Marine Sediment’s Profile for Mercury as Pollution Indicator at Karachi Coast

Total mercury (regardless of its form) is investigated as a pollutant in the marine system of coastal regions of Karachi for the period between 2006-2008. Seawater, sediment, and filter feeders have been focused for total mercury content (THg). Seven sites were selected for analyses. Sites have been categorized into polluted and safe areas. Polluted area happens to be near the city and safe area is beyond the civil activities. Manora is identified as most polluted station. Industrial and domestic effluents have been identified to be a major source of pollution. Bioaccumulation and bio-amplification in ecosystem has also been monitored through analyses on sediment and filter feeder (barnacles, oyster, and mussels). For a period of three years seasonal variations have also been marked. Monsoon and non-monsoon metal load was specifically recorded and compared. Future THg levels are also being predicted as an outcome pertaining to three years data. Cold vapor AAS is employed as a major analytical tool. As another independent analytical technique the anodic stripping voltammetry (ASV) was employed to ascertain these results. Physicochemical parameters also support the THg analyses outcomes. Several statistical tests like ANOVA and PCA have been employed for comparison and data reduction.