Prepared in cooperation with the NEW YORK STATE DEPARTMENT OF ENVIRONMENTAL CONSERVATION Pesticides and their Metabolites in Wells of Suffolk County, New York, 1998 u -^^ 41 °[ NEW YORK IO Base from U.S. Census TIGER/line files (1990) Albers equal-area conic projection 1:100,000 scale Figure 1. Map of Suffolk County showing location of sites sampled. ABSTRACT or suspected residues. Laboratory residue, and some samples Five insecticide residues and analytical methods with extremely contained as many as 11 different 20 herbicide residues were low detection limits - from 0.001 pesticides or pesticide detected in water samples to 0.2 jog/L (micrograms per liter) metabolites. Only four water- collected from 50 shallow wells - were used to analyze the quality standards were exceeded screened in the surficial sand and samples for 60 pesticide residues. in the samples collected in this gravel aquifer in Suffolk County, Forty-four of the samples study. Dieldrin exceeded the New Long Island in areas with known contained at least one pesticide York State Class GA standard U.S. Department of the Interior WRIR 99-4095 U.S. Geological Survey June 1999 (0.004 jog/L) in samples from INTRODUCTION a statewide monitoring program eight wells. The Federal and New to assess pesticide occurrence in York State Maximum The permeable soils in ground water and surface water of Contaminant Level for simazine Suffolk County make the surficial Long Island and the State of New (4 jog/L) was exceeded in samples sand-and-gravel aquifer highly York. This report describes the from two wells, and the State susceptible to contamination from results of a joint study conducted Class GA standard for simazine activities on the land surface. This by the NYSDEC, USGS, and (0.5 Jig/L) was exceeded in highly permeable aquifer is a SCDH to sample wells in Suffolk samples from six wells. Federal source of water for domestic and County (including water supply water-quality standards have not public supply systems in the wells) with known or suspected been established for many of the County, and is hydraulically pesticide residues. The primary compounds detected in this study, connected to underlying aquifers purpose of this study was to including herbicide metabolites. that are also used for public supplement the SCDH pesticide- Maximum concentrations of supply. Because of the monitoring program. Because all four herbicide metabolites - vulnerability and importance of of these samples are from raw, metolachlor ESA (ethanesulfonic the surficial sand-and-gravel untreated water from the surficial acid), metolachlor OA (oxanilic aquifer, and in response to aquifer, the results reported here acid), and the alachlor metabolites documented contamination of the are not representative of chemical alachlor ESA and alachlor OA - surficial aquifer by aldicarb in the characteristics of drinking water. exceeded 20 Jig/L. The maximum early 1980's (Zaki and others, The pesticide residues concentration of one herbicide 1982; Baier and Robbins, 1982; monitored in this study include (tebuthiuron) exceeded 10 jag/L, Soren and Stelz, 1984; Eckhardt many not monitored by SCDH. and the maximum concentration and Stackelberg, 1995), the For example, the samples of three herbicides (simazine, Suffolk County Department of collected in this study were metolachlor, and atrazine) and one Health Services (SCDH) analyzed for the herbicide herbicide metabolite established a ground-water tebuthiuron, which is commonly (deisopropylatrazine) ranged from monitoring program for pesticides used in association with simazine, 1 to 10 jog/L. The herbicide and other chemicals of concern. and the metolachlor metabolites metolachlor, which is used on The SCDH program has metolachlor ethanesulfonic acid potato fields in Suffolk County, consistently demonstrated the (metolachlor ESA), metolachlor and its metabolites (metolachlor presence of older, persistent oxanilic acid (metolachlor OA), ESA and metolachlor OA) were residues from pesticides like and the simazine metabolite most frequently detected in aldicarb, which are no longer used deisopropylatrazine. Other samples from agricultural areas. on Long Island. More recent pesticides monitored in this study The herbicides simazine and monitoring by the SCDH has include many of the most tebuthiuron, which were used in shown that the herbicides commonly used pesticides in the utility rights-of-way, and the metolachlor and simazine are country. The laboratory methods simazine metabolite commonly detected in the shallow used to analyze the samples deisopropylatrazine were detected ground water of Suffolk County collected in this study have lower at concentrations greater than 0.05 (Baier and Trent, 1998). detection limits for many jog/L most frequently in samples Metolachlor has been used on pesticides than do the methods from residential and mixed land- potato crops, and simazine has used by SCDH. use areas. The results of this recently been used for weed Because this study was investigation are not necessarily control at utility substations. intended to complement the representative of