Author
James, Rosalind | |
ELLIS, J. - University Of Florida | |
Duehl, Adrian |
Submitted to: Agricultural Sciences
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/17/2012 Publication Date: 1/15/2013 Citation: James, R.R., Ellis, J., Duehl, A.J. 2013. The potential for using ozone to decrease pesticide residues in honey bee comb. Agricultural Science. 1(1): 1-16. Interpretive Summary: The potential for using high concentrations of ozone was evaluated to determine its ability to reduce pesticide contamination of honeycomb and empty honey bee hives. Honey bees can become exposed to pesticides when they forage for nectar and pollen in agricultural fields, and when beekeepers use in-hive chemical pest control measures. Some of these pesticides can build up in the comb over years, potentially harming the bees. Beekeepers remove the comb every year for honey extraction and then store the comb during the winter. We tested whether the stored combs could be fumigated with ozone to reduce pesticide contamination levels. Fumigation rates of 920 mg O3/m3 for 10-20 h, can reduce coumaphos residues by 93-100%, and tau-fluvalinate by 75-98% on glass. However, ozone was much less effective at eliminating pesticides on beeswax comb, especially in very old, dark-colored comb. Other pesticides that were significantly reduced with ozone fumigation included dimethylphenyl formamide, chlorpyrifos, and fenpyroximate. Ozone was more effective at eliminating pesticide contamination in new combs (< 3 y old) than old combs (>10 y old), and thus should not be used on old comb. Ozone treatment does give comb an off-odor, but the break down products found were harmless. Technical Abstract: As a strong oxidizer, ozone is known to breakdown some organic pesticides, and we evaluated the potential for using a gaseous fumigation of ozone to decontaminate honeycomb and empty honey bee hives. Honey bees are inadvertently exposed to pesticides when they forage for nectar and pollen in agricultural fields, and when beekeepers use in-hive chemical pest control measures. Persistent pesticides can accumulate in the hive over years, potentially harming the bees. Honeycomb is removed from bee colonies by beekeepers for annual honey extraction, and subsequent to this activity, the empty combs could be fumigated to reduce pesticide contamination levels. Ozone, when used at a rate of at least 920 mg O3/m3 for 10-20 h, can reduce coumaphos residues by 93-100%, and tau-fluvalinate by 75-98% on glass. Ozone was much less effective at eliminating pesticides on a beeswax substrate, especially when the pesticides were formulated or incorporated into very old comb. Other pesticides that were significantly reduced in honeycomb were dimethylphenyl formamide, chlorpyrifos, and fenpyroximate. Pesticide residues are more effectively oxidized in new combs (< 3 y old) than in old combs (>10 y old). When combs are treated with ozone, they obtain an off-odor, but volatiles being released were primarily straight chain aldehydes and carboxylic acids, which are probably harmless to the bees and humans at post treatment levels. The addition of a strong hydrolyser would probably increase the pesticide degradation rates, but more importantly, the ozone needs to penetrate into wax, a goal not fully accomplished by this method. |