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Nonpoint Contamination of Groundwater on Long Island, New York 9 INTRODUCTION GRANT E. KIMMEL U.S. Environmental Protection Agency Long Island, New York, lies south of the coast of Connecticut and east of that of New Jersey along the shores of the Atlantic Ocean (Figure 9.1~. It has a total area of about 1400 mi2 and is 120 mi long by up to 20 mi wide. It includes the counties of Kings and Queens in New York City, which have been population centers for centuries; Nassau County, which grew in population remarkably from the 1940s to about 1970; and Suffolk County, where population growth has been rapid since the 1960s. The island developed slowly for the first three cen- turies after European settlement in the seventeenth century. The principal use of the land east of New York City was ag- ricultural. Following World War II the rate of suburban de- velopment increased, and in this expansion a great deal of farm and estate land changed to housing, light industrial, and com- mercial development. Today about 8 million people live on Long Island; 3 million in Nassau and Suffolk Counties. Fresh groundwater stored in unconsolidated sand aquifers underlies virtually the entire island. Kings and part of Queens Counties are supplied with water by sources outside the island, but the remainder of the island relies on this groundwater reservoir. Although an abundant supply of groundwater made development possible anywhere on the island, the effect of discharges in and on the ground has affected the water quality. This chapter describes the regional contamination of the groundwater supply resulting from the use of the land by all forms of man's activity. Nonpoint contamination is nearly island wide because urbanization and agriculture have both contrib- uted to the problem. 120 GE OHYDRO LOGY Exploration of the island's water resources began early in this century by Veatch et al. (1906) and Fuller (1914), who described the basic geology and hydrology of the island, and from that time the sources and general movement of the water were known. Most recently the geohydrology of the island was de- scribed by McClymonds and Franke (1972~. The island consists of a series of beds of sand, silt, and clay dipping somewhat less than 1 toward the south and into the continental shelf. These deposits are underlain by crystalline bedrock of very low permeability. Over most of the island these unconsolidated deposits contain freshwater down to the bedrock. The top of this groundwater reservoir is overlain by glacially related de- posits that are mostly of high permeability. Overall the unconsolidated sediments can be separated into four aquifers and two confining beds (Figure 9.2~. The Lloyd aquifer overlies bedrock that is the bottom of the groundwater reservoir. The Lloyd ranges in thickness from about 100 ft in the north to about 400 ft along the southern edge of the island, where it is about 1800 ft below the surface. The Lloyd aquifer is overlain by a confining layer of about 300 ft of silty and solid clay and sand, called the Raritan clay. The Lloyd aquifer is not extensively used areally but is im- portant for some south-shore communities as it is their only source of freshwater and, being at the bottom of the system, is least altered by contaminants from above. Freshwater is found in the Lloyd throughout the main part of the island; however, freshwater encounters saltwater near the periphery of the island or offshore. The freshwater-saltwater interface

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Nonpoint Contamination of Groundwater 41--- ~ 73o ~ it_ 121 ~ Lot G ISLAND S ~ iS ~ ~~ 1 BROr IX /; ~ if ~~J 1 ~ ~~` ~ ~ ~ SUFFOLK COUNTY MAN HATTAN ISLAND ~ i~ NASSAU j | QUEENS ~ COUNTY I S // It's ~ ' COUNTY: hong :~_; ~ -e= ~5~ ~TLaNTIC oCEa FIGURE 9.1 Location and general geographic features of Long Island. probably follows the north shore of the island where the Lloyd often is in contact with younger, Pleistocene deposits on the updip, eroded edge. The interface on the southern side of the island is seaward of the shore but curves inland in the vicinity of the island7s north and south forks. The Magothy aquifer overlies the Raritan clay confining beds and currently is the most heavily pumped water-bearing unit on the island. It is up to 1000 ft thick along the south shore and about 500 ft thick along the north shore. As the aquifer thickens toward the south shore, the transmissivity in the southern part of the island is about twice that of the northern part. Details of the saltwater-freshwater interface in the Ma- gothy are known only in southeastern Queens and southwest- ern