Content And Traceability Of Pb In Clam Ruditapes Philippinarum With ICP-MS

Using inductively coupled plasma mass spectrometry (ICP-MS) to detect the Pb content inthe clam Ruditapes Philippines under both simulated experimential condiation and coastcultureareas offshore, because of "fingermark characteristic" of the isotope Pb, the possible source of Pbin R. philippinarum could be traced. The results as following:(1) Adsorption of Pb in Chlorella vulgaris. In this experiment, in order to observe the effectof different Pb concentration on the growth of C. vulgaris, different Pb concentrations was set.The results showed that with the Pb concentration increased from20μg/L to200μg/L, theabsorption value and cell density of C. vulgaris were both decreased. The absorption valuedecreased from0.902to0.217, the density of C. vulgaris decreased from1.08×106number/mLto6.12×105number/mL, this indicated that the inhibit effects of Pb on C. vulgaris growth wasobviously appeared. In addition, it can be found the C. vulgaris has ability on Pb adsorptipon,and can reach the adsorbed equilibrium very quickly. The adsorption rate of C. vulgaris reached82%-95%at the end of experiment. Meanwhile, the value of206Pb/207Pb,207Pb/208Pb，206Pb/208Pbin C. vulgaris was checked. It is confirmed that the Pb source of C. vulgaris is adsorbing fromdissolved Pb2+in seawater.(2) In order to trace the source of Pb in R. philippinarum, the C. vulgaris-R. philippinarumfood chain enrichment processes was investigated, including both206Pb in seawater-R.Philippines adsorption process and C. vulgaris–R. Philippines food chain enrichment process.Based on the ratio of206Pb/207Pb、207Pb/208Pb、206Pb/208Pb in seawater, C. vulgaris, and R.philippinarum, it could be concluded that the C. vulgaris-R. philippinarum food chainenrichment processes is the important way of Pb enrichment.(3)In order to assess the lead pollution in Dalian typical coastculture areas and trace thepollution source, Dalian Jinshitan, Dalijia and Pikou were served as the typical monitoring area,and R. philippinarum was selected as the target shellfish. Meanwhile, the possible source of leadin R. philippinarum was traced using a stable isotope tracer technique. The results showed thatthe concentration of lead in seawater was below the second degree of Sea Water QualityStandard, as well as the potential ecological risk of lead in the sediment was belonged to the lightdegree. The content of lead in R. philippinarum was below the limit standard of pollution-free aquatic product. At the same time, the value of206Pb/207Pb in R. philippinarum was approximateto the sediment, which indicated the lead in R. philippinarum maybe came from the sediment.