Irradiation Recommended to Reduce Beeswax Contamination

Pesticide Build-Up Could Lead to Poor Honey Bee Health
Penn State (USA), 8/18/2008

Philadelphia, Pa. -- Honey bees industriously bring pollen and nectar to the hive, but along with the bounty comes a wide variety of pesticides, according to Penn State researchers. Add the outside assault to the pesticides already in the waxy structure of the hive, and bee researchers see a problem difficult to evaluate and correct. However, an innovative approach may mitigate at least some beeswax contamination.

The researchers present their analysis of pollen, brood, adult bees and wax samples today (Aug. 18) at the 236th national American Chemical Society meeting in Philadelphia. Those results show unprecedented levels of fluvalinate and coumaphos -- pesticides used in the hives to combat varroa mites -- in all comb and foundation wax samples. They also found lower levels of 70 other pesticides and metabolites of those pesticides in pollen and bees.

"Everyone figured that the acaricides (anti-varroa mite chemicals) would be present in the wax because the wax is reprocessed to form the structure of the hives," says Maryann Frazier, senior extension associate. "It was a bit of a shock to see the levels and the widespread presence of these pesticides."…

While beekeepers will have a difficult time controlling pesticide exposure outside the hive, the researchers tested a method for reducing the acaricide load in beeswax. Using gamma radiation from a cobalt 60 source housed at Penn State's Breazeale Reactor, they irradiated the sheets of beeswax that beekeepers use as the structural foundation for the bees to build their combs. They used radiation levels at the high end of that used to irradiate foods. Irradiation broke down about 50 percent of the acaricides in the wax.

"Gamma radiation is often used to kill viruses and other disease causing agents," says James L. Frazier, professor of entomology, Penn State. "Commercial irradiation firms usually decontaminate medical instruments or foods."

The researchers tried irradiation at a commercial plant and though some modifications were necessary to irradiate the wax sheets, it is possible. Some beekeepers already irradiate their equipment to get rid of any disease causing agents. However, it might be more efficient if the wax sheet supplier irradiated their product before sale to the beekeepers…

"We do not know that these chemicals have anything to do with Colony Collapse Disorder, but they are definitely stressors in the home and in the food sources," says Dr. Frazier. "Pesticides alone have not shown they are the cause of CCD. We believe that it is a combination of a variety of factors, possibly including mites, viruses and pesticides."…