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1997 PRL Annual Report Water Quality Monitoring for Pesticides

IV. Water Quality Monitoring for Pesticides (ECL §33-0714)

A. Introduction and Purpose

Pursuant to the Pesticide Reporting Law (ECL §33-0714), (See Appendix A, p. A-2), the Department has developed a Water Quality Monitoring for Pesticides Program that obtains information that can be used to more effectively manage the pesticide program. Early results suggest that this program has already been helpful towards achieving this goal.

The following are key results of this program's first year's findings:

  • The United States Geological Survey monitored and analyzed surface waters outside of Long Island for a number of pesticides. In general, the USGS results showed that the levels of pesticides in surface waters are consistently lower (in parts per trillion) than drinking water standards. The monitoring also identified areas where further study or continued study is warranted.
  • It is not surprising that pesticides are detected in extremely small concentrations in surface waters. It is the Department's mission to assure these levels do not significantly impact human health or the environment. The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) requires the EPA Administrator to balance the need for a pesticide with its impacts to assure it will perform its intended function without unreasonable adverse effects on the environment.
  • Monitoring on Long Island confirmed previously known groundwater contamination. The monitoring data included in this report identified levels of some pesticides in individual drinking water wells above drinking water standards. The affected individuals were informed by the applicable county of alternatives for obtaining acceptable drinking water. However, many of these homeowners already have carbon filters on their wells which effectively strip the contaminants from their drinking water.
  • To date, the program has detected two previously unknown contaminant plumes of non-registered pesticides in shallow groundwater on Long Island. The Department has initiated follow-up investigations to assess the extent of these plumes.
  • Detection of pesticides above drinking water standards in past monitoring programs has led the Department to require changes in labeling of products such as Simazine and Dacthal to prohibit certain usage rates and exclude geographical locations that were considered inappropriate. In addition, the detection of certain pesticides and their metabolites (break-down products of chemical decomposition) in this monitoring program has caused the Department to include restrictions regarding their use.
  • The data showing the sensitivity of certain areas of New York confirm the necessity of state-specific pesticide registration decisions to protect the water resources of New York State.

B. Program Components

In developing the Water Quality Monitoring for Pesticides Program, the Department initially established an informal Steering Committee made up of State, local and Federal agency staff who are involved with pesticide use and water quality. (The members of the Steering Committee are listed in Appendix E.) This committee provided Department staff with a broad understanding of the monitoring needs and issues associated with pesticide use in New York State and was a tremendous asset during startup of this new program. The Department is grateful for the participation and input provided by all of the Steering Committee members.

Due to the vast amount of work required to monitor the entire state's waters for pesticide impacts, the Department has sought to find partners to share the burden by identifying other State and Federal agencies that have similar monitoring interests. This partnership approach was called for in the Pesticide Reporting Law in the requirement that the Department work ". . .in coordination with the United States Geological Survey National Water Quality Assessment Program, the New York State Water Resources Institute and other parties. . ." This coordinated approach has allowed the Department to achieve significant progress where a partner has had an existing monitoring program for pesticides. In some cases, because of this shared need for monitoring information, the Department was able to enter into agreements where the partners would provide matching funds to help complete the work.

Currently, the Water Quality Monitoring for Pesticides Program has three distinct components with each component managed by one of the monitoring partners: the United States Geological Survey; the Suffolk County Department of Health Services; and the New York State Water Resources Institute.

As the program grows and matures, additional partners may be added.

A description of the three components of the program follows:

  • United States Geological Survey (USGS)

    Working under an existing Cooperative Agreement between the Department and the USGS, State and Federal funds have been used to expand and extend the Hudson River Basin study of the USGS National Water Quality Assessment (NAWQA) program into other areas of the state. Information currently being gathered will be used by the Department to identify high-priority areas and specific sites within these areas for long- term monitoring of trends in pesticide migration and impacts throughout the state. In this program, surface water samples are collected around the state at two types of sites, "synoptic" and "fixed." Synoptic sites are located over a wide geographic area and are sampled once each year during baseflow conditions. Fixed sites are sampled as many as ten times throughout the year. Using extremely sensitive analytical methods, the information developed by this program will be used to assess trends in pesticide contamination throughout the State and to provide an early warning system for unexpected pesticide levels.

    Monitoring in the USGS program has been accomplished by using three different, highly precise analytical methods with levels of detection down to parts per trillion. The pesticide products and metabolites (break-down product of chemical decomposition) being sought in each analytical method and the detection levels that can be achieved are included as Appendix F. This high level of precision is needed to obtain useful data for most pesticides, which typically are found at extremely low levels. Without these precise methods, low-level residues would go undetected and accurate trend analysis, a key factor in evaluating past registration decisions, would be impossible.

