EASON, STREAMFLOW, AND LAND USE 

IN SEVEN NEW JERSEY STREAMS 

National Water-Ouality 

Assessment Program 

Long Island - New Jersey 

Study Unit 

Abstract 

Jersey streams was documented by analyzing 146 samples 

collected from the streams from April 1996 through June 1998. 

The samples were analyzed for 85 pesticides, including 50 

herbicides, 28 insecticides, and 7 degradation products, at 

method detection limits that ranged from 0.001 to 0.018 Ilg/L 

(micrograms per liter). Pesticides were frequently detected ; 

however, concentrations were generally low. The pesticides most

frequently detected were atrazine, in 97 percent of the samples; 

prometon, 96 percent; metolachlor, 95 percent; desethyl-atrazine,

91 percent; simazine, 88 percent; diazinon, 58 percent; alachlor, 

56 percent; and carbaryl, 54 percent. Detection frequencies were 

highest during the growing season (April-September). At least 

one pesticide was detected in all but one of these samples, and 

49 percent of the samples contained 9 or more pesticides. The 

numbers of pesticides detected at a given site ranged from 13 

to 29. 

Ten pesticides were detected at concentrations that 

exceeded established water-quality criteria. Thirty-one of these 

detections were in samples collected during the growing season

and one during the nongrowing season. The pesticides that 

exceeded the U.S. Environmental Protection Agency (USEPA) 

maximum contaminant level for drinking water were atrazine, 

which exceeded 3 IlglL in four samples, and alachlor, 21lg/L 

in two samples. Cyanazine exceeded the USEPA lifetime 

health advisory level (HAL) of 1 Ilg/L in two samples. These 

eight detections occurred during runoff shortly after spring 

pesticide applications and represent a potential threat to municipal water supplies in the Raritan River basin. Concentrations of

chlorpyrifos, chlorthalonil, diazinon, ethyl-parathion, and 

methyl-azinphos exceeded the chronic life criteria for the 

protection of aquatic life (AQCR) in 20 samples at four 

sites during the growing season. Dieldrin was detected 

in four samples and DDE in two samples at concentrations that exceeded New Jersey Department of Environmental Protection (NJDEP) human health criteria. 

Individual and total-pesticide concentrations and 

total numbers of pesticides detected in the samples varied 

with season and flow conditions. Median and maximum 

concentrations of most of the pesticides were highest during 

runoff in the growing season. Pesticide concentrations were 

typically lower and less variable in the nongrowing season 

than in the growing season, regardless of changes in 

of most pesticides were slightly lower during runoff than during 

base flow. The median total-pesticide concentration and median 

total number of pesticides detected were highest and most 

variable in runoff samples in the growing season. In the nongrowing season, the median total-pesticide concentration was 

lowest in runoff samples and least variable during base-flow 

conditions. Median total numbers of pesticides were lowest and 

least variable in the nongrowing season during base-flow 

conditions at most sites. 

The highest total-pesticide concentrations were detected in 

samples from the two small agricultural basins (greater than 25 

percent of land use is agricultural) during runoff in late spring 

and early summer. In general, insecticides were detected more 

frequently and in greater concentrations at urban sites. Concentrations of agricu ltural herbicides generally decreased with 

increasing tlow at the four sites with less than 10 percent agricultureland use and increased with increasing flow at the three 

o 

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EXPLANATION 

Large basin with mixed land use 

Small basin with a single, predominant land use 

Stream 

Long Island-New Jersey studyunit boundary 

Surface-water sampling site, number, and location: 

A 01382000 Passaic River at Two Bridges, N.J. 

01390500 Saddle River at Ridgewood, N.J. 

01395000 Neshanic River at Reaville, N.J. 

01401000 Stony Brook at Princeton, N.J. 

01403300 Raritan River at Queens Bridge at 

Bound Brook, N.J. 

01403900 Bound Brook at Middlesex, N.J. 

01410784 Great Egg Harbor River near 

Sicklerville, N.J. 

20 KILOMETERS 

The presence and variability of pesticides in seven New 

u.s. Department of the Interior 

U.S. Geological Survey 

hydrologic conditions; however, median concentrations 

Figure 1. Locations of seven stream sites sampled for pesticides from 

April 1996 through June 1998. 

WRIR 99-4154 

November 1999 
sites with more than 25 percent agricultural land use. Most of the 

pesticides that correlated positively with streamflow were 

detected at sites where land use in the basin would indicate the 

use of those particular pesticides. Most of the pesticides that 

correlated negatively with streamflow were present at the site in 

the Coastal Plain or at sites in which the land use in the basin 

would not indicate heavy use of those particular pesticides. 

Introduction 

The U.S. Geological Survey (USGS) National Water 

Quality Assessment (N A WQA) program is designed to assess 

the status of the Nation's water quality, describe trends in water 

quality, and provide a sound scientific understanding of the 

primary natural and human factors that affect the quality of the 

Nation's water resources (Gilliom and others, 1995). One 

component of the NAWQA program is the study of pesticides to 

determine their presence, concentrations, and seasonal variability 

in surface and ground water. 

The Long Island-New Jersey coastal drainages study unit 

(LIN]), one of 59 areas studied as part of the NAWQA program, 

includes all of Long Island, New York, and New Jersey, except 

for those areas that drain to the Delaware and Hudson River 

basins (fig. 1). The 6,000-square-mile study area has a population of more than 10 million people (U .S. Bureau of the Census, 

1991) and includes one of the most densely populated areas in 

the United States. In 1990,44 percent of the land in the study 

area was used for residential, commercial, and industrial 

purposes; 30 percent was forested; 12 percent was used for 

agriculture; 8 percent was wetlands; and 6 percent was classified 

as miscellaneous. (Percentages were modified from Fegas and 

others, 1983, by using the method described by Hitt, 1994.) 

The purpose of the study described here was to determine 

the presence and distribution of dissolved pesticides in seven 

streams in the LINJ NAWQA study area and to evaluate the 

variability in concentrations of the pesticides by season, 

streamflow, and land use. Total numbers and total concentrations 

of pesticides were included in this study to evaluate the presence 

and distribution of multiple pesticides. The synergistic effects of 

multiple pesticides on human and aquatic health is an area of 

active research. The U.S. Environmental Protection Agency 

(USEPA) is considering establishing health standards for 

combinations of triazine pesticides (U.S. Environmental Protection Agency, 1994). 

Purpose and Scope 

This report documents the presence and distribution of 

dissolved pesticides in seven streams in the LINJ NAWQA study 

area and evaluates the variability in concentrations by season, 

streamflow, and land use. The results of analyses of 146 streamwater samples collected at the seven sites during April 1996 

through June 1998 are presented. Samples from four stream sites 

were collected only in the growing season (April through 

September). Samples at the other three sites were collected 

during both the growing and nongrowing seasons (October 

through March). Concentrations were determined for 85 pesticides. Total number of pesticides and total concentrations of 

pesticides were evaluated to determine the presence of multiple 

pesticides. 

Pesticide Use 

Pesticides are chemical substances and biological agents 

used to control pests. The pesticides analyzed in this study 

include classes of synthetic organic insecticides, herbicides, and 

fungicides widely used in the United States. Approximately 1.1 

billion pounds of pesticides are used annually in the United 

States (Ware, 1994). Pesticides are used primarily for agriculture, lawn care, golf course maintenance, termite control, and 

right-of-way maintenance. In 1991 , 76 percent of the pesticides 

sold in the United States were used for agricultural purposes. 

Industry and government use represented 18 percent and home 

and garden use represented 6 percent of total sales (Ware, 1994). 

The use of herbicides has quadrupled during 1966-91 (Larson 

and others, 1997). 

In New Jersey, licensed applicators applied approximately 

2.4 million pounds of pesticides per year during 1992-95 (Curtis 

Brown, New Jersey Department of Environmental Protection, 

Pesticide Control Program, written commun., 1992-95). Agricultural use accounted for about 66 percent of the total use in New 

Jersey. The herbicides atrazine and alachlor were the most 

heavily applied pesticides in the United States during 1990-91 

(Ware, 1994), but ranked sixth and seventh, respectively, in their 

use in New Jersey. The fungicide chlorthalonil was the most 

heavily applied pesticide in New Jersey, of those analyzed in this 

study, but ranked 13th nationwide. 

Sixteen of the 25 most heavily applied pesticides used for 

agriculture and 7 of the top 10 pesticides used for nonagricultural uses in the United States were analyzed for in this study. 

Some of the most heavily applied pesticides in New Jersey that 

were not analyzed for in this study include metam sodium, a 

fumigant; sodium aluminofluoride, an insecticide; glyphosate, a 

herbicide; and mancozeb, a fungicide. 

The herbicides most commonly used in New Jersey, and 

which were analyzed for in this study, are metolachlor, atrazine, 

and alachlor used for agriculture; pendimethalin, benfluralin, and 

trifluralin used for professional lawn care; DCPA, 

pendimethalin, and benfluralin used for golf courses; and diUl·on, 

2,4-D, and simazine used for weed control along transportation 

and utility rights-of-way. The most commonly used insecticides 

analyzed for in this study are methyl-azinphos, carbaryl, and 

chlorpyrifos used for agriculture; chlorpyrifos, carbaryl, and 

onofos used for professional lawn care; chlorpyrifos, carbaryl, 

and ethoprop used on golf courses; chlorpyrifos and permethrin 

used for termite control; and malathion and permethrin used for 

mosquito control. Chlorthalonil, the fungicide most heavily used 

in lawn care and on golf courses and the most heavily used in 

agriculture, second to sulfur, was the only fungicide analyzed for 

in this study. Eight pesticides-acetochlor, alachlor, carbofuran, 

linuron, methyl-azinphos, metribuzin, pebulate, and terbacilare used only in agriculture (Curtis Brown written commun., 

1992-95). 

Pesticide use has significantly increased agricultural 

productivity, benefiting both farmers and consumers. At the 

ame time, potential adverse effects of pesticides on nontarget 

rganisms and the environment, in general, have become a 

oncern. Organochlorine insecticides such as DDT and dieldrin 

ere banned from use in the United States in 1973 and 1984, 

espectively, because of bioaccumulation in the foodchain and 

elated adverse health effects on nontarget organisms (Harte and 

f

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others, 1991). Some organochlorine insecticides were replaced 

by less persistent and more water-soluble organophosphate and 

carbamate pesticides. The higher solubility of the insecticides 

and herbicides currently used reduces the risk of accumulation in 

sediments and the food chain, but increases the risk of widespread low levels of dissolved pesticides entering surface- and 

ground-water systems. 

Previous Investigations 

Two previous investigations of pesticides in surface water 

in the study area focused on relatively small areas. A study of 

pesticides from agricultural runoff in six New Jersey drainage 

basins detected low-level concentrations of 10 of the 21 pesticides targeted for analysis (lvahnenko and Buxton, 1994). Six 

drainage basins used for public-water supply and considered the 

most susceptible to pesticide contamination were chosen for 

study, including Lower Mine Hill Reservoir, South Branch of the 

Raritan River, the main branch of the Raritan River, Millstone 

River, Manasquan River, and Matchaponix Brook. All but Lower 

Mine Hill Reservoir basin lie within the LINJ study unit. 

Although atrazine and metolachlor were detected in 86 percent 

of the samples, alachlor in 55 percent, and diazinon in 45 

percent, only one concentration, in the 28 samples collected, 

exceeded the U.S. Environmental Protection Agency (USEPA) 

recommended Lifetime Health Advisory Limit. Atrazine and 

metolachlor were detected in the highest concentrations during 

storms. 

The second study assessed the vulnerability of public 

water supplies to contamination by 20 pesticides in the Millstone 

and Shark River basins (Buxton and Dunne, 1993). In the 

Millstone River, the 4 pesticides detected in 8 base-flow and 24 

stormflow samples were atraz ine, in 66 percent of samples; 

simazine, in 47 percent; metolachlor, in 38 percent; and alachlor, 

in 16 percent. No pesticides were detected in 8 base-flow and 13 

stormflow samples from Shark River. The method detection 

limit (MOL) for most pesticides analyzed for in these studies 

was 0.03 Ilg/L (micrograms per liter). The MOL's in the present 

study ranged from 0.001 to 0.03 Ilg/L. 

