Abstract
The Arc River and Berre lagoon are one of important river basin hydrosystem in the South of France that receives industrial and municipal wastewaters from the adjacent area.
Due to its social and economic impact as well as ecological function of basin, an assessment of environmental risk due to mobilization of contaminants is necessary. Thus, the study aims to determine the spatial distribution of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine and organophosphorous pesticides in surface sediments and their potential origins by using gas chromatography coupled to mass spectrometry.
Total alkanes concentrations ranged from 563 to 5,068 mu g kg(-1) sediment dry weight (dw), the sum of 17 PAHs ranged from 153 to 1,311 mu g kg(-1) dw, the sum of seven PCBs concentrations ranged from 0.3 to 466.8 mu g kg(-1) dw, and the total pesticides concentrations ranged from 0.02 to 7.15 mu g kg(-1) dw. Ratios of specific n-alcanes (carbon preference index, natural n-alkanes ratio, and terrigenous/aquatic ratio) and ratios of selected PAH (anthracene (Ant)/(Ant + Phe), fluoranthene (Fl)/(Fl + pyrSne (Pyr)), BaA/(BaA + chrysene (Chry)), indeno[1,2,3,c,d]pyrene (IPyr)/(IPyr + BghiP)) were calculated to evaluate the possible sources of hydrocarbons.
The evaluations suggest the sources of hydrocarbons in the sediments were generally biogenic and markedly more pyrolytic rather than petrogenic. In the perspectives of environmental risk assessment, all contaminants levels were also compared with sediments quality guidelines (SQG) resulting that the contamination levels in all stations were most of the time lower than their respective SQG. While, for PCBs concentrations, three stations (A8, B1, and B2) were higher than their effect range median values which may indicate high potential toxicity of the sediment with probable adverse effects to the living biota.