The Heavy Metal Pollution And Risk Assessment On Human Health Of Farmland Soil In The Goldfield

Soil is an important factor of the natural environment, as well as the keystonethat human relies on for. It is crucial and necessary to study heavy metalpollution and risk, especially for soil environment monitoring warning systemand rational use of land resource.This paper chose the heavy metal contents offarmland soil and crops in Xiaoqinling goldfield as the research objects.7kindsof these heavy metals in them are tested to map its regional distribution andidentify pollution. Set up the time-predict model of soil heavy metal in currentsituation.By using different evaluation techniques and criteria, this paperquantitively evaluated the heavy metal pollution of soil and its potential eco-risk,then evaluated its human health risk, and compared human health risks in spotswith different pollution levels. Finally summarized some results:(1) The pollution characters of7kinds of heavy metal are summarized.According to the cumulative indexes of every single element, Hg, the elementsof Pb, Cd, Cu, Zn, Cr are accumulated by the input from mining activities.According to the pollution index,58%soil samples are polluted,95.95%land area is polluted. According to potential eco-risk indexs, more than80%samples’integrated risk exceeded the serious level.(2) Ascertain the main polluting elements are Hg, Pb, Cd, Cu, these fourelements value are the top4in the following five parameters respectively duringall elements: single cumulative indexes of single element, rate of contributionfor comprehensive cumulative index, content variation rate from2005to2009,exceeding standard times, potential eco-risk index. Therefore, the recoveringworking should start with those4elements, and mainly monitor those4elements.(3) Find out the heavy metal pollution regional distribution. The maximumvalue of Hg, Pb, Cd, Cu are distributed in the same or near spots, so these4elements share the same origin. The maximum value site in Wenyu, Xiyu,Shuangqiao river basin and Xiyao village, the location of these place are thesame with the pollution source of mining activities, so the soil heavy metalpollution are caused by mining activities.(4) Among the studied expose pathways, dietary intake is the main to bringabout human health risk. The heavy metals go into the food chain, finally got into the human body and create harm. The non-carcinogenic risk illustrated theresidents’ health is in danger seriously, the most dangerous elements are Pb, Crand Cu. The carcinogenic risk exceeds the regulation of USEPA, and Cd causesa higher carcinogenic risk.(5) No matter the dietary intake or the skin exposure, the orders ofnon-carcinogenic risk and carcinogenic risk caused by soil pollution are thesame to the heavy metal comprehensive pollution index. The more soil pollution,the more risk to the human health.