissolved material in the water. Conductivity is measured microsiemens per centimeter (µs/cm). Distilled water has a conductivity range of 0.5 to 3 µs/cm. The conductivity of rivers in the United States generally ranges from 50 to 1500 µs/cm. Studies of inland fresh waters indicate that streams supporting good mixed fisheries have a range between 150 and 500 µ/cm. Conductivity outside this range could indicate that the water is not suitable for certain species of fish or macroinvertebrates. h. Dissolved Oxygen (DO) Dissolved oxygen is measured in milligrams per liter (mg/l) or "percent saturation." Milligrams per liter are the amount of oxygen in a liter of water. Percent saturation is the amount of oxygen in a liter of water relative to the total amount of oxygen water can hold at that temperature. In addition to being required by aquatic organisms for respiration, oxygen is used for decomposition of organic matter and other biological and chemical processes. DO concentrations greater than 3 mg/l can support most vertebrates and other forms of aquatic life in the Piedmont of North Carolina. DO concentrations below 3 mg/l are stressful to most vertebrates and other forms of aquatic life in the Piedmont of North Carolina.

9 APPENDIX B: Sampling Equipment ADC Map book First aid kit Cooler for sample bottles Sharpie Marker for labeling bottles Sample scoop DI water for rinsing scoop Samples bottle (for lab analysis) Backpack Camera Cell phone Tablet PC or Trimble GPS unit Clip boards (aluminum case clips) Forms (Outfall and WQ Investigations) Bright flash light Handheld GPS unit Nitrile gloves 12 ft Tape measure Safety shoes ANSI 2 safety vest Kleen wipes Insect repellant DO, Conductivity, Temperature probe ph pen Turbidity (EPA) Hach chlorine kit Chemetrics V Multi- analyte Photometer Liquid dyes Manhole hooks Chemetrics kits

10 APPENDIX C: Chemetrics Waste Disposal and Segregation Chemetrics test kits for field analytical measurements contain disposable ampoules, some which are hazardous in nature. The use of Chemetrics test kits generate waste which must be properly segregated and disposed. It is the responsibility of all City of Durham Stormwater Services Division staff that use Chemet test kits to follow the proper procedures for segregation and disposal of these wastes. Based upon information contained within the individual Chemetrics material safety data sheets (MSDS), chemetrics wastes generated by the City of Durham Stormwater Services Division staff shall be segregated into 6 separate waste groups as follows: Chemetrics Waste Group 1 (Container # 1) Name Catalog # ph Incompatibilities Known Hazards Strong Acid Phosphate Ampoule Chromate Acidifier Solution R 8510D 0.5 A Strong Bases Heat Reducing materials Bases Metals Hazardous Decomposition Soluble molybdenum compound (Carcinogen) Strong Acid Hazardous Decomposition Chemetrics Waste Group 2 (Container # 2) Name Catalog # ph Incompatibilities Known Hazards Caustic Ammonia Ampoule R Strong Acids Oxidizers Mercury compound Hazardous Decomposition

11 Chemetrics Waste Group 3 (Container # 3) Name Catalog # ph Incompatibilities Known Hazards Ammonia Stabilizer Solution A None None Chlorine Neutralizer Solution Chlorine Ampoule Chlorine Ampoule Copper Ampoule A Heat R Heat R Heat R Heat Hazardous Decomposition Hazardous Decomposition Formaldehyde (Carcinogen) Hazardous Decomposition Hazardous Decomposition. Chemetrics Waste Group 4 (Container # 4) Name Catalog # ph Incompatibilities Known Hazards Detergents Ampoule R Strong Bases, Metals, Strong Oxidants, Heat Flammable, Hazardous Decomposition, Chloroform (Carcinogen)

