Distribution and environmental geochemical indices of mercury in tar contaminated beaches along the coast of Qatar.

The current study aimed to gauge total mercury (THg) concentration and the environmental geochemical indices in tarmat contaminated sediments and test their presence in targeted coastal species. Layers of hard asphalt-like tarmats and sediment samples were collected from 34 sites along the coast of Qatar. The mean concentration of THg in tarmat-sediment mixture is 89 ± 20 ng·g-1. THg concentration varies significantly between the northern and eastern coasts. Geographically, sampling area were divided into four zones according to the relative closeness with low to serious potential ecological risk index (Er), moderate pollution load index (PLI), moderate Geoaccumulation index (Igeo), and no toxic risk (TRI) trending as Northern (Zones 4, 3) > North-Eastern (Zone 1) > Western (Zone 2) coasts. Three biota classes (Gastropoda, Bivalvia, and Crustacea) were sampled on the tarmat which the hermit crab (Clibanarius signatus) from Ras Rakan island obtained the highest THg (977 ng·g-1) and BSAF (29.70).

Baseline concentrations and distributions of Polycyclic Aromatic Hydrocarbons in surface sediments from the Qatar marine environment.

Coastal sediments in marine waters of Qatar have the potential of being contaminated by Polycyclic Aromatic Hydrocarbons (PAHs) due to extensive petroleum exploration and transportation activities within Qatar's Marine Exclusive Economic Zone. In this study, the concentration and distribution of sixteen PAHs classed as USEPA priority pollutants were measured in sediments from the eastern Qatari coast. PAHs were recovered from sediments via accelerated solvent extraction and then analyzed using Gas Chromatography-Mass Spectrometry. Total concentrations of the PAHs were in the range of 3.15-14.35µg/kg, and the spatial distribution of PAHs is evaluated in the context of sediment total organic content, depth and the grain size together with and the proximity of petroleum exploration and transportation activities. The data show that the concentrations of PAHs within the study area were in the low-range, suggesting a low risk to marine organisms and limited transfer of PAHs into the food web.