Watts M J, Mitra S, Marriott A L, Sarkar S K
Inorganic Geochemistry, Centre for Environmental Geochemistry, British Geological Survey, Nottingham NG12 5GG, UK.
Department of Marine Science, University of Calcutta, 35, Ballygunge Circular Road, Calcutta 700019, India.
Mar Pollut Bull. 2017 Feb 15;115(1-2):130-140. doi: 10.1016/j.marpolbul.2016.11.057. Epub 2016 Dec 29.
The work examined the distribution, possible sources and ecotoxicological assessment of 51 trace elements covering 13 sampling stations in surface sediments of coastal regions of Sundarban mangrove wetland and adjacent Hugli river estuary. The element concentrations exhibited an increasing trend towards downstream of the estuary (except lanthanides) with maximum enrichment for 22 elements at Gangadharpur (Sundarban region). According to Sediment Quality Guidelines (SQGs), the concentrations of Cu, As, Cr and Cd exceeded the Effects-Range-Low values, while Ni at certain stations exceeded the Effects-Range-Medium suggesting adverse effects on the sediment-dwelling organisms. The geoaccumulation index revealed that the stations were unpolluted to moderately polluted. Risk Index (357.61) and Enrichment factor (11.42) depicted that Nimtala station (upstream) was at high ecological risk zone. The result of PCA endorsed that organic carbon and clay fraction play crucial role in accumulating the elements in sediments. This pilot study contributes to a better understanding of the geochemistry of this complex deltaic ecosystem.
该研究考察了孙德尔本斯红树林湿地沿海地区及邻近胡格利河河口表层沉积物中51种微量元素的分布、可能来源及生态毒理学评估，研究覆盖了13个采样站。元素浓度向河口下游呈上升趋势（镧系元素除外），在甘加德哈布尔（孙德尔本斯地区）有22种元素富集程度最高。根据沉积物质量指南（SQGs），铜、砷、铬和镉的浓度超过了效应范围低值，而某些站点的镍超过了效应范围中值，表明对底栖生物有不利影响。地累积指数表明这些站点未受污染至中度污染。风险指数（357.61）和富集因子（11.42）表明尼姆塔拉站（上游）处于高生态风险区。主成分分析结果证实，有机碳和黏土部分在沉积物中元素的积累过程中起关键作用。这项初步研究有助于更好地理解这个复杂三角洲生态系统的地球化学特征。
