摘要:
为了解南海西北部表层沉积物中的重金属元素含量空间分布规律,利用等离子体原子发射光谱仪对研究区385个表层沉积物样品重金属元素Cu、Pb、Zn、Cr进行了分析,结果表明,其丰度大小依次为Zn > Cr > Cu > Pb。元素间相关性表明,Cu和Zn、Cu和Sc、Zn和Sc的相关性较好,Cu、Zn、Sc与OrgC、Al2O3、沉积物平均粒径相关性较好,而Pb与OrgC、Al2O3、沉积物平均粒径相关性较差,Cr与OrgC、平均粒径呈负相关,与Al2O3相关性较差。采用富集因子及地累计指数对研究区重金属污染状况进行评价,结果表明,研究区各元素富集及污染程度依次为Cr > Zn > Pb > Cu。区域对比揭示,研究区重金属元素含量介于南海北部湾口和南海南部之间,总体上接近于自然背景值,呈无污染状态,Pb、Cr 2个元素在靠近海南岛沿岸及陆架局部海域受到工业或人类活动的影响而呈中等污染。
Abstract:
A total of 385 surface sediment samples were collected during the period of 2006-2011 from the northwestern SCS for investigation of heavy metal distribution pattern and assessment of pollution status. Heavy metals, such as Cu, Pb, Zn and Cr were selected as major indicators. The total and average concentrations (in mg·kg-1 for dry weight)of the elements change in ranges as follows:Zn:16 to 281(average 83.2); Cr:14.9 to 175(average 64.68); Cu:2.25 to 77.6 (average 20.10) and Pb:2.96 to 218(average 19.60). Positive correlations obviously occur between Cu-Zn, Cu-Sc, and Zn-Sc,as well as between Cu、Zn、Sc and OrgC,Al2O3, and mean grain size, while negative correlation between Cr-OrgC and between Cr-mean grain size. Enrichment factors (EF) and geoaccumulation indexes (Igeo) suggest that Pb, Cr contamination exist only in few restricted areas, such as the area near the coast and parts of shelf area. No Cu and Zn contamination has been discovered in the study area.
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