Mercury [Hg, 80]

Mercury-cell technology is being replaced by newer diaphragm and membrane-cell technology at chloralkali plants. Mercury is considered a global, hazardous pollutant, which is widespread, mobile and easily bioaccumulated. Its lowest contents are reported for soils of Sweden, 0.043 mg/kg. However, it widely varies depending on sampling sites; in water from open seas, it is within the range of 0.5-3.0 ng/L, and in coastal and bay water, it varies from 2 to 65 ng/L. It is taken up by fish straight from the water, as well as from their fodder. Mercury content of plants has recently received much attention because of its pathway into the food chain. However, plants cultivated in industrial regions may contain its higher concentrations. Mercury methylation and bioaccumulation in water depend on several parameters, such as Hg loading, microbial activity, pH and redox potential, temperature, and several factors.