A study of pesticide data from 463 surface-water sites in 

the Mid-Atlantic region (Ferrari and others, 1997) detected at 

Table 1. Drainage Basin Characteristics and Sampling Frequency 

[1986 Land-use data from New Jersey Department of Environmental Protection, 1996; USGS, U.S. Geological Survey; mi 2, square miles] 

Number of 

Land use (in percent) 

samples coll ected Drainage 

USGS site USGS site name area Urban 

number Schedule Schedule (mi2) Forest Agriculture Other Non- 200 1 2050 Residential residential 

Passaic River at Two Bridges, N.J. 01382000 361 8 3 32 15 35 3 15 

Saddle River at Ridgewood, N.J. 01390500 21.6 9 5 75 II II 2 I 

Neshanic River at Reaville, N.J. 01398000 25.7 7 5 15 4 27 53 I 

Stony Brook at Princeton, N.J. 01401000 44.5 8 5 18 5 46 28 3 

Raritan River at Queens Bridge at 01403300 804 28 25 19 6 35 30 10 Bound Brook, N.J. 

Bound Brook at Middlesex, N.J. 01403900 48.4 44 41 50 23 25 1 1 

Great Egg Harbor River near 

Sicklerville, N.J. 01410784 15.1 46 39 24 8 43 10 15 

least one compound at more than 90 percent of the sites and 

frequently detected 16 pesticides, 3 at concentrations greater 

than the USEPA's maximum contaminant level (MCL). 

The LINJ NAWQA project has recently completed two 

studies of pesticides in surface water and ground water of New 

Jersey and Long Island, New York. Water-quality data from a 

50-site surface-water synoptic network sampled in June 1997 

were used to compare pesticide concentrations to land use and 

pesticide application (Reiser and O'Brien, 1998). Median 

pesticide concentrations and detection frequencies of some 

pesticides were related to land use. The 10 most frequently 

detected pesticides in the synoptic study were also the most 

frequently detected in this study. Analysis of samples from a 

network of 72 monitoring wells in southern New Jersey indicated that the 5 most frequently detected pesticides in ground 

water (Stackelberg and others, 1997) were also the 5 most 

frequently detected in the 50 stream-water samples. 

Study Approach 

Selection of Sampling Sites and Sampling 

Frequency 

Seven stream sites were chosen to represe~t the variety of 

land uses, physiographic settings, and other drainage-basin 

characteristics in the study area (fig. 1; table 1). Five of the sites, 

all in New Jersey, were chosen to represent water-quality 

conditions in small basins (less than 50 mi2) associated with 

specific types of land use and physiography. Four of these five 

sites are in the Piedmont physiographic province; the Great Egg 

Harbor River site is in the Coastal Plain physiographic province. 

The Saddle River at Ridgewood site represents a drainage basin 

that consists predominantly of suburban residential land. The 

Bound Brook at Middlesex site represents a largely urban 

drainage basin with older residential, commercial, and industrial 

areas. Agriculture is the dominant land use in the drainage basin 

representing the Neshanic River at Reaville site. The Stony 

Brook at Princeton site represents a basin in transition from a 

predominantly forested and agricultural area to a suburban 

residential area. The Great Egg Harbor River near Sicklerville 

site represents a drainage basin with urban land use in the 
1 

Coastal Plain. Samples were collected more frequently at the 

Bound Brook and Great Egg Harbor River sites than at the other 

sites to investigate the effects of urban land use in relatively 

small basins in the two major physiographic provinces in the 

study area (Piedmont and Coastal Plain). 

Two of the sites, Passaic River at Two Bridges and Raritan 

River at Bound Brook, were chosen to represent large drainage 

areas that integrate the effects of many different types of land 

uses, physiographic settings (Piedmont, Coastal Plain, and New 

England), and point-source discharges. No streams on Long 

Island were chosen for sampling because surface water on the 

island is not used as a source of public supply and because 

samples were collected during synoptic studies (O'Brien and 

others, 1998; Reiser and O'Brien, 1998). 

Surface water was sampled at fixed intervals for pesticides 

at the Bound Brook, Great Egg Harbor River, and Raritan River 

sites during April 22, 1996, to June 9, 1998. Additional samples 

were collected during storms. Samples for pesticide analysis 

were collected monthly only in the growing season of 1996 and 

once in June 1997 at the Passaic River, Saddle River, Neshanic 

River, and Stony Brook sites. The data from these samples are 

available in Reed and others (1997-98) and DeLuca and others 

(1999). 

Field and Laboratory Methods 

Stream samples were collected in Teflon® bottles using the 

equal-width-increment (EWI) sampling method (Edwards and 

Glysson, 1988). The samples were split into equal aliquots by 

using a Teflon® cone splitter (Capel and others, 1995). Samples 

were filtered at the site by using baked glass-fiber filters with 

0.7-millimeter pore diameter to remove suspended particulate 

matter and were shipped on ice to the USGS National Water 

Quality Laboratory (NWQL). 

All 146 samples were analyzed for the 47 pesticides listed 

in laboratory schedule 2001, which includes 25 herbicides, 20 

insecticides, and two degradation products, (Zaugg and others, 

1995) as well as nutrients, major ions, suspended sediment, 

dissolved organic carbon, and suspended organic carbon. An 

additional 41 pesticides listed in laboratory schedule 2050, 

which includes 25 herbicides, 10 insecticides, 5 degradation 

products, and 1 fungicide (Werner and others, 1996) were 

analyzed for in 119 of the 146 samples. Three pesticides analyzed for are in both schedules, but only concentrations obtained 

by using the schedule 2001 method are used in this study 

because this method can detect these pesticides at lower concentrations. The 41 pesticides from schedule 2050 were analyzed for 

in 91 of the 119 samples collected during the growing season 

and in all 27 samples from the nongrowing season. 

NWQL used C-18 solid-phase extraction (SPE) columns to 

remove 47 pesticides and metabolites from the filtered water 

samples by using schedule 2001 methods. The SPE columns 

were eluted with hexane-isopropanol (3: 1). The eluant was 

evaporated by using a gentle stream of nitrogen. Extracts of the 

SPE cQlumn eluant were analyzed by a capillary-column gaschromatograph/mass spectrometer operated under a selected-ion 

monitoring mode (Zaugg and others, 1995). 

NWQL uses a 0.5-gram Carbopak-B graphitized carbonbased SPE cartridge to extract an additional 41 pesticides from 

the filtered water samples designated for schedule 2050 analysis. 

Two extract fractions, one containing the absorbed base and 

neutral pesticides and the second containing the acidic pesticides, were eluted from the SPE cartridge. High performance 

liquid chromatography using ultraviolet spectrometry was 

performed on each fraction to detect, identify, and quantify the 

41 compounds (Werner and others, 1996). 

The NWQL techniques allow for the accurate detection 

and quantification of pesticides at minimum concentrations 

ranging from 0.001 to 0.018 Ilg/L for the 47 schedule-2001 

pesticides and 0.01l to 0.05 IlglL for an additional 41 schedule2050 pesticides. Results from the laboratory were censored when 

concentrations could not be accurately determined because of 

analytical and other limitations. "Less than" values are reported 

when a pesticide is either not detected or is not present at a 

concentration that can be identified and measured by NWQL 

analytical procedures. Estimated values "E" are reported when 

the presence of a compound is certain, but there is decreased 

confidence in accurate quantitation . Four pesticides, azinphosmethyl, carbaryl, carbofuran, and desethylatrazine, were always 

estimated because of variable quantification performance (Zaugg 

and others, 1995). For statistical purposes, estimated concentrations were considered to be the same as non-estimated concentrations. 

Quality Assurance 

Quality-assurance samples were collected to evaluate the 

reliability and reproducibility of the data. Three types of qualityassurance samples were evaluated-blanks, replicates, and 

spikes. Results of 12 field-equipment blank samples documented 

that no systematic contamination occurred during sampling and 

processing of the samples. Only 1 of the 12 blank samples had a 

single detection of a pesticide (0.004 Ilg/L of trifluralin). 

Seven sets of split replicate samples were used to evaluate 

the reproducibility of the analytical techniques. The environmental and replicate samples were collected and processed simultaneously. Ninety-six percent of the detections occurred in both the 

environmental and replicate samples. Two detections in the 

environmental samples were not found in the paired replicates. 

One pesticide found in a replicate sample was not found in the 

paired environmental sample. The detected concentrations were 

within 0.008 Ilg/L of the MDL. Differences in concentrations 

detected in both the environmental and replicate samples varied 

from no difference to 20 percent difference. Environmental and 

replicate samples with the greatest percentage of difference were 

those with the lowest pesticide concentrations and differences 

less than or equal to 0.005 Ilg/L. 

Split spiked samples were used to evaluate potential bias 

and the ability of the analytical technique to recover analytes 

from the water-sample matrix. Six spiked environmental samples 

were analyzed for schedule 2001 pesticides, and five samples 

were analyzed for schedule 2050 pesticides. The mean percent 

recoveries for schedule 2001 pesticides ranged from 75 to 150 

percent, except for carbaryl which had a mean recovery of 213 

percent. The mean percent recoveries for most of the schedule 

2050 pesticides detected in this study ranged from 34 to 95 

percent; however, aldicarb, which degrades rapidly, had a mean 

percent recovery of only 7 percent. The degradation products of 

aldicarb, aldicarb sulfone and aldicarb sulfoxide, had recoveries 

of 14 and 58 percent, respectively. These results indicated that 

the schedule 2050 method provides a very conservative estimate 

of compound concentrations and detection frequencies. 
Three pesticides-carbaryl, carbofuran, and linuron-were 

measured by using both schedule 2001 and schedule 2050 

methods. These pesticides were detected more frequently by the 

2001 method, which uses an analytical laboratory technique with 

lower detection levels. The results from the 2001 method are 

used in this study. 

Statistical Methods 

Water samples were categorized by the season and the 

hydrologic condition in which they were collected. The growing 

season is April through September, and the nongrowing season is 

October through March. All samples were grouped into one of 

two flow categories, base flow or runoff. During base flow, most 

of the flow in the stream is contributed by water coming out of 

storage, from lakes, wetlands, and ground-water sources. A 

sample was considered to be collected during base-flow conditions if flow in the stream did not increase by more than 5 

percent from the previous day and if decreases in flow from the 

previous day were less than IS percent. This is a rather strict 

definition of base flow; with this definition some flow conditions 

are considered runoff that would otherwise be considered base 

flow when using base-flow separation techniques. A sample was 

considered to be collected during runoff if the definition of base 

flow was not met. 

To make unbiased comparisons between pesticides, 

detection frequencies were computed using (1) all pesticideconcentration data and (2) only those pesticide concentrations 

that exceeded a common threshold of O.Ol/lglL. All pesticide 

concentration values were censored to 0.01 /lg/L because this is 

a level higher than the MDL for all but four pesticides. Detections of these pesticides below the MDL is common; therefore, 

potential bias is minimized. Contingency table analysis was used 

to determine whether detection frequencies at a site were 

dependent on season or flow condition (Helsel and Hirsch, 

1992). Contingency tables also were used to determine whether 

the number of detections of a pesticide at a site was significantly 

different among sites. The chi-square test was used to determine 

significance when the number of expected detections in each 

category was greater than five. The Fischer's exact test was used 

when expected detections were less than or equal to five. A 

significance level of 0.05 was used for this study. 

The median and 90th percentile concentrations were used 

to summarize the data and to make comparisons at each site and 

among sites by season, flow, and land use. Total-pesticide 

concentrations in each sample were computed by adding the 

concentrations of each detected compound and by assigning a 

concentration of 0 /lglL to all censored values. The inner quartile 

range (IQR) was used to measure the variability of pesticide 

concentrations. It measures the range of the central SO percent of 

the data and is defined as the 75th percentile minus the 25th 

percentile (Helsel and Hirsch, 1992). IQR was used instead of 

variance or standard deviation because it is not influenced by 

outliers. 

One-way analysis of variance (ANOVA) was applied to 

the ranks of pesticide concentrations to determine whether 

median concentrations. varied among sites by season and flow 

condition, and whether concentrations at a single site varied by 

seasons and flow conditions. The null hypothesis (Ho) states that 

mean rank concentrations are equal at each site. The alternate 

hypothesis states that the mean rank concentration from at least 

one site differs from the others. If the null hypothesis is rejected, 

Tukey's test was used to determine which pairs of mean rank 

concentration were significantly different at the 0.05 level. 

Tukey 's groups are represented by letters A through C. Sites in 

group A have the highest mean rank concentration, and those in 

groups B through C have successively lower rank concentrations. Sites containing one or more of the same letters do not 

differ significantly (Helsel and Hirsch, 1992). 

Multivariate ANOVA (MANOVA) was applied to ranks of 

pesticide concentrations to simultaneously test the significance 

of season, flow, and land use as factors contributing to concentrations and numbers of pesticides. MANOVA also was applied 

to ranks of pesticide concentrations to simultaneously test the 

significance of season, flow, and season as a function of flow as 

factors contributing to concentrations and numbers of pesticides 

at each of the three sites sampled in both seasons. 