Nassau Counties, where it is landward of the ocean. In the remainder of the south shore it lies seaward of the barrier beaches (Lusczynski and Swarzenski, 19601. The extent of the part of the fresh groundwater reservoir seaward of the land is unknown and could be sizable. The Jameco aquifer, composed mainly of sand and gravel, overlies the Magothy locally on the west end of the island and along the north shore. It is unim- portant regionally but does contain a moving, saltwater wedge (Cohen and Kimmel, 1971~. The Gardiners clay and the 20-ft clay are important confining beds of up to 300 ft in thickness (McClymonds and Franke, 1972) separating the Magothy and lameco from the overlying upper glacial aquifer along the south part of the island. The upper glacial aquifer covers the surface of the island and consists largely of those deposits left by the latest episodes of glaciation. It consists of moraine and outwash deposits of sandy, gravelly character. Fresh groundwater on Long Island originates as precipitation _~ 5 0 5 10 15 20 1. ,.,1 1 1 1 1 MILES ,~ falling on the island, about half of which percolates through a fairly permeable surface to the water table. Under natural con- ditions, the reservoir of freshwater underlying the island moves from the water table downward and outward through the res- ervoir to discharge around the periphery of the island by streams, by subsurface flow into bays and saltwater bodies surrounding the island, and by evaporation. Streams are an important groundwater discharge about 40 percent of the recharge to groundwater discharges through streams (Cohen et al., 1968~. In nonurbanized areas where runoff is not channeled directly into the stream and the water table has not been artificially lowered, about 90 percent of stream flow is derived from groundwater. Consequently, the quality of shallow ground- water in a stream basin is reflected in the base flow of the stream. This feature has been used by some to evaluate the effect of mitigation measures on the water quality. Beginning in the 1930s stormwater recharge basins were used extensively in Nassau and Suffolk Counties as a measure to facilitate the recharge of water and to dispose of storm runoff. Street runoff is funneled into these basins, where it percolates down to the water table. The infiltration capacity of a basin can be as much as 2 million gallons per day (mad) (Aronson and Frill, 1977~. The effect of these basins on the quality of ground- water has not been studied in detail, but de-icing salts applied to highways and streets must yield some amount of soluble ions such as chloride in the recharge water. Although the dan- ger exists for contamination to enter the groundwater system, the basins have not been found to contribute significantly to pollution. However, they are a significant contribution to groundwater recharge (Seaburn and Aronson, 1974~. Public supply pumpage on Long Island averaged 394 mad

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122 FIGURE 9.2 Major hydrogeologic units and flow systems of groundwater reservoirs of Long Island. _ _ Clay in 1980. About 50 percent of this was from Nassau County, an area somewhat less than one quarter of the island. Most of the pumpage is from wells screened from 200 to 600 ft below the surface in the Magothy aquifer. Groundwater is the sole source for freshwater in Nassau and Suffolk Counties and was so designated by the U.S. Environ- mental Protection Agency (EPA) under Section 1424(e) of the Safe Drinking Water Act (Public Law 93-523) in June 1978. Sufficient groundwater is available to meet the needs of Nassau and Suffolk Counties for the forseeable future, but water quality will not remain the same for many parts of Long Island (Kop- pelman, 1978~. NATURAL WATER-QUALITY CONDITIONS The natural, uncontaminated quality of groundwater on Long Island can be determined from unsettled areas in the eastern part of the island and from deep parts of the system where the age of groundwater is such that contaminants could not have reached wells and the water does not reflect the activities of man. Pristine groundwater usually contains less than 50 mg/L of total dissolved solids (TDS), which change little as water moves through the system. It also has a low pH and, sometimes, a bothersome iron content (Franke and McClymonds, 1972, p. 351. Dissolved materials consist mostly of sodium, potassium, magnesium, chloride, sulfate, carbonate, and bicarbonate. Ni- trate-nitrogen concentration is less than 0.2 mg/L in uncon- taminated water (Perlmutter and Koch, 1972~. With the ex- GRANT E. KIMMEL al . Z,^ o z NORTH ~ I LONG ISLAND .5: SOUTH LONG ISLAND ~ ~~ ~ ~ ~ ATLANTIC _~.