Martin G D, George Rejomon, Shaiju P, Muraleedharan K R, Nair S M, Chandramohanakumar N
Department of Chemical Oceanography, School of Marine Sciences, Cochin University of Science & Technology, Cochin 682016, India.
ScientificWorldJournal. 2012;2012:972839. doi: 10.1100/2012/972839. Epub 2012 May 3.
Concentrations and distributions of trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in surficial sediments of the Cochin backwaters were studied during both monsoon and pre-monsoon periods. Spatial variations were in accordance with textural charaterstics and organic matter content. A principal component analysis distinguished three zones with different metal accumulation capacity: (i) highest levels in north estuary, (ii) moderate levels in central zone, and (iii) lowest levels in southern part. Trace metal enrichments are mainly due to anthropogenic contribution of industrial, domestic, and agricultural effluents, whose effect is enhanced by settling of metals due to organic flocculation and inorganic precipitation associated with salinity changes. Enrichments factors using Fe as a normalizer showed that metal contamination was the product of anthropogenic activities. An assessment of degree of pollution-categorized sediments as moderately polluted with Cu and Pb, moderately-to-heavily polluted with Zn, and heavily-to-extremely polluted with Cd. Concentrations at many sites largely exceed NOAA ERL (e.g., Cu, Cr, and Pb) or ERM (e.g., Cd, Ni, and Zn). This means that adverse effects for benthic organisms are possible or even highly probable.
在季风期和季风前期对科钦回水区表层沉积物中的痕量金属（镉、钴、铬、铜、铁、锰、镍、铅和锌）的浓度及分布进行了研究。空间变化与质地特征和有机质含量一致。主成分分析区分出了三个具有不同金属积累能力的区域：（i）河口北部含量最高，（ii）中部区域含量中等，（iii）南部含量最低。痕量金属的富集主要归因于工业、生活和农业废水的人为排放，由于有机絮凝和与盐度变化相关的无机沉淀导致金属沉降，其影响得以增强。以铁作为归一化剂的富集因子表明，金属污染是人为活动的产物。对沉积物污染程度的评估将沉积物分类为：铜和铅为中度污染，锌为中度至重度污染，镉为重度至极度污染。许多地点的浓度大大超过了美国国家海洋和大气管理局的效应浓度低值（例如铜、铬和铅）或效应浓度中值（例如镉、镍和锌）。这意味着对底栖生物可能会产生不利影响，甚至极有可能产生不利影响。
