A global meta-analytical evaluation of heavy metal pollution in freshwater surficial sediments using heavy metal indices and multivariate statistical methods.

Freshwater systems globally are continually stressed by anthropogenic activities and indiscriminate pollution stemming from urban and population growth. Surface sediments are an integral part of freshwater systems and serve as a repository of organic and inorganic pollutants. Sediments are an especially abundant source of heavy metals which are degradation-resistant, inorganic contaminants that stabilize in freshwater sediment beds through adsorption, coprecipitation, and other reaction processes. The sediments subsequently serve as a point source of recontamination of the overlying water with remobilized trace metals depending on changes in the physico – and biogeochemical conditions. Our current study adopts a meta-analytical approach to assess heavy metal levels in surface sediments globally using globally-accepted pollution and ecological indices as well as applying multivariate statistical approaches to investigate environmental risks and potential sources of heavy metals. Heavy metals including As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, and Zn were analyzed from 120 publications with only average concentrations of Co and Zn within the USEPA recommended sediment quality guideline values. The environmental indices and source determination with multivariate statistical analysis methods are currently being analyzed.