秦皇岛河口及附近水域沉积物砷分布特征及生态风险评价

2011年4月在秦皇岛汤河和戴河选取13个具有代表性的表层沉积物样品,利用氢化物发生-原子荧光光谱仪测定沉积物中As含量,分析沉积物As含量与沉积物有机质、pH以及上覆水体As含量之间的相关关系,结果表明——2条河流沉积物As含量的分布均为:河口>近海岸>河段。沉积物中As含量与上覆水体中As含量呈极显著正相关关系,与沉积物的有机质含量呈显著正相关关系,与pH呈显著负相关关系。另外,文章还采用地积累指数法和潜在生态危害指数法对沉积物中砷的污染水平和潜在生态危害进行评价,评价结果显示汤河河段沉积物和戴河所有取样点沉积物As含量较低,属《海洋沉积物质量标准》第一类,其地积累指数(Ige)o属清洁水平。而汤河河口和海岸沉积物中As含量较高,属《海洋沉积物质量标准》第二类,其地积累指数(Ige)o属轻度污染或偏中度污染水平。2条河流沉积物的单因子潜在生态危害指数(Er)i均属轻微生态危害水平。

Distribution Characteristics and Ecological Risk Assessment of Arsenic in Surface Sediments of Qinhuangdao Estuary and Its Adjacent Waters

13 representative samples of surface sediments from Tang River and Dai River in Qinhuangdao were selected to measure arsenic concentration by hydride generation atomic fluorescence spectrometry(HG-AFS)in April,2011.Distribution of arsenic in these two rivers was investigated,and correlation of arsenic concentration,organic matter,pH in sediment and arsenic concentration in overlying water were also studied.Results showed that arsenic in sediments distributed from high to low as estuary,coast and river section.They were highly significant positive correlation of arsenic concentration in sediments with that in overlying water,and significant positive correlation with organics concentration in sediments.Correlation between arsenic and pH was negative.The arsenic pollution and its potential ecological risk were assessed by index of geoaccumulation and potential ecological risk index.Arsenic pollution showed that they were low in sediments of Tang River and all sampling points of Dai River,satisfying Grade I of Marine Sediment Quality Standard.It was high in estuary and coastal sediments of Tang River which reached Grade II.Results indicated that the pollution level was clean in sediment of Tang River and all sampling points of Dai River,and light/partial moderate pollution in estuary and coastal sediments of Tang River.Potential ecological risk index showed that they were both light ecological risk in sediments.