CHAMPAIGN — Sixty years ago, an Illinois farmer could expect to harvest about 50 bushels of corn per acre. Today, yields can approach 200 bushels, thanks in part to herbicides that reduce competition from weeds.

Such bountiful harvests fuel our food and energy economy while maximizing production per acre. But along with the many benefits, there are costs that should be acknowledged and minimized.

Conventional crop production involves the intensive use of chemical inputs such as fertilizers, insecticides, fungicides and herbicides. Some of these chemicals, such as DDT and chlordane, were found to be unsafe and have since been banned.

One of the most controversial chemicals still in use in the United States is the herbicide atrazine, which has been banned in the European Union.

Atrazine is applied to the majority of corn acres in Illinois. It can be found in more than 20 corn herbicide premixes, including some formulations of Bicep, Harness Xtra and Keystone. It is popular among farmers because of its low cost and ability to kill grasses and broadleaf weeds without harming corn plants. But atrazine affects more than just plants. Studies using animals suggest that atrazine is an endocrine disruptor capable of altering sexual development and reproduction. Implications for human health remain unclear, but we are wise to heed the warning signs.

Atrazine is capable of reaching farm families and other residents living downwind or downstream. People can inhale atrazine that moves by aerial drift after an application. Atrazine is one of the most frequently found herbicides in groundwater in the Midwest, so rural residents who rely on wells may ingest atrazine in their tap water.

Atrazine also is in many of our rivers and surface drinking water supplies, including Lake Vermilion. The herbicide is typically applied in May, and spikes in river and lake concentrations can be observed for weeks afterward. According to the Illinois Environmental Protection Agency, more than 280 stream miles and 3,755 lake acres in Illinois are polluted by too much atrazine.

The health and safety of Illinois residents and the natural world rely on the responsible use of chemicals, whether those chemicals are industrial, agricultural, or residential in nature. While farmers do not intend for atrazine to leave their fields, wind and rain carry some atrazine away. Application and field management techniques can reduce the loss of this valued farm input. But herbicide applicators must also realize they are applying atrazine, which may be but one of the active ingredients in herbicide mixtures.

Complying with application setback requirements will reduce the chance of atrazine leaving the farm. The label instructions state atrazine is not to be applied within 200 feet of lakes and 66 feet of streams or rivers that receive field runoff. Application also must not occur within 50 feet of wells, and 66 feet of tile inlets unless certain conditions are met.

The establishment of vegetation between agricultural fields and inlets, wells, or surface waters can reduce the chance of atrazine getting into water systems.

Avoiding application before storms also is recommended because less atrazine will wash away with runoff. Keeping atrazine on the land is not only in the best interest of public and environmental health, but also makes economic sense.

The Illinois Department of Agriculture and University of Illinois Extension encourage the use of practices that reduce application rates and/or prevent atrazine from reaching water. In fact, in their 2009 factsheet on atrazine (http://www.agr.

state.il.us/Environment/AtrazineBMPGuide.pdf), they seem to warn that such practices are necessary by stating: “To help keep this weed control option, producers should begin now to reduce atrazine losses, protect the local water supply and help their neighbors.” If action is not taken soon, regulations could be on the horizon like they are in Wisconsin.

Atrazine has the potential not only to cause health problems, but to impose economic costs as well. Drinking water suppliers have to ensure the finished water meets federal standards. If atrazine in the water supply exceeds these standards, suppliers have to adopt the technologies to reduce atrazine to acceptable concentrations. These costs may be passed on to customers. In the case of domestic wells, homeowners living near corn fields may want to test their tap water for atrazine and invest in an appropriate filtration system if the herbicide is detected. Unfortunately, in some cases protective measures may be cost-prohibitive.

Spring is on its way, and with it will come the annual ritual of corn planting and atrazine application. Lake Vermilion, the drinking water supply for Danville and surrounding towns, will be fed by the spring rains that drain the agricultural fields of northeastern Vermilion County. Atrazine will likely spike well above the 3 parts-per-billion drinking water standard. Or maybe it will not. Hopefully enough people will take steps to make a difference.

Dr. Stacy James is vice-chair of the Lake Vermilion Water Quality Coalition and a water resources scientist with Prairie Rivers Network, a statewide river conservation organization. The group is based in Champaign. Visit:  http://www.prairierivers.org.