U.S. Geological Survey

Cover image from WRIR 02-4063 (click for enlargement, 71 KB) Concentrations of Pesticides and Pesticide Degradates in the Croton River Watershed in Southeastern New York, July-September 2000

by Patrick J. Phillips and Robert W. Bode

U.S. GEOLOGICAL SURVEY
Water-Resources Investigations Report 02-4063


ABSTRACT

Thirty-seven pesticides and (or) pesticide degradates were detected in baseflow samples collected from 47 stream sites in the Croton River Watershed (374 square miles) in southeastern New York in the summer of 2000. The Croton Reservoir provides about 10 percent of New York City's water supply. Maximum concentrations of most pesticides detected did not exceed 0.1 μg/L (micrograms per liter). This study, by the U.S. Geological Survey in cooperation with the New York State Department of Environmental Conservation, was conducted from July through September 2000 and entailed analysis of the samples for more than 150 pesticides and their degradates. Nine compounds were detected at a concentration greater than 0.10 μg/L; three of these were insecticides (diazinon, carbaryl, and imidacloprid), one was a fungicide (mycobutanil), and five were herbicides (simazine, 2,4-D, diuron, hexazinone, and 2,4-D methyl esther). Only two of these compounds (simazine and 2,4-D) were detected at a concentration exceeding 1 μg/L; the simazine concentration exceeded the New York State surface-water standard of 0.5 μg/L. Two insecticides (diazinon and azinphos-methyl) exceeded aquatic-life-protection standard in one sample each. Concentrations of three insecticides (chlorpyrifos, carbaryl, and malathion) were more than 50 percent of the aquatic-life-protection standards in one sample each. 

Total concentrations of insecticides and herbicides (the sum of the concentrations, whereby all concentrations below the detection limit were set to zero), and the concentrations of the herbicide prometon and the insecticide diazinon, were highest in samples from watersheds with population densities greater than 510 per square mile (21 sites); therefore, the presence of these compounds is attributable to urban, residential, and other developed land uses. 

The data obtained in this study are useful for making general comparisons among watersheds with differing land uses, but the concentrations represent baseflow conditions and, thus, are probably lower than the annual maximum concentrations in these streams. A July baseflow sample had total insecticide and fungicide concentrations of less than 0.03 μg/L, whereas a stormflow sample collected at the same site 2 weeks later had a corresponding concentration greater than 0.10 μg/L. Total herbicide concentrations for the July baseflow and stormflow samples were around 0.03 μg/L, but that for a stormflow sample collected at the same site 2 months later was greater than 20 μg/L. 


Citation: Phillips, P.J., and Bode, R.W., 2002, Concentrations of Pesticides and Pesticide Degradates in the Croton River Watershed in Southeastern New York, July-September 2000: U.S. Geological Survey Water-Resources Investigations Report 02-4063, 20 p.

Download full PDF report   [Full Report, Acrobat PDF (2.2M)]

Adobe Acrobat's .pdf (portable document file) format can be viewed using the free Adobe Acrobat Reader available for DOS, Windows, Macintosh, and UNIX.

Users with visual disabilities can visit this site for conversion tools and information to help make PDF files accessible.


For more information, contact

U.S. Geological Survey
425 Jordan Rd
Troy, New York 12180
(518) 285-5602
E-mail









To order copies of printed reports, contact

U.S. Geological Survey
Information Services
Box 25286, Federal Center
Denver, CO 80225
1-888-ASK-USGS
E-mail

Return to the New York District Home Page



USGS Water Biology Geology Mapping On-Line Water Resources Investigations Reports On-Line Water-Resources Reports

U.S. Department of the Interior, U.S. Geological Survey
Maintainer: New York District Publications
URL: http://ny.water.usgs.gov/pubs/wri/wri024063/index.html
Last update: 09:38:43 Tuesday 15 January 2013
Privacy Statement || Disclaimer
FirstGov, 'Your First Click to the U. S. Government'