    In addition, a lack of precise methods would mask the presence of some pesticides that may only occur at extremely low levels in the environment. This masking would frustrate the efforts of those seeking to correlate the study's data with observable health impacts. Higher levels of detection than those used by USGS would also make it impossible to firmly demonstrate a lack of migration for the many commonly used pesticides that are generally not moving into the waters of New York State. This information is crucial to support registration decisions for the many registered products that are not impacting New York waters.
  • Suffolk County Department of Health Services (SCDOHS)

    Under a two-year joint funding agreement with the Department, SCDOHS has been conducting an intensive study of public and private water supply wells and selected monitoring wells to identify any unknown pesticide contamination plumes in Nassau and Suffolk counties.

    SCDOHS is sampling approximately 2,000 public and private water supply and monitoring wells through March 31, 1999. All samples will be analyzed for an expanded list of pesticide compounds and metabolites, including many that have not been analyzed previously on Long Island. In addition, the levels of detection will be, in many cases, lower than the levels previously sought by SCDOHS. A list of the compounds and the minimum detection levels being achieved by SCDOHS are included as Appendix G.
  • New York State Water Resources Institute (WRI)

    Working under an existing contract between the Department and Cornell University, the WRI is using data obtained in previous years and new data collected by the USGS in the Canajoharie Watershed, to evaluate the efficacy of modeling as a tool in predicting pesticide migration within a watershed. WRI will use the model to make predictions that can be checked against data being gathered by the USGS in the watershed.

    If the modeling effort proves successful, the work being done by WRI will have a number of benefits. It will provide the Department with an important new tool to assist in making registration decisions and reviewing suspensions and cancellations of pesticide registrations. For those in agriculture, the model may help them to assess the benefits of implementing different farm management practices to reduce pesticide impacts before they occur. For health researchers, this model may be valuable for evaluating pesticide impacts on public health and the environment. In many ways, this program may provide a link between data collection and the ability to predict potential impacts of pesticide use.

    The result of this pesticide monitoring program will also be coordinated with the Department's Division of Water (DOW) as part of New York State's responsibility to assess and report to the EPA on the quality of the state's waters under Section 305(b) of the Clean Water Act. New York State is required to summarize the quality of the state's waters (both surface and ground) according to established EPA guidance and submit reports every two years.

In addition, individual basins are to be assessed by DOW on a rotating basis across the state every five years.

C. Focus of Current Monitoring and Analytical Results

United States Geological Survey (USGS), ($32,000 SFY 1996-97, $271,000
SFY 1997-98)

The work being performed by the USGS in State Fiscal Years 1996-1998 included analysis of a wide variety of pesticides and their metabolites at six fixed sites and 50 synoptic sites. Appendix H shows the location of these sites. These sites were targeted to evaluate ambient surface water quality, not public or private drinking water supply intakes. Appendix H provides a description of each site and the analytical method being used at each site. Each of the fixed sites has typically been sampled ten times during the period, providing information on seasonal changes at these sites. In the synoptic study, water samples were collected once per site from a statewide network of 64 sites from early June to early July 1997, after most agricultural pesticides had been applied, in order to obtain information on the spatial distribution of pesticide residues under base-flow conditions.

Many of the sites in this year's sampling were located in the highly agricultural areas of western New York State, an area with significant pesticide use and very little existing pesticide monitoring data for groundwater and surface water.

A supplemental work plan, executed near the end of the State Fiscal Year 1997-98, extended the USGS work to include the analysis of samples in areas of concern that have been identified by SCDOHS.

The results from the synoptic study (64 sites sampled one time in the spring of 1997) are summarized below and are the subject of a USGS fact sheet that will be published shortly. (A preliminary copy of this fact sheet is included as Appendix I.)

The results of the synoptic sampling generally show low concentrations of 25 different pesticides that rarely exceeded 0.1 micrograms per liter (ug/l). No pesticides exceeded Federal or State maximum contaminant levels (MCLs) for public water supplies; aquatic surface water standards were only rarely exceeded. Twenty-three pesticides that were analyzed in the study were not detected in any sample.

The most frequently detected pesticides in upstate New York were the corn herbicides Atrazine, Metolachlor and the Atrazine degradation compound, Deethylatrazine. These pesticides were detected at low concentrations in 80 percent or more of the streams sampled. Other common corn herbicides, Alachlor and Cyanazine, were detected in roughly 40 and 50 percent of the streams sampled, respectively. Simazine, a herbicide commonly used in orchards and vineyards, was detected in 72 percent of the streams sampled.

The detection of pesticides was clearly related to the relative amount of land used for the various agricultural purposes in each watershed. Rivers and streams with the highest concentrations of Simazine drain watersheds with large areas dedicated to orchards and vineyards. The highest concentrations of corn herbicides occurred in streams that drain areas with the highest corn production.

For a complete description of this study and a more complete reporting of the levels of pesticides detected, see Appendix I, which is a preliminary copy of the USGS fact sheet, "Pesticide Concentrations in Surface Waters of New York State in Relation to Land Use." This fact sheet can be obtained on the World Wide Web at
and data from the synoptic sites can be found at
on the World Wide Web.

