Researchers at U. Southern California have found that men in California’s Central valley who have been exposed to certain pesticides exhibit a greater prevalence of prostate cancer than those who were not.

The study used the cancer state registry to recruit 173 men, aged between 60 and 74, from the Tulare, Fresno and Kern counties. These men had been diagnosed with prostate cancer between August 2005 and July 2006.

The researchers then studied where these men had lived and worked between 1974 and 1999 and compared it with the pesticide use in those regions.

Researchers observed a greater cancer risk among persons exposed to pesticides with prostate-specific biologic effects; specifically, methyl bromide and a group of organochlorines.

The study brings into focus the pesticide drift related laws in the state, especially because the study focused on residential, and not occupational, exposure to the pesticides.

Dr. Myles Cockburn, one of the researchers, noted that “California’s Central Valley has by far the largest use of pesticides and the largest population potentially exposed to them in the U.S.”

However, the study is not without its critics. Dr. Robert Krieger, a toxicologist at U. California-Riverside, stated “pesticide use doesn’t equal pesticide exposure of bystanders” and it would have been better to calculate potential for absorption.

He also questioned the ability of research participants to accurately provide details of locations of pesticide exposure, which would skew the results.