Water

Other

Forest land

Agricultural land

Sampling location

Urban, residential

 and built-up land

EXPLANATION

0

0 10 20 30 40 50

10 20 30 40 50 MILES

KILOMETERS

County boundary

Watershed boundary



PA

NY

VT

NH

MA

CT

NJ

Mohawk River Subbasin

Hudson River Basin

74°

75°

43°30'

42°30'

LOCATION MAP

Schoharie 

Fulton

Montgomery

Herkimer

Greene

Oneida

Mohawk River

Schenectady Otsego

Delaware

Albany

Saratoga

Madison

Hamilton

Canajoharie Creek near Canajoharie

Lewis

Mohawk River at Cohoes

Lisha Kill at

Niskayuna

Schoharie 

Creek

Introduction and Basin Description

The National Water Quality Assessment (NAWQA) program is 

designed to describe the status and trends in the water quality of large 

representative parts of the Nation’s surface-water and ground-water 

resources and to provide a scientific understanding of the major natural and 

human factors that affect the quality of these resources. The Hudson River 

Basin, one of 60 NAWQA project areas, encompasses 13,400 mi2 (square 

miles) in New York and adjacent states, and the Mohawk River is the largest 

tributary to the Hudson River (fig. 1). The Mohawk subbasin encompasses 

3,519 mi2

 and represents about 25 percent of the Hudson River Basin. 

About 55 percent of the Mohawk subbasin is forested land, 33 percent is 

agricultural land, 7 percent is urban/residential land, and 5 percent is 

wetland, water, or other land cover (fig. 1). The diverse land use within this 

large subbasin makes it a probable major contributor of various pesticides to 

the Hudson River.

Water samples collected from streams in the Mohawk River subbasin 

were analyzed for a broad suite of pesticides, which included both 

herbicides and insecticides. Herbicides are used to control weeds in 

agricultural fields as well as lawns, commercial land, and other open areas 

in urban and residential settings; 

insecticides are used to control insects 

in agricultural and urban settings. 

Because pesticides can be transported 

from application areas to surface 

waters, stream and river monitoring for 

pesticides in the Hudson River Basin is 

needed to insure both a safe drinking 

water supply and the ecological health 

of streams. This fact sheet summarizes 

results of a study of pesticides in 

streams in the Mohawk River subbasin.

Pesticide Sampling

Three surface water sites were sampled monthly or 

weekly for 47 pesticides (for a complete list of pesticide 

analytes, refer to Firda and others, 1994) from March 1994 

through September 1995 to determine the variability of 

pesticide concentrations with respect to season, streamflow 

conditions, and land use. These sites included (1) 

Canajoharie Creek, which drains a 60 mi2 watershed, 66 

percent of which is agricultural land, (2) Lisha Kill, which 

drains a 15 mi2 watershed, 56 percent of which is urban land, 

and (3) the Mohawk River at Cohoes which represents the 

outlet of the Mohawk River which drains a combination of 

urban, forested, and agricultural land. Canajoharie Creek 

and Lisha Kill watersheds are nested within the Mohawk 

River subbasin and shown in figure 1.

Pesticides in Surface Waters of the Hudson River 

Basin —Mohawk River Subbasin

Figure 1: Land use and sampling locations in Mohawk River 

subbasin, New York

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

UNITED STATES GEOLOGICAL SURVEY
May-August

September-April

Mohawk River at Cohoes

Lisha Kill at Niskayuna

Canajoharie Creek nr Canajoharie

PERCENTAGE OF SAMPLES WITH DETECTION

May-August / September-April

 Number of Concentration (micrograms per liter )