12 Chemetrics Waste Group 5 (Container # 5) Name Catalog # ph Incompatibilities Known Hazards Strong Acids Phenols Ampoule R Ammonia Heat Hazardous Decomposition Chlorine Activator Solution A Heat Hazardous Decomposition Note: Never store unlike Chemetrics waste products (ampoules & solutions) together other than described above. Dangerous reactions may occur if these waste products are improperly segregated. Requirement of proper waste containers Once an ampoule is used, it becomes waste and must be properly disposed of. Each City of Durham Stormwater Services Division vehicle that possesses a Chemetrics test kit of any kind must also keep a properly labeled waste container (250 ml polypropylene bottle) for each type of waste category (shown above) in order to ensure that Chemetrics wastes are properly segregated in the field. A properly labeled container is defined as such indicating which used Chemets and Chemetrics solution wastes can be stored in them as well as indentifying potential hazards of each waste product. Procedure for proper segregation and disposal (from field to office) After each individual use, used chemets and chemetrics solution wastes must be properly segregated and stored into the appropriate 250 ml polypropylene waste container (based upon the 6 waste groups listed above). Large Chemetrics waste containers and 4 mm. thick plastic hazardous material disposal bags are located in the chemical storage locker in the Stormwater

13 Lab. When each individual 250 ml polypropylene waste container becomes ½ full, it is the responsibility of the staff member using that container to: 1) Empty the contents into a new 4 mil thick plastic hazardous material disposal bag 2) Place the plastic hazardous material disposal bag w/ chemetrics waste into the appropriate large (4 gallon HDPE) Chemetrics waste container (based upon the 6 waste groups listed above). Note: Each large Chemetrics waste container is labeled similar to the 250 ml waste containers and identifies which Chemets and Chemetrics solution wastes can be stored in them. 3) Place the lid back on the container so that it is tightly secured, return the waste container to the cabinet, and close the cabinet. Procedure for proper disposal (from office to Transfer Storage & Disposal Facility) The chemical waste disposal coordinator will contract with and outside waste disposal company to ensure chemical waste generated by the City of Durham Stormwater Services Division is disposed of in a timely and proper manner.

14 APPENDIX D: Exceptions to Prohibited Discharges While NPDES permit NCS requires the City to prohibit most non- stormwater flows from entering the MS4, it does provide for exceptions. These exceptions include discharges authorized by and in compliance with a valid NPDES permit. Control of the impact of permitted discharges should be accomplished through appropriate discharge limits, conditions, and provisions in the permit. The City s NPDES permit also exempts discharges determined to be incidental non- stormwater flows that do not significantly impact water quality, and lists a number of examples which are conditionally allowed, provided they are not determined to have a significant impact: Dechlorinated water line flushing; landscape irrigation; uncontaminated groundwater infiltration and pumped groundwater; minor discharges from potable water sources; air conditioning condensate (commercial/residential); irrigation waters (does not include reclaimed water as described in 15A NCAC 2H.0200); lawn watering; residential and charity car washing; dechlorinated swimming pool discharges; street wash water; flows from emergency fire fighting. Exceptions for the above examples are conditional on the discharge not having a significant impact on water quality. In the past, all discharges of potable water were considered not to have a significant impact. At that time the City used free chlorine in potable water to provide a disinfectant residual to keep pathogenic organisms from reproducing in the distribution system. Free chlorine dissipates fairly quickly in the environment. Following the City s switch from free chlorine to chloramines as a distribution system disinfectant, specific instances were found where large or persistent discharges of potable water were found to impact water quality. Chloramines are less reactive than free chlorine, and as a result they are four to ten times more persistent. Chloramines are also less effective as a disinfectant, and thus, dosage may need to be increased. The change in persistence (possibly combined with adjustments in dosage) that accompanied the switch to chloramines required treating potable water more cautiously. During hydrant flushing operation, the City s Water Management Department now uses diffusers that contain dechlorinating agents (Vita- C is one type) to remove most of the chloramines. Currently minor discharges of potable water - typically small amounts not discharged on a regular or continuous basis - continue to be exempted.