From The Changing Illinois Environment: Critical Trends, 1994, Summary Report of the Critical Trends Assessment Project

As was noted in the Foreword to this report, environmental data in Illinois has typically been collected for regulatory and management purposes. That effort has been essential in achieving many pollution control successes since the 1960s. But baseline data to monitor broader ecological conditions has not generally been systematically collected on a statewide basis.

The Present

CTAP's analysis found that data on environmental pollution in Illinois is collected by different agencies acting under different laws, often using different standards. Data collection also changes with changes in the laws mandating it. Data of several kinds have not been gathered long enough to allow scientists to speculate reliably about trends. Data-gathering also tends to have a narrow focus; apart from pioneer ecological work on Illinois streams done earlier in this century, most data-gathering has limited ambitions--to test the drinkability of well water, or a company's compliance with antipollution regulations, or to count the potential harvest of a few animal species desired for sport or commerce.

Here are some specific examples drawn from CTAP reports:

Agriculture. The precise amount of fertilizers and pesticides being applied either to Illinois croplands or to urban areas is not known. Per-acre applications have changed with changing farm practice, but farm chemical use traditionally has been measured by the number of acres sprayed, not the amount of chemicals sprayed per acre.

Regarding erosion, the Sediment Benchmark Network was set up in 1981 with some 120 instream sediment data stations; by 1990 the network had shrunk to 40 stations, the majority of which have data for only one to three years. Some stations on the sediment network take readings daily, some weekly, which makes calculations of sediment loads and "budgets" unreliable.

Air. Firms obligated to report releases of toxic materials to the atmosphere are not required to report every chemical released. Also the reporting requirements have varied from year to year, and much of the data must be estimated.

Some air pollutants, including some considered toxic, have not been measured routinely in Illinois for reasons that usually involve the cost of analysis and/or the technical ability to detect their extremely low concentrations in the atmosphere.

Streams and Rivers. Even though records of flows in the Mississippi River go back 113 years and several other flow records go back 77 years, the length of even these stream-gauging records is generally not sufficient to identify fluctuations that recur less frequently than every few decades.

Not all water quality parameters are recorded at all of the more than 200 monitoring stations on Illinois waters. This makes possible more efficient use of scarce funds to monitor compliance with discharge permits, but more comprehensive data would be useful in charting ecological trends over space and time.

Current law requires that reservoirs funded by or licensed by federal agencies provide for minimum flow releases to protect the ecological integrity of downstream reaches of parent streams. Specifying an appropriate minimum flow requires knowledge of the minimum water levels suitable to various fish species, taking into account the geometries of riffles and pools, fluctuations in flow, and short- and long-term rainfall trends. Setting streamwater quality standards that are appropriate to various uses is equally difficult. There are few streams about which scientists know enough to attempt either calculation with confidence.

Groundwater. Damage from the operation of waste injection wells is known to have occurred in Illinois, but no inventory of such contamination has been made.

Most drinking well records in Illinois date from after 1970 and focus on only a few water quality criteria.

More recent samples have tested for compliance with more comprehensive drinking water regulations, and so also were analyzed for organic compounds such as pesticides or industrial solvents.

Private well records draw from more locations across the state, but tests on municipal wells tend to span more time; neither is sufficient to track long-term changes statewide.

Land. Detailed geologic mapping needed to detect earthquake hazards, chart new groundwater sources, etc. remains to be done; only 4% of the state's surface has been mapped to a scale of 1 inch : 2,000 feet.

The federal Resource Conservation and Recovery Act sets forth rules to deal with certain hazardous wastes destined for disposal on land, but the definitions under the law do not cover many of the wastes that are potentially threatening to human health and the larger environment. The staff of the Illinois Hazardous Waste Research and Information Center have concluded that it was not until 1986 that data on hazardous waste generation were reliable and sophisticated enough to warrant year-to-year comparisons.

Wetlands. Long-term interdisciplinary study is needed to learn the quality and distribution of the state's surviving wetlands; the function and values of wetlands (including their sediment, nutrient, and pollution-trapping abilities) need to be measured. Not enough is known about wetland fauna, including long-term population trends in game animals and the relationship between wetlands and bird populations. Standards for the construction and monitoring of created wetlands need to be devised and tested, as do methods for managing sediment inflows and changes in hydrology.

Even ample facts about the Illinois environment do not always lead to a proportionate increase in knowledge. Illinois scientists often are obliged to use whatever data on environmental trends are available, which often means data gathered for some purpose other than scientific inquiry. Compliance data regarding industrial and other wastes are the most numerous, but often they are not very useful in measuring pollution prevention or evaluating the risks to human health and the environment on an ecosystem basis. Likewise, researchers are hampered in their attempts to describe the spatial contours of air pollutant concentrations statewide because the limited number of sampling sites are concentrated in Chicago and Metro-East. These sites are appropriate for the purposes the monitoring was set up to achieve; if one is testing industrial pollution, one is wise to set up monitors where industry is. But the data thus collected will give only partial answers to broader questions of ecological function.

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