 Samples Maximum Median

24 / 10 0.17 / 0.024 0.025 / 0.010

24 / 10 0.37 / 0.021 0.048 / 0.016

24 / 10 0.043 / 0.014 0.009 / 0.007

14 / 9 0.034 / 0.006 0.007 / 0.006

24 / 10 0.073 / -- 0.020 / --

24 / 10 0.017 / -- 0.009 / --

24 / 10 0.021 / 0.007 0.011 / 0.007

24 / 10 0.026 / -- 0.016 / --

24 / 10 0.003 / -- 0.003 / --

24 / 10 0.027 / -- 0.027 / --

24 / 10 0.025 / -- 0.025 / --

24 / 10 0.01 / -- 0.010 / --

24 / 10 0.002 / -- 0.002 / --

24 / 10 -- / 0.010 -- / 0.010

25 / 11 4.3 / 0.062 0.042 / 0.029

25 / 11 1.3 / 0.023 0.020 / 0.011

25 / 11 0.22 / 0.053 0.016 / 0.015

26 / 11 2.1 / 0.006 0.022 / 0.006

19 / 11 0.035 / 0.024 0.008 / 0.016

26 / 11 0.033 / -- 0.027 / --

26 / 11 0.018 / -- 0.013 / --

25 / 11 0.004 / -- 0.004 / --

26 / 11 0.035 / -- 0.035 / --

26 / 11 -- / 0.002 -- / 0.002

13 / 12 0.13 / 0.55 0.042 / 0.030

22 / 12 0.023 / 0.005 0.008 / 0.004

25 / 12 0.11 / 0.009 0.019 / 0.006

25 / 12 0.86 / 0.2 0.057 / 0.020

25 / 12 0.007 / -- 0.004 / --

25 / 12 0.071 / -- 0.024 / --

25 / 12 0.029 / -- 0.024 / --

25 / 12 0.013 / -- 0.011 / --

24 / 12 0.023 / -- 0.023 / --

25 / 12 0.21 / -- 0.210 / --

25 / 12 0.016 / -- 0.016 / --

25 / 12 0.009 / -- 0.009 / --

25 / 12 0.008 / -- 0.008 / --

25 / 12 0.006 / -- 0.006 / --

Alachlor

Pendimethalin

EPTC

Simazine

Metribuzin

Diazinon

Cyanazine

Deethylatrazine

Metolachlor

Atrazine

Pendimethalin

Alachlor

Chlorpyrifos

Molinate

alpha BHC

Terbacil

Simazine

Metribuzin

Prometon

Deethylatrazine 

Carbaryl

Atrazine

Metolachlor

Diazinon

0 10 20 30 40 50 60 70 80 90 100

Tebuthiuron

EPTC

Terbacil

Prometon

Metribuzin

2,6 - Diethylanaline 

Carbaryl

Alachlor

Simazine

Cyanazine

Diazinon

Deethylatrazine

Atrazine

Metolachlor

Dashes (--) indicate no detections during this period.

Figure 2: Percent detection, maximum and median (of samples with detection) concentrations of detected 

pesticides at sampling sites (site locations shown in fig. 1)

Results of Sample Analyses

Eighteen pesticides were detected among the three sites 

(table 1), including 12 herbicides, two herbicide-degradation 

products (metabolites), and four insecticides. Of the 108 samples 

collected at the three sites, only two contained any pesticide at a 

concentration that exceeded the maximum contaminant level 

(MCL) or health advisory (HA) level as established by the U.S. 

Environmental Protection Agency (USEPA, 1996), and both 

samples were from Canajoharie Creek. One sample exceeded the 

MCL for the herbicide atrazine1

 with a concentration of 4.3 μg/L 

(micrograms per liter). This sample was collected after a runoffproducing storm in July 1994 and represents the largest 

instantaneous discharge associated with any sample collected at 

Canajoharie Creek during the growing seasons of 1994 and 1995. 

The other sample, collected after a smaller storm in June 1995, had 

a cyanazine concentration of 2.1 μg/L, which exceeds the HA 

standard for cyanazine.

The highest concentrations of all but three pesticides detected 

at the three sites (alachlor – seven detections, 2,6-diethylanaline – 

three detections, and tebuthiuron – one detection) were in samples 

from either Canajoharie Creek or Lisha Kill (table 1). These three 

pesticides were in 8 separate samples (six from the Mohawk River 

site). Tebuthiuron and 2,6-diethylanaline were detected only at the 

Mohawk River site, and all three 2,6-diethylanaline detections 

were in association with alachlor in samples collected on June 21, 

29 and July 6, 1994.

