1997 PRL Annual Report - Appendix J
Water Quality Monitoring Program To Detect Pesticide Contamination In Groundwaters Of Nassau and Suffolk Counties, NY
Interim Report
June 1998
Suffolk County Department of Health Services
Division of Environmental Quality
Joseph H. Baier, P.E., Director
Bureau of Groundwater Resources
Martin Trent, Project Manager
Pesticide contamination of groundwater has become a national issue due to growing concerns about potential public health impacts. These concerns are particularly acute on Long Island, where groundwater is the sole-source of drinking water for Nassau and Suffolk County residents. The Suffolk County Department of Health Services is conducting a comprehensive pesticide monitoring program in cooperation with the New York State Department of Environmental Conservation, Division of Solid & Hazardous Materials. The project was initiated to fulfill the requirements of Section 33-0714 of the Environmental Conservation Law (ECL), to conduct a water quality monitoring program to detect and assess pesticide contamination of ground and surface waters on Long Island and throughout the state. The objective of the program is to identify and define pesticide impacts on Long Island groundwater from use by agriculture, residents, businesses, and institutions. The program is innovative from the perspectives of both the large number of compounds being tested and the geographic distribution of sample sites.
This interim report provides the results of testing for the NYSDEC Water Quality Monitoring Program to Detect Pesticides in Groundwaters of Nassau and Suffolk Counties. The interim findings presented are based upon testing conducted between October 1, 1997 and March 31, 1998, coinciding with the end of the state fiscal year. The term pesticide as used herein refers to any compound or element utilized as an insecticide, nematicide, herbicide, or fungicide, or any metabolite of these chemicals. A total of 2,000 samples is contracted to be analyzed over a two-year period. Sampling for the project began on October 1, 1997.
Wells were sampled in all thirteen townships across the two counties to provide full geographic coverage. Many sample sites were selected based upon their high vulnerability due to the proximity to areas of known pesticide use -- agricultural as well as industrial -- shallow well depths -- and previous testing that had shown pesticides. Site-specific surveys were conducted to sample additional private wells where significant or unexpected analysis results were obtained. New monitoring wells were drilled and sampled in both highly impacted areas and in regions where no other sampling points were available. Monitoring wells provide data on impacts to the groundwater resource that may not be detected if testing were conducted only at public or private drinking water supply wells. Raw (untreated) water was tested at drinking water supplies where filtration or treatment exists.
Sample collection is being conducted by the Suffolk County by the Department of Health Services (SCDHS) and the Nassau County Department of Public Works. Samples collected in Suffolk are transported directly to the SCDHS Public and Environmental Health Laboratory (PEHL), while samples from Nassau County wells are refrigerated and delivered to the SCDHS PEHL twice weekly. Through March 31, 1998, a total of 1,111 samples was analyzed representing 898 wells.
Each sample set is analyzed utilizing the following eight methodologies: metals (USEPA Method 200.8), volatile organic compounds (524.2), microextractable compounds (504), chlorinated pesticides (505), methyl carbamate pesticides (531.1), semi-volatile pesticides (525.2), chlorinated acids (555), and dacthal metabolites (SCDHS developed method, published and peer reviewed). The eight methods provide information on 157 chemicals, of which approximately 70 may be considered pesticides. Appendix A contains a listing of the compounds analyzed by each method, and the minimum detection level (MDL) for each parameter.
Sample Distribution
Tables I through III indicate the number of wells sampled in each county and township, the number of wells in which pesticides were detected, and the number of those detections that exceeded state and federal drinking water Maximum Contaminant Levels (MCLs). Seventeen percent of the total number of wells tested were located in Nassau County and 83% in Suffolk County. Samples were collected in all 13 townships across the two counties, with the fewest number of wells being tested on Shelter Island (9), and the greatest number within the Town of Southold (173).
