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The distribution and interactions of phytoplankton and 14 polychlorinated biphenyls (PCBs) were investigated using canonical correspondence analysis in autumn in the Qinhuai River, Nanjing, China. Concentrations of PCBs in water and algal samples ranged from 33.78 to 144.84 ng/L and from 0.21 to 19.66 ng/L (0.06 to 3.04 ng/mg biomass), respectively. The predominant residual species of PCBs in water samples were tri- through hexachlorobiphenyls, and the predominant residuals in algae were tri-, tetra-, and heptachlorobiphenyls. The degree of eutrophication affected phytoplankton composition and PCB bioaccumulation, and led to sample site- and algal species specificity of PCB residues in the study area. Chlorophyta, Bacillariophyta, and Euglenophyta had strong capacities to take up PCBs, whereas Cyanophyta was less involved in the transfer of these compounds. Bioaccumulation of PCBs by algae may be affected by water quality, chlorination, phytoplankton composition, and the structure of the PCBs and the algal cell walls.

The sediments’ samples were collected from Changdang Lake for the concentration of fourteen polycyclic aromatic hydrocarbons in March (dry season), June (wet season), and September (temperate season) 2013. The highest average value of∑PAHswas detected as 295.28 ng/g dw in March, followed by 240.91 ng/g dw in June and 165.81 ng/g dw in September. Source characterization studies based on the analysis of diagnostic ratio (triangular plot method) suggested that the PAHs in sediments from Changdang Lake were mainly from the mixed combustion source of biomass and petroleum, and the origins of PAHs in different sampling sites have a great deal of temporal and spatial variability during different water seasons. Redundancy analysis was applied to identify the impact factors and the possible relationship between PAHs and environmental parameters. The predicted results showed that the main factors impacting PAHs temporal distribution were temperature, dissolved oxygen, pH, and oxidation-reduction potential, while conductivity showed secondary impacts on the PAHs distribution. Risk assessment of PAHs in sediments was carried out based on the US Sediments Quality Guidelines (SQGs). By comparing the present study results with SQGs standard values results showed that the adverse effects are not expected at the present levels of PAHs contamination observed in the sediments from Changdang Lake.

Safe drinking water is one of the basic human rights and essential need for healthy life. In Pakistan, the quality of drinking water is not being managed properly and various studies provide evidence that most of the drinking-water supplies are contaminated. In this study, 60 drinking water samples from both urban and rural areas of district Kohat were analyzed chemically and microbiologically, to find out their suitability for drinking purposes. Fifty-four samples were collected from hand pumps, streams, tanks, wells and tube wells, at 15 main population zones selected. Six bottled water samples were also taken from the open market for analysis. These were investigated for various chemical parameters including sodium (Na +), potassium (K +), sulfate (SO 4 2-), phosphate (PO 4-3), nitrate (NO 3-), and nitrite (NO 2-), using standard methods of analysis recommended by American Public Health Association (APHA). Microbiological analysis was also carried out for Escherichia coli, to find out any fecal contamination. The results of parameters showed variations from the WHO and Pakistan standard values for drinking water (Table 1). The K + and NO 2 − of 3%, SO 4 2− of 7%, Na + of 9% and NO 3 − of 16% samples were found to be higher than the WHO/Pakistan recommended values for drinking water. E. coli were found present in 70% of samples. From the results it was confirmed that majority of water sources are not safe to drink. Therefore, proper measures by the concerned authorities are required, to avoid health hazards.

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