1

Use of trade, product, or firm names is for descriptive purposes only and 

does not imply endorsement by the U.S. Government.
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J JJJJJJ J J J J JJ J JJ MAR JUN SEP DEC MAR JUN

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STREAMFLOW, IN CUBIC FEET PER SECOND

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ATRAZINE CONCENTRATION, IN MICROGRAMS PER LITER

Canajoharie Creek near Canajoharie

Lisha Kill at Niskayuna

Mohawk River at Cohoes

Below Detection (<0.001 micrograms per liter)

Below Detection (<0.001 micrograms per liter) 

1994 1995

detected

Pesticides Detection

Use MCL/HA

Maximum

Concentration

1 2

A H1 trazine 03 3 .00 4.

C H4 yanazine 011 .00 2.

M H2 etolachlor 0 0 .00 1 3 0 1.

C I3 arbaryl 0 0 .00 7 6 0 0.8

D I2 iazinon 0 6 .00 0 5 . 0.5

D M2 eethylatrazine 0 a .00 n 2 0.2

a I2 lpha BHC 0 a .00 n 1 0.2

P H8 rometon 0 0 .01 1 1 0 0.07

P H4 endimethalin 0 a .00 n 5 0.03

M H4 etribuzin 0 0 .00 1 3 0 0.03

T H7 erbacil 0 0 .00 9 3 0.02

A H2 lachlor 02 1 .00 0.02

S H5 imazine 04 8 .00 0.01

M H4 olinate 0 a .00 n 6 0.01

T H1 ebuthiuron 0 0 .0 5 1 0 0.0

C I4 hlorpyrifos 0 0 .00 2 9 0.00

E H2 PTC 0 a .00 n 4 0.00

2 M3 ,6 - Diethylanaline 0 a .00 n 3 0.00

(micrograms per liter)

detected Limit

Table 1. Pesticides detected 

Colors indicate the site at which the maximum concentration was found 

Yellow - Canajoharie Creek, Red - Lisha Kill, Blue - Mohawk River 1

H - herbicide, I - insecticide, M - metabolite, 

2

MCL - Maximum Contaminant Level, HA - Health Advisory level

The presence and concentrations of pesticides detected at the 

three sites is depicted in figure 2. Metolachlor, atrazine, and 

deethylatrazine were nearly always detected in both the 

Mohawk River and Canajoharie Creek, although the maximum 

and median concentrations in Canajoharie Creek were typically 

greater than those in the Mohawk River. 

Diazinon was detected most frequently in samples from Lisha 

Kill and was present in more than 80 percent of samples collected 

from May through August and in more than 60 percent of samples 

collected from September through April. Diazinon is applied 

almost exclusively in urban/residential areas; thus, the greater 

frequency of detection and higher concentrations of diazinon in 

samples from the Lisha Kill than in the Mohawk River is attributed 

to the larger proportion of urban/residential land in the Lisha Kill 

watershed. No samples from Canajoharie Creek, which drains an 

area that is less than 1.5 percent urban/residential, had detectable 

concentrations of diazinon.

The higher percentage of pesticide detections during the 

growing season (May through August) than in the nongrowing 

season (fig. 2) reflects the amount of time since pesticides were 

applied to fields and urban areas. Most detections during the 

nongrowing season were likely the result of pesticide infiltration 

to ground water and its subsequent discharge to streams and rivers 

later in the year.

The Mohawk River drains a large watershed, and receives water 

from many tributaries draining forested, urban, and agricultural 

lands. The lower concentrations of pesticides found at the Cohoes 

site than at the Canajoharie Creek and Lisha Kill sites, therefore, 

can be attributed to dilution. 

Canajoharie Creek is adjacent to areas where agricultural 

chemicals are applied; therefore, the detection of agricultural 

pesticides, including atrazine, cyanazine, metolachlor, 

pendimethalin, metribuzin, and simazine in relatively high 

concentrations was not surprising. Similarly, the highest 

concentrations of all four insecticides found were in samples 

from the Lisha Kill, as this watershed contains many urban/

residential areas. 