The SCDHS installed and sampled 42 new monitoring wells to gain information on groundwater quality in areas in which it was lacking in Suffolk County. Many of the wells drilled were sampled at several levels in the aquifer in order to vertically profile water quality and detect zones where contamination might exist. Other monitoring wells were installed to target specific land uses such as golf courses.
Sampling Results
The project's data indicate that 24 different pesticides or metabolites have been detected in groundwater samples to date (see Table V), and that eight of these compounds have exceeded drinking water MCLs. The compounds that have exceeded MCLs are: alachlor, aldicarb, bis 2-ethylhexylphthalate, 1,2-dichloropropane (DCP), 1,2-dibromoethane (ethylene dibromide or EDB), simazine, tetrachloroterephthalic acid (TCPA is a dacthal metabolite), and 1,2,3-trichloropropane (see Table V). When an MCL is exceeded, the homeowner is notified by SCDHS, told not to drink their water, and advised of alternative water supply sources.
A total of 234 individual wells (26 percent of the wells tested) contained detectable concentrations of at least one pesticide or metabolite compound. One in every ten wells (90 of 898) sampled exceeded a pesticide-related drinking water MCL. The vast majority of the exceedances were from wells located in the agricultural areas of Suffolk County. Eleven wells in agricultural areas exceeded MCLs for more than one pesticide or metabolite compound.
It is important to recognize that these contamination statistics are not representative of public drinking water supplies where treatment is provided to remove any contamination. Approximately one-half of all the wells tested were targeted specifically in areas considered to have a high potential for pesticide impacts, and 80 percent (%) of the total wells tested were either domestic private wells or monitoring wells. Four public (community) supply wells located in eastern Suffolk County exceeded pesticide MCLs, but these wells have granular activated carbon filtration in place for contaminant reduction.
Well locations exceeding MCLs are depicted on the map of Long Island attached as Appendix B. The map in Appendix B.1 shows a detail of impacted areas of the north and south forks of Suffolk County.
The most frequently detected pesticides or metabolites are listed below together with the number and percent of wells in which the chemical was found. Each insecticide and herbicide listed is applied directly to the soil, as opposed to foliar application. The four most commonly detected pesticide compounds are no longer actively used on Long Island.
| Pesticide | # Detects | % of Wells |
|---|---|---|
| aldicarb (sufoxide/sulfone) | 121 | 13.5 |
| Tetrachloroterephthalic acid (TCPA) | 50 | 5.5 |
| 1,2-dichloropropane | 35 | 3.9 |
| ethylene dibromide | 21 | 2.3 |
| metolachlor | 19 | 2.1 |
| 1,2,3-trichloropropane | 11 | 1.2 |
| simazine | 11 | 1.2 |
Aldicarb (trade name Temik), a systemic carbamate insecticide applied primarily to potato crops, was withdrawn from the Long Island market in 1979. Its manufacturer, Rhone Poulenc Ag Company, voluntarily withdrew the chemical from use on potatoes in 1990 nationwide due to concerns about groundwater contamination. Carbon filters are provided to homes when the aldicarb standard is exceeded. The United States Environmental Protection Agency suspended the use of ethylene dibromide (EDB) as a soil fumigant in 1983.
Dacthal, of which TCPA is a metabolite, was withdrawn from use on Long Island in 1988. Distribution labels were modified at the request of NYSDEC in 1991. DCP (1,2-dichloropropane) applications to the island's nematode-infested potato farms by the U.S. Department of Agriculture were halted in 1982. The widespread findings of these chemicals many years later demonstrates their stability and persistence in Long Island's groundwater environment.
Of the 90 wells found to exceed pesticide MCLs, the vast majority (86) were impacted by agricultural chemicals (including nursery and sod uses). A majority of the 86 were due to aldicarb(47). The five easternmost townships of Suffolk County accounted for 46% of the wells tested and 94% of the wells that exceeded a pesticide-related standard. Homeowner use or residential applications of pesticides were not implicated in any of the findings of wells exceeding drinking water standards.
