春季和夏季辽东湾表层沉积物中重金属的分布及来源

为研究辽东湾表层沉积物中重金属的分布特征及其来源,于2013年5月(春季)和8月(夏季)在辽东湾设置38个采样点,采集表层沉积物样品,测定6种典型重金属(Cu、Pb、Zn、Cd、Hg、As)的质量分数,并采用相关性、主成分及聚类分析对重金属来源进行研究. 结果表明:春季和夏季辽东湾表层沉积物中w(Cu)、w(Pb)、w(Zn)、w(Cd)、w(Hg)、w(As)平均值分别为28.77、26.62、108.89、0.50、0.03、12.09 mg/kg和26.05、24.22、71.93、0.22、0.05、11.03 mg/kg；单因子方差分析结果表明,w(Cu)、w(Zn)、w(Cd)、w(Hg)在春季和夏季有显著差异,w(Pb)、w(As)无差异. 重金属高值区春季主要分布在辽东湾北部西侧小凌河口外至葫芦岛以南海域,夏季主要分布在北部河口及鲅鱼圈、金州湾附近,低值区均位于辽东湾中部海域. 春季辽东湾表层沉积物重金属的来源主要包括有机质络合、海上活动、工业排污入海与河流所携带的工业和生活污水,夏季来源主要包括海上活动、工业排污入海、河流携带的工业和生活污水以及地表径流. 所调查的38个采样点重金属在污染程度上可分为3类,其中Cu、Zn、Hg和As属轻度污染,Pb属中度污染,Cd为严重污染；整体空间分布特点为西部和北部近河口区域重金属质量分数偏高,中部远河口海域较低. 

Distribution and Source Analysis of Heavy Metals in Surface Sediments of Liaodong Bay in Spring and Summer

Abstract: To investigate the distribution and possible origins of metallic pollutants in surface sediments of Liaodong Bay, 38 samples were collected over two consecutive seasons, May (spring) and August (summer) 2013. The concentrations of six typical metallic pollutants were monitored and analyzed, and correlation, principal component, and cluster analyses were used to establish the linkages between different parameters, to determine the possible origins of the pollutants. The results indicated that the concentrations of copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd), mercury (Hg) and arsenic (As) in spring were 28.77,6.62,8.89,0.50,0.03 and 12.09 mg/kg, while in summer they were 26.05,4.22,1.93,0.22,0.05 and 11.03 mg/kg, respectively. One-way analysis of variance showed that there were significant differences between the concentrations of Cu, Zn, Cd and Hg in surface sediments in spring and summer, but not between the concentrations of Pb and As. In spring, trace metal contamination was mainly confined to the northwestern coastal area of Liaodong Bay, from the mouth of the Xiaoling River to the south of Huludao; however, during summer it was distributed throughout the northern area of the bay, and also throughout Bayuquan and Jinzhou Bay. The main sources of heavy metal contamination in spring were organic matter complex, marine anthropogenic sources, industrial wastewater, urban sewage and river discharge, while in summer, with the exception of organic matter complex, the sources remained the same, but were supplemented with additional stormwater runoff. The pollution statuses of heavy metals of the 38 monitoring stations were divided into three groups based on the average enrichment factors (AEF). Cu, Zn, Hg and As belonged to slight degree, Pb belonged to medium degree, and Cd belonged to strong degree, which showed that the concentrations of metallic pollutants around the western and northern offshore areas were much higher than those in the central region of the study area.