Screening of Insecticides in Bats from Indiana

This study identified insecticides that were detected in bats obtained from Indiana’s Lake Michigan watershed. Forty bats collected from Lake, Porter and LaPorte Counties, Indiana, were analyzed for pyrethroid, organochlorine, organophosphate and carbamate insecticides. Additionally, brain cholinesterase activity of 332 bats from throughout Indiana was measured and cholinesterase reactivation tests were performed. Organochlorine pesticides (dieldrin, DDT, DDE, DDD and heptachlor epoxide) were detected in 97.5% of the tested bats; organophosphate compounds (primarily diazinon) were detected in 30%; pyrethroids in 12.5% and carbamates in 2.5% of the bats, respectively. Cholinesterase determination and reactivation tests yielded both false negative and false positive errors, which indicate that reactivation methods are not suitable for analyzing tissues from animals that are not recently dead. These results are among the first reported detections of pyrethroids and carbamates in bat tissues.