- I. . ~e~.~.~_ Upper glacial ~ and undifferRntiA,.~ I .~' . ' _ . . .. ,..._. _ :; - ,.,..-.1 ?~ .~ _ ~ . aquifer `- Do. : #,(/~ EXPLANATION . .-. .-.. ..... _ ,..... . .-. . : - Sand clay. clayey sand. and silt 1 ::1 1-:. :1 Gravel Sand ~9 Consolidated rock ception of iron, unusual concentrations of heavy metals or other substances are not known in pristine groundwater. SALTWATER ENCROACHMENT When overpumping lowers the hydraulic pressure near the saltwater-freshwater interface, saltwater is drawn landward. A well-known example of this occurred in Kings County (Brook- lyn) between about 1900 and 1947 when overpumping caused encroachment of salty water. The water table in Kings County was below sea level in 1936 virtually throughout the county and dropped to as much as 35 ft below sea level in the northern part of the county (Lusczynski, 1952~. Groundwater encroach- ment in previous freshwater environments resulted in chloride and TDS content sufficient to render them unpotable. As other sources of public water were available for Brooklyn, withdrawal for public supply ceased. Public supply pumpage in southern Queens County, which averages about 60 mad, continues to cause a sizable, below- sea-level depression in the water table. Although Soren (1971) reported some encroachment of freshwater by salty water in other parts of Queens County, seawater has not been a con- taminant for these wells. Contamination from above as opposed to saltwater encroachment from the side has been a major problem. In southeastern Queens and southwestern Nassau Counties, Lusczynski and Swarzenski (1960) defined three wedges of salty water in the Magothy and above-lying deposits; the deepest of these lies along the base of the Magothy aquifer and threatens

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Nonpoint Contamination of Groundwater southwest Nassau County supply wells that are screened near it. However, movement of the entire wedge was not mea- surable from 1960 to 1969 (Cohen and Kimmel, 19711. The effect of the withdrawal of even 200 mad in Nassau County produces a very slow movement of the saltwater wedge. This movement will continue as pumpage exceeds recharge. Further east from the middle of the south shore of Nassau County, the saltwater-freshwater wedge in the Magothy lies offshore. It returns to shore in central Suffolk County, off the Hampton Bay area. In the Lloyd aquifer, the interface is off- shore in the southwestern part of the island. In one location on the south shore of Nassau County, salty water has not been encountered after perhaps 40 yr of pumping with hydraulic pressures in the aquifer below sea level. These features suggest that a considerable quantity of fresh, virtually uncontaminable water lies beneath and off the south shore of the central part of the island and could still be considered for development should costs for treatment of contaminated water further into the island become excessive. The full extent of the freshwater south of the island is unknown. N ITRATE For the most part, surface material on Long Island readily allows the migration of water-soluble products into ground- water. Nitrate is soluble with respect to groundwater and con- servative (nonreactive) in regard to sorption. The widespread use of individual waste-disposal systems (e.g., cesspools and septic tanks) on Long Island is the source that is largely re- sponsible for the increase in nitrate content of groundwater. The use of these systems as urbanization spread eastward on the island contributed a major load of nitrate as well as TDS, sulfate, and chloride. Sewerage, which began in Brooklyn about 1850, moved eastward over the island, somewhat behind pop- ulation growth. Most of Nassau County was only recently sew- ered after about 30 years of urbanization. In the later part of the 1960s the nitrate content of streams draining urbanized portions of Nassau County contained 14 times more nitrate than urbanized portions of Suffolk County (Koch, 19701. The earliest source of widespread NO3 contamination may have been the use of manure fertilizer on farmland in the nineteenth and early twentieth centuries. Nitrogen fertilizers are still an important source of nitrate in groundwater in both urbanized and agriculture areas. Ragone et al. (1981) estimated the maximum nonpoint nitrogen load to groundwater in 1975 in Nassau County to be between 10,000 and 10,500 metric tons. A surprising amount of this, 5200 tons, is estimated to come from fertilizers, principally lawn fertilizers; other sources are individual waste-disposal systems, exfiltration from sewers, recharge basins, animal (pet) wastes, rainfall and runoff, land- fills, and