某化工厂周边不同介质中铬含量及形态特征

SPECIATION CHARACTERISTICS AND CONTENT OF CHROMIUM IN DIFFERENT MEDIA AROUND A CHEMICAL FACTORY

为了解某化工厂附近土壤铬污染状况及其生物有效性,研究了该化工厂周边的土壤、粉尘、排污底泥、工业废渣和水等不同介质中重金属含量及Cr的化学形态特征。结果显示,该区域土壤出现以化工厂为中心的大面积Cr异常;废渣和部分底泥中Cr的含量是土壤背景值的近100倍乃至上万倍;表层土壤和粉尘中Cr元素含量与化工厂距离变化曲线的一致性,表明化工厂粉尘是引起大面积Cr异常的主要污染源;不同介质中Cr元素主要以残渣态(生物不可利用态)存在,但底泥中Cr的潜在可利用态、废渣中Cr的可利用态存在一定的比例,会对当地的动植物和人体产生负面的生态效应,应重视其可能引起的生态后果。

Speciation characteristics and content of chromium （Cr） in different media around a chemical factory were studied to under-stand Cr pollution status in soils and its bio-availability. The media included soil, dust fall near the surface, bottom sludge, waste resi-due, and water. The sheet abnormal chromium areas centered at the chemical factory were found. The Cr content of waste residue and some bottom sludge reached one hundred or thousands times the soil background value. The Cr concentrations of topsoil and atmospheric dust samples were similar when the distance was taken into account, suggesting that the dust fall of the chemical factory is the main source of large-area pollution of Cr anomaly. Chromium in media exists mainly in residual speciation, but the average proportion of bio-available Cr in waste residue and potential bio-available Cr in some bottom sludge is 9.52% and 51.08%, respectively. Chromium has a significant negative effect on the health of organisms in the study area due to its high concentration and biological activity. Thus, it is essential to take measures to protect the ecological environment and plan the reasonable land use.