Eutrophication and sediment-water exchange of total petroleum hydrocarbons and heavy metals of Hashilan wetland, a national heritage in NW Iran.

The heavy metal(loid)s concentrations in water and sediments were analyzed in the Hashilan wetland to assess the spatial distribution, pollution status, fate, partitioning, and ecological risk and also to identify the heavy metal(loid)s sources in sediments using PMF (Positive Matrix Factorization) and APCs-MLR (absolute principal component score-multiple linear regression) receptor models. According to the pollution indices, (Ni, Cu, Cr, Mo), and (Zn, Cr, and Cu) are considered the most important pollutants in sediments and water, respectively. Ni, Cr, and Cu are the main contributors to ecological risks in sediments of some stations. The potential ecological risk assessment proposed low ecological risk in water of the study area. Higher distribution coefficient (Kp) values of Ni, Cr, Mn, Cu, Co, Pb, As, and Zn indicated the majority of these heavy metals present in the sediments; whereas, the majority of Cd concentration occurs in water. PMF and APCs-MLR results indicated the natural sources were the main factors affecting the concentrations of Ni, Cr, Zn, Al, Co, Fe, Pb, As, Cd and somewhat Cu. Mixed natural and agricultural activities are the main sources of Mo, and somewhat Cu. According to the results, there is low pollution of TPH (total petroleum hydrocarbons) in the sediment samples. Also, phosphate (PO42-) and nitrate (NO3-) concentrations were below the recommended permissible limits at all sampling sites except the S8 station for NO3-.

Spatial distribution, partitioning, ecological risk and source apportionment of potential toxic elements in water and sediments of the Hoor Al-Azim wetland and their bioaccumulation in selected commercial fish species.

The potentially toxic elements (PTEs) concentrations in water and sediments were measured in the Hoor Al-Azim wetland to evaluate the spatial distribution, pollution rate, fate, partitioning, and ecological risk and also to recognize the PTEs sources in sediments using MLR-APCs (multiple linear regression-absolute principal component scores) receptor model. The human health risk was investigated based on the seven fish species consumed in the study area. Based on the results, water and sediment contamination was observed at some stations in the southern part of the wetland where agricultural water drains. Also, the sediments of oil well drilling disposal site was polluted by PTEs. Based on the MLR-APCs model, 80.8% of Mo and 81.5% of Se originated from agricultural source. Total target hazard quotients (TTHQ) values suggested that the children could experience adverse health effects due to consumption of Coptodon zillii, Aspius vorax, Carassius auratus and Carasobarbus luteus.

Polycyclic aromatic hydrocarbons (PAHs) in water and sediment of Hoor Al-Azim wetland, Iran: a focus on source apportionment, environmental risk assessment, and sediment-water partitioning.

The concentration, source, and ecological risk of 16 polycyclic aromatic hydrocarbons (PAHs) in water and sediment samples in Hoor Al-Azim wetland, a significant freshwater wetland in Lower Mesopotamia, were evaluated. Total PAHs concentrations varied from 15.3 to 160.15 ng/L, and 15.78 to 410.2 µg/Kg in water and sediment, respectively. PAHs pollution levels in sediments compared with sediment quality guidelines (SQG) were found to be moderate in two stations and low in water and the rest of sediment stations. Based on the diagnostic ratio analysis, cluster analysis (CA), and principal component analysis-multiple linear regression (PCA-MLR), the mean percentage contributions were 62.62% for mixed pyrogenic and petrogenic sources (e.g., unburned and combusted fossil fuels from fishing boats and vehicle engines, incomplete combustion, oil leakage), 20.68% for auto emission, and 16.7% for pyrogenic sources (fossil fuels and biomass combustion). According to the sediment risk assessment indices such as mean effects range-median quotient (M-ERM-Q), the ecological risk of multiple PAHs was low. Risk quotient (RQ) calculation of water samples suggested high ecological risk level for Benzo[a]anthracene (BaA), and low to moderate for other individual PAHs and ΣPAHs. The result of PAHs partitioning between sediment and water phases revealed that most PAHs prefer to accumulate in sediment. Sediments probably act as a secondary source for some PAHs in the oil collection and pumping station.