Spatial and Temporal Distribution of Heavy Metals in Marine Sediment Along the Doha Bay

Abstract

Concentrations of twenty five heavy metals (Ag, Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Sr, V, Zn, and Hg) in surface sediment from ten transects each with five stations were studied. The sediment samples were collected in May and December 2012 in order to examine the spatial and temporal variation and investigate the pollution sources. Significant differences were observed in metal concentrations between the sampling locations and durations. Higher concentrations were observed in areas where there are a lot of anthropological activities. The distribution of selected metals were presented in contour maps showing the variation between the two periods. Moreover, it was observed that December 2012 sampling was significantly higher than May 2012. In order to further study particle size effect on metals uptake, two different grinding times were administered on four randomly selected samples and the results showed no significant difference on the analysis in the ICP-OES instrument. The overall results of metal analyses were within the international standards criteria and the results were comparable to the previous studies conducted around Qatar. A monitoring approach is recommended for the sediment quality assessment. Additional examinations were conducted using contour maps that show the distributions of the metals around Doha Bay during May and December 2012.