Due to the longer term monitoring at the fixed sites, compilation of the results is not yet complete. A fact sheet summarizing this work will be completed this summer. Both fact sheets will be made available over the USGS and DEC web sites and will be distributed by the Department. Also, the results of the USGS work on Long Island will be made available as soon as the data is compiled and reviewed for accuracy.

Suffolk County Department of Health Services (SCDOHS) ($100,000 SFY 1997-98)

SCDOHS has analyzed samples throughout Nassau and Suffolk counties during 1997 and 1998, focused primarily on the five eastern townships of Suffolk County where the majority of Long Island's agricultural land is concentrated. Some of the tested wells, primarily those containing Aldicarb and Tetrachloroterephthalic acid (TCPA), were known to be contaminated from previous monitoring programs. Therefore, the sampling was not random and the results cannot be viewed as typical of groundwater in the counties or portions thereof. Between October 1, 1997 and March 31, 1998, 898 monitoring, private and public wells were sampled and 36 different compounds were detected, primarily pesticides or their metabolites.

The most frequently detected compounds (many at levels below drinking water standards) include:

Most Frequently Detected Compounds
Compound Percent of wells
Aldicarb (sulfoxide/sulfone)
1,2-dichloropropane (DCP)
Ethylene dibromide (EDB)

Of these, Simazine and Metolachlor are the only pesticides still registered for use on Long Island. The Department is currently working with SCDOHS and the agricultural community to reduce these impacts.

Six pesticide related compounds have exceeded State drinking water maximum contaminant levels (MCLs) including:

Compound MCL Max. Concentration Found
1,2-dichloropropane (DCP)
1,2-dibromoethane (EDB)
Tetrachlorterephthalic acid (TCPA)
2 ug/l
7 ug/l
0.05 ug/l
4 ug/l
50 ug/l
6.66 ug/l
41.0 ug/l
11.0 ug/l
77.8 ug/l
12.3 ug/l
7.66 ug/l

Two pesticides were detected above DEC Water Quality Standards for Class GA fresh groundwater.

Compound Class GA Std. Max. Concentration Found
0.004 ug/l
0.35 ug/l
0.78 ug/l
1.7 ug/l

Of these, only Alachlor, Methomyl and Simazine are currently registered for use as pesticides on Long Island.

Two other compounds, sometimes related to pesticide use, were also found in excess of MCLs: bis-2-ethylhexylphthalate and 1,2,3-trichloropropane.

Most of the 90 wells that exceeded a pesticide-related State drinking water MCL were concentrated in the highly agricultural areas of the eastern townships of Suffolk County. Many of these were already known to be contaminated from earlier monitoring efforts and were resampled in this study. The five easternmost townships of Suffolk County accounted for 46 percent of the wells tested and 94 percent of the wells that exceeded a pesticide-related standard. In the more urban areas, only about 1 percent of the wells (1 of the 152 wells sampled in Nassau County and four of the 329 wells in the more suburban western towns of Suffolk County) had an exceedance of an MCL.

Of the 90 wells with MCL violations, 62 were private wells, 22 were monitor wells and 6 were community or non-community (schools etc.) public water supplies. (All of the public water supply wells now use carbon filtration or have already been closed.) Many of the private wells were known to be contaminated from previous investigations and are being treated.

Of the 90 wells, 86 of these were related to agricultural sources (including nursery and sod uses), two wells were contaminated by industrial pesticide applications, one was near a golf course and one was from an unknown source. Homeowner use or application of pesticides was not implicated in any of the wells that exceeded drinking water standards.

This information is more fully described in the June 1998 interim progress report from Suffolk County included as Appendix J of this Annual Report.

Water Resources Institute ($50,000 SFY 1997-98)

The WRI work on the Canajoharie Watershed project this year included development and implementation of a pesticide use survey and data compilation for development of the model. No data outputs are currently available; however, the Department expects to receive the survey results later this year from the WRI. As soon as this information is available, preliminary model runs will begin. This information will be used to predict levels of pesticides that should be expected at various sites within the watershed. Ultimately, these predictions will be compared with data obtained in previous years and new data that is being collected by the USGS in the Canajoharie Watershed. This modeling effort is expected to be completed in December 1998.

D. Areas for Future Study

By design, this statewide monitoring program has had to prioritize areas of study. Much important information has already been gained, but there still is much work to be done.

In State Fiscal Year 1998-99, the USGS and SCDOHS will continue existing programs to obtain follow-up data in areas of concern. The USGS program will also be expanded to include monitoring of Cayuga Lake and a number of public water supply reservoirs in the western part of the state where independent studies by the USGS and the State Health Department have suggested further monitoring is needed.

Discussions also have been held within the Department and with other agencies to develop similar monitoring programs in the New York City Watershed and the Susquehanna River Basin as part of ongoing investigations aimed at source water protection for public water supplies.

Finally, in order to identify other areas where monitoring is needed, the Department intends to reconvene the Water Quality Monitoring for Pesticides Program Steering Committee this fall to review the data and to seek input on other priority areas for investigation of pesticide impacts to the ground and surface waters of New York State.

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