A controversial herbicide used widely in the Peoria area and throughout the Midwest is the subject of a presentation from noon to 2 p.m. Sunday at Universalist Unitarian Church, 3000 West Richwoods Boulevard. The presentation is free and open to the public.

Dr. Paul Winchester, medical director of the NICU at St. Francis Hospital, Indianapolis, will speak about his research into the effects of atrazine, an endocrine disrupting chemical, on human health.

In one study, he found statistically significant correlations between birth defects among children conceived during peak periods of atrazine application. His further research found statistically significant correlations between learning disabilities among children conceived during peak periods of atrazine application.

Atrazine, an herbicide widely used on corn, is found pervasively on surface water in this country. It has been banned by the European Union. A class action lawsuit over atrazine in drinking water was settled in 2012 for $105 million. Peoria and Springfield  were among central Illinois communities that shared in the settlement because atrazine is found regularly in the communities’ tap water.

When Winchester first joined the hospital staff, he noted what he thought was an inordinately high number of birth defects among newborns. He found no plausible explanation, so he designed a study. He correlated 30.11 million births nationwide between 1996 and 2002 with birth defects diagnosed in the first days of life. In a paper published in Acta  Paediatria, a peer reviewed journal, Winchester reported disproportionately high rates of birth defects for children conceived between April and July, the peak period of atrazine applications.

“The positive correlation was so strong I couldn’t believe it,” Winchester said. “This study is one of the most shocking things on the planet. It’s frightening to me.”