Distributions, Compositions And Sources Of PCDD/Fs, DL-PCBs In Surface Sediments From Jiulong River Estuary And West Harbor

Surface sediment samples were collected from Jiulong River Estuary and West Harbor in Jan.of 2007.The concentration,distribution,composition and sources of PCDD/Fs(Polychlorinated dibenzo-p-dioxins and dibenzofurans,PCDD/Fs) and DL-PCBs(dioxin-like polychlorinated biphenyls,DL-PCBs) were studied.The conclusions were showed as follow:The concentrations of PCDD/Fs in sediments from Jiulong River Estuary and West Harbor were 59.99 pg/g d w-4 089.19 pg/g d w(1 706.55 pg/g d w in average) and OCDD was the main component.While the concentration of DL-PCBs were 3.1 pg/g d w -39.82 pg/g d w(18.00 pg/g d w in average).The main components were penta-CBs.The positive correlation was observed between PCDD/Fs and DL-PCBs.The toxicity equivalent(TEQ) concentrations of PCDD/Fs were 0.174 pg/g d w-6.785 pg/g d w(3.483 pg/g d w in average).OCDD gave the greatest contribution to it.While the toxicity equivalent concentrations of DL-PCBs were 2.40×10^-3 pg/g dw-97.45×10^-3 pg/g d w(50.41×10^-3 pg/g d w in average) and penta-CBs played the main role in them.The total TEQ were 0.176 pg/g d w -7.875 pg/g d w.The values were all smaller than related evaluation standards.According to the toxicity in sediments:TEQ_PCDDs＞TEQ_PCDFs＞TEQ_DL-PCBs.From the estuary to the open sea,the concentrations of PCDD/Fs and DL-PCBs were decreased gradually.It indicated that river water was the main source.PCDD/Fs in the sediment were probably introduced by using of PCP(polychlorinated biphenyl) in Jiulong river basin.Moreover,gain size and content of organic matter in sediment effected the distribution of PCDD/Fs and DL-PCBs at different sampling stations,seriously.Clay sediments which posses fine particle and high content of organic matter greatly adsorbed PCDD/Fs and DL-PCBs.