sewage treatment plants. Although nitrate from individual waste-disposal systems was found to be a significant source of the total N load in Nassau County, according to Ragone et al. (1981, p. 49>, fertilizers are the major source in sewered areas. Landfills, a point source, contribute extensive areas of nitrate contamination if located 123 far enough into the island, and the reduced form of nitrogen, ammonia, is oxidized to nitrate. Nitrate concentrations greater than 10 mg/L (as N) are con- sidered dangerous to health (U.S. Environmental Protection Agency, 19761; consequently, this forms a basis for rejecting water for potable purposes. In recent years nitrate concentra- tions greater than this have been found in many parts of Long Island. The depth of nitrate penetration in the aquifer system in Nassau County was examined by Perlmutter and Koch (1972), Ku and Sulam (1976), and Ragone et al. (1981~. They found alterations of pristine-quality water extending to the base of the Magothy aquifer, some 500 to 600 ft below the surface in the center of the island. Laterally, in the upper glacial aquifer, concentrations of nitrate exceed 10 mg/L in widespread areas of Nassau County. Nitrate contamination follows the regional flow of groundwater in the system and, in the Magothy aquifer, extends about halfway between the central part of the island and the south shore. Concentrations greater than 6.5 mg/L were found in the upper glacial aquifer in many parts of Suffolk County from 1972 to 1975 (Sorer, 1977~. Ragone et al. (1976a) found significantly elevated nitrate concentrations in water from the deep part of Suffolk County, beginning in the late 1960s. In Kings County, nitrate occurs in concentrations of over 20 mg/L in widely scattered upper glacial wells. Of 67 analyses of water from the upper glacial aquifer from 1942 to 1971, the mean value of nitrogen was 13 mg/L (Kimmel, 1972~. It was concluded that nitrogen came from exfiltration of sewers. M ETALS Analyses of heavy-metal content in Long Island groundwater are not as extensive as those of nitrate. Harr's (1973) sampling of 39 wells in Nassau and Suffolk Counties and Soren's (1977) sampling of 193 wells in Suffolk County are the most extensive studies. Except in areas of point-source contamination, heavy metals have not been found in appreciable amounts. Contam- ination from metals is not a nonpoint problem. Concentrations of arsenic, barium, cadmium, chromium, lead, mercury, and silver were not found to exceed EPA standards but in some cases may be above that of background concentrations. Copper, which can be dissolved from household plumbing and flushed through septic and cesspool systems, is widespread in urban- ized areas but has not been found to exceed 0.5 mg/L in either of the two studies cited. ORGANIC S OLVE NTS In the mid-1970s additional problems developed as chemical analyses became sensitive enough to identify microgram amounts of organic substances thought to be harmful to human health. By 1979, 37 of 421 public supply wells in Nassau County con- tained more than 10 ~g/L of synthetic organic chemicals (SOC); 23 were closed by New York State Department of Health be- cause the organic chemicals exceeded 50 ~g/L, the guideline

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124 for closure of community supplies. By 1979, 500 wells had been tested in Suffolk County; of these, 13 were closed because of SOC (Kim and Stone, 1980~. Tetrachloroethylene, 1,1,2-trichloroethylene, chloroform, 1, 1,1-trichloroethane, and carbon tetrachloride were the most commonly found constituents in Long Island water (Kim and Stone, 1980~. In 1980, 13 public supply wells screened in the upper glacial and Magothy aquifers in southeastern Queens County con- tained SOC; 6 of the 13 were closed. Trichloroethylene and tetrachloroethylene were the main organic chemicals present. In 1977 a Nassau County Department of Health survey dis- closed that at least 292,000 gallons of SOC, principally solvents and cleaning fluids, were used there. Many of these chemicals are deposited directly into individual disposal systems and in- filtrate to groundwater. In 1977 about 58 mix of densely pop- ulated, unsewered area remained in Nassau County. In that year, the county estimated that 67,500 gallons of cesspool cleaner and the like were sold locally. Evaluation of the cleaner found that over 80 percent was composed of aromatic and halogenated organic solvents. Petroleum distillates make up the remainder of the cleaner. A survey of the distribution of SOC in the upper glacial aquifer (Koppelman, 1978) found the chemicals widespread. Although this aquifer is little used for public