Sample Results - Agricultural Areas
In addition to being the most frequently detected pesticide, aldicarb also exceeded its MCL of 7 µg/L more than any other contaminant. Parent aldicarb was not found, metabolites aldicarb sulfoxide and aldicarb sulfone were detected. Forty-seven wells in 15 communities in eastern Suffolk County were found to exceed the aldicarb standard. The highest concentration of aldicarb detected was 41 µg/L. Aldicarb, used on Long Island from 1975-1979, was applied directly to the soils of over 20,000 acres of potato fields.
Sampling in an agricultural area of Calverton led to the discovery of nine private wells impacted by the soil fumigant EDB. EDB concentrations in the private wells ranged from 0.16 to 29.8 micrograms per liter (µg/L). The drinking water MCL for EDB is 0.05 µg/L. A series of monitoring
wells were installed and vertically profiled to help determine if the unusual findings resulted from a point source or from field applications. EDB was found at multiple levels in the groundwater and in a cross section of wells approximately 0.5 miles wide, indicating applications to several fields as potential sources. An EDB point source within this area also remains a possibility since a monitoring well installed at a hot spot contained 91.9 µg/L EDB (April 1998), a level more than 1,800 times the MCL. Seventeen of the 20 wells exceeding the MCL for EDB were within this area of Calverton. EDB exceeding standards were also detected in Mattituck, Cutchogue, and Orient on Suffolk's north fork.
The dacthal metabolite tetrachloroterephthalic acid (TCPA) exceeded the Unspecified Organic Compound (UOC) standard of 50 µg/L (established in Part 5 of the NYS Sanitary Code) in 29 wells in eight communities. Twenty-eight of the 29 wells exceeding the TCPA MCL are located in agricultural areas of Suffolk County on the north and south forks. Dacthal is a pre-emergence herbicide that is applied to the soil. Of the pesticides found, TCPA was detected in the highest concentration during the program at 766 µg/L in a private well in Riverhead. Private wells in this area have contained concentrations as high as 1,753 µg/L TCPA (April 1996).
Soil fumigants 1,2,3-trichloropropane and 1,2-dichloropropane exceeded the 5 µg/L MCL for each compound in one and four wells, respectively. These chemicals were widely applied to potato acreage for nearly 30 years, beginning in the 1950s on Long Island, at very high application rates. The wells found exceeding standards are located in Cutchogue, Melville, Wainscott, and Water Mill.
The herbicide alachlor was found in two wells exceeding its 2 µg/L MCL in Shelter Island and Water Mill. In recent sampling by the SCDHS, alachlor was detected in numerous private wells adjacent to landscape nurseries in several Suffolk communities.
Sample Results - Suburban Areas
Simazine, a triazine herbicide, exceeded its 4 µg/L MCL in two monitoring wells located in Aquebogue and Great River, and one private well in Shirley. Simazine is another chemical product that may be soil applied. The two monitoring wells are downgradient of LILCO substations. LILCO applied the chemical for weed control at 101 substations in Suffolk County at industrial application rates (~10 times greater than agricultural rates) between 1979 and 1993. In cooperation with LILCO a separate SCDHS survey was completed and detected simazine in wells located in proximity to the substations. NYSDEC has required label restrictions that prohibit higher application rates.
Only one well was found to exceed pesticide-related MCLs in Nassau County, and four wells exceeded standards in the more suburban western five towns of Suffolk County, despite the fact that these areas account for nearly 54% of the total number of wells sampled. The low rate of pesticide detections in Nassau County may be at least partially explained by the fact that 40 (26%) of the wells tested in Nassau were greater than 300 feet deep, with several over 1,000 feet deep. These depths are typical for public water supply wells, and are considered the least vulnerable to pesticide contamination.
