Evaluation of Mercury Contamination in the Caspian Sea's Sediment by GIS and Geostatistic

Heavy metals, in particular mercury, are important for the public health due to their toxicity and endurance in the environment. In the present study, the distribution of mercury was surveyed along the coast of the Caspian Sea (Mazandaran province). Twelve stations were selected and from each station 5 samples were randomly collected followed by chemical analyses. An inverse weightdistance method was used to interpolate the distribution of mercury. The correlation among physicochemical characteristics of sediments, organic matter, electrical conductivity, acidity, and the distribution of mercury was investigated using the distribution map of all these parameters. Overlaying the distribution maps of mercury concentration and the measured sediment parameters indicated that the mercury concentration was accordance with organic content and electrical conductivity. Generally, the total amount of mercury in the investigated stations was lower than the maximum levels recommended by NOAA. The findings of the present study provide useful information about distribution of heavy metals along the coast of the Caspian Sea that can help monitoring and assessment of sediments in the region.