supply, it feeds the Magothy with contaminants as a result of the recharge relation between the upper glacial and Magothy aquifers. Anal- yses from the county's public supply wells indicate that the distribution of organic contaminants in the Magothy occurs in a wide area in the middle of the county and some locations in north-shore communities. Past use and disposal of SOC can be expected to cause similar problems in Suffolk County, where sewerage is less extensive. METHYLENE BLUE ACTIVE SUBSTANCES A number of studies have documented the presence of meth- ylene blue active substances (MBAS) in the groundwater on Long Island. These chemicals are synthetic detergents added largely through the discharge of individual waste-disposal sys- tems, but leaking sewers and sewage waste disposal in landfills are also contributors. Coin-operated laundries in unsewered areas are large contributors and initially drew attention to the problem. The occurrence of about 1 mg/L of MBAS can cause foaming in water, and for aesthetic reasons a maximum of 0.5 mg/L has been recommended. Initially, the synthetic detergents industry used alkyl ben- zene sulfonate (ABS). This compound was found to persist in the environment, which led to the use of biodegradable linear alkyl sulfonate (LAS) in 1965; however, under anerobic con- ditions, even this compound may persist. Consequently, in 1971 the Suffolk County legislature passed a ban on laundry detergents containing MBAS. In 1981 the ban on laundry de- tergents in Suffolk County was lifted. Because of the interconnection between streams and ground- water on Long Island, a shallow subsystem of groundwater flow GRANT E. KIMMEL develops around streams. This subsystem has flushing rates on the order of decades (Franke and Cohen, 1972), and several studies have been made to determine the cleansing action of streams on groundwater. Koch (1970) analyzed chemical data from the period 1966 through 1969 for streams draining polluted areas of Nassau County and compared them with data from relatively clean areas of Suffolk County. Average MBAS in Nassau County was 0.7 mg/L, while that from Suffolk County was less than 0.1 mg/L demonstrating how urbanization affected the shallow groundwater quality in Nassau County. Cohen et al. (1971>, using data from 1962 to 1969 for Suffolk County streams, found that MBAS content decreased in relation to chloride content and concluded that, in part, this relative decrease may be due to the change in formulation of detergents. From stream-qual- ity data taken between 1961 and 1976, Ragone et al. (1976b) found that MBAS content of streams in Suffolk County was decreasing as a result of the detergent ban, the change in formulation, or both. Further evidence that efforts to reduce MBAS content of groundwater in Suffolk County were effective was found by Soren (19777. After sampling 171 shallow wells from 1972 to 1975 he noted that concentrations were low (up to 0.15 mg/L) except in the highly urbanized, unsewered southwest part of the county, where the MBAS content was as high as 0.5 ma/ L. This area was sewered in the 1970s and should show im- provement in the coming decade. The Long Island comprehensive waste-treatment manage- ment plan also found regional decreases in Nassau and Suffolk Counties (Koppelman, 19789. The cleansing action of shallow groundwater by groundwater discharge to streams within the time frame of decades as predicted by Franke and Cohen (1972) apparently is operating, but the complication of a lower water table due to sewerage may prolong the process. Because the streams are largely groundwater fed, a decline in the water table shortens the stream and reduces its discharge. PE STICIDE S Until 1977 the occurrence of pesticides and herbicide com- pounds known to have been used on the soil was not found to be a major problem in the groundwater. Harr (1973) in the most extensive survey of pesticides at that time (1972) sampled 10 wells in Nassau and Suffolk Counties and found less than 0.5 ~g/L in four wells. In a survey of the shallow groundwater in Suffolk County from 1972 to 1975, Soren (1977, p. 24) found that 15 of 180 well samples contained one or more of 000, DDE, DDT, diazon, and dieldrin, mostly in amounts less than 0.1 ~g/L. The herbicides silvex and 2,4-D were found in even smaller quantities in nine samples. More recently, Katz and Mallard (1981, p. 179) found diel- drin and heptachlor epoxide and polychlorinated biphenols at concentrations of about 1 ~g/L or less at depths of up to 200 ft in central Nassau County. In 1975 the pesticide aldicarb was introduced in potato fields on the eastern part of the island for control of the potato beetle.

