Predicted aquatic and human health risks associated with the presence of metals in the Syr Darya and Shardara Reservoir, Kazakhstan.

Due to the decline of the Aral Sea fishery and recent efforts to expand the fisheries sector in Kazakhstan for both local consumption and global export, there is a need to sustain other fisheries in the area, including the Shardara Reservoir, which lies in the Syr Darya basin. Metals are present in the Syr Darya; yet, their impacts on fishery and consumer health remain unclear. Thus, the objectives of this study were to evaluate: 1) the potential impacts of metals on Syr Darya basin fish and 2) the human health risks posed by consumption of Shardara Reservoir fish. The health of the fishery was assessed by comparing surface water metal concentrations to maximum permissible concentrations (MPCs), calculating water quality index (WQI) and degree of contamination (Cd) values, and evaluating gene expression biomarker responses in wild-caught roach (Rutilus rutilus). To assess the risk to consumers, metal concentrations in roach were used to calculate hazard quotients (HQs) and hazard indices (HIs). Water concentrations of Cu, Fe, Mn, