THE mighty irrigation schemes of California's Central Valley Project, begun in the 1930s, turned arid land in the Sacramento and San Joaquin Valleys into an agricultural cornucopia. But in doing so, they intensified a chemical threat that could end the agricultural productivity of much of the western United States. "Death in the Marsh," by Tom Harris, is in part a record of the discovery of that threat.
The book opens at the Kesterson National Wildlife Refuge in 1983, which became the repository for runoff water from some San Joaquin Valley farms in 1975. Two government biologists canoeing through a Kesterson marsh are uneasy at the unnatural silence, startled by the sterile clarity of the marsh water, and finally shocked by the discovery of many dead, deformed hatchlings in the few waterfowl nests. Laboratory tests show that the element selenium is poisoning the birds.
Selenium occurs naturally in a type of marine shale commonly found in the arid West. Beneficial in tiny amounts, it can be toxic to plants, animals, and even humans in larger doses.
Prompted by the findings, Harris and another environmental reporter for the Sacramento Bee surveyed sites throughout the western United States and discovered large amounts of the element. Death, they found, was not only in the marsh, but on the prairie, in fishing holes, and in selenium-concentrating vegetation. The investigation was the start of what Harris calls "the equivalent of an agricultural Superfund in the West."
In revealing dangerous levels of the element over thousands of square miles in 15 states, the reporters uncovered paradox as well as poison. Ranchers were losing livestock, garden plants, and even domestic pets. Families often suffered ill effects from locally obtained food and water. Yet most were reluctant to cooperate with the probe. Concern over property values and the salability of surviving livestock often made them hostile to the reporters who wanted to ask pointed questions and came to their land
to take samples of the soil and water.
Human actions exacerbated the problem by concentrating the runoff wastes from fertilizers and animal feed containing high concentrations of selenium at places like Kesterson. But the larger story is the widespread nature of selenium's threat, and the bureaucratic attempts to manipulate the facts.
Harris uncovered a good deal of existing but little-known research. Scientists knew about the danger of selenium concentrations in Western soils and water as early as 1929, Harris says, but were pressured by superiors to downplay or withhold reports for economic or political reasons.
The implications of selenium are enormous, and Western agriculture may hang in the balance. If no action is taken, continuing contamination will force the abandonment of nearly half a million acres of irrigated farmland in the San Joaquin Valley alone.
A five-year government study of Kesterson made major recommendations, including reducing the amount of applied irrigation water. But the rest of the West awaits the results of a study by the US Department of Interior. The government is apparently putting an optimistic spin on its conclusions, Harris writes.
"Death in the Marsh" is sometimes heavy with technical and chemical details. But it is a fascinating study of the defensive reactions of individuals and bureaucracies when faced with a threat they cannot see, the dire consequences of which they would rather not contemplate.