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Nonpoint Contamination of Groundwater 125 By 1979 the pesticide had reached public water supply wells in the streamflow of Suffolk County, Long Island, N.Y., U.S. Geol. in one north fork community. In 1980 it was identified in at Surv. Prof. Pap. 750-C, C210-C214. least 1200 farm and residential wells in the north and south Franke, O. L., and P. Cohen (1972~. Regional rates of ground-water r . . 1 . ~ ~1 1 movement on Long Island New York U.S. Geol. Surv. Prof. Pap. forks. Concentrations of ald~caro In one rarm well were as muon 800-C, C27 -c277. as 430 AWL. Franke, O. L., and N. E. McClymonds (1972). Summary of the hy- drologic situation on Long Island, N.Y., as a guide to water-man- agement alternatives, U.S. Geol. Surv. Prof. Pap. 627-F, F1-F59. Fuller, M. L. (1914). The geology of Long Island, New York, U.S. CONCLUSION In summary, the data show that the central part of Long Island has experienced contamination of one sort or another from the surface. Shallow water in this location is critical because it flows down and outward through the groundwater flow system; thus it recharges the deeper aquifers that are the principal water supply for the island. Nitrate and organic chemicals have pen- etrated deep within the system. Both agricultural practices and urbanization are responsible for this contamination. In an area where people live on the recharge areas of their water supply it may be impractical to avoid contamination of that supply. Even though the recharge and discharge relations of the groundwater were understood previous to the major development of Nassau and Suffolk Counties, systems of dis- posal, land use, and pumpage practices were employed that led to the degradation of the water. Though better planning could have reduced this problem, it takes time and research to demonstrate the effect of certain land-use practices. Mon- etary expenditures are necessary to research and mitigate the contamination, and time is needed to educate people that many of their practices are, indeed, harmful. So much of the reservoir is contaminated at this time, par- ticularly in the central part ofthe island, that treatment systems for some water supplies may become necessary. In fact, de- nitrification is utilized in one water supply. Still, large volumes of uncontaminated water occur in the southern part of the island, which overlies the major part of the groundwater res- ervoir. This area also is more densely populated. Because the transmissivity is twice as great on the south side than it is on the north side of the island the problem is less dramatic than it otherwise might be, and large supplies may be available from the offshore part of the reservoir. Transfer of water from areas of no contamination is possible should the cost of treatment exceed that of transportation. REFERENCES Aronson, D. A., and R. C. Prill (1977). Analysis of the recharge po- tential of storm-water basins on Long Island, New York, J. Res. U.S. Geol. Surv. 5, 307-318. Cohen, P., and G. E. Kimmel (1971). Status of salt-water encroachment in 1969 in southern Nassau and southeastern Queens Counties, Long Island, New York, U.S. Geol. Surv. Prof. Pap. 700-D, D281-D286. Cohen, P., O. L. Franke, and B. L. Foxworthy (1968). An Atlas of Long Island's Water Resources, New York State Water Resources Commission Bulletin 62, 117 pp. Cohen, P., D. E. Vaupel, and N. E. McClymonds (1971). Detergents ~ , v vat Geol. Surv. Prof. Pap. 82, 231 pp. Harr, C. A. (1973~. Chemical constituents in water from selected sources in Nassau and Suffolk Counties, Long Island, New York, U.S. Geol. Surv. Open-File Rep., 25 pp. Katz, B. C., and G. E. Mallard (1981). Chemical and biological mon- itoring of a sole source aquifer intended for artificial recharge, Nassau County, New York, in Chemistry in Water Reuse, Vol . 