Subject: PANUPS:Well Contamination

From: Pesticide Action Network North America Reg Ctr <[email-masked]>
Date: Thu, 15 Oct 92 16:13:14 PDT

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PESTICIDE ACTION NETWORK NORTH AMERICA UPDATES SERVICE
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NEW EVIDENCE OF ATRAZINE WELL CONTAMINATION

October 15, 1992

	A recent study measuring atrazine breakdown products in 
Wisconsin well water indicates that previous testing substantially 
underestimated the extent of contamination. Using gas 
chromatography to reanalyze water from 236 contaminated wells, a 
1992 study by Ciba-Geigy (atrazine's major manufacturer) found that 
three chlorinated atrazine breakdown products were not detected by the 
standard chemical assays for atrazine.  As a result of this finding, a 
third of the well owners in the study were advised to stop drinking the 
water from their wells.
	An initial study conducted by the state of Wisconsin in 1990 
surveyed 2,187 Wisconsin wells, using a conventional immunoassay 
for atrazine parent compounds.  Immunoassay tests are used to 
determine the presence of specific compounds.  The immunoassay tests 
used in the 1990 study do not provide information about level of 
contamination, or the presence of breakdown products.  Of the wells 
tested by the state, 351 were identified as contaminated with atrazine.
	Only wells with the highest atrazine levels in the 1990 study 
were retested for total atrazine residues (including breakdown 
products) in the 1992 study.  The more sensitive tests employed in 1992 
revealed that over a third of the retested wells contained atrazine 
levels above the Wisconsin regulatory Preventive Action Limit (PAL) 
of 0.35 parts per billion (ppb) of atrazine.  In all the retested wells, 
deethylatrazine, deisopropylatrazine, and diaminoatrazine (atrazine 
breakdown products of toxicological concern) were detected at total 
levels above the current PAL (0.30 ppb for total atrazine residues).  
Many of the wells no longer contained the parent compound, and in 
some wells, breakdown product levels far exceeded those of the parent 
compound.  Atrazine breakdown products are also likely to be present 
in many of the wells that were not retested, although people drinking 
from those wells may have been advised that their water was not 
contaminated, based on the earlier test results.
	In Wisconsin, over 100 drinking water wells thus far have been 
identified as contaminated above 3.0 ppb, the state and federal drinking 
water standard for atrazine.  The Wisconsin Department of Agriculture 
estimates, based on statistical extrapolation, that at least another 100 
wells are contaminated above the drinking water standard.
	Atrazine, a triazine herbicide, is the most widely used pesticide 
in the U.S. (70-90 million pounds of active ingredient in 1989).  
Atrazine was the pesticide most frequently detected in the U.S. 
Environmental Protection Agency's (EPA) 1990 National Drinking 
Water Survey, and has been widely detected in rainwater, surface 
water, and lakes and ponds.  It is a severe eye irritant, a mild skin 
irritant and has demonstrated numerous chronic health hazards in test 
animals, including reproductive effects and various cancers.  EPA 
considers atrazine to be a possible human carcinogen.
	Atrazine's defenders have contended that high levels of the 
herbicide are found only in spill sites and/or isolated areas.  It is now 
apparent, however, that atrazine contamination is widespread in 
Wisconsin groundwater.  This raises important questions about the 
continued use of atrazine and other pesticides known to contaminate 
water, and the dangers of relying solely on conventional 
immunoassays to measure the extent of water contamination.
	The Wisconsin Department of Agriculture has proposed a rule 
that would prohibit all use of atrazine in areas contaminated above the 
drinking water standard.  Under this rule, areas with wells 
contaminated below the 3.0 ppb level will be allowed to use atrazine in 
a restricted manner.  There is no evidence proving the restricted use 
will adequately protect the drinking water supply.  The Wisconsin 
Public Intervenor is pressuring the Department of Agriculture to adopt 
a more stringent rule that would, at a minimum, prohibit the use of 
atrazine in the areas where atrazine has been detected over the PAL 
(0.35 ppb).  Public comments to the Wisconsin Department of 
Agriculture will assist the state to adopt the more protective rule.  Send 
letters urging the adoption of the Public Intervenor's suggestions to: 
Wisconsin Department of Agriculture, Secretary Alan Tracy, 801 
Badger Road, Madison, WI 53708.

Sources:  Memo from Tom Dawson, Public Intervenor, State of 
Wisconsin (July 1, 1992); Journal of Pesticide Reform, Winter 1991.

Contact:  Tom Dawson, Wisconsin Department of Justice, 123 West 
Washington Ave., P.O. Box 7857, Madison, WI 53707-7857.

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This information is provided by the Pesticide Action Network North 
America Updates Service (PANUPS), a pesticide-related news service 
from the Pesticide Action Network (PAN) North American Regional 
Center. Updates are posted weekly on EcoNet in the "en.pesticides," 
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PENpages agriculture information service at Penn State Univ. Hard-
copy compilations of these updates are also available. For more 
information about PAN activities and publications, contact: PAN NA 
RC, 965 Mission Street #514, San Francisco, CA 94103. Tel: (415) 541-
9140. Fax: (415) 541-9253. Telex: 156283472 PANNA. E-mail address on 
EcoNet: [email-masked]
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