Illinois
Fertilizer Conference Proceedings
January 23-24, 1990
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D.E. Kuhlman1
Hardly a day has gone by during the past year when a newspaper, magazine, radio or television program has not been proclaiming a "crisis" or concern about pesticides and water quality. This issue has attracted the attention of the general public, farmers, legislators, environmentalists, pesticide industry, scientists and almost everyone who has access to the news media.
Virtually every state has passed some legislation to deal with the issue of
pesticides and water quality. New, more stringent regulations that Congress
and many state legislatures have passed, or are considering, are just the beginning.
The debate over pesticide contaminants in water will likely rage well into the
1990s.
News headlines are feeding a fire that continues to become larger and hotter.
When the fire is finally extinguished, farmers and pesticide dealers undoubtedly
will be working with a different set of guidelines or regulations for chemical
use.
On a scale of one to 10 (with 10 being the worst possible situation), the general public is probably giving the pesticide/water quality issue an eight or nine. In reality, I believe we're at the other end of the scale, not at one, but maybe a two or three.
The problem is simply the perception of a problem fueled by inflammatory headlines. But that doesn't mean that it's a lesser problem. Perceptions wield a lot of power in our society.
People who believe agricultural chemicals are a threat to our health and the environment might be viewed as radicals by some in the agricultural community. But they may not be radicals as much as they are people asking some very tough questions.
To answer those questions, we need to deal with facts, and at this point, we don't have enough facts about the status of pesticide contaminants in groundwater in Illinois. However, state and federal agencies are conducting monitoring programs to address the concern the public has about pesticides and water quality. A summary of some of the water quality monitoring studies and programs underway in Illinois follows.
The U.S. Environmental Protection Agency is currently conducting a national pesticide survey (NPS) of community and domestic wells. The survey is designed to provide nationwide estimates of nitrate and pesticide occurrence in drinking water wells. The focus of the survey is on the quality of drinking water in wells, rather than the quality of groundwater, surface water or drinking water from the tap.
The survey will include 600 community wells representing approximately 51,000 community water systems nationally, and 750 domestic wells representing approximately 13 million domestic wells. The EPA testing program will be completed later this year.
A preliminary report on the results of the NPS is scheduled for release by the EPA in the fall of 1990, with a full analysis available in early 1991.
Table 1
Preliminary federal tests show a small number of wells with concentrations of pesticides above safe drinking levels, according to the EPA. The EPA, after receiving Freedom of Information requests, released the data in September, 1989 with cautions that no conclusions should be drawn at this stage of the national pesticide survey testing.
The NPS is designed to provide nationwide estimates of pesticide contamination. It is not designed to provide a statistically valid assessment of pesticide contamination of wells at local, county or state levels.
The preliminary findings show that six (3 percent) of 180 community water wells sampled showed some level of pesticide residues (Table 1). Seventy-nine (44 percent) of the community wells sampled showed some level of nitrate residues. None of the detections in the community wells were above EPA health advisory levels.
Of the 115 domestic wells sampled, nine (8 percent) showed some level of pesticide residue. Three of the domestic wells exceeded EPA health advisory levels; these three detects were due to two pesticides now banned by the EPA. Sixty-six domestic wells (57 percent) contained nitrate residues, eight wells (7 percent) exceeded the maximum contaminant level of 10 parts per million for nitrates.
During testing of a proposed new analytical procedure to determine concentrations of triazine herbicides in water, detectable amounts were found in 55 percent of 150 stream sites sampled in 10 Midwestern states. The testing was conducted by scientists from the U.S. Geological Survey, Department of Interior.
The steam sampling was done during early spring, 1989, before new applications of herbicides to fields.
Follow-up sampling in may and June -- after herbicides had been applied to the fields to control weeds -- yielded detectable levels at about 90 percent of the downstream sites. States included in the study were Iowa, Illinois, Indiana, Kansas, Minnesota, Missouri, Nebraska, Ohio, South Dakota and Wisconsin.
In the second round of sampling, 34.6 percent of the samples exceeded the EPA's proposed drinking water maximum contaminant level for alachlor, 56 percent exceeded the health advisory for atrazine, 11.8 percent exceeded the health advisory for cyanazine and 4 percent exceeded the health advisory for simazine.
The Illinois Environmental Protection Agency initiated a surface water monitoring program for pesticides and nitrates in October 1985, at 30 stream sites in Illinois. The 30 stations, located in predominantly agricultural watersheds, are sampled six times per year. Results for the period October 1985 through October 1988 are shown in Table 2.
The Illinois Environmental Protection Agency has established a multi-year statewide monitoring network that utilizes 3,000 community water supply wells. These wells supply water to 50 percent of Illinois' population and 74 percent of the state's community water systems. This program, initiated in 1985, included the first comprehensive statewide sampling program for volatile and aromatic chemicals, inorganics and special monitoring for extractable organics such as pesticides on a subset of wells.
The pesticide subnetwork of community wells was selected from IEPA monitoring that targeted vulnerable areas where reliance on groundwater was heavy and geological susceptibility to contamination was high. The pesticide subnetwork of community water supply wells, 50 to 100 feet in depth, were sampled for 34 pesticides. These pesticides included chlorinated hydrocarbon pesticides, organophosphate insecticides, chlorophenoxy herbicides and other select herbicides at detection limits sensitive to 20 parts per trillion. If a pesticide compound was detected, follow-up tests were conducted to confirm results.
The IEPA recently published the results of 446 water supply wells sampled through Jan. 17, 1989. Trace levels of pesticide contaminants were detected and confirmed in only five of the 446 public wells. The pesticides detected were atrazine, alachlor, cyanazine, metolachlor, and metribuzin. Pesticide levels ranged from 0.069 to 4.8 ppb for atrazine, 0.007 to 18 ppb for alachlor, 0.07 to 4.5 ppb for cyanazine, 1.2 to 12.0 ppb for metolachlor, 0.058 to 3.9 ppb for metribuzin and 0.012 for chlordane.
Initial monitoring studies by the IEPA and USEPA in Illinois indicate that pesticide levels in surface streams and public water wells are very low. Levels of pesticide contaminants, almost without exception, have been below the health advisories established by the USEPA.
Illinois Environmental Protection Agency. "A Plan for Protecting Illinois Groundwater." Submitted to the Governor, Illinois General Assembly and the Illinois Pollution Control Board, 1986.
Good, G. and A.G. Taylor. "A Review of Agrichemical Programs and Related Water Quality Issues." Illinois Environmental Protection Agency, Springfield, Illinois, 1986.
Table 1. USEPA Survey for Pesticides and Nitrates in Water Systems
Table 2. IEPA Ambient Water Quality Monitoring Pesticide Subnetwork
1Donald E. Kuhlman is Program Leader for Environmental Issues, College of Agriculture, University of Illinois at Urbana-Champaign.