1, Ann Arbor Science, Cooper, NJ. Kim, N. K., and D. W. Stone (1980). Organic Chemicals and Drinking Water, New York State Department of Health, Albany. Kimmel, G. E. (1972). Nitrogen content of groundwater in Kings County, Long Island, N.Y., U.S. Geol. Surv. Prof. Pap. 800-D, D199-D203. Koch, E. (1970~. Effects of urbanization on the quality of selected streams in southern Nassau County, Long Island, N.Y., U.S. Geol. Surv. Prof . Pap . 700-C, C189-C192. Koppelman, L. E. (1978~. The Long Island Waste Treatment Man- agement Plan, Nassau-Suffolk Regional Planning Board, Hauppague, New York. Ku, H. F. H., and D. J. Sulam (1976). Distribution and trend of nitrate, chloride, and total solids in water in the Magothy aquifer in southeast Nassau County, New York, from the 1950's through 1973, U.S. Geol. Surv. Water Resour. Invest. 7644, 47 pp. Lusczynski, N. J. (1952). The recovery of ground-water levels in Brook- lyn, New York from 1947 to 1950, U.S. Geol. Surv. Circ. 167, 29 PPe Lusczynski, N. J., and W. V. Swarzenski (1960~. Position of the salt- water body in the Magothy (?) formation in the Cedarhurst-Wood- mere area of southwestern Nassau County, Long Island, NY, Econ. Geol. 55, 1739-1750. McClymonds, N. E., and O. L. Franke (1972). Water-transmitting properties of aquifers on Long Island, NY, U.S. Geol. Surv. Prof. Pap. 627-E, E1-E24. Perlmutter, N. M., and E. Koch (1972). Preliminary hydrogeologic appraisal of nitrate in groundwater and streams, southern Nassau County, Long Island, NY, U.S. Geol. Surv. Prof. Pap. 800-B, B225- B235. Ragone, S. E., B. G. Katz, J. B. Linder, and W. J. Flipse, Jr. (1976a). Chemical quality of groundwater in Nassau and Suffolk Counties, Long Island, New York 1952 through 1976, U.S. Geol. Surv. Open- File Rep. 76-845, 93 pp. Ragone, S. E., A. A. Guerrera, and W. J. Flipse, Jr. (1976b). Change in methylene blue active substances and chloride levels in streams in Suffolk County, New York, 1961-1976, U.S. Geol. Surv. Open- File Rep. 76-600, 65 pp. Ragone, S. E., B. G. Katz, G. E. Kimmel, and J. B. Linder (1981). Nitrogen in groundwater and surface water from sewered and un- sewered areas, Nassau County, Long Island, New York, U.S. Geol. Surv. Water Resour. Invest. 80-21, 64 pp. Seaburn, G. E., and D. A. Aronson (1974~. Influence of recharge basins on the hydrology of Nassau and Suffolk Counties, Long Island, New York, U.S. Geol. Surv. Water Supply Pap. 2031, 66 pp. Soren, J. (1971). Groundwater and geohydrologic conditions in Queens County, Long Island, NY, U.S. Geol. Surv. Water Supply Pap. 2001- A, A1-A39.

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126 Soren, J. (1977). Groundwater Quality near the Water Table in Suffolk County, Long Island, New York, Suffolk County Department of Environmental Control, Long Island Water Resources Bulletin LIWR- 8, 33 pp. U.S. Environmental Protection Agency (1976). National Interim Pri- GRANT E. KIMMEL mark Drinking Water Regulations, EPA-570/9-76-003, Washington, D. C., 159 pp. Veatch, A. C., C. S. Slichter, I. Bowman, W. O. Crosby, and R. E. Horton (1906). Underground water resources of Long Island, New York, U.S. Geol. Sure. Prof. Pap. 44, 394 pp.