The five contaminated suburban area wells and potential sources of the contamination are described below. The single shallow (monitoring) well exceeding an MCL in Nassau contained TCPA and is downgradient of a golf course in Sands Point. A monitoring well in Commack exceeded the standard for bis 2-ethylhexylphthalate, a plasticizer that is also used as a pesticide carrier. This well also contained simazine and is located downgradient of a LILCO substation. DCP (1,2-dichloropropane) was detected in a new SCDHS monitoring well drilled in a former potato farming area of Melville. Simazine was found to exceed the MCL in a monitoring well downgradient of a LILCO substation in Great River. A private well in Shirley that exceeded the simazine MCL also contained high concentrations of toluene and other volatile organic compounds(VOCs) from an unknown source. Although past testing by SCDHS has occasionally attributed a few private well contaminations to residential applications of pesticides, none were implicated in any of the findings of wells exceeding drinking water standards in this program.
Sample Results - Golf Courses
Twenty wells located on or downgradient of 10 different golf courses were sampled to examine impacts of golf course pesticide use on groundwater. The wells included 12 new shallow monitoring wells installed by the SCDHS at three Suffolk County operated courses at Timber Point, West Sayville, and Indian Island. The monitoring wells were targeted in areas immediately downgradient of greens, fairways and tees -- areas expected to be the most heavily treated with pesticides (and fertilizers). The results, as previously noted, show one well in Sands Point that exceeded the MCL for TCPA, and two monitoring wells at West Sayville contained detectable traces of bis 2-ethylhexylphthalate and 4-nitrophenol. There were no detections of pesticides or metabolites in the remaining 17 wells at golf courses.
Sample Results - Surface Waters
Groundwater provides the base flow for Long Island's streams and rivers. Sampling was conducted at twelve rivers near the end of March. The results of the testing indicated no detection of pesticide related parameters in any of the rivers. VOCs were detected in seven of the 12 rivers sampled. Methyl-tert-butyl ether (MTBE), trichloroethene (TCE), and tetrachloroethene (PCE), were the most common VOCs detected. PCE exceeded the drinking water MCL in two streams. Nitrate was detected in 11 of 12 streams, and the average stream nitrate concentration was 2.2 mg/L. Additional surface water testing is planned.
Metals Results
There were low-level detections of some metals that may have had utilization in pesticide formulations in the past. It is unclear whether any of these findings are actual remnants of pesticide applications. Arsenic and cadmium were detected in 16 and 22 samples, respectively. With the exception of one cadmium finding, all detections were below drinking water MCLs, the lone exception being a well in Nassau County that exceeded the cadmium MCL of 5 µg/L. The original sample of this well showed 1.12 µg/L cadmium, and a resample 11.2 µg/L. Cadmium was registered for lawn and turf uses from 1959 to 1986 by the USEPA.
Initial analysis of some samples indicated detections of mercury in concentrations less than one microgram per liter. The results of resampling showed no detections in 15 of 16 analyses. The exact cause of the false positives has not been conclusively determined. Method limitations have been discussed with the laboratory instrument's manufacturer, and it is possible that there may have been random contamination of sample bottles used in the very sensitive analysis by the Inductively Coupled Plasma/Mass Spectrometer.
Nitrate Results
Nitrate analyses were also conducted, where possible, for wells sampled in Suffolk County. Wells in Nassau were not tested for nitrate due to the restriction of analytical method holding times. Excess nitrate in drinking water is of public health importance due to the potential occurrence of methemoglobinemia (blue baby syndrome).
Sixty-five (12%) of the 565 Suffolk County wells (see Table VII) tested during this phase of the project for nitrate exceeded the drinking water MCL of 10 milligrams per liter (mg/L). The highest concentration of nitrate found was 31.3 mg/L in a Manorville private well located downgradient of a large nursery operation. A 1996 study by the SCDHS of the results of testing over 45,000 private wells in Suffolk from 1972-1994 showed that 7.4% of the wells exceeded the nitrate MCL. The greater percentage in the current project may be attributable to the concentrated testing in agricultural areas where fertilization practices contribute to elevated nitrate levels in groundwater.