Relations between instantaneous streamflow and concentration were analyzed at each of the sites. Pesticides detected in 

more than SO percent of the samples from a site were analyzed 

by using tobit regression (Cohn, 1988). The tobit method uses 

censored data to develop the relation. If censored data accounted 

for more than SO percent of the values at a site, the results are 

not considered reliable and are not discussed in this report. The 

relation was considered to be significant if the slope of the 

regression line was different from zero at the 0.05 level of 

significance. A base-lO logarithm transformation of streamflow 

was used to normalize the data before using tobit regression. 

Presence and Distribution of Pesticides 

Pesticides were detected in 145 of the 146 samples 

collected from April 1996 through June 1998. Forty-one of the 

85 pesticides analyzed for were detected in these samples. More 

than 97 percent of the samples contained at least five pesticides, 

and 49 percent contained nine or more pesticides. Detection 

frequency and median, 90th percentile, and maximum concentrations of detected pesticides from all environmental samples 

collected are listed in table 2, along with USEPA MCL's and 

other water-quality criteria. The 44 pesticides not detected in any 

of the samples are listed in table 3. 

Water-Quality Criteria 

Water-quality criteria have been established for 33 of the 

41 pesticides detected (table 2). The USEPA has established 

human-health criteria, including MCL's, health advisory levels 

(HAL's) for lifetime exposure, and (or) a risk-specific dose 

(RSD) for drinking water for 30 of the 41 pesticides detected. 

The NJDEP has established human health criteria (HHC's) for 

dieldrin and DDE. Water-quality criteria for the protection of 

aquatic life were established for 21 of the detected pesticides by 

either the USEPA, NJDEP, Canadian Council of Resource and 

Environment Ministers, or International Joint Commission of 

Canada and the United States. 

Ten pesticides, including 6 insecticides, 3 herbicides, and 1 

fungicide, were detected at concentrations that exceeded 

established water-quality criteria. Eight pesticides were detected 

at concentrations that exceeded USEPA drinking-water standards 

or chronic life criteria for the protection of aquatic life (AQCR), 

and two pesticides were detected at concentrations that exceeded 
Table 2. Pesticides detected in samples collected from seven streams in New Jersey April 1996 through June 1998 

[Data containing an E suffix are incl uded in the data set of detected val ues used for statistical analysis. MOL, Method Detecti on Limit (values 

listed in parentheses have an increased detection limit as of Dec. 15, 1997; EPA MCL, drinki ng-water maximum contaminant level (U.S. Environmental Protection Agency, 1996); EPA HAL, health-advisory level, 70 kg adult, lifetime (U.S. Environmental Protection Agency, 1996); 

NJ HHC, New Jersey human health criteria, (New Jersey Department of Environmental Protection, 1998). Water-quality criteria for aquatic life 

are as follows: EPA, U.S . freshwater chronic criteria for aquatic life (U.S. Env ironmental Protection Agency, 1995); EPA2, U. S. fres hwater 

chronic aquatic life criteria (U.S. Environmental Protection Agency, 1991); CAN, Canadian water-quality guidelines (Canadian Council of 

Resource and Environment Ministers, (991); GL, Great Lakes Water Qua lity Objective (International Joint Corrunission Canada and United 

States, 1977); RSD5 , risk-spec ific dose at level IX 10-5 (U.S. Environmenta l Protection Agency, 1996); NJ, New Jersey freshwater water 

quality criteria (New Jersey Department of Environmental Protection, 1998); J.tg/L, micrograms per li ter; --, criteria do not exist; LD, less than 

the MOL; E, estimated value; %, percent; #, number; *, compounds analyzed in only 119 of the 146 samples collected (Schedule 2050); Red, 

number of detections exceeding criteria; Blue, pesticides not currently applied by licensed applicators in New Jersey. 

Median Delecl- 90lh Maximum Aqualic Life conccntra- Sileof MCL. HAL. or MDL ion freq- percenlile concentral- Critereon Compound name Trade name ion of all max imum HHC (I1g1L). (# (l1g/L) uency, % of all ion delecled (I1g1L)(# in samples concentration in exceedance) (#) samples (I1g1L) exceedance) (l1g/L) 

Alrazine AAtrex . Crisazina 0.001 97 ( 141 ) 0.025 0.12 10E Siony Brook 3 EPA MCL (4) 2CAN (4) 

PromelOn Pramitol, Princep 0.0 18 96 ( 140) 0.020 0.06 0. 10 Bound Brook 100 EPA HAL --

Melolachlor Dual, Pennant 0.002 95 ( 139) 0.0 19 0. 152 5.2E Raritan River 70 EPA HAL 50 8CAN 

Alrazine. Deselhy l 

(Alrazine melaboli le) 0.002 9 1 ( 133) 0.007E 0.034 0.25E SlOny Brook -- --

Simazine Aquazinc, Princep 0.005 88 ( 129) 0.009 0.024 0.5 1 SlOny Brook 4 EPA MCL 10CAN 

Diazillon D.z. n .• Sarolex 0.002 58 (84) 0.003 0.063 0.30 Bound Brook 0.6 EPA HAL 50 0.08 GL ( 12) 

Alachlor Lasso. Bullel 0.002 56 (82) 0.004 0.017 4.7E Slony Brook 2 EPA MCL( I) --

Carbaryl Sevin, Carbamine 0.003 54 (79) 0.008 0. 157 1.5E Bound Brook 700 EPA HAL --

DCPA Daclhal 0.002 36 (53) LD 0.004 0.012 Raritan River -- --

Chlorpyrifos Genpesl. Eradex 0.004 3 1 (45) LD 0.015 0.064 Saddle River 20 EPA HAL 0.041 EPA2 (2) 

Dimon DCMU. Ka rmex 0.020 *27 (32) LD 0. 17 1.2E Raritan River 10 EPA HAL --

Trillurali n Trenin. Tri-4 0.002 26 (38) LD 0.005 0.0 15 Saddle River 5 EPA HAL 0. 1 CAN 

Tebulhiuron Spike. Tebusan 0.0 10 25 (37) LD 0.008 0.Q75 Bou nd Brook 500 EPA HAL 1.6CAN 

2,4-Dich lorophe- 2,4 D. Lawn-keep. 0.Q35 *20 (24) LD 0.32 1.7E Siony Brook 70 EPA MCL 4CAN noxy acetic acid Auqa Kleen (0. 15) 

Cyanazine Bladex. Forlrol 0.004 19 (28) LD 0.0 15 1.9E Siony Brook I EPA HA L (2) 2CAN 

Pendimelhali n Prowl. Slomp 0.004 15 (22) LD 0.0 12 0.046 Raritan River -- --

Carbofuran Furandan, Yahox 0.003 13 ( 19) LD 0.008 O.064E Raritan River 40 EPA MCL 1.75 CAN 

0.030 Great Egg Ch lorothalon il Bravo, Exothenn ' 13 ( 15) LD 0.007 0.7 10E 15 RSD5 0. 18 CAN (3) (0.48) Harbor River 

Benlluralin Benefin. Balan. 12 ( 18) LD 0.003 Bound Brook -- -- Bonalan 0.002 0.007 

Acelochl or Harness, Pl us 0.002 1 (16) LD 0.008 4.7 Stony Brook -- --

Melribuzin Lcxon. Sencor 0.004 8.9 ( 13) LD LD 0. 11 Rari tan River 100 EPA HAL I.OCAN 

Ma lathion Cythion 0.005 8.9 ( 13) LD LD 0.Q78 Bound Brook 200 EPA HAL 0. 1 EPA2 

Fluometuron Flo-Mel. Cotoran 0.Q35 *3.4 (4) LD LD O. II E Raritan River 90 EPA HAL --

Fonofos Dyfonatc. Tycap 0.008 3.4 (5) LD LD 0.054 Bound Brook 10 EPA HAL --

0.02 RSD5 0.0625 EPA2 Dieldrin Panoram D-3 1. 0.0001 35 NJ 0.00 1 2.7 (4) LD LD 0.005 Saddle River OClalox HHC(4) 0.00 19 NJ (4) 

4-Chloro-2-meth- 0.050 MCPA. Metaxon *2.5 (3) LD LD 0.20 Bound Brook 10EPA HAL 2.6 CAN ylphenoxy acetic acid (0. 17) 

Lilluron Lorex) Linex 0.002 2. 1 (3) LD LD 0.62 Stony Brook -- 7CAN 

Napropamide Devrinol 0.003 2. 1 (3) LD LD 0.0 19 Rari tan River -- --

Great Egg Azinphos.Methyl- GU lhion 0.00 ] 1.4 (2) LD LD 0.039E -- 0.0 1 EPA2 ( I) Harbor River 

HCH, gamma- Lindane 0.004 1.4 (2) LD LD 0.0 14 Bound Brook 0.2 EPA MCL 0.08 EPA2 

0. 1 RSD5 

0.000588 NJ DDE.p,p- 0.006 1.4 (2) LD LD 0.OO3E Raritan River 0.000588 NJ (2) HHC(2) 

Acitluorfen Blazer. Tackle 2S 0.035 *0.8 (I) LD LD 0. 130 Raritan River 10 RSD5 --

0.0]6 7 EPA MCL Aldi carb Temik. Ambush *0.8 (I) LD LD 0. 130 Bound Brook 1.0 CAN (0.55) 

Basagran, Benla- Bentazon zone 0.014 *0.8 ( I) LD LD 0.070 Stony Brook 200 EPA HAL --

Brolllocii Bromax. Urox B 0.Q35 *0.8 ( I) LD LD 0.050 Bound Brook 90 EPA HAL --

Dicamba Banval, Dianal O.Q3S *0.8 (I) LD LD 0.040 Bound Brook 200 EPA HAL 10 CAN 

Neshanic MollOate Ordram 0.004 0.7 ( I) LD LD 0.0 17 -- -- River 

Parathion. Ethyl- Roethyl-P. AlkIDn 0.004 0.7 ( I) LD LD 0.01 8 Bound Brook -- 0.0 13 EPA2 (I) 

Propachloe Ramrod. Salecid 0.007 0.7 ( I) LD LD 0 .01 8 Bound Brook 90 EPA HAL --

Propanil Stampede. Wham 0.004 0.7 (I) LD LD 0.005 Raritan Ri ver -- --

Terbufos Counler Pil arfox 0.01 3 0.7 J) LD LD 0.033 Bound Brook 0.9 EPA HAL --
NJDEP HHC's and (or) AQCR's. Thirty-two detections in 

samples collected during April 23, 1996, to August 22,1996; 

May 26,1997 to July 25, 1997; and November 11 , 1997, 

exceeded criteria. There were 10 detections at concentrations 

greater than USEPA and NJDEP human health criteria-MCL's, 

HAL's, and HHC's- and 22 detections at concentrations greater 

than USEPA and NJDEP AQCR's (table 2) in the 146 samples 

collected. Seven detections of herbicides exceeded the criteria 

and 12 detections of the insecticide diazinon exceeded the 

criteria; all were present in samples collected during runoff 

events. Eight of 10 detections of the other 5 insecticides that 

exceeded criteria occurred during base-flow conditions. Two of 

the three detections of the fungicide chlorthalonil that exceeded 

a criterion occurred during base-flow conditions. 

Concentrations of atrazine, alachlor, and cyanazine 

exceeded the USEPA human health criteria in samples collected 

during runoff shortly after spring applications of these pesticides; these concentrations represent a potential threat to 

municipal water supplies in the Raritan River basin. Concentrations of alachlor, atrazine, and cyanazine exceeded HHC at three 

sites in the basin. Concentrations of atrazine exceeded the 

USEPA's MCL (3.0 Ilg/L) in four samples collected during 

runoff in June 1996 and May 1997 from the Neshanic River, 

Stony Brook, and Raritan River sites. The concentration of 

alach lor exceeded the MCL (2.0 Ilg/L) in one sample collected 

during runoff in June 1996 at the Stony Brook site. Concentrations of cyanazine exceeded the HAL ( 1.0 Ilg/L) in two samples 

collected during runoff in June 1996 and May 1997, one at the 

Stony Brook site and one at the Raritan River site. 

Concentrations of chlorpyrifos, chlorthalonil, diazinon, 

ethyl-parathion, and methyl-azinphos exceeded AQCR's in 

samples from four sites. Diazinon exceeded the Great Lakes 

Water Quality Objective (GL) AQCR of 0.08 IlglL in 10 samples 

collected during runoff conditions during June and July 1996 

and 1997, and September 1996 at the Bound Brook site and in 2 

samples collected during runoff conditions in July 1996 and 

1997 at the Raritan River site. Chlorthalonil exceeded the 

Canadian fresh-water chronic aquatic-life criteria of 0.18 Ilg/L in 

two samples collected in July 1997 samples-one during base 

flow and one during runoff-at Bound Brook and in one July 

1997 base-flow sample at Great Egg Harbor River. Chlorpyrifos 

exceeded the USEPA criteria of 0.0411lglL in a June base-flow 

sample at Saddle River and a June runoff sample at Bound 

Brook. Ethyl-parathion exceeded the EPA AQCR (0.0l3 Ilg/L) in 

an April base-flow sample at Bound Brook. Methyl-azinphos 

exceeded the EPA AQCR (0.01 Ilg/L) in a June base-flow 

sample at Great Egg Harbor River. 

