上海、乌鲁木齐与昌吉三市城市土壤重金属富集特征比较研究

选择上海、乌鲁木齐、昌吉3个城市,通过对其城市土壤重金属含量水平、分布特征及活性的比较研究,发现城市土壤中Cr、Cu、Pb、Zn含量均远高于背景值,但Mn、Fe含量与背景值差别不大;上海市Cr、Pb、Zn含量最高,而昌吉市Cu含量最高,城市规模的大小并不能直接反映土壤重金属含量的高低,工业污染物排放量、交通量、城市规模大小、城市发展历史、工业区位置及变迁、土壤背景值等因素均会影响土壤重金属含量水平。除Mn、Fe无明显的功能区分布差异外,各城市重金属功能区分布规律并不相同,城市污染来源的不同可能是主要原因。重金属活性并未与其含量分布规律完全一致,上海土壤重金属活性大于乌鲁木齐、昌吉,上海土壤pH值小于乌鲁木齐、昌吉可能是主要影响因素,但也存在上海土壤中个别重金属活性小于乌鲁木齐、昌吉的现象,污染物来源存在差异等可能是主要原因。也可能较强,反之亦然。

A Comparative Study of Heavy Metals Enrichment Characters of Urban Soils in Shanghai, Urumqi and Changji

Results were presented from a comparative study of heavy metal enrichment characters in Urban Soils of three cities in China. The first （Shanghai） was a super large urban area （population of 18.88 million）, the second （Ummqi） was a large urban area （population of 2.31 million）, the third, Changji, a small one （population of 0.35 million）. Several trends were identified： contents of Cr, Cu, Pb, Zn were lfigher than background values, contents of Mn, Fe were close to background values. Since discharged of industry contamination, and current traffic movements, industrial and urban processes entirely influenced heavy metals concentration, the size of city were not therefore reflect direct enrichment level of heavy metals in urban soil. The main contaminated sources varied with the cities resulted in different of heavy metals distributing in different functional areas except for Mn and Fe. Contents of active fraction in heavy metals were not consistent with the contents of heavy metals.