The average nitrate concentration in the 19 golf course wells sampled in Suffolk County was 4.9 mg/L. In comparison, The Suffolk County Water Resources Management Plan (1987) and previous studies have concluded that developing land at a density of 1 and 2 dwelling unit(s) per acre yields an average nitrate concentration of 4 and 6 mg/L, respectively, and comparatively, Nitrate and Pesticide Impacts on Groundwater Quality, Suffolk County, NY (1996) found that the 20 year average nitrate concentration of monitoring wells in agricultural areas was 11.3 mg/L.
Conclusions & Recommendations
The initial sampling of groundwaters for this project was concentrated at shallow wells in areas thought to be vulnerable to pesticide contamination. Because of this, the data cannot be considered representative of all groundwater on Long Island.
The interim results of the study demonstrate the vulnerability of Long Island's groundwater to impacts from pesticides and their metabolites, particularly to agricultural chemicals applied to the land surface. These findings are clearly most evident in agricultural areas in eastern Suffolk County where nearly all of the MCL exceedances were found.
Based upon the data, the following recommendations are made:
- Continue to provide the necessary resources to expand analytical capability to monitor the groundwater for additional pesticides and metabolite compounds.
- A high priority should be given to taking the steps necessary to provide for remediation of areas with contaminated private wells through the extension of public water supplies.
| Nassau | Suffolk | Blanks | Total |
|---|---|---|---|
| 152 | 746 | 213 | 1,111 |
| Township | # Wells Sampled | # Detects | # >MCL |
|---|---|---|---|
| Hempstead | 73 | 5 | 0 |
| North Hempstead | 35 | 3 | 1 |
| Oyster Bay | 44 | 2 | 0 |
| Totals | 152 | 10 | 1 |
| Township | # Wells Sampled | # Detects | # >MCL |
|---|---|---|---|
| Babylon | 23 | 3 | 0 |
| Brookhaven | 124 | 12 | 1 |
| East Hampton | 58 | 19 | 5 |
| Huntington | 53 | 12 | 1 |
| Islip | 21 | 4 | 1 |
| Riverhead | 86 | 41 | 28 |
| Shelter Island | 9 | 1 | 1 |
| Smithtown | 108 | 6 | 1 |
| Southampton | 91 | 36 | 9 |
| Southold | 173 | 90 | 42 |
| Totals | 746 | 224 | 89 |
| Monitoring | Community | Non-Comm | Private | Surface |
|---|---|---|---|---|
| 306 | 45 | 118 | 417 | 12 |
| Result | Nassau County | Suffolk County | |||
|---|---|---|---|---|---|
| Pesticide | Max.Conc. | Pesticide | MCL | Max. Conc. | |
| Greater than MCL |
TCPA (1) | 89.0 µg/l | alachlor (2) aldicarb sulfoxide & sulfone (47) bis 2-ethylhexyl phthalate (2) 1,2-dichloropropane (4) EDB (20) simazine (3) TCPA (29) 1,2,3-trichloropropane (1) |
2.0 7.0 6.0 5.0 0.05 4.0 50.0 5.0 |
6.66 µg/l 41.0 µg/l 14.0 µg/l 11.0 µg/l 77.8 µg/l 12.3 µg/l 766.0 µg/l 6.0 µg/l |
| Greater than MDL |
