Just before Christmas, Minnesota state agencies issued an alarming report about an agricultural watershed in trouble. But instead of analysis and recommendations to protect the watershed, the agencies took a reticent approach (“Major fish kill to remain a mystery,” Dec. 23).

The 367-page report of the fish kill investigation in the South Branch of the Whitewater River has a familiar theme: Move along, nothing to see here. The unified response from the Minnesota Department of Agriculture, the Department of Natural Resources and the Minnesota Pollution Control Agency details the five-month investigation but does not identify the cause or those responsible. Families who use groundwater as a source for drinking, as well as anglers and others who use the Whitewater for recreation are wondering why our state agencies take such a passive approach. Why won’t they tell us about the risks to our health and the environment?

At the end of July, a 2-inch summer rain muddied the Whitewater River between Utica and Altura. It was typical weather, but this time the rain followed weeks of intense aerial spraying — of insecticides on soybeans, fungicides on corn — and manure spreading on freshly cut hay or peas. The river rose rapidly as the runoff from the surrounding farms turned the silt-, pesticide- and manure-laden water into a toxic stew that killed the trout, suckers, minnows and crawfish in a 6.5-mile stretch of a blue-ribbon trout stream.

No individual leaks, spills or toxic releases were identified; only typical agricultural activity occurred on the nearby fields that drained to the kill site. Other nearby streams were unaffected. According to the final report, the investigation estimated that 9,000 to 10,000 fish had been killed by toxins, with their gills described as “fried.”

In the days after the event, the investigators found traces of 14 pesticides in the water, high levels of nitrates from fertilizers and troubling levels of toxic metals in manure from local farms, but no smoking gun and, strikingly, no assessment of the combined toxic effect of multiple farm chemicals.

The public is left wondering: Is the Whitewater River safe? Will the fish kill be repeated? Was the groundwater affected, and is it safe to drink? What can be done to avoid a new disaster? Have our resource agencies abandoned the state’s citizens?

The finding that there was no single perpetrator was clear within weeks, but now, months later, the agencies have run away from the obvious conclusion — that modern farm chemicals currently authorized for crop protection can kill fish and pollute our water even when the chemicals are applied at recommended and currently legal rates. Our agencies have totally failed to communicate the possible health and environmental impacts and seem intent on ignoring the interests and values of Minnesotans.

We can explain the lack of risk assessment and clear communication by looking at the goals of each of the agencies involved: The Ag Department is intent on protecting the chemical companies from the onslaught of criticism over our polluted waters; the DNR is careful not to discourage anglers and outdoor enthusiasts who buy the licenses that support the agency; and the MPCA is careful not to criticize the rural residents and land managers who might someday make needed watershed improvements.

As an environmental consultant with 25 years’ experience, I know that risk assessment and communication is a mature field, which I believe has been largely ignored here by the state agencies. Basic principles of environmental hazard oversight must involve citizens with local knowledge and expertise in the assessment, communication and management of environmental risks. Experienced risk managers know that both alarming statements and over­assurance should be avoided, and uncertainty should be acknowledged. Agency transparency, clarity and simplicity of messaging is always needed to gain trust and is necessary to prevent future environmental problems.

We must demand Minnesota agency leaders who are capable of acknowledging and communicating environmental risks throughout Minnesota — leaders who can, and will, honestly acknowledge, and manage, both the known and the potential risks. Otherwise, the state’s agencies will condemn our rural watersheds to repeated calamities, as witnessed this summer.

In the Whitewater basin, we can’t simply move along. We can’t ignore the fact that current agricultural production practices will kill our fish and pollute our water.

Jeffrey S. Broberg, of St. Charles, Minn., is a geologist and environmental consultant. He lives in the Whitewater watershed, three miles from last summer’s fish kill.