Effects Of Black Carbon On Accumulation And Bioavailibility Of PCBs To Earthworms In Soils

Black carbon (BC) is ubiquitous in the soils and sediments. Recent studies have shown that the presence of BC could somehow affect the bioavailability of some contaminants in the soils and sediments. In this study, Batch adsorption experiments were conducted to study the partition between water, soil, BC and soil, earthworm lipid respectively in the ideal state. BC was manually adding into the soil by different proportion (0%,0.5%,1.5%and3.0%) to study the bioaccumulation of2-PCB,4-PCB and2,3,4,5,6-PCB in35days respectively.We firstly establish the extract, purification and separation method of2-PCB,4-PCB and2,3,4,5,6-PCB in soil and earthworm and the earthworm laboratory culture method. The experiment result shows that: the partition to BC dominates in the partition process of PCBs in water, soil and BC. The presence of BC increase the soil adsorptivity of PCBs, and there present a positive correlation between the soil adsorptivity and BC content. The logKow of PCBs can affect the PCBs partition relationship between soil, water, BC and earthworm lipid.In the dynamic accumulation process of PCBs by earthworm, the partition to BC dominates in the partition process of PCBs between soil, BC and earthworm lipid. The presence of BC can shorten the equilibration time of2,3,4,5,6-PCB bioaccumulation to earthworm to10days. BC can reduce the bioavailability of2-PCB,4-PCB and2,3,4,5,6-PCB to some different extent, PCBs bioavailability decreased with the increase of BC proportion in soil. The influence degree is different between2-PCB,4-PCB and2,3,4,5,6-PCB.2-PCB and4-PCB bioavailability is greatly influenced by BC in the soil, the influence to2,3,4,5,6-PCB is not so remarkable in comparison with2-PCB and4-PCB.