To spray or not to spray

August 16, 2007

THE MASSACHUSETTS Highway Department has gone back and forth on whether to use herbicides to control roadside vegetation. It sprayed them in the 1990s, stopped until 2003, and then resumed using them that year. It should go on the wagon again.

The alternatives are to use nontoxic, organic herbicides and to remove plants by hand or with mowers or weed whackers. These options are the preference of the Massachusetts Coalition for Pesticide Reduction, which includes such groups as the Toxics Action Center and Environment Massachusetts. Twelve legislators have joined in opposing the spraying.

The core of the coalition's argument is that humans and the environment at large are already exposed to enough harmful chemicals without additional ones from the highway department. The department says that it removes unwanted bushes and weeds manually or mechanically on the vast majority of the 48,200 acres it maintains but needs the herbicides for about 188 acres -- less than half of 1 percent of the total -- where manual removal is too hazardous to workers. Commissioner Luisa Paiewonsky says that much of the vegetation removal is needed for safety reasons, to maintain drivers' sight lines. She says the state takes all precautions to protect its workers from the chemicals.

Yet the country's basic approach to toxic substances that have been in use for decades -- innocent until proven guilty -- makes more sense with defendants in courts than with chemicals in the environment. Except in the most obvious cases, like DDT or Agent Orange, conclusive guilt is difficult to prove. So the country's farmlands, orchards, utility and railroad rights of way, and highways continue to be sprayed with chemicals.

There are indications, however, that their toxicity extends beyond the vegetation or insects they are intended to kill. Oust, one of the herbicides the state uses, has been shown to harm animal reproductive systems. Cornell University professor David Pimentel says the country loses 67 million birds each year to pesticide use on farmland alone.

The commissioner says the department does not spray near residential areas or wetlands. "We take extraordinary steps to limit the environmental impact," she says. And she suggests that the alternatives are not always sufficient. Scientists at the University of Massachusetts studying organic herbicides or steam applications as ways of controlling road vegetation have reported in a preliminary finding, she said, that such methods do not attack nuisance plants as systematically as commercial herbicides do. She also said the organic herbicides require more frequent applications than toxic herbicides.

Those disadvantages have to be weighed against the cost to the environment. The state should return to its old policy of controlling unwanted vegetation without herbicides.