Water Quality In Indiana's White River Basin Affected By Urban And Agricultural Activities

April 08, 1998

Water quality in the White River Basin is impacted by urban and agricultural activities, according to the results of a five-year investigation by the U.S. Geological Survey (USGS), Department of the Interior.

A variety of pesticides used for agricultural or urban uses were commonly found in streams throughout the White River Basin. In contrast, only a few pesticides were found in ground water, and these were at much lower concentrations. Pesticide concentrations in streams in the White River Basin were among the highest found at USGS monitoring stations nationwide.

Twenty-five different pesticides or pesticide degradation products were found in at least 5 percent of samples near the mouth of the White River. The widely used agricultural herbicides atrazine and metolachlor were always found. "In a few samples, concentrations of the herbicides atrazine, alachlor, or cyanazine exceeded Federal drinking-water standards or advisories; however, annual average concentrations of each of these compounds in the White River were below their respective standard or guideline," said USGS hydrologist Charles G. Crawford, project leader of the White River Basin study.

Fourteen different pesticides were found in a network of 94 shallow monitoring wells; six were found more than once. However, Crawford said, "No pesticide concentration found in ground water came close to exceeding a Federal drinking-water standard or advisory." In cropland areas with a surficial sand and gravel aquifer that is particularly vulnerable to contamination but is also an important source of drinking water for residents of the basin, atrazine compounds were found in two-thirds of monitoring wells but only at trace levels. Shallow wells are most susceptible to contamination and provide insight into the effects of pesticides and fertilizers on ground-water quality. Pesticide concentrations typically decrease with depth in an aquifer. The presence of only low pesticide concentrations in shallow wells indicates they are probably not present in the deeper ground water used most commonly for domestic or public supply.

Most, but not all, of the pesticides found were associated with agricultural use. Pesticide concentrations in streams differ according to land use. Crawford said that lawn insecticides (such as diazinon) are commonly found in streams in urban areas, whereas corn herbicides (such as atrazine) are more commonly found in streams in agricultural areas. Pesticide concentrations in streams are highest in areas with permeable, well-drained soils, all other factors being equal. Agricultural tile drains play a major role in transporting pesticides to streams in areas with poorly drained soils. Nitrate concentrations in ground water are low (commonly not found) in some aquifer settings and high (sometimes exceeding the Federal drinking-water standard) in others. Nitrate concentrations in stream water typically are between these extremes. Median concentrations of nitrate at monitoring sites in streams generally ranged from 2 to 6 milligrams per liter-higher than those at most other USGS monitoring sites in the United States.

Soil drainage is a major factor controlling nitrate concentrations in streams. "Concentrations tend to increase as the proportion of naturally or artificially drained soils in the basin increases," said Crawford. "Manure from farm animals also increases nitrate concentrations in some streams." Nitrate concentrations in stream water rarely exceeded the Federal drinking-water standard of 10 milligrams per liter.

Surficial sand and gravel aquifers underlying cropland had high nitrate concentrations. Samples from 17 percent of shallow monitoring wells in this setting exceeded the Federal drinking-water standard. However, deeper wells (25 to 50 feet below the water table) in these unconfined aquifers typically had little or no detectable nitrate. In many parts of the basin, nitrate concentrations in ground water were low. For example, sand and gravel aquifers protected by overlying clay typically had low concentrations of nitrate. Such aquifers are present in more than half the basin and are a common source of water for rural domestic users.

Runoff from urban areas degrades the quality of streams and ground water. "Concentrations of trace metals and organic compounds in streambed sediments tended to be above background concentrations in urban areas, particularly Indianapolis," said Crawford. "Concentrations are generally not a human-health concern; however, fish-consumption advisories for PCB's and mercury are in effect for some locations in the basin." Several chemicals whose use has long been banned (chlordane, dieldrin, and PCB's) persist in streambed sediments and are concentrated in organisms such as freshwater clams.

Fish communities have significantly improved since the early 1970's, although degraded communities of fish still are found in streams with poor water quality. Some streams with good fish habitat presently have degraded communities of fish, a disparity indicating nonhabitat stresses (such as poor water quality). In areas where the fish communities are poorer than expected on the basis of fish habitat present, nutrient and pesticide concentrations are high.

The White River Basin study is one of more than 50 studies across the nation being done by the U.S. Geological Survey as part of its National Water-Quality Assessment (NAWQA) Program. Through the NAWQA Program, the USGS provides policymakers and citizens with information about current conditions and trends in water quality and an assessment of the factors that affect water quality across the United States.

The report, "Water Quality in the White River Basin, Indiana, 1992-1996," by Joseph M. Fenelon is published as U.S. Geological Survey Circular 1150. Copies of the report are available free of charge from the USGS Indiana District Office, 5957 Lakeside Boulevard, Indianapolis, IN 46278, (317) 290-3333 or the USGS Branch of Information Services, Box 25286, Denver Federal Center, Denver, CO 80225, (303) 202-4700 [fax requests to (303) 202-4693; an order form is available at URL: http://www-nmd.usgs.gov/esic/to_order.html].
-end-


US Geological Survey

Related Pesticides Articles from Brightsurf:

More plant diversity, less pesticides
Increasing plant diversity enhances the natural control of insect herbivory in grasslands.

In pursuit of alternative pesticides
Controlling crop pests is a key element of agriculture worldwide, but the environmental impact of insecticides is a growing concern.

Two pesticides approved for use in US harmful to bees
A previously banned insecticide, which was approved for agricultural use last year in the United States, is harmful for bees and other beneficial insects that are crucial for agriculture, and a second pesticide in widespread use also harms these insects.

Dingoes have gotten bigger over the last 80 years - and pesticides might be to blame
The average size of a dingo is increasing, but only in areas where poison-baits are used, a collaborative study led by UNSW Sydney shows.

Pesticides can protect crops from hydrophobic pollutants
Researchers have revealed that commercial pesticides can be applied to crops in the Cucurbitaceae family to decrease their accumulation of hydrophobic pollutants, thereby improving crop safety.

Honeybee lives shortened after exposure to two widely used pesticides
The lives of honeybees are shortened -- with evidence of physiological stress -- when they are exposed to the suggested application rates of two commercially available and widely used pesticides.

Pesticides increase the risk of schistosomiasis, a tropical disease
Schistosomiasis is a severe infectious disease caused by parasitic worms.

A proposal to change environmental risk assessment for pesticides
Despite regulatory frameworks designed to prevent environmental damage, pesticide use is still linked to declines in insects, birds and aquatic species, an outcome that raises questions about the efficacy of current regulatory procedures.

SDHI pesticides are toxic for human cells
French scientists led by a CNRS researcher have just revealed that eight succinate dehydrogenase inhibitor pesticide molecules do not just inhibit the SDH activity of fungi, but can also block that of earthworms, bees, and human cells in varying proportions.

Pesticides deliver a one-two punch to honey bees
A new paper in Environmental Toxicology and Chemistry reveals that adjuvants, chemicals commonly added to pesticides, amplify toxicity affecting mortality rates, flight intensity, colony intensity, and pupae development in honey bees.

Read More: Pesticides News and Pesticides Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.