Study On The Complex Pollution Of Heavy Metals In Liangtan River

In the rapid development of industry and agriculture, due to advanced technology and management level, the human ability is greatly improved to change the objective world, and people's living standard is booming. But the pollution and destruction to environment being brought by the economic benefits can't be forgotten.Heavy metals include mercury, lead, copper and other metals having biological toxicity, sometimes also including these metals provided with certain toxic, such as zinc, nickel, cobalt etc.. Through discharge of industrial wastewater, the use of pesticides and fertilizers and the accumulation of mining residue, many heavy metals are taken into the environment, and their accumulation over time in the bodies of animals can cause serious illness by the way of food chain. The Shuiyu disease and Gutong disease in japan are the most famous pollution incident in the history of environmental protection, respectively caused by the pollution of mercury and cadmium. So the heavy metals pollution received the attention from domestic and international researchers. However, few relate researches about the heavy metals pollution of mainly subprime rivers in three gorges area, especially the liangtan river.In the investigation, we also found another pollution source in liangtan river, that is the breeding pollution. Liangtanhe river basin is located in the outskirts of chongqing, and convenient transportation provides a good condition for the development of livestock and poultry farms, a important part of the pillar industries. However, because of the large quantities of wastewater without treatmen is wantonly emissioned into Liangtanhe river from livestock and poultry farms, a very serious pollution is brought to this basin, which also increase the metal element enrichment.Therefore, the upper-middle liangtan river, where large waste water containing heavy metals was discharged, was researched in this article, and 6 heavy metal elements (Including zinc, lead, copper, cadmium, chromium and nickel) and 3 trace elements (Including iron, magnesium and manganese) were respectively measured by flame atomic absorption spectroscopy and inductively coupled plasma optical emission spectrometer, which were token from water, sediment, soil and plants.The conclusions are as follows:â‘ Heavy metal pollution has both been existing in the mainstream and tributaries of upper-middle liangtan river, and the concentration of mainstream is higher. The contents of heavy metals is ascend in first and descend at last along the flowing direction, and reach their peaks in the middle reaches;â‘¡Through the comparison with the limits in corresponding environmental function areas, the contents of Zn and Cr in water and plants fail to meet the standard, especially Zn pollution largely from electroplate workshop is serious evere, and other heavy metals pollution also exist in soil and sediment;â‘¢Using the method of potential ecological risk index, the conclusions are sum med up from evaluating e potential ecological harm degree: Only 29.2% samples from liangtan river show lower harm, which demonstrates that a lot of heavy metals have potential ecological risks, including Cd with the strongest potential ecological risks;â‘£Lots of Fe, Mn and Mg are distributed in XiYong-Tuzhu site, where many Livestock and poultry farms are built here. This result explains that the concentration of these metal elements is closely related to the livestock farming systemsis.Finally, some views and suggestions are put forward by author on how to prevent two big pollution prevention mentioned above in liangtanhe river basin.