锦州湾及附近河口沉积物中砷含量、分布及形态

Arsenic concentration, distribution,and forms in the waters and sediments of Jinzhou Bay and its adjacent estuaries

对葫芦岛3条河流和锦州湾水体、沉积物中As的含量、分布和形态进行了研究。结果表明:葫芦岛的连山河和五里河未受到明显的As污染,沉积物总As含量低于10mg·kg-1,河水As含量低于10μg·L-1,茨山河下游紧邻葫芦岛锌厂,受到了一定程度的As污染,沉积物As含量达75.2mg·kg-1;五里河口区As污染非常严重,锌厂在该区排污口处沉积物As含量高达3176.1mg·kg-1,超过国家沉积物As标准158倍;受锌厂排污的影响,锦州湾As污染也很严重,沉积物中As最高含量达到569.5mg·kg-1,沉积物和孔隙水含量在剖面上具有相似的变化趋势,表明孔隙水As含量主要受沉积物As含量影响;锦州湾沉积物中As主要以可交换态存在,残渣态次之,盐酸提取态最少,表明锦州湾沉积物中As的活性很强,有大量的可交换态As随时会进入上覆水体,是重要的As释放源,而铁对As行为的影响占次要地位;沉积物中大量As的释放可能会对葫芦岛和锦州湾地区生态系统造成严重的威胁。

Sediment and water samples were collected from Jinzhou Bay and three rivers of Huludao to investigate their arsenic concentration, distribution, and forms. The arsenic concentration in the sediments and waters of Lianshan River and Wuli River, and in the sediments of the downstream of Cishan River adjacent to zinc refining plant was lower than 10 mg·kg^-1 and 10 μg·L^-1, and reached to 75.2 mg · kg^- 1, respectively, indicating that the former two rivers did not suffer significant arsenic pollution, while the downstream of Cishan River was arsenic-polluted to a certain degree. Wuli Estuary was very seriously arsenic-polluted. In the effluent of zinc refining plant at Wuli Estuary, the arsenic concentration was as high as 3176. 1 mg · kg^-1 , being 158 times higher than the national sediment guideline. Because of the release of effluent and slag from the zinc refining plant, Jinzhou Bay was also very seriously polluted, with the highest concentration of arsenic reached to 569. 5 mg · kg^- 1. There was a similar vertical distribution pattern of arsenic concentration in the sediments and pore-water, suggesting that the arsenic concentration in pore-water was mainly controlled by that in sediments. The results of sequential extraction showed that exchangeable arsenic was the dominant form, followed by residual arsenic, and amorphous Fe oxides-arsenic, illustrating that the arsenic in the sediments was very active and easily released to the above waters, possessing a chronic and serious threat on the ecosystems of Huludao and Jinzhou Bay. The influence of Fe oxides on the behaviors of arsenic in the sediments was not significant.