Leaching characteristics of Hexabromocyclododecane from expanded polystyrene buoy fragments in marine water

Abstract

Polystyrene (PS) is a very important plastic material for building insulation. To prevent it’s burning, HBCD(globally eliminated in May 2013) is frequently added as flame retardant. Expanded polystyrene buoys (EPS) areextensively used as floating device (2 million buoy/year) in aquaculture farming of oyster and mussel in Koreaand end up in the environment as marine debris. Due to irregular addition of HBCD in EPS buoy (~70-85 μg/gof EPS), it may be considered as a cause of HBCD contamination through leaching by sea water. Therefore,leaching characteristics of HBCD from EPS buoy fragments in water under laboratory and field conditionswere clarified. First-order reaction reflecting fast-leaching initially followed by slow-desorption over time wasobserved. Gamma-HBCD was the most abundant isomer followed by αHBCD and βHBCD of the total HBCDconcentration (4.7-10.9 μg/L, ~20%) leached in deionized water at room temperature after 96h. Significantlyenhancement in leaching with increase in temperature was attributed to fact of solubility especially αHBCDindicated high α/γ ratio. Agitation effect was more or less on similar line but not statistically different because ofdesorption-cum-absorption of HBCD. Lower salinity was favoured for leaching of HBCD. Field studies followthe order: dark exposure<sunlight exposure<sea surface with an approximately loss of 46.64, 57.39 and 66.73μg/g, respectas floating device (2 million buoy/year) in aquaculture farming of oyster and mussel in Koreaand end up in the environment as marine debris. Due to irregular addition of HBCD in EPS buoy (~70-85 μg/gof EPS), it may be considered as a cause of HBCD contamination through leaching by sea water. Therefore,leaching characteristics of HBCD from EPS buoy fragments in water under laboratory and field conditionswere clarified. First-order reaction reflecting fast-leaching initially followed by slow-desorption over time wasobserved. Gamma-HBCD was the most abundant isomer followed by αHBCD and βHBCD of the total HBCDconcentration (4.7-10.9 μg/L, ~20%) leached in deionized water at room temperature after 96h. Significantlyenhancement in leaching with increase in temperature was attributed to fact of solubility especially αHBCDindicated high α/γ ratio. Agitation effect was more or less on similar line but not statistically different because ofdesorption-cum-absorption of HBCD. Lower salinity was favoured for leaching of HBCD. Field studies followthe order: dark exposure<sunlight exposure<sea surface with an approximately loss of 46.64, 57.39 and 66.73μg/g, respect