arsenic (6) atrazine (3) cadmium (9) 2,4-D (1) dieldrin (1) dinoseb (1) prometon (1) simazine (1) TCPA (2)
|
30.9 µg/l 0.2 µg/l 11.2 µg/l 0.97 µg/l 0.78 µg/l 0.59 µg/l 0.2 µg/l 0.4 µg/l 33.0 µg/l |
alachlor (2) aldicarb sulfoxide & sulfone (74) arsenic (10) atrazine (5) bis 2-ethylhexyl phthalate (5) cadmium (13) carbofuran (3) 2,4-D (6) 1,2-dichloroethane (4) 1,2-dichloropropane (31) 1,3-dichloropropane (1) dieldrin (1) dinoseb (5) EDB (1) endosulfan sulfate (1) MCPP (1) metalaxyl (7) methomyl (1) metolachlor (19) metribuzin (2) 4-nitrophenol (4) oxamyl (8) prometon (2) simazine (7) TCPA (18) 1,2,3-trichloropropane (10) |
2.0 7.0 50.0 3.0 6.0 5.0 40.0 50.0 5.0 5.0 5.0 5.0 7.0 0.05 50.0 50.0 50.0 50.0 50.0 50.0 50.0 50.0 50.0 4.0 50.0 5.0 |
0.28 µg/l 6.9 µg/l 11.0 µg/l 0.77 ug/l 3.9 ug/l 2.89 ug/l 4.7 ug/l 1.08 ug/l 1.0 ug/l 4.0 ug/l 1.0 ug/l 0.33 ug/l 2.61 ug/l 0.03 ug/l 1.99 ug/l 1.8 ug/l 1.2 ug/l 1.7 ug/l 11.4 ug/l 0.21 ug/l 2.41 ug/l 11.0 ug/l 3.8 ug/l 3.0 ug/l 33.0 ug/l 4.0 ug/l |
Unquantified Positives |
deet (1) dicamba (1) dichloroprop (1) oxamyl (1) pentachlorophenol (1) propoxur (1) |
bromacil (1) butachlor (1) chlorobenzilate (1) diazinon (1) dichloroprop (2) pentachlorophenol (5) propoxur (2) |
|||
| PESTICIDE | COMMUNITY | # WELLS |
|---|---|---|
| Alachlor | Shelter Island Water Mill |
1 1 |
| Aldicarb sulfoxide & sulfone | Amagansett Bridgehampton Calverton Cutchogue East Hampton Jamesport Laurel Mattituck Orient Peconic Riverhead Sagaponack Southold Wainscott Water Mill |
1 1 8 12 1 2 3 5 1 1 2 3 3 2 2 |
| bis 2-ethylhexylphthalate | Commack Water Mill |
1 1 |
| 1,2-Dichloropropane | Cutchogue Melville Wainscott Water Mill |
1 1 1 1 |
| Ethylene Dibromide | Calverton Cutchogue Mattituck Orient |
17 1 1 1 |
| Simazine | Aquebogue Great River Shirley |
1 1 1 |
| TCPA | Calverton Cutchogue East Marion Jamesport Orient Riverhead Sands Point (N) Water Mill |
5 10 4 1 3 5 1 1 |
| 1,2,3-Trichloropropane | Cutchogue | 1 |
|
Well Locations |
# |
|---|---|
| Bridgehampton Bellport Calverton Cutchogue East Hampton East Marion East Moriches East Quogue Flanders Head of Harbor Huntington Laurel Manorville Mattituck Medford Melville Montauk New Suffolk Orient Peconic Riverhead Ronkonkoma Sagaponack Saint James Shelter Island Southold Speonk Wainscott Water Mill West Sayville Yaphank |
1 2 1 9 2 4 1 1 1 1 2 1 1 1 1 7 2 1 3 3 1 1 1 5 1 4 1 1 1 2 2 |
# Analyses: 545
# Exceed MCL: 65 (12%)
Highest Concentration: 31.3 mg/l
APPENDIX A
| Analyte | MDL µg/l |
|---|---|
| Aluminum Antimony Arsenic Barium Berylium Cadmium Chromium Cobalt Copper Lead Manganese Mercury Molybdenum Nickel Selenium Silver Thallium Thorium Titanium Vanadium Zinc |
5.0 1.0 2.0 5.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.4 1.0 1.0 2.0 5.0 1.0 1.0 1.0 1.0 50 |
| Analyte | MDL µg/l |
|---|---|
