Our previous research on atmospheric samples suggested that Lake Ontario might receive significant amounts of Dechlorane Plus(DP),a highly chlorinated flame retardant,from the atmosphere and from inputs from DP's manufacturing facility in Niagara Falls,New York.To confirm this suspicion,a sediment core from the central basin of Lake Ontario was analyzed for the two isomers of DP,for polybrominated diphenyl ethers(PBDEs),and for 1,2-bis-(2,4,6-tribromophenoxy)ethane(TBE).The results showed that the concentration of DP in sediment increased rapidly starting in the mid-1970s and reached its peak concentration(310 ng g~(-1)dry weight)in the mid-1990s.The peak flux and total inventory of DP were estimated to be 9.3 ng cm~(-2)yr~(-1)and 120 ng cm~(-2),respectively.These values suggest that the total burden of DP in Lake Ontario is ~20 tons and that the maximum load rate was ~2 tons per year.The highest concentrations of PBDEs and TBE were found in the surficial sediment,with average concentrations of 2.8,14,and 6.7 ng g~(-1)d.w.for PBDE_(3-7)(tri-through hepta-BDEs),BDE-209,and TBE,respectively.The surface fluxes were 0.08,0.43,and 0.20 ng cm~(-2)yr~(-1),and the inventories were 0.87,3.9,and 1.8 ng cnr2 for PBDE_(3-7),BDE-209,and TBE,respectively.The concentration of DP in Lake Ontario sediment exceeds that of the brominated flame retardants combined.
展开▼
School of Public and Environmental Affairs,Indiana University,Bloomington,Indiana 47405,Water Science and Technology Directorate,Environment Canada,Burlington,Ontario,L7R 4A6 Canada;