Figure 3: Annual atrazine concentrations at each site (site locations 

shown in fig. 1)
Seasonal Atrazine Patterns

Pesticide concentrations at Canajoharie Creek and Mohawk 

River sites peaked during the first major runoff-producing storms 

after pesticide application. In general, seasonal patterns (not 

necessarily concentrations) of detected pesticides at these sites 

mimicked those of atrazine (fig. 3). The highest atrazine 

concentrations were at Canajoharie Creek watershed and occurred 

during June and July, when they ranged from 0.04 to more than 

1 μg/L. During the remainder of the year, atrazine concentrations 

generally ranged from 0.02 to 0.04 μg/L. 

Atrazine concentrations in the Mohawk River at Cohoes 

ranged from 0.04 to 0.37 μg/L during the growing season and 

were less than 0.04 μg/L during the remainder of the year. The 

sample with the highest atrazine concentration at this site was 

collected in July 1994, about 1 week after the maximum atrazine 

concentration observed at Canajoharie Creek. The timing of 

maximum concentrations of metolachlor and cyanazine at this site 

parallel those of atrazine; the maximum concentration of 

deethylatrazine was observed after a stormflow in August 1994.

Atrazine concentrations at Lisha Kill were lower, and the 

maximum observed concentrations occurred later, than at the 

Mohawk River and Canajoharie Creek sites. Atrazine was 

detected at Lisha Kill only between March and September of 

1994 and 1995, and the peak concentration observed at Lisha 

Kill was not associated with a runoff-producing storm. The 

maximum concentration of neither metolachlor nor 

deethylatrazine corresponded to the maximum concentration of 

atrazine at Lisha Kill.

Differences in the timing of observed peak concentrations of 

atrazine in the summer of 1995 among the three sites (fig. 4) is due 

to differences in the time of application and the response of 

streamflow to precipitation. The 1995 sample with the maximum 

atrazine concentration at Canajoharie Creek was collected in early 

June, and, as in 1994, 7 days before the maximum atrazine 

concentration detected in the Mohawk River at Cohoes. This delay 

in peak concentration is not surprising, however, because a small 

watershed will generally respond faster to a storm than a large 

basin, and this, combined with the large proportion of agricultural 

land in the watershed, resulted in a more rapid increase in atrazine 

concentration, and higher concentrations, than at the two other 

sites. Because the Mohawk site is downstream from Canajoharie 

Creek and receives runoff from several other small watersheds 

dominated by agricultural land, elevated concentrations in the 

Mohawk are sustained longer than in Canajoharie Creek. In 

addition, several impoundments along the Mohawk River 

probably slow the movement of atrazine and other herbicides 

toward the Cohoes site. 

Because land use in the Lisha Kill watershed is predominantly 

urban/residential, and a much smaller proportion of the watershed 

is agricultural than in the Mohawk or Canajoharie watersheds, the 

later peak in atrazine concentration at Lisha Kill could be the 

result of a different usage and timing of applications.

—Gary R.Wall and Patrick J. Phillips

References Cited

USEPA, 1996, Drinking Water Regulations and Health 

Advisories, EPA 822-B-96-002.

Firda, G. D., Lumia, R., Murray, P. M., and Freeman, W. O., 

1994, U.S. Geological Survey Water-Data Report 

NY-94-1.

For additional information contact:

Hudson River NAWQA Project Chief

U.S. Geological Survey

425 Jordan Road

Troy, NY 12180

This fact sheet and related information can be found on 

the World Wide Web at: http://wwwdnyalb.er.usgs.gov

Additional earth science information can be 

obtained by accessing the USGS “Home Page”

on the World Wide Web at: http://water.usgs.gov 

July 1997

Figure 4: Atrazine concentrations at the three sites, May-September 

1995 (site locations shown in fig. 1)

U.S. DEPARTMENT OF THE INTERIOR—U.S. Geological Survey Fact Sheet FS-237-96

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ATRAZINE CONCENTRATION, IN 

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Canajoharie Creek

Mohawk River

Lisha Kill