| 1,2-Dichlorobenzene(o) 1,2,4-Trimethylbenzene 1,1,1,2-Tetrachloroethane 1,2,3-Trichloropropane 1,2-Dichloropropane 1,3,5-Trimethylbenzene 1,1,2-Trichloroethane 1,1-Dichloroethane 1,1,1-Trichloroethane 1,2-Dichloroethane 1,2,4,5-tetramethylbenzene 1,1-Dichloroethene 1,1,2,2-Tetrachloroethane 1,2,4-Trichlorobenzene 1,2,3-Trichlorobenzene 1,1,-Dichloropropene 1,4-Dichlorobutane 1,1-Dichloroethene 1,1,2,2-Tetrachloroethane 1-Bromo-2-chloropropane 1-Methylethylbenzene 2,3-Dichloropropene 2,2-Dichloropropane 2-Bromo-1-chloropropane 2-Butanone(MEK) 2-Chlorotoluene 3-Chlorotoluene 4-Chlorotoluene Benzene Bromobenzene Bromochloromethane Bromodichloromethane Bromoform Bromomethane Carbon tetrachloride Chlorodifluoromethane Chloroethane Chloroform Chloromethane Chorobenzene cis-1,2-Dichloroethene cis-1,3-Dichloropropene Dibromomethane Dichlorodifluoromethane Dimethyldisulfide 0.5 Ethenylbenzene (Styrene) Ethylbenzene Freon 113 Hexachlorobutadiene Isopropyltoluene(p-cymene) m,p-Dichlorobenzene m-Xylene Methy-tert-butyl-ether Methyl sulfide Methylene chloride n-Butylbenzene n-Propylbenzene Napthalene o-Xylene p-Diethylbenzene p-Xylene sec-Butylbenzene T.Chlorotoluene T.Xylene tert-Butylbenzene Tetrachloroethene Tetrahydrofuran Toluene trans-1,3-Dichloropropene Trans-1,2-Dichloroethene Trichloroethene Trichlorofluoromethane Vinyl chloride |
0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 20. 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 20.0 0.5 0.5 0.5 0.5 0.5 0.5 |
| Analyte | MDL µg/l |
|---|---|
| 4,4-DDE 4,4-DDD 4,4-DDT Alachlor Aldrin alpha-BHC beta-BHC Chlordane Dacthal delta-BHC Dieldrin Endosulfan I Endosulfan II Endrin Endrin aldehyde gamma-BHC (Lindane) Heptachlor Heptachlor epoxide Methoxychlor |
0.2 0.2 0.2 0.5 0.2 0.2 0.2 1.0 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.5 |
| Analyte | MDL µg/l |
|---|---|
| 2,4-DB 2,4,5-T 2,4-D 3,5-Dichlorobenzoic Acid 4-Nitrophenol Acifluorfen Bentazon Chloramben Dicamba Dichloroprop Dinoseb MCPA MCPP Pentachlorophenol Picloram Silvex (2,4,5-TP) |
0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 |
| Analyte | MDL µg/l |
|---|---|
| 1,2-dibromoethane 1,2-dibromo-3-dichloropropane |
0.02 0.02 |
| Analyte | MDL µg/l |
|---|---|
| Monomethyltetrachloroterephthalate Tetrachloroterephthalic acid (TCPA) |
10.0 10.0 |
| Analyte | MDL µg/l |
|---|---|
| Alachlor Atrazine Benzo(a)pyrene Bis(2-ethylhexyl)adipate Bis(2-ethylhexyl)phthalate Bromacil Butachlor Dacthal Diazinon Hexachlorobenzene Hexachlorocyclopentadiene Metolachlor Metribuzin Prometon Propachlor Simazine |
0.2 0.2 0.2 0.5 2.0 0.5 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.5 0.2 0.2 |
| Analyte | MDL µg/l |
|---|---|
| 1-Naphthol 3-Hydroxycarbofuran Aldicarb sulfone Aldicarb sulfoxide Aldicarb Carbaryl Carbofuran Methiocarb Methomyl Oxamyl Propoxur |
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 |
Appendix B and Appendix B.1
