By Dan Klepal
Enquirer staff writer

The Little Miami River and Great Miami River watersheds have levels of pesticides and other harmful chemicals that are among the highest in the country, according to a three-year study.

At least one pesticide was found in all of the samples taken during the U.S. Geological Survey of the main rivers and many streams and creeks that feed them - an area that drains thousands of miles of land and stretches from Hardin County in the northern part of the state to the Ohio River in Hamilton County in the south.

HOW IT HAPPENS

See a representation of how chemicals get into rivers and streams and read about the effects those chemicals have. (Acrobat PDF, 508k) Click here to view PDF.

Those pesticides, used on agricultural fields and home lawns or gardens, were found largely at or above limits set by the federal government to protect human health and wildlife.

Pesticides and the other chemicals found in the water can change the nature of the stream by creating algae blooms that foul the water and kill fish.

They can also harm the reproductive systems of fish and other wildlife that live in or around the streams, and harm humans who eat too much fish out of the streams or drink untreated water from aquifers under the waterways.

"These chemicals are ingested by fish to the point that a number of fish populations have disappeared and some are difficult to separate by sex, so who knows what will happen to us?" said Mike Fremont, president of Rivers Unlimited, a statewide activist group.

Atrazine, a herbicide used by farmers for weed control, was found in 98 percent of the water samples analyzed for the study. The U.S. Environmental Protection Agency has classified atrazine as a possible human carcinogen.

The chemical also can cause eye irritation at lower exposure levels and affect the nervous system at higher levels.

"Atrazine is cheap and it's everywhere," Fremont said.

The U.S. Geological Survey conducted the study in the Southwest Ohio and Southeast Indiana river basins from 1999 to 2001.

It is studying 51 other watersheds across the country to determine what pollutants threaten the nation's waterways.

In addition to pesticides, the study of the Miami river basins found other harmful chemicals in the water, or in fish tissue, including:

• Polychlorinated biphenyls, or PCBs, which were banned in the 1970s, but are still present in fish tissue at some of the highest levels in the nation.PCBs do not break down, so bottom-feeding fish still ingest PCBs that were deposited in streams decades ago.

• Mercury, a highly toxic metal that gets into waterways largely through energy company smokestacks, was found in fish tissue at a level equivalent to the national average. The Ohio Environmental Protection Agency has warned people to limit the number of fish meals they eat out of the Miami rivers, largely because of mercury.

• Nutrients, such as phosphorus and nitrates, which primarily come from fertilizer applied to cropland and discharges from sewage treatment plants, exceeded drinking water standards in 10 of 104 samples taken from underground water sources during the study. But nutrients in the two rivers and their feeder streams were among the highest in the nation.

Heavy loads of nutrients can lead to algae growth that limits recreation and kills fish. The Great Miami River basin has 5.7 tons of nitrogen per square mile and 700 pounds per square mile of phosphorus. By comparison, the Mississippi River basin yielded 1.4 tons per square mile of nitrogen and 240 pounds per square mile of phosphorus.

Some good news

About half of the 116 household chemicals and pharmaceuticals the study tested for were detected, but at low concentrations that pose no threat to wildlife or humans. These include disinfectants, antibacterial chemicals and antibiotics.

The study also found that water treatment plants do a good job of removing harmful chemicals from city drinking water supplies.

Fly fishing is a favorite pasttime for Bob Ireton from Eastgate (left) and Bob Kimsey from Cherry Grove. The duo fished the Little Miami near Milford Sunday morning. (Enquirer photo/MICHAEL E. KEATING)

Dave Reutter, a hydrologist with the U.S. Geological Survey who helped write the report, said the pesticides in the water are a concern for fish and the wildlife that eats them, more so than humans. "Those pesticides do have some effect on aquatic life," Reutter said. "How much of an effect is a good question. We're still trying to understand that. But they are present at concentrations that exceed aquatic life guidelines. So it's a concern.''

As far as human consumption, the water treatment plants do a good job of removing those chemicals."

Bob Ireton, a 57-year-old member of the Buckeye United Fly Fishers group, has caught fish from most of the Miami rivers and their tributaries. Ireton said he wouldn't eat anything he catches out of any of the streams. In fact, he usually wears waders to keep the water off his skin.

"I always catch and release, because a good fish is becoming too rare a commodity," Ireton said.

Bruce Koehler, president of the activist group Friends of the Great Miami River, called the report a "call to action." Koehler said the pesticides and other chemicals present in the streams make their way into underground aquifers. When private wells draw from the aquifer, it pulls water from the surface into the underground lakes, he said.

Koehler said people who tap directly into the aquifer for their drinking water aren't protected from the chemicals.

---

E-mail dklepal@enquirer.com