Leaching of decabromodiphenyl ether and hexabromocyclododecane from fabrics under simulated landfill conditions

摘要

A series of laboratory experiments were conducted to examine the leaching of decabromodiphenyl ether (BDE-209) and hexabromocyclododecane (HBCDD) from a mix of three fabrics. Consistent with previous reports that such leaching is governed by second order kinetics, concentrations in leachate were markedly higher in the first 24?h of leaching, and diminished by an order of magnitude after 1 week. The influence of the waste:leachate ratio was examined for the first time, with leaching of both BDE-209 and HBCDD significantly greater (p??0.05) at a waste:leachate ratio of 0.005?g/mL than at 0.05?g/mL. Using dissolved humic matter (DHM) solutions as proxy for simulating organic landfill leachates we found that leaching of both BDE-209 and HBCDD was also significantly greater at a DHM concentration of 1,000?mg/L in leachate compared to that observed at DHM values of 100 and 0?mg/L. Agitation of waste:leachate mixtures significantly enhanced leaching. While leaching of HBCDD decreased significantly as leachate pH increased from 5.8, through 6.5, to 8.5; no significant impact of pH on leaching of BDE-209 was detected. Concentrations in leachate of both BDE-209 and HBCDD decreased significantly on increasing leachate temperature from 20?°C to 60?°C and 80?°C. This is considered most likely due to volatilisation of these contaminants into the headspace of the leaching vessel at higher temperatures.