conditions In 1997, the New York State SCDH program, however, many throughout the remainder of Long Department of Environmental pesticides that are commonly Island, because these samples Conservation (NYSDEC) in detected by the SCDH (including were collected in areas of known cooperation with the U.S. aldicarb and its degredates) were or suspected residues. Geological Survey (USGS) began not investigated in this study. Thus, the results of this study will not represent a complete description of all pesticide WHAT ARE METABOLITES? residues in ground water in Suffolk County. Metabolites are formed when a parent compound This report presents data degrades. Metabolites commonly are present at higher on the concentration and concentrations than the parent compound. Some metabolites frequency of detection of the 60 can form from the degradation of more than one compound. pesticide residues monitored in For example, deisopropylatrazine can form from the this study and discusses the degradation of either atrazine or simazine (Thurman and concentrations in relation to others., 1994). Other metabolites are specific to only one parent Federal and State water-quality compound. For example, metolachlor ESA and metolachlor standards. This report also relates OA are derived solely from the parent compound metolachlor. the detection of selected herbicide Sampling for herbicide metabolites in this study was residues to the predominant land motivated in part by findings in the midwestern United States use around the 50 wells sampled, that have shown that metolachlor ESA, metolachlor OA, and and discusses the concentrations deisopropylatrazine commonly are present in ground water in of these residues in relation to agricultural areas (Kolpin and others, 1997; Kolpin and one another. others, 1998). Concentrations of these metabolites often equaled or exceeded those of the parent compound. Few, if any, federal water-quality standards have been established for these metabolites. STUDY METHODS Samples were collected from 50 wells that tap the surficial sand-and-gravel (upper glacial) water-table aquifer in Suffolk County by personnel from the utility rights-of-way, or Environmental Protection SCDH and USGS between May metolachlor, aldicarb, or other Agency and includes some of the and August 1998 (fig. 1, table I). pesticides used in agricultural most commonly used pesticides Most (41) of these wells were fields. These residues were not in the nation. installed by the SCDH, and are caused by small-scale spillage of Each well sampled was part of their water-quality pesticides, but rather are the classified according to the land monitoring network. Well depths result of larger scale, nonpoint, use - agricultural, residential, or range from 9 to 202 feet below pesticide use. mixed within a quarter-mile land surface. The depth of the Samples were analyzed by radius of the well. Land-use data midpoint of the screened interval the USGS for 60 pesticides or are based on mapping-data ranges from 8 to 200 feet, and the pesticide metabolites using imagery generated from satellite depth of the median midpoint of methods described by Zaugg and data collected in 1994 (U. S. the screened interval was less others (1995), Meyer and others Geological Survey, 1997). than 60 feet. Depth to water (1993), and Ferrer and others Agricultural wells include those ranged from less than 10 feet to (1997) (table 2). The detection with more than 35 percent 130 feet, and the median depth to limits of the methods used to agricultural land use (row crop water was less than 50 feet. analyze the samples ranged from and pasture and hay), but less than The wells selected for 0.001 to 0.2 ng/L. The analytical 30 percent residential land within sampling are in areas known or method devised by Zaugg and a quarter-mile radius of the well. suspected to contain pesticide others was developed in Residential wells include those residues from simazine used on cooperation with the U.S. with more than 55 percent of the Table 1. Data on Wells sampled in Suffolk County, Long Island, New York, April- August 1998 [Depths are in feet below land surface. A dash (-) denotes missing data. Well Numbers for water supply wells are listed in bold] Sampling Number USGS Station date Depth to Depth of Land on fig. 1 Well Number no. (mo/d/yr) Community water screened interval use* 1 SI 12740.1 404319073055101 6/23/98 W. Sayville 10 10- 15 MI 2 S 71280.1 410106072293701 5/27/98 Cutchogue 20 42.0 - 44.5 AG 3 S 51566.1 405716072413301 6/10/98 Riverhead 55 76-86 AG 4 S51571.1 405805072403701 6/10/98 Riverhead 76 96 - 106 AG 5 SI 12499.1 404953073170501 6/18/98 Commack 95 130- 140 RE 6 SI 12248.1 404717073201301 5/28/98 Dix Hills 35 48-58 RE 7 SI 12422.1 405554072352201 7/1/98 Jamesport 6 15-20 MI 8 SI 12679.1 405626072442701 5/14/98 Baiting Hollow 76 100- 110 AG 9 SI 12870.1 404719073205701 6/3/98 Dix Hills 46 51-61 RE 10 SI 12328.1 404707073234201 5/19/98 Melville 55 68-78 RE 11 SI 12741.1 405516072183401 7/2/98 Mecox 10 16-26 AG 12 SI 12742.1 405730072364101 6/25/98 Aquebogue 35 39-49 AG 13 SI 12307.1 404900072451701 6/29/98 E.