Dieldrin was detected in four samples and DDE in two 

samples at concentrations that exceeded NJDEP human health 

criteria; because the MOL is greater than the HHC, other 

samples also may have exceeded the criteria. Dieldrin concentrations exceeded the HHC (0.000135IlglL) and theAQCR (0.0019 

IlglL) in four samples collected during base flow during May 30 

to August 22, 1996, three samples at the Saddle River site and 

one at the Stony Brook site. DOE concentrations exceeded the 

HHC (0.0000588 IlglL) in two samples, one collected during the 

receding limb of the hydrograph in August 1996 at the Raritan 

River site and one collected during base-flow conditions in 

November 1997 at the Great Egg Harbor River site. 

Table 3. Pesticides analyzed for but not detected in stream samples 

from seven stream sites in New Jersey April 1996 through June 1998 

[IUPC, International Union of Pure and Applied Chemistry; Blue indicates pesticides and degradates of pesticides applied by licensed applicators in New Jersey; *, compounds analyzed in only 119 of the 146 

samples collected (schedule 2050); MDL, Method Detection Limit 

(values listed in parentheses have an increased detection limit as of Dec. 

15, 1997; flg/L, micrograms per liter; --, no trade name.] 

Compound name (IUPAC) Trade name MDL 

(llglL) 

*Aldicarb Sulfone Standak, Aldoxycad 0.0 16 (0.100) 

* Ald icarb Sulfoxide -- 0.021 

*Bromoxy nil Torch, Buctril 0.035 

Butylate Genate Plus, Suntan+ 0.002 

*]·hydrx y-carbofuran -- 0.014 

*Chloramhen Amiben.methyl 0.0 II (0.42) 

*Chlorpyralid Stringer 0.050 

*Dichlobcnil Barrier, Casoron 0.020 (1.20) 

*2.4-Dichlorophenoxy butyric acid 2,4 DB, Butyrac 0.035 (0.24) 

*Dachthal, MA -- 0.0 17 

*Dichlorprop 2,4 DP, Sertux 50 0.032 

Diclhylallalinc Metabolite of Alach lor 0.003 

*Dinitrocresol DNOC, Trifocide 0.035 (0.42) 

*Dinoseb DNPB,Dinosebe 0.035 

Disu lfoton Disyston, Solvinex 0.0 17 

EPTC Eptam, Alirox 0.002 

*Esfenvalerate Asana, Sumi-alpha 0.0 19 

Ethal flUnll i n Sonalan, Curbit 0.004 

Ethoprop Mocap, ethoprophos 0.003 

*Fenuron Beet-Klean, Fenulon 0.0 13 

HCH, alpha- alpha-Lindane, alpha-BHC 0.002 

*Mcthi ocarb Mesurol, Slug-Geta 0.026 

*Mcthomyl Lannate, Lanox 0.017 

*-l-2-Methyl-4·chlorphenoxy 

bu tyric ac id 

MCPB, Tropotox 0.050 

* I-Naphtho l Alpha Napthol 0.007 

*Neburon Neburea, Neburyl 0.0 15 

*NorOurazon Eu itol, Predict 0.024 

*OryzaJin Surflan, Dirimal 0.0 19 (0.3 1) 

*OxyamyJ Vydate, Pratt 0.0 18 

Parathion, Methyl- Penncap-M 0.006 

Pebul ate Tillam, PEBL 0.004 

Pcrmelilrin,cis- Ambush, Astro 0.005 

Phorate Th imel, Rampart 0.002 

* Picloram Grazon, Tordon 0.035 

ProJ1 Hl11iue Kerb, Propyzamid 0.003 

Pf'opargite Omite,Omamite 0.0 13 

*Propham Tuberite 0.Q35 

*Propoxur Baygon, Blattanex 0.035 

*Silvex 2,4,5-TP, Fenoprop 0.02 1 

Terbacil Counter, Sinbar 0.013 

Thiobencarb Bolero, Saturn 0.002 

Tri allate Avadex BW, Far-Go 0.001 

*2,4,5-Trichlorophenoxy acetic acid 2,4,5T 0.035 

*Triclopyr Garlon, Grandstand 0.050 (0.25) 

Detection Frequency 

Pesticides were detected in 145 of the 146 samples 

collected. The only sample without any pesticide detections was 

from the Great Egg Harbor River and was collected during the 

receding limb of the hydrograph in October 1996. Detection 

frequencies were computed using (1) all pesticide-concentration 

data and (2) only those concentrations that exceeded a common 

threshold of O.OlllglL in order to make unbiased comparisons 

between pesticides (fig. 2). 

The 41 pesticides detected in the 146 stream samples 

collected for this study consist of 26 herbicides, l3 insecticides, 

1 fungicide, and 1 degradation product. The pesticides most 

frequently detected in the 146 samples were atrazine, in 97 

percent of the samples; prometon, in 96 percent; metolachlor, in 

95 percent; desethyl-atrzine, in 91 percent; simazine, in 88 
100~------------------------------------------------------------------------------------------, 

rz 

w 

90 

80 

1i? 70 

W 

CL 

Z 

~ 60 

U 

Z 

W 

::J 50 a 

w 

a:: 

LL 40 

Z 

o 

f= 

&l 30 rw 

o 20 

10 

o 

cg All Samples 

cg April-September, (growing season) 

cg October-March, (non-growing season) 

_ All samples censored to 0.01 ~g/L 

April-September, (growing season) censored to 0.01 Ilg/L 

October-March, (nongrowing season) censored to 0.01 p.g!L 

Atrazine Prometon Metolachlor Desethyl-Atrazine Simazine Diazinon Alachlor Carbaryl 

MDL = 0.001 ~g/L MDL = 0.018 ~g/L MDL = 0.002 ~g/L MDL = 0.002 pg/L MDL = 0.005 pg/L MDL = 0.002 Ilg/L MDL = 0.002 pg/L MDL = 0.003 pg/L 

PESTICIDE 

Figure 2. Pesticides most frequently detected in all samples and in samples collected during growing and nongrowing 

seasons at seven sites in New Jersey during April 1996 to June 1998. 

percent; diazinon, in 58 percent; alachlor, in 56 percent; and 

carbaryl, in 54 percent. Seven of the eight most frequently 

detected pesticides remained the same regardless of the method 

used. Prometon replaced atrazine as the most frequently detected 

compound, carbaryl moved from eighth to forth place, and 

diuron replaced alachlor in the top eight when a common 

threshold of 0.01 IlglL was used to compute detection frequencies. Five of the eight most frequently detected pesticides are 

herbicides, two are insecticides and one is a degradation product 

of atrazine. Ten pesticides, including the eight most frequently 

detected, DCPA, and cyanazine, were detected at least once at all 

seven sites. The Bound Brook site had the most pesticides 

detected (29), and Passaic River at Two Bridges had the least 

(13). 

Relation to Season 

Seasonal variability in detection frequencies of pesticides 

was analyzed by comparing results from the growing season 

with results from the nongrowing season for the Raritan River, 

Bound Brook, and Great Egg Harbor River sites. The detection 

of pesticides in the growing season was significantly higher than 

in the nongrowing season at each of the three sites. Detection 

frequencies of 38 of the 41 pesticides detected during this study 

were higher at each of the three sites during the growing season. 

Detection frequencies of most of these pesticides, however, were 

not found to be significantly higher in the growing season. Six of

the eight most frequently detected pesticides were detected at 

equally high frequencies during both seasons at each of the three 

sites. None of the 41 pesticides detected had significantly higher 

frequencies in the nongrowing season. 

Thirty-nine pesticides were detected during the growing 

season and 20 pesticides were detected during the nongrowing 

season. Twenty-one pesticides were detected only during the 

growing season; however, three of these compounds--dieldrin, 

bentazon, and molinate--were detected at sites sampled 

exclusively during the growing season. Two herbicides--

acifluorfen and propanil--were detected only during the 

nongrowing season and only at the Raritan River site. 

Detection frequencies of the eight most frequently detected 

pesticides were compared among the seven sites (fig. 3). On the 

basis of contingency table analysis, high detection frequencies of 

atrazine and prometon at each site were not significantly 

different between sites. Detections of the other six pesticides 

were significantly higher at one or more sites than at the other 

sites. Detections of three pesticides used in or associated almost 

exclusively with agricultural practices--metolachlor, desethylatrazine, and alachlor--were higher than expected at the three 

sites located in the basins with greater than 25 percent agricultural land use. Carbaryl and diazinon detections were highest at 

the four most urbanized sites. The number of simazine detections 

was significantly higher at the Bound Brook and Neshanic River 

sites than at the other sites. 

Detection frequencies of all but four pesticides were 

higher at the seven sites sampled during this study than those 

sampled during the June 1997 synoptic study when streams were 

sampled at or near base-flow conditions (Reiser and O'Brien, 

1998). DCPA had the same frequency of detection in both 

studies, and dieldrin, linuron, and malathion had higher detection 

frequencies during the synoptic study. Fonofos, gamma-HCH, 

p,p-DDE, molinate, ethyl-parathion, propachlor, propanil, and 

terbufos were detected during routine sampling at the seven sites 

but were not detected during the synoptic study sampling. 

Terbacil and pebulate were detected during the synoptic study 

but not during routine sampling at the seven sites. 

Relation to Pesticide Use 

Sixty-six of the 85 pesticides analyzed for in this study are 

currently used by licensed applicators in New Jersey to control 
10 0 

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W 

::Ifaz 

W W 6 a:u 

LLa: 

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W 

tu 

o 

0 

0 

0 

0 

0 

Alrazlne Prometon Melolachlor Desethyl-Atrazine 

~ Simazine Diazinen Alachlor Carbaryl 

EXPLANATION 

• Passaic 

River 

o Saddle 

River 

Neshanic 

River 

o Stony 

Brook 

o Raritan 

River 

• Bound Brook 

a:

o 20 

10 U 5 

(7}(8}(7}(9}(27}(41 }(42) (7}(9}(7}(9}(26}(42)(40) (7)(6}(7)(9)(27)(42)(41) (3)(7}(7)(9}(27)(39)(41) (7)(9)(6}(9)(26}(31 }(4 1) (6}(7}(3)(4}(16}(37)(11) (3)(1 }(6)(7}(23}(10}(32) (5)(4}(4}(4}(18}(35}(9) 

• Great Egg Harbor River 

~ ffi 2 

Z f- 1 -::i 0.5 

~ 0 

~-'4AJt~-,it~ ~ All samples 

censored at 

lab MDLs 1§ ffi 0.2 

- 0.. 0.1 ti' (fJ 0.05 

a::2 0.02 !z « 0.01 W a: 0.005 

U (9 0.002 Z 0.001 o 0.0005 U Atrazine 

MDL = 0.001 ~g/L 

Prometon 

MOL = 0.D18 ~Ig/L 

Metolachlor Oesethyl-Atrazine 

MOL = 0.002 ~g/L MOL = 0.002 ~g/L 

Simazine Diazinon Alachlor 

MOL = 0.005 ~g/L MOL = 0.002 pg/L MOL = 0.002 ~g L 

Carbaryl 

MOL = 0.003 pg/L 

• Allsamples 

censored at 

0.01 (~g/L) 

micrograms 

Method De" 

tection Limit 

(MDL) 

(7) Number of 

detections 

Figure 3. Detection frequencies and measured concentrations of the most frequently detected pesticides in the 146 samples 

collected by stream site. 

pests. Thirty-six (55 percent) of these 66 pesticides were 

detected in samples collected during this study. An additional 

five pesticides-aldicarb; DDE, p,p-; dieldrin ; molinate; and 

propanil-were detected but are not presently applied in New 

Jersey by licensed applicators (N.J. Department of Environmental Protection, 1994). 

The pesticides most commonly used are not always the 

most frequently detected (Reiser and O'Brien, 1998). Atrazine, 

metolachlor, alachlor, and carbaryl are the only pesticides among 

the eight most frequently detected that are also among the eight 

most commonly used in New Jersey. Prometon and simazine 

were detected in 96 and 88 percent of the samples, respectively, 

but ranked 36th and 23d in pounds of active ingredient applied. 

Diazinon, the seventh most frequently detected pesticide in the 

study, ranked 14th in pounds of active ingredient applied. 

Diazinon and prometon, however, are active ingredients in 

products used by unlicensed applicators for home and garden 

use. 

Physical and chemical properties and application rates of 

pesticides affect their detection frequencies in streams. Prometon 

may be detected more frequently than expected because of its 

high solubility in water, low soil-adsorption coefficient, and long 

half-life in soil (U.S. Department of Agriculture, 1995). Higher 

than expected detection frequencies of simazine, despite its low 

solubility in water and short half-life in soil, might be explained 

by its low soil-adsorption coefficient. Larson and others (1995) 

found a larger percentage of simazine than any other pesticide in 

streamwater based on the amount of pesticide applied within a 

drainage basin in five of the nine basins studied within the 

Mississippi River basin. Pendamethalin and chlorpyrifos are 

among the four most heavily applied pesticides of those studied 

(Reiser and O'Brien, 1998); however, detections were minimal, 

due in part to their low water solubility and high soil-adsorption 

coefficient. 

Concentrations 

Concentrations of individual pesticide compounds ranged 

from less than 0.00 I to 10.0 Ilg/L. Median concentrations of the 

pesticides detected ranged from < 0.00 I Ilg/L for dieldrin and 

azinphos, methyl to 0.025 Ilg/L for atrazine (table 2) for all 

samples collected during this study. The 90th percentile values 

ranged from less than the MDL to 0.32 Ilg/L for 2,4-D (table 2). 

The maximum concentrations of 37 of the 41 pesticides detected 

occurred during the growing season. The maximum concentrations of 24 of these 37 pesticides occurred during runoff conditions. The four pesticides with maximum concentrations 

occurring during the nongrowing season were collected during 

base-flow conditions. 

The maximum concentrations of 10 pesticides were 

detected in samples collected after a night of heavy rain on June 

13, 1996-atrazine, 10 Ilg/L; acetochlor, 4.7 Ilg/L; desethyl 

atrazine, 0.25 Ilg/L; alachlor, 4.7 IlgJL; 2,4-D, 1.7 IlgJL; 

cyanazine, 1.9 Ilg/L; and Iinuron, 0.62 Ilg/L-at Stony Brook at 

Princeton (01401000) and metolachlor, 5.2IlgJL; metribuzin, 

0.1 I Ilg/L; and pendimethalin, 0.046 Ilg/L at Raritan River at 

Queen's Bridge (01403300). 

The maximum concentrations for all but four pesticides 

detected in this study are higher than those detected in the June 

1997 synoptic study (Reiser and O'Brien, 1998). The four 

pesticides-carbofuran, dieldrin, simazine, and tebuthiuronoccurred at maximum concentrations in this study during the 

same time of year and same hydrologic conditions, in late May 

and June at or near base-flow conditions. A comparison of the 

concentrations of pesticides detected in both studies indicated 

that only dieldrin and tebuthiuron had lower median concentrations in this study. All of the dieldrin detections and 80 percent 

of tebuthiuron detections occurred during base-flow conditions. 

Relation to land use 

The highest median, 90th percentile, and maximum 

concentrations of a particular pesticide typically occurred at a 

site where land use in the drainage basin upstream from the site 
10 100,000 

01403300 Raritan River at Queens Bridge at Bound Brook, NJ 70,000 

0 • ~g ggg Median by season 0: • 30,000 0 Growing: 0.079 ~ • Nongrowing: 0.028 20,000 

~ 

-0: 

zw 

Of- 0.7 

~::J 0.5 0:0: 0.4 f-W 0.3 zCl. 

wen 0.2 • 0::;; 

z« 

00: 0.1 OC!) 

W 

z 

N 

« • • 0: 

!;:( 0.02 • • 200 • • am 100 

M J J A S 0 N 0 J F M A M M A M 

1996 1996 

0.1 10,000 0 

Z 

0.07 • .. • 01403900 Bound Brook at Middlesex, NJ Median by season 

Growing: 0.021 

Nongrowing: 0.008 

5,000 0 

0 

0.05 

0.04 • • W 

2,000 en 

0: 

0.03 • 1,000 W Cl. 

0.02 500 fW 

W EXPLANATION u. 200 0 Mean daily flow 1ii 0.01 100 :J • 0 Detection 50 ~ 

~ 0 Non-Detection 

20 0 

...J 

10 u. 

~ 

;;: 

0 

z 

« 

W 

::;; 

M J J A SON 0 J F M A M J J A SON 0 J F M A M 

1996 1997 1998 

In--.-'~.-.--r~--rT'--r-.--r-'--.-.-''-'-'--.-'--'-'--r-.--r-~ 100 

0.07 

0.05 

0.04 

0.007 

0.005 

0.004 

0.003 

0.002 

• 

01410784 Great Egg Harbor River at Sicklerville, NJ 

Median by season 

Growing: 0.079 

Nongrowing: 0.028 

70 

50 

40 

30 

20 

10 

0.001 l..L-L-.l __ L--"--'-Q-l __ L-+--'----L---l'--'---'--L----' __ -'---"--L----' __ t--'----'----'-__ '---"-' 

M J J A SON 0 J F M A M J J A SON 0 J F M A M 

1996 DATE 1997 1998 

Figure 4. Measured atrazine concentrations and mean daily flow at the three sites 

sampled during growing and nongrowing seasons from April 1996 to June 1998 

(Method detection limit is 0.001 micrograms per liter). 

would indicate the use of that particular pesticide. Five herbicides used almost exclusively for agriculture -- acetochlor, 

alachlor, atrazine, cyanazine, and metolachlor -- and another 

herbicide -- 2,4-D -- used for multiple purposes were the only 

pesticides with 90th percentile concentrations that exceeded 1.0 

I1glL. All the detections that exceeded 1.0 I1glL were at the three 

sites with the most agricultural land use (01398000, 0140lO00, 

and 01403300), These same herbicides also showed the largest 

variations in concentration with season and flow condition. 

Concentrations of atrazine in relation to mean daily flow are 

shown in figure 4. Concentrations varied by more than two 

orders of magnitude at the three sites with greater than 25 

percent agricultural land use. Concentrations of agricultural 

herbicides increased as much as 500 percent during spring 

runoff, The largest inner quartile ranges (IQR's) observed were 

for atrazine and metolachlor at these three sites, Median concentrations of the insecticides, diazinon and carbaryl, were detected 

at significantly higher concentrations at one or more of the most 

urbanized sites. 

The median concentrations of six herbicides--atrazine, 

metolachlor, desethyl-atrazine, alachlor, cyanazine and 

acetochlor--used almost exclusively in agriculture were 

significantly higher at the three sites with greater than 25 percent 

agricultural land use than the concentrations at the other four 

sites. The distribution of detected concentrations of four herbicides and one insecticide at each site ordered by percent agriculturalland use is shown in figure 5. Eleven of the 15 pesticides 

present in maximum concentrations at the urban Bound Brook 

site are associated primarily with lawn care, rights-of-way 

maintenance and mosquito control. Two pesticides are used for 
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Neshanic 

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River 

Saddle Bound 

River Brook 

Raritan 

River 

Stony 

Brook 

Great Egg 

Harbor River 

10 

0.1 

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0 0.010 fw 

:::;: 0.005 Z 

« • 

is 0 w 0 :::;: 5 

• Median Metolachlor 

concentration 

Least-squares regression line 

y = 0.0012x + 0.0081 

Adjusted r sq = 0.969 

P = 0.00004 

• 

10 15 20 25 30 35 40 45 50 55 

AGRICULTURAL LAND USE, IN PERCENT 

agriculture only; the other two are not applied by licensed 

applicators in New Jersey, and their uses are unknown. Water 

samples from the urban-residential site on the Saddle River 

contained the maximum individual and (or) 90th percentile 

concentrations of three herbicides associated primarily with law

care, two insecticides used formerly or presently for termite 

control, and one insecticide used for mosquito control. Six of the

nine pesticides found in maximum concentrations at the Stony 

Brook site, whose drainage basin is changing from agriculture to 

urban land use, are used exclusively for agriculture, and the 

other three are used primarily for agriculture. (Reiser and 

O'Brien, 1998). 

Median and 90th percentile concentrations of the eight 

most frequently detected pesticides from each of the seven sites 

were evaluated with respect to land use at the sites by using least

squares linear regression (Ott, 1988). Median concentrations of 

metolachlor, desethyl-atrazine, alachlor and atrazine (adjusted r2

ranged from 0.97 to 0.62) increased significantly as the percentage of agricultural land increased (fig. 6). In contrast, median 

concentrations of metolachlor and desethyl atrazine decreased 

n 

~ ~)___8-D-=- ;""---'~ Figure S. Land use distribution in the drainage basins of 

the seven streams and concentrations of five of the most 

frequently detected pesticides in stream samples collected 

during April 1996 to June 1998. 

Figure 6. Relation of median concentration of metolachlor 

to percent of agricultural land use at each of the seven sites. 

significantly with an increase in percentage of urban land 

(adjusted r2= 0.59 and 0.46, respectively) and median concentrations of metolachlor decreased significantly with an increase in 

population density. Concentrations of diazinon at the 90th 

percentile increased significantly with increased commercial! 

industrial land use and population density (adjusted r2= 0.81 and 

0.74 respectively). Concentrations of prometon at the 90th 

percentile were also found to increase with an increase in 

commercial/industrial land use and population density. 

The variability of pesticide concentrations as defined by 

the IQR was typically greatest at sites in which land use in the 

drainage basin upstream from the site is generally associated 

with expected pesticide applications. The IQR of eight herbicides and one insecticide associated with agricultural use was 

highest at either Neshanic River or Raritan River, the two sites 

with the most agricultural land use. The IQR's of six herbicides 

used primarily for lawn care or rights-of-way maintenance and 

of three insecticides used in urban areas were highest at the 

Bound Brook site. The IQR of dieldrin was highest at Saddle 

River, the basin with the highest percentage of urban-residential 

land use. 

Variation in Pesticide Concentrations 

Relation to Season 

Pesticides with median concentrations greater than the 

MDL were compared by season at each of the three sites 

sampled throughout the year. Median concentrations of the eight 

most frequently detected pesticides were significantly higher in 

the growing season than in the nongrowing season at all three 

sites. Sixteen pesticides had median concentrations greater than 

the MDL in at least one season at one site. Tebuthiuron was the 

only pesticide of the 16 with a median concentration greater than 

the MDL in the nongrowing season only and only at the Bound 

Brook site. Median concentrations of tebuthiron at other sites 

were less than the MDL in both seasons. 

The median concentrations of the eight most frequently 
ALACHLOR ATRAZINE 

AB B A A A B AB C C A A A BC B 

100 ~ 100 

10 1 10 

~ * ~ ~ ~ 0.1 * ~ 0.1 

~ * i ~ 0.01 ~ Q 0.01 0 a ~ ~ 0.001 * 0 0.001 0.0001 

ATRAZINE,DESETHYL CARBARYL 

C C A A A B B A AB AB AB A A B 

100 100 

10 10 

0.1 bl Q Q 0.1 

a: 

~ B ~ 0 ~ ~ ~ w 0.01 

~ ~ 0.01 

I- 0 0 

--' 0.001 -, 0.001 

a: 0.0001 0.0001 W 

[L 

DIAZINON METOLACHLOR (jJ 

::2: AB ABC C BC ABC A C BC C A A A B AB 

« 100 100 

a: 

C.? 10 10 

0 

~ g ~ a: 

u 

~ ~ - 0.1 0 B 

0.1 

~ ::2: 

Z ~ 0.01 * [5 ~ ~ 0.01 El g 0.001 0.001 Z * 

0 0.0001 0.0001 

I-

« PROMETON SIMAZINE a: 

I- AB C C BC AB A C A A B A A B AB z 100 100 W 

U 

Z 10 10 

0 

u 

6 0.1 

~ ~ 0.1 

0.01 * 8 i ~ ia g E:i ~ 0.01 1:1 i ~ ~ 0.001 Ir 0.001 

0.0001 0.0001 

TOTAL CONCENTRATION TOTAL NUMBER OF COMPOUNDS DETECTED 

BC C AB AB AB AC C AB AB AB AB A A B 

100 20 

~ ,-

10 __ 

~ ~ ~ ~ j 

~ 0 10 

~ ~ ~ ~ ~ ~ ~ 0.1 

-'-

0.01 l I 0 1 I ~ 

zooo or:,oO '0000 \000 3300 3900 01'OA 

0\3'0 0\39 0\39 O\AO O\AO O\AO O\A\ 

ZOOO 0r:,00 '0000 \000 3300 3900 01 SA 

0\3'0 0\39 0\39 O\AO O\AO O\AO O\A\ 

SITE NUMBERS SITE NUMBERS 

Figure 7. Distribution of pesticide concentrations in the growing season and results of Tukey's test at the seven stream 

sites in New Jersey. [Boxplots consist of a center line (median) splitting a rectangle defined by the 75th and 25th 

percentiles, whiskers are drawn to 10th and 90th percentiles, circles and asterisks are outliers (Helsel and Hirsch, 1992). 

Significant differences in mean rank concentration between sites from Tukey's test: from A, the highest, to C, the lowest]. 
detected pesticides during the growing season were compared 

among the seven sites. (fig 7). The median concentrations of 

atrazine, desethyl atrazine, metolachlor, and alachlor, compounds used or associated almost exclusively with agricultural 

use, were significantly higher at the Neshanic River, Raritan 

River, and Stony Brook sites than at the other four sites. The 

drainage basins represented by these sites contain greater than 25 

percent agricultural land use. The median concentrations of 

prometon, carbaryl, and diazinon, pesticides used in urban areas, 

were significantly higher at the Bound Brook site than at the 

other sites. The Bound Brook drainage basin contains 73 percent 

urban land use. Simazine was found to be significantly higher at 

Saddle River, Raritan River, Passaic River, and Stony Brook 

than at the other three sites. The highest median concentrations 

appear to be related to mixed land uses at these sites. Simazine is 

used primarily for agriculture, but also for lawn care and rightsof-way maintenance. 

Results of ANOYA and Tukey's test at the three sites 

sampled in the nongrowing season were similar to the results 

from the growing season. The median concentrations of atrazine, 

desethyl atrazine, and metolachlor were significantly higher at 

the Raritan River site than at the other two sites. Alachlor was 

significantly higher at Raritan River and Great Egg Harbor River 

than at Bound Brook. Prometon, diazinon and carbaryl were 

significantly higher at Bound Brook than the other two sites. No 

significant differences in median simazine concentrations were 

determined to exist between the three sites. 

The variability of individual pesticide concentrations was 

generally greater during the growing season than the 

nongrowing season at each of the three sites (fig. 4). Tebuthiuron 

was the only pesticide with a higher IQR in the nongrowing 

season at the Bound Brook and Great Egg Harbor River sites. 

Both atrazine and desethyl atrazine have a higher IQR in the 

nongrowing season at the Great Egg Harbor River site. 

Relation to Flow Condition 

Samples collected at base-flow conditions were compared 

to those collected during storms. The median concentrations of 

the 8 most frequently detected pesticides in all 70 base-flow 

samples were compared by season to those in all 76 runoff 

samples collected in this study. ANOYA indicated that the 

median concentrations of atrazine, prometon, metolachlor, 

desethyl-atrazine, diazinon, alachlor, and carbaryl were highest 

during runoff conditions in the growing season. The median 

simazine concentration was highest during the growing season 

regardless of flow condition. The lowest median concentrations 

of atrazine, prometon, metolachlor, simazine and alachlor 

occurred during runoff conditions in the nongrowing season. 

Both desethyl atrazine and diazinon are equally low during baseflow and runoff conditions in the nongrowing season. Median 

carbaryl concentrations are less than the detection limit «0.003 

IlglL) during all hydrologic conditions, except during runoff 

conditions in the growing season when the median concentration 

was 0.045 IlglL. 

A comparison between sites of median concentrations of 

the eight most frequently detected compounds indicated that, in 

general, concentrations were lower during base-flow conditions 

than during runoff conditions at all sites. The three most urbanized sites had significantly higher median concentrations of 

prometon, diazinon, and carbaryl than the other sites regardless 

of flow conditions. The only exception was that samples from 

the Saddle River had significantly lower concentrations of 

carbaryl than those from all other sites during base flow. Median 

concentrations of the agricultural herbicides and the metabolite 

desethyl atrazine were consistently higher at the three most 

agricultural sites than at the other sites during all flow conditions 

and seasons. The only exception was the median concentration 

of alachlor during base-flow conditions in the growing season, 

which was higher at the Great Egg Harbor River site than at two 

of the three sites with the most agricultural land use. Significantly higher concentrations of the four pesticides associated 

with agriculture were present in samples from one or more of the 

agricultural sites than in samples from the other sites during each 

flow condition in each season. 

Simultaneous comparison to season, streamflow, and 

land use 

Concentrations of pesticides from all samples were 

evaluated simultaneously by the predominant land use at each 

site, season, and flow condition using MANOYA. The concentrations of each of the eight most frequently detected pesticides 

varied as a function of season and land use. Flow condition was 

significant only in predicting variability in concentrations of 

diazinon and carbaryl. Forty-eight percent of the variability of 

concentrations of diazinon and carbaryl was related to season, 

flow, and land use. Twenty-seven to 59 percent of the variability 

in concentrations of the other six pesticides was related to season 

and land use only. Concentrations of some pesticides were 

significantly higher in runoff during the growing season at 

specific sites, but when concentrations from both seasons were 

analyzed, flow became insignificant. 

Concentrations of pesticides were evaluated simultaneously by season, flow condition, and flow condition as a 

function of season at each of the three sites with samples 

collected during both seasons. At the Raritan River site, 83 

percent of the variability in the concentrations of simazine was 

related to flow and season. Twenty-nine to 52 percent of the 

variability in carbaryl and prometon concentrations was related 

significantly to flow only. Forty-two percent of the variability in 

atrazine concentrations was attributed to flow as a function of 

season. The other four compounds did not relate significantly to 

any of the three variables in the model. 

At Bound Brook, five of the eight pesticides related 

significantly to season only, accounting for 15 to 24 percent of 

the variability in concentration. Diazinon and carbaryl related 

significantly to flow and season, accounting for 38 percent of 

variability in concentration. At Great Egg Harbor River diazinon 

and prometon concentrations were related to season only, 

accounting for 18 to 21 percent of variability. Flow and season 

accounted for 38 to 42 percent of the variability in atrazine and 

simazine concentrations. Metolachlor was significantly related to 

season and flow as a function of season, and desethyl atrazine 

was related to flow, accounting for 21 and 18 percent of variability, respectively. 

Total-Pesticide Concentration and 

Numbers of Pesticides Detected 

Total-pesticide concentrations in each sample were 

computed by adding the concentrations of each detected com-
100 

50 Median by season 

G NG 

Total concentration 0.400.15 

Total number 11 8.5 

1 a: 

W 0.5 

I-

::; o. 

a: 0.1 

W 0.05 0.. 

(fJ 0.02 

:2 0.01 

« M J A S 0 N D F M A M a: 1996 1997 (9 

0 10 

a: 5 Median by season () 

~ G NG 

~ 1 

Z 0.5 0 

~ 0.2 a: 

I- 0.1 

t5 0.05 () 6 0.02 

() 0.01 

W M A S 0 N D F M A M 0 1996 1997 C3 1 i= 

(fJ 0.7 

W 0.5 0.. 0.4 ...J 0.3 

~ 

f2 o. 

0.02 

0.01 M A S F M A M 

1996 1997 

DATE 

A 

A 

20 EXPLANATION 

01403300 Raritan River at • Total pesticide concentration Queen s bridge at Bound 

Brook, N.J. 15 

• Total number of pesticides 

0 Growing season 

0 Nongrowing Season 

G Growing season 

NG Nongrowing Season 

0 S 0 N D F M A M 

1998 (fJ 

20 W 

0 

01403900 Bound Brook at C3 

i= Middlesex , N.J. 15 (fJ 

W 

0.. 

LL 

10 0 

a: 

W 

tll 

:2 5 => 

z 

..J 

~ 0 0 S 0 N D F M A M I1998 

12 

01410784 Great Egg Harbor 

4 

2 

A S 0 N D 0 F M A M 

1998 

pound and by assigning a concentration of 0 /J.g/L to all censored 

values. Total-pesticide concentrations and total numbers of 

pesticides in all samples at a site were compared among sites. 

Total concentrations in a sample ranged from 26.4 /J.g/L at the 

Stony Brook site during runoff in June 1996 to 0.00 /J.g/L at the 

Great Egg Harbor River site during runoff in October 1997 when 

no pesticide concentrations exceeded the detection limit. The 

highest number of pesticides detected (l8) were present in four 

samples collected during spring runoff; three samples were from 

Bound Brook and one from Stony Brook. The highest total 

concentrations and numbers of pesticides occurred at each of the 

seven sites during runoff in the growing season. The smallest 

total concentrations and numbers of pesticides at each site 

typically occurred during runoff events in the nongrowing 

season. The number of pesticides detected at each site over the 

2-year sampling period ranged from 29 at Bound Brook to 13 at 

Passaic River. 

Median total-pesticide concentrations and median total 

number of pesticides from all 70 base-flow samples were 

compared to those from 76 runoff samples, by season. The 

median total-pesticide concentration was highest (0.41 /J.g/L) in 

runoff samples in the growing season and lowest (0.087 /J.g/L) in 

the nongrowing season regardless of flow condition. The median 

total-pesticide concentrations in base-flow and runoff samples 

increased in the growing season. The median total number of 

pesticides was highest (10) in runoff samples in the growing 

season and lowest (6) in runoff samples in the nongrowing 

season. The median total number of pesticides in base-flow and 

runoff samples also increased significantly in the growing 

season. 

Relation to Season and Flow Condition 

Total-pesticide concentrations and total numbers of 

pesticides at the three sites sampled throughout the year were 

compared by seasons using ANOYA. Median total concentrations and median total numbers of pesticides were significantly 

higher in the growing season at each of the three sites (p<0.05). 

A seasonal pattern was observed at each site (fig. 8). The median 

total-pesticide concentration during the nongrowing season, 

however, was the same as that during base-flow and runoff 

conditions at the Raritan River and Bound Brook sites and 

decreased slightly during runoff conditions at the Great Egg 

Harbor River site. The median total number of pesticides during 

runoff conditions in the nongrowing season was larger than 

during base flow at the Raritan River site, remained the same at 

the Bound Brook site, and was smaller at the Great Egg Harbor 

River site. 

Total-pesticide concentration and total number of pesticides in all samples collected during the growing season were 

compared among the seven sites. The median total concentration 

and median total number of pesticides were higher during runoff 

conditions than during base flow at each site during the growing 

season (table 4). The median total-pesticide concentration was 

highest at the Bound Brook site (0.65 /J.g/L) and smallest at the 

Saddle River and Great Egg Harbor River sites (0.12 /J.g/L). 

Tukey's test showed that samples from the Bound Brook site 

Figure 8. Total-pesticide concentration and total number of pesticides in all samples collected 

during April 1996 to June 1998. 
'I

Table 4. Median total pesticide concentration and total number of pesticides by season and flow condition for each sampling site 

[Significant differences in mean rank concentrati on between sites by season, from Tukey's test: A=highest, AB=middle, B=lowest, 

N=no significant difference. Significant differences between flow conditions by site: * significantly hi gher at this flow condition. Inner 

quartile range is the 25th percentile minus the 75th percentile; Brown indicates value is less during runoff than during base flow; I-lg/L, 

micrograms per liter] 

Total number of pesticides per sample Total pesticide concentration per sample (l-lglL) 

Station name Median Inner-quartile range Median Inner-quartile range 

Base fl ow Runoff Base flow Runoff Base flow Runoff Base flow Runoff 

Growing Season 

Passaic River 7 (N) 10 (AB) I 0 0.11 (AB) 0.28 (AB) 0.07 0.008 

Saddle River 8 (N) II (AB) 2 5.5 0.06 (B) * 0.23 (AB) 0.02 0.21 

Neshanic River 6.5 (N) 14 (A) 2 5 0.25 (A) 1.37 (AB) 0.20 9.8 

Stony Brook 7.5 (N) 10 (AB) 5 12 0.20 (A) 0.43 (AB) 0.89 26 

Raritan River 8 (N) 11.5 (A) 2 6.5 0.19 (A) 0.48 (AB) 0.10 2.3 

Bound Brook 9 (N) 13.5 (A) 3 4.5 0.27 (A) 0.80 (A) 0.35 1.0 

Great Egg 7 (N) 8 (B) 2.5 2 0.13(8 ) 0.10 (AB) 0.04 0.08 Harbor River 

Nongrowing Season 

Raritan River 7 (N) 10 (A) 2 3 0.13 (A) 0.13 (A) 0.12 0.12 

Bound Brook 7 (N) 7 (AB) 0 I 0.09 (AB) 0.09 (AB) 0.03 0.06 

Great Egg * 8 (N) 6 (B) I 3 0.006 0.06 * 0.08 (B) 0.07 (B) Harbor River 

Both Seasons 

Raritan River 7 (N) * 10 (A) I 4 0.14 (A) 0.34 (A) 0.08 1.5 

Bound Brook 8 (N) * 13 (A) 3 6 0.22 (A) 0.74 (A) 0.26 1.2 

Great Egg 7 (N) 7 (B) 2 2 0.09 (B) * 0.11 (8 ) 0.05 0.07 Harbor River 

contained significantly higher total-pesticide concentrations than 

those at other sites, and samples from the Saddle River and 

Great Egg Harbor River sites contained significantly lower total 

concentrations. Tukey's test showed that the median total 

numbers of pesticides at the Bound Brook and Raritan River 

sites were significantly higher than those at the other sites and 

the total number was significantly lower at the Great Egg Harbor 

River site. 

Total-pesticide concentration and total number of pesticides in all samples collected during the nongrowing season 

were compared between the three sites. The median total 

concentration at the Raritan River site was significantly greater 

than that at the Bound Brook and Great Egg Harbor River sites. 

The medians of total numbers of pesticides were not significantly different between sites. 

Variability, as determined by the IQR of observations, in 

total-pesticide concentrations and total numbers of pesticides 

detected in samples collected during the growing season was 

compared among the seven sites (table 4). Variability in totalpesticide concentrations for all growing season samples was 

highest at the Raritan River site (1.49 I-1g/L) and lowest at the 

Great Egg Harbor River site (0.05 I-1g/L). Variability in total 

numbers of pesticides detected in a sample was highest at the 

Neshanic River site (8) and lowest at the Passaic River, Saddle 

River and Great Egg Harbor River sites (3). 

During the nongrowing season, the IQR in total-pesticide 

concentration was essentially the same at each site (0.04-0.06 

I-1g/L). The IQR of total numbers of pesticides detected was one 

at Bound Brook and three at Raritan River and Great Egg Harbor 

River. Variability was substantiall y lower in the nongrowing 

season than in the growing season at the Bound Brook and 

Raritan River sites, but remai ned the same at the Great Egg 

Harbor River site. (table 4). 

Relation to Flow Condition 

Median total-pesticide concentrations of pesticides in 

base-flow and runoff samples in the growing and nongrowing 

seasons were compared among sites. Median total-pesticide 

concentrations were highest during runoff in the growing season 

at the Neshanic River site (table 4), the site with the most 

agricuituralland use, and significantly higher than at the other 

sites. The second highest total-pesticide concentration was at the 

Bound Brook site, a site with 68 percent urban land use and 24 

percent commerciallindustrial land use. The highest median 

total-pesticide concentrations at base-flow conditions during the 

growing season ranged from 0.19 to 0.27 I-1g/L at the Bound 

Brook, Neshanic River, Raritan River, and Stony Brook sites. 

The lowest median at Saddle River (0.06 I-1g/L) was significantly 

lower than that at all the other sites. Median total concentrations 

ranged from 0.07 to 0.13 I-1g/L in the nongrowing season and did 

not vary with flow conditions. The Raritan River site had the 

highest median concentration, which was significantly higher 

than that at the Great Egg Harbor River site. 

Median total numbers of pesticides in base-flow and runoff 
samples were compared among sites. Total numbers of pesticides 

at Bound Brook and Raritan River during runoff were significantly higher than those at Great Egg Harbor River. No other 

significant differences were found between sites during runoff 

conditions. Total numbers of pesticides detected at base-flow 

conditions did not vary significantly among sites. 

The differences in median total numbers between sites also 

were compared by flow and season. Numbers were not significantly different between sites at base-flow conditions in the 

nongrowing or growing season. The highest median number of 

pesticides (14) occurred during runoff conditions in the growing 

season at the Neshanic River site (table 4) and was significantly 

higher than the median at Great Egg Harbor River. The Great 

Egg Harbor River site had the lowest median number (8), which 

was significantly lower than the Neshanic River, Raritan River, 

and Bound Brook sites. During runoff conditions in the 

nongrowing season, the median total number of pesticides at the 

Raritan River site (10) was significantly higher than the lowest 

number (6) at Great Egg Harbor River. 

Variability in total-pesticide concentrations and total 

numbers, as defined by the IQR, was compared between baseflow and runoff samples at each site. Variability in total numbers 

was greatest during runoff conditions at each site except for the 

Passaic River and the Great Egg Harbor River in the growing 

season (table 4). In addition, variability in total concentrations 

was greater during runoff conditions at all sites, except Passaic 

River. 

Variability in total-pesticide concentrations and total 

numbers was compared among sites. Pesticide concentrations at 

the three sites with the most agricultural land use had the 

greatest variability in samples collected during runoff conditions 

(table 4). Variability at base-flow conditions was greatest at the 

Raritan River site during the nongrowing season and at the 

Stony Brook and Bound Brook sites during the growing season. 

Variability in total numbers was generally greatest in runoff 

samples at the agricultural sites in the growing season. Variability in total numbers at base-flow conditions was nearly equal 

between sites. 

Simultaneous Comparison to Season, Stream flow, 

and Land use 

Total-pesticide concentrations and total numbers of 

pesticides from all samples were compared simultaneously to the 

predominant land use at each site, the season, and the flow 

condition by using MANOVA. Both totals varied as a function 

of season, land use, and flow condition. Forty-seven percent of 

the variability in total concentration and 35 percent of the 

variability in total numbers resulted from a combination of 

season, flow condition, and land use. 

Total concentrations and total numbers of pesticides were 

compared simultaneously to season, flow condition, and flow 

condition as a function of season at the three sites with samples 

collected in both seasons. At Raritan River, total concentrations 

did not relate significantly to any of the three variables. Total 

concentrations related significantly to season, however, when 

flow was removed from the model. Total concentrations were 

significantly related to season at Bound Brook and Great Egg 

Harbor River, with 61 percent and 32 percent of the variability at 

these sites, respectively, accounted for by season only. Total 

numbers differed significantly in relation to flow at Raritan 

River, to season at Bound Brook, and to flow as a function of 

season at Great Egg Harbor River. These factors accounted for 

24 to 51 percent of the variability in total numbers at these sites. 

Relation of Concentration to Streamflow 

Relations between pesticide concentrations and streamflow 

were evaluated for 16 of the 41 pesticides detected in this study. 

Pesticides detected in more than 50 percent of the samples from 

a site were analyzed by using tobit regression (Cohn, 1988). All 

data, including censored values, are used with the tobit method 

to develop a relation between concentration and flow. If censored data accounted for more than 50 percent of the values at a 

site, the results are not considered reliable and are not discussed 

in this report. The relation was considered to be significant if the 

slope was different from zero at the 0.05 level of significance. A 

base-lO logarithm transformation of streamflow was used to 

normalize the data before using tobit regression. 

Concentrations of at least four pesticides were significantly correlated to streamflow at each of the three sites sampled 

routinely throughout the year (table 5). Concentrations of four of 

the eight most frequently detected pesticides in this study 

decreased significantly with flow during both seasons at the 

Great Egg Harbor River site. At the urban Bound Brook site, 

eight pesticides were significantly related to streamflow, more 

than at any other site. Atrazine, des ethyl atrazine, and simazine, 

associated primarily with agricultural use, decreased significantly as stream flow increased. Three insecticides and two 

herbicides associated with mixed uses increased significantly 

with stream flow. Four pesticides increased significantly with 

flow at the Raritan River site. Diazinon, an insecticide used for 

agriculture and lawn care, increased as streamflow increased 

during both seasons. Simazine concentrations increased as 

streamflow increased only during the growing season, and 

alachlor and carbaryl increased only when concentrations from 

both seasons were analyzed. 

Pesticide concentrations also were correlated with 

streamflow at three of the four sites sampled only during the 

growing season. Concentrations of prometon, metolachlor, 

trifluralin, and pendimethalin, herbicides used for lawn care, 

increa ed with increasing streamflow, and simazine, used 

primarily for agriculture, decreased with increasing streamflow 

at the Saddle River site. Concentrations of desethyl-atrazine, a 

metabolite of atrazine, and DCPA, used in agriculture, golf 

course, and lawn care, increased with increasing streamflow; 

simazine decreased with increasing streamflow at the Passaic 

River site. Simazine was also found to decrease successively in 

downstream order at three sites in the Passaic River basin during 

base-flow conditions in June 1997 (Reiser and O'Brien, 1998). 

Metolachlor, alachlor, and cyanazine, herbicides used primarily 

in agriculture, increased significantly with increasing streamflow 

at the Stony Brook site. No pesticide concentrations were related 

to streamflow at the Neshanic River site. 

Total-pesticide concentrations increased significantly with 

increasing streamflow at Saddle River, Stony Brook, and Bound 

Brook and decreased significantly with increasing streamflow at 

Great Egg Harbor River (table 5). Total concentrations, in 

general, increased with increasing streamflow at the Passaic 

River, Neshanic River, and Raritan River sites, but the relations 

were not statistically significant. 
Table S. Tobit regression slopes of significant relations between pesticide concentrations and stream flow, and total numbers of 

pesticides and streamflow, April 1996 to June 1998, by season 

[+, positive regression slope indicates concentration increases with increasing flow; -, negative regression slope indicates 

concentration decreases with increasing flow; NSR, no significant relation at 0.05 level; ---, less than 50 percent detections, 

therefore , no results given] 

Pesticide 

Passiac 

River 

Saddle 

River 

Neshanic 

River 

Stony 

Brook Raritan River Bound Brook Great Egg Harbor River 

Growing Growing Growing Growing All Growing Nongrowing All Growing 

Nongrowing 

All Growing Nongrowing 

AU'azine NSR NSR NSR NSR NSR NSR NSR NSR NSR - 0.09 - 0.42 - 0.16 - 0.98 

Prometon NSR + 0.28 NSR NSR NSR NSR NSR NSR NSR NSR - 0.24 - 0.20 -0.38 

MelOlachlor NSR +0.96 NSR + 0.75 NSR NSR NSR NSR NSR NSR NSR + 0.39 NSR 

Atrazine, Desethyl + 0.33 NSR NSR NSR NSR NSR NSR NSR NSR -0.26 - 0.31 - 0.20 - 0.66 

Simazine -0.32 -0.19 NSR NSR NSR + 0.36 NSR - 0. 12 - 0.12 NSR - 0.32 NSR - 0.46 

Diazinon NSR NSR --- --- + l.l5 + 1.12 + 1.1 9 + 0.38 + 0.41 --- NSR --- ---

Alachlor --- --- NSR + 1.27 + 0.59 NSR NSR --- --- --- -0.52 - 0.42 - 0.72 

Carbaryl NSR --- NSR --- + 0.73 NSR --- + 0.50 + 0.46 NSR --- --- ---

DCPA + 0.39 --- --- --- NSR NSR --- + 0.20 + 0.20 --- NSR --- ---

Chlorpyri fos NSR NSR --- --- --- --- --- + 0.23 NSR --- --- --- ---

Diuron --- --- --- --- --- --- --- NSR NSR --- --- --- ---

Trifluralin --- + 0.5 1 --- --- --- --- --- --- + 0.40 --- --- --- ---

Tebuthiuron --- --- --- --- --- --- --- --- --- NSR --- --- ---

Cyanazine --- --- --- + 1..72 --- NSR --- --- --- --- --- --- ---

Pend imetha lin --- + 1.1 0 --- --- --- --- --- --- --- --- --- --- ---

Acetochlor --- --- NSR --- --- --- --- --- --- --- --- --- ---

Total Concentration NSR +0.88 NSR + 0.86 NSR NSR NSR NSR + 0.28 NSR - 0.53 - 0.20 NSR 

Total Number NSR NSR NSR NSR + 0.15 + 0.15 + 0. 16 NSR NSR NSR - 0.22 NSR NSR 

The numbers of pesticides detected significantly increased 

with streamflow at the Raritan River site and decreased significantly at the Great Egg Harbor River site. For four of the five 

other sites, numbers of pesticides detected, in general, increased 

as streamflow increased, but the relations were not statistically 

significant. 

Summary and Conclusions 

Pesticides were frequently detected in water samples 

coll ected from seven New Jersey streams from April 1996 

through June 1998. Pesticides were present in streams throughout the year, but rarely at concentrations that exceeded established water-quality criteria. The pesticides most frequently 

detected were atTazine, in 97 percent of the samples; prometon, 

in 96 percent; metolachlor, in 95 percent; desethyl-atrazine, in 91 

percent; simazine, in 88 percent; diazinon, in 58 percent; 

alachlor, in 56 percent; and carbaryl, in 54 percent. More than 97 

percent of the samples contained at least five pesticides. Twentynine pesticides were detected at the highly urbanized Bound 

Brook site throughout the sampling period, the most detected at 

any site, and 13 pesticides were detected at the Passaic River 

site, which drains a large basin of mixed land uses, the fewest at 

any site. 

Pesticides were detected more frequently during the 

growing season than during the nongrowing season. Thirty-nine 

pesticides were detected during the growing season and 20 

pesticides during the nongrowing season. Twenty-one pesticides 

were detected only during the growing season; however, three of 

these-dieldrin, bentazon and molinate-were detected only at 

sites sampled exclusively in the growing season. 

The concentrations of 10 pesticides infrequently exceeded 

established water-quality criteria. Thirty-one detections occurred 

during the growing season and one during the nongrowing 

season. Concentrations of atrazine, alachlor, and cyanazine 

exceeded the U.S. Environmental Protection Agency human 

health criteria during runoff shortly after spring applications of 

these pesticides, and represent a potential threat to municipal 

water supplies in the Raritan River basin. Concentrations of 

chlorpyrifos, ch lorthalonil, diazinon, ethyl-parathion, and 

methyl-azinphos exceeded chron ic life criteria for the protection 

of aquatic life (AQCR) at four sites during the growing season. 

. Dieldrin was detected in four samples and DDE in two samples 

at concentrations that exceeded New Jersey Department of 

Environmental Protection (NJDEP) health advisory levels. 

Dieldrin concentrations also exceeded the NJDEP AQCR. 

The highest individual concentrations and highest median 

concentrations of most of the pesticides detected occurred during 

runoff in the growing season, and the lowest typically occurred 

during runoff in the nongrowing season. The median concentrations of most pesticides at most sites were equally low during 

base flow and runoff in the nongrowing season. Typically, 

concentrations were least variable during base-flow conditions in 

the nongrowing season. All 24 pesticides with the highest 

concentrations during runoff were sampled in the growing 

season. The fo ur pesticides with highest concentrations during 

the nongrowing season were sampled during base-flow 

conditions. 

Pesticide concentrations were related to land use in the 

drainage basin upstream from the sampling site. The highest 

median concentration and the maximum concentration of a 

pesticide were typically found at a site where land use in the 

drainage basin upstream from the site is generally associated 

with applications of that pesticide. Herbicides associated with 
agricultural land use, such as atrazine, generally were detected in 

higher concentrations than other pesticides, showed the strongest 

correlation to land use, and had the largest variability in concentration with season and streamflow. In general, insecticides were 

detected more frequently and in greater concentrations at urban 

sites than at other sites. The highest individual and median 

concentrations of 10 of the 13 insecticides detected were present 

in samples from the two sites with the highest urban land use. 

Ten of the 13 insecticides were detected at the highest frequencies at the three most urbanized sites. 

Concentrations of 13 pesticides were significantly 

correlated with streamflow at one or more sites. The strongest 

relations were (1) concentrations of two herbicides used for lawn 

care at a suburban site and two herbicides used for agriculture at 

a site in a small basin with 28 percent agricultural land use 

correlated positively with streamflow during the growing season 

and (2) concentrations of the insecticide diazinon correlated 

positively with streamflow during both seasons at the site that 

drains the large Raritan River basin. Concentrations of five 

pesticides, total concentration, and total number of pesticides 

decreased significantly with flow at the Great Egg Harbor River 

site, a mixed land-use site in the Coastal Plain. In general, most 

of the pesticides that correlated positively with streamflow were 

detected at sites where the predominant land use is associated 

with the use of the detected pesticide. Most of the pesticides 

with a negative relation to streamflow were detected at sites 

where the land use in the basin would not indicate use of the 

detected pesticide. 

The highest total concentrations of pesticides occurred 

during runoff in late spring and early summer in small agricultural basins (greater than 25 percent agricultural land use). The 

smallest total concentrations and numbers of pesticides at each 

site typically occurred during runoff in the nongrowing season, 

with the smallest values occurring at the Great Egg Harbor River 

and Bound Brook sites. The highest number of pesticides 

detected in a sample (18) occurred during the growing season at 

both Bound Brook and Stony Brook sites. Total-pesticide 

concentrations and total number of pesticides generally increased as streamflow increased at all sites except Great Egg 

Harbor River. The number of pesticides detected was found to 

increase significantly as streamflow increased at the Raritan 

River site and to decrease with increased streamflow at the Great 

Egg Harbor River site. Nu~bers of pesticides generally increased with increased streamflow at four of the five other sites; 

the exception was the Passaic River site. 

The median total-pesticide concentrations were highest in 

runoff samples in the growing season at all sites and lowest in 

the nongrowing season regardless of flow conditions at all sites. 

The median total number of pesticides was highest in runoff 

samples collected in the growing season at all sites and lowest in 

runoff samples collected in the nongrowing season at all sites, 

except the Raritan River site. Variability in total-pesticide 

concentrations and total numbers of pesticides was greatest 

during runoff in the growing season and least during base-flow 

conditions in the nongrowing season at most sites. 

-Robert G. Reiser 

References Cited 

Buxton, D.E., and Dunne, Paul, 1993, Water-quality data for the 

Millstone River at Weston, New Jersey, and the Shark River 

at Remson Mill, New Jersey, March - September 1992: U.S. 

Geological Survey Open-File Report 93-444, 16 p. 

Canadian Council of Resource and Environmental Ministers, 

1991, Canadian water quality guidelines: Ottawa, Onterio, 

Environment Canada, Inland Waters Directorate, Water 

Quality Branch (updated May 1996), variously paged. 

Capel, P.D., Nacionales, F.C, and Larson, S.1., 1995, Precision 

of a splitting device for water samples: U.S. Geological 

Survey Open-File Report 95-293,6 p. 

Cohn, T.A., 1988, Adjusted maximum estimation of the moments of lognormal populations from type 1 censored 

samples: U.S. Geological Survey Open-File Report 88-350, 

34 p. 

DeLuca, M.1., Oden, J.H., Romanok, K.M., and Riskin, M.L., 

1999, Water resources data for New Jersey-Water year 

1998, Volume 3. Water-quality data: U.S. Geological Survey 

Water-Data Report NJ-98-3, 450 p. 

Edwards, T.K. , and Glysson, D.G. , 1988, Field methods for 

measurement of fluvial sediment: U.S. Geological Survey 

Open-File Report 86-531 , 118 p. 

Fegeas, RG., Claire, R.W., Guptill, S.C, Anderson, K.E., and 

Hallam, CA., 1983. Land use and land cover digital data: 

U.S. Geological Survey Circular 895-E, 21 p. 

Ferrari, M.1. , Ator, S.W., Blomquist, J.D., and Drysart, J.E. , 

1997, Pesticides in surface water of the Mid-Atlantic region, 

1997: U.S. Geological Survey Water-Resources Investigations Report 97-4280, 12 p. 

Gilliom, R.1., Alley, W.M., and Gurtz, M.E., 1995, Design of the 

National Water-Quality Assessment Program: Occurrence 

and distribution of water-quality conditions: U.S. Geological Survey Circular 1112, 33p. 

Harte, John, Holdren, Cheryl, Schneider, Richard, Shirley, 

Christine, 1991, Toxics A to Z: A guide to everyday pollution hazards: Berkeley and Los Angeles, Calif., University 

of California Press, 479 p. 

Helsel, D.R., and Hirsch, R.M., 1992, Statistical methods in 

water resources: New York, Elsevier Science Publishing 

Company Inc., 522 p. 

Hitt, K.J., 1994, Refining 1970's land-use data with 1990 

population data to indicate new residential development: 

U.S. Geological Survey Water-Resources Investigations 

Report 94 4250, 15 p. 

International Joint Commission Canada and United States, 1977, 

New and revised Great Lakes water quality objectives, 

Volume II, An UC report to the governments of the United 

States and Canada: Windsor, Ontario, Canada, UC 

Ivahnenko, Tamara, and Buxton, D.E., 1994, Agricultural 

pesticides in six drainage basins used for public water 

supply in New Jersey, 1990: U.S. Geological Survey WaterResources Investigations Report 93-4101, 56 p. 

Larson, S.1., Capel, P.D., Goolsby, D.A., Zaugg, S.D., and 

Sandstrom, M.W., 1995, Relations between pesticide use 

and riverine flux in the Mississippi River basin: Chemosphere, v. 31, no. 5, p. 3305-3321. 
Larson, SJ., Capel, P.D., and Majewski, M.S., 1997, Pesticides 

in surface waters - Distribution, trends, and governing 

factors: Chelsea, Michigan, Ann Arbor Press, 373 p. 

New Jersey Department of Environmental Protection, 1996, New 

Jersey geographic information system: Trenton, NJ., CDROM series 1, v. 2. 

_ _ 1998, Surface water quality standards: NJ.A.C. 7:9B: 

Trenton, NJ., New Jersey Department of Environmental 

Protection, Office of Environmental Planning, April 1998, 

122 p. 

O'Brien, A.K., Reiser, R.G., and Gylling, Helle, 1998, Volatile 

organic compounds in New Jersey and Long Island streams: 

U.S. Geological Survey Fact Sheet 194-97, 6 p. 

Ott, L., 1988, An introduction to statistical methods and data 

analysis: Boston, Mass. , PWS-Kent Publishing Company, 

835 p. 

Reed, TJ., Centinaro, G.L., DeLuca, MJ., Hutchinson, IT, and 

Scudder, Jeffrey, 1997, Water resources data for New 

Jersey-Water year 1996, Volume 1. Surface-water data: 

U.S. Geological Survey Water-Data Report NJ-96-1, 562 p. 

Reed, TJ., Centinaro, G.L., DeLuca, MJ., and Oden, J.H., 1998, 

Water resources data for New Jersey- Water year 1997, 

Volume 1. Surface-water data: U.S. Geological Survey 

Water-Data Report NJ-97-1 , 608 p. 

Reiser, RG., and O'Brien, A.K., 1998, Occurrence of pesticides 

in streams in New Jersey and Long Island, New York, and 

relation to land use: U.S. Geological Survey WaterResources Investigation Report 98-426], 12 p. 

Stackelberg, P.E., Hopple, J.A., and Kaufman, L.J., 1997, 

Occurrence of nitrate, pesticides, and volatile organic 

compounds in the Kirkwood-Cohansey aquifer system, 

southern New Jersey: U.S. Geological Survey WaterResources Investigations Report 97-4241, 8 p. 

U.S. Bureau of the Census, 1991, Census of population and 

housing, 1990: Public Law 94-171 data for New Jersey: 

Washington, D.C., U.S. Bureau of the Census [machine 

readable data fi les (CD ROM)]. 

U.S. Department of Agriculture, 1995, ARS Pesticide Properties 

Database (Last update: May 1995): U.S.Department of 

Agriculture, Agricultural Research Service. (Accessed July 

1, 1998, on the World Wide Web at URL http:// 

www.arsusda.gov/rsrnl/ppdb2.html.) 

U. S. Environmental Protection Agency, 1991, Water-quality 

criteria summary Office of Water, Office of Science and 

Tech., Health and Ecological Effects Division (poster). 

__ 1994, Atrazine, simazine, cyanazine; notice of initiation of 

special review: Federal Register, v.59, p. 60412-60443 

(Accessed July 8, 1998, on the world wide web at URL 

http://www.epa.gov Ifedrgstr/EPA -PEST /1994/N ovemberl 

Day-23/pr-54.html). 

__ 1995, Guidance for assessing chemical contaminant data 

for use in fish advisories: Volume 1, Fish sampling and 

analysis, 2d ed.: Office of Water, EPA 823-R-95-007, 436 p. 

__ 1996, Drinking water regulations and health advisories: 

Office of water, EPA 822-B-96-002, Washington, D.C., Oct., 

1996, 16 p. 

Ware, G.W., 1994, The pesticide book: Fresno, Calif., Thomson 

Publications, 386 p. 

Werner, S.L., Burkhardt, M.R, and DeRusseau, S.N., 1996, 

Methods of analysis by the U.S. Geological Survey National 

Water Quality Laboratory-determination of pesticides in 

water by Carbopak-B solid-phase extraction and highperformance liquid chromatography: U.S. Geological 

Survey Open-File Report 96-216, 42 p. 

Zaugg, S.D., Sandstrom, M.W. , Smith, S.G., and Fehlberg, 

K.M. , 1995, Methods of analysis by the U.S. Geological 

Survey National Water Quality Laboratory-determination 

of pesticides in water by C-18 solid-phase extraction and 

capillary-column gas chromatography/mass spectrometry 

with selected-ion monitoring: U.S. Geological Survey 

Open-File Report 95-181,49 p. 
Copies of this report can be purchased from: 

U.S. Geological Survey 

Branch of Information Services 

Box 25286, Building 810 

Denver, CO 80225-0286 

Information about the NAWQA Program 

can be obtained from: 

LlNJNAWQA Project Chief 

U.S. Geological Survey 

Mountain View Office Park 

810 Bear Tavern Road, Suite 206 

West Trenton, NJ 08628 

On the web: http://wwwrvares.er.usgs.gov/nawqaJ or 

http://nj.usgs.gov/nawqaJ