The Geochemical Characteristics And Environmental Quality Assessment Of Soils From Liaohe River Basin,Liaoning Province

As one of the major plains in northeast China,Liaohe River Basin is the main agricultural area of production in China,so it is the mainly study region in this paper.The soil samples were collected using geochemical survey of traditional methods,and the 54 elements were tested and analyzed.The compilation of geochemical map was drawn,and the source,migration and transformation of abnormal elements was researched.Then,the soil geochemical characteristics were identified,and the environmental quality was evaluated.That provided a scientific basis for improving the market competitiveness of agricultural products and adjusting agricultural structure.The conclusions were showed as following.(1)The content of elements in the plain area was overall in enrichment state compared with the national soil background value or the average value of the Liao River Basin.Compared with the whole basin,the content of soil elements in hilly area is relatively poor,except for Si and K.Influenced by the widespread distribution of aeolian sandy soil,the contents of Si,K in the hilly areas are higher than those in other areas,while the extreme lack of other elements.Meanwhile,the organic carbon,Sr and Zr are highly enriched in the mountain area(including the edge of Liaodong mountain and the west of Liaoning Province).(2)Through single index evaluation,it showed that the pollution range of cadmium,nickel,copper and mercury was greater than arsenic,chromium,lead and zinc.Related to the degree of urban economic development and the scale of industrial production,cadmium,mercury,lead and zinc were the highest in urban areas,industrial areas and mining areas.Meanwhile,the pollution distribution characteristics of chromium,copper and nickel were more related to natural factors.The pollution degree of heavy metals is very small in the basin,except for cadmium,and most of the soil conformed to the one or two grade soil environmental standard.(3)Through the fuzzy weighted evaluation,we could see that the soil environmental quality in Liaohe River basin was good as a whole.The first grades and second grades of soil were larger,accounting for 87.88% and 6.16% of the total soil area,and the third grade and four grade were 4.67% and 1.28%,respectively.94.04% of soil in Liaohe River Basin was good,which was suitable for safe use of agricultural production;5.95% of the soil was polluted,which was not suitable for the safe production of crops.49164 km2 in Liaohe River Basin of Liaoning province,accounting for 94%,was suitable for the development of pollution-free agriculture,and 48240 km2,accounting for 92%,was suitable for the development of green agriculture.