Heavy Metal Pollution In Oil Refinery On The Loess Plateau Environment Evaluation

It is well known that hazardous gas, solid wastes or waste water can come into the environment in the course of operation of mining or chemical production. If these hazardous materials can not be treated well before they move to the environment they will pollute the air, soil or water. Especially, the heavy metal contamination of soils or sediment of river around the mining area or petrochemical factory is always concerned by people. Therefore, the heavy metal contamination is one of the serious environmental issues. In this thesis, the contents and distributions in soils, sediments of river or plants around Yongping Petroleum Refinery and Yan’an Petroleum Refinery located in the different area of Loess Plateau were investigated. The assessment on heavy metal contamination of soils and sediment was carried out. Some conclusions were drawn as followings.(1) Although the conditions of natural environments of Yongping Petroleum Refinery and Yan’an Petroleum Refinery are different, the contents of macroelements and microelements of plants growing in these two areas are not significantly different in terms of the same variety of plant, however, he contents of macroelements and microelements of plants are totally different in terms of the different variety of plant. The contents of K and Ca in most of the plants are greater than that of Mg in plants. The order of microcontents of plants is Fe>Mn>Cu, Zn. The contents of elements in most of the plant stems are greater than that in plant leaves. The relationship between the contents of element in plant stems and that in plant leaves is linear which indicates that contents of elements in plant leaves rise with the increase of contents of elements in plant stems.(2) The contents f heavy metals in soils around Yongping Petroleum Refinery and Yan’an Petroleum Refinery are not significantly different in terms of the same metal element. Some of the heavy elements move down the sublayer of soil, and others accumulate in the top layer according to the distributions of elements in soil profile. The order of contents of heavy metals in soils is Fe>Mn>Zn,Cr>Cu,Pb, As>Cd, Hg。(3) The contents in sediments of rivers near by Yongping Petroleum Refinery and Yan’an Petroleum Refinery is very close to that in the soils of these two areas. However, sediment in different section of river shows a very little difference. The contents of elements in the river section close to the refinery is a little higher than that in the sections far away the refinery.(4) The soils and sediments around Yongping Petroleum Refinery and Yan’an Petroleum Refinery can not contaminated by the heavy metals according to the results of assessment of the contamination of heavy metals.