A recent article in the Star Tribune, a Minnesota newspaper, highlights two related risks of pesticide applications – drift and volatilization. The article doesn’t deal with invasive species, and the chemical of concern is a fungicide, not an herbicide. Nevertheless, the article does point out the importance of controlling drift and volatilization from pesticide applications – which of course are commonly used to control invasive species.
The investigation was spearheaded by the Pesticide Action Network (PAN) and concerned the use of the fungicide chlorothalonil on potato crops. In an effort coordinated by PAN, residents near potato fields in northwestern Minnesota set up and checked 19 monitors at schools, in yards, and on porches. The monitoring revealed low concentrations of the fungicide in the air in and around the town of Perham, Minnesota, 68 percent of the time during the monitoring period.
One troubling aspect is that the concentrations of the fungicide in the air appear to have resulted from legal applications of the fungicide according to Linda Wells, the Midwest Coordinator for PAN of North America. It appears therefore that the chlorothalonil moved off-site some time after application such as by volatilization, i.e., the fungicide changed to a gas after application. This is concerning because it may be hard to correct the problem.
The United States Environmental Protection Agency (EPA) is currently reviewing health risks from the inhalation of chlorothalonil. In addition, EPA’s Office of Research and Development has launched a research program to assess Drift Reduction Technology.
However, until EPA acts, officials at the Minnesota Department of Agriculture, indicate there are few options. This is troubling since Minnesota state health officials find the data credible. The Star Tribune article quotes Rita Messing, a toxicologist with the Minnesota Department of Health’s division of environmental health who is familiar with the findings. Messing says “We are inclined to believe it until there is other data that is better.”