UC Engineering Researchers Find Mercury In Cicadas

Think twice before you eat one of Cincinnati's Brood-X cicadas. That's the warning from researchers at the University of Cincinnati College of Engineering, who have found surprising levels of mercury in these insects.

Because of the once-in-17-years cicada emergence throughout the Eastern United States and media reports of various food dishes involving cicadas, Tim Keener of UC's department of civil and environmental engineering department and Soon-Jai Khang of UC's department of chemical and materials engineering have measured the mercury content of fully developed cicadas taken from three different communities in Cincinnati.   

"Our results indicate that there are measurable and, in some instances, significant levels of  mercury in the cicadas, with the majority of the concentrations ranging from 0.02 - 0.20 parts per million, but some at higher levels," Keener said. The higher levels, he said, approach those in fish that have earned government warnings.

Keener and Khang are attempting to identify the source of the mercury to determine if these concentration variations are natural to cicadas or if man-made sources are contributing to the mercury levels.

"We recommend that humans, especially pregnant women and young children, limit the amount of cicadas they eat as a result of these preliminary findings.  We do not believe that eating a small number of these insects will result in irreparable harm, but mercury exposure may harm an unborn baby or young child's developing nervous system," Keener said.