| River ecological system is featured of great basin area, abundant fresh water resources, largepopulation, high–density towns and developed industrial and agricultural. Environmental issuesof some large basin are being concerned by governments and scientists all over the world. TheSonghua river is the largest branch of Heilongjiang right bank, and one of7largest rivers in China,and also the largest river within the territory of Heilongjiang province.According to the southernsongnen plains1:25million multiobjective geochemistry survey results show that the nen river,main stream local area of songhua river, ALunHe, Harbin and qiqihar, etc in areas surrounding thecities along the existing Pb, Cd, Hg and other harmful element anomaly. Soil, surface water,underground water pollution is serious, water loss and soil erosion problems such as increased.According to the1:25million multiobjective geochemistry survey data, tracking the songhuariver basin anomaly element migration pathways and source. Mainly in songhua river mainchannel and the main branch into the opening place, system acquisition suspended matter andstream sediments, river sediment and water sample. Analysis of heavy metal elements, beneficialelements, and determined the heavy metal elements, beneficial elements and settle in quantity,find out the heavy metal and beneficial elements transfer the main way and control factors, thestudy of human production and living to major element migration influence degree; At the sametime using isotope dating techniques, computing the past100years flood plain average depositionrate, the reconstruction of heavy metal elements, constant element geochemical history, predictionof heavy metal element change trend.Songhua river basin in the suspended matter element content variation characteristics showthat the songhua river basin of suspended matter is the large span element migration of the maincarrier; The content of heavy metal elements in the suspended from upstream to downstream isrising distribution features, the downstream of the second songhua river and ASHLEY river heavymetal elements in the upper reaches of the significantly higher than the other branch; The second songhua river is the study of the element years output flux largest tributary.The results by Source-Indicating&Tracking on heavy metals in suspended matter elementanomaly show that heavy metal pollution in ASHLEY river is in serious.The results of recovery element sedimentary history showed that element content of heavymetals in the surface sediments of sedimentary column is lower than limits of the National SoilEnvironmental Quality Grade II; and changing characteristic over time of the content of heavymetals coincides with some important historical events such as founding of new China, thecultural revolution, reform and opening up and process of large-scale industrialization in China;As per prediction and alerting on security geochemical of Songhua River valley ecosystem:the content of heavy metals of Cd, Hg etc shows rising trend in recent years in sediment columnin lower reaches of Qiqihar, Bayan reach and Arun He branch; and on current trends, the contentof Cd in lower reaches of Qiqihar, Bayan reach and Arun He branch will respectively exceed limitvalue in the national " soil environment quality standard "(GB15618-1995) grade III. by theyear2100,2060, and2061.Therefore, human activity is one main reason which results in anomaly of heavy metalelements in Songhua River basin. |
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