Study On The Determination And Assessment Of Metal Elements In The Sediment Of The Le'an River Basin And Poyang Lake By Microwave-assisted-ICP-AES

In order to determine correctly the inorganic elements in sediments of PoyangLake, a microwave digestion method and ICP-AES (Inductively CoupledPlasma-Atomic Emission Spectrometry) method were studied in this paper .Thedigestion method was investigated and optimized by using different digestionsolutions; the amount of acids; digestion procedure and the amount of sample whichwill be digested. The seasonal, annual and alongshore variation and the pollutionsituation of the heavy metals' degree of the sediment of Poyang Lake during theseyears were also determined and discussed as well. Meanwhile, the matter elementanalysis has been used to optimize points selection of water quality monitoring in thedrainage area of Le'an River, it's the preparation of the wide scale optimized pointsselection of Poyang Lake basin. The results showed that:(1) The 13 traditional monitoring points in the drainage area of Le'an Rivercan be optimized to 9monitoring sites.(2) An optimal digestion method was established to carry out the furtheranalysis of all sediment samples: weigh up 0.5 g sample, take apretreatment by heating in the electric plate for about 15 min at 180℃,adding HNO₃-HF-HClO₄ or HNO₃-HF-H₂O₂ in the proportions of 4:4:2,microwave digestion procedure was 5 atm/3 min-10 atrn/2 min-15atm/5 min-20 atm/10 min.(3) Content of the elements in the sediment of Poyang Lake were changingby seasons and years. Generally, the content of each element inlower-water period is higher than the higher-water period; and thecontent of each element was decreased with the year changing. FromRaohe River to the Raohe River at the intake of Poyang Lake, thecontent of each element trend to decrease gradually.(4) The order of the analyzed elements arranged from highest to lowestpollution degree, is as follows: Cu＞Pb＞Zn＞As＞Cr;(5) The ecological risk of each elements to Poyang Lake is: Cu＞As＞Pb＞ Cr＞Zn;(6) Use microwave-assisted-ICP-AES to determine the trace element in thesediment of Poyang Lake, the method of operation is simple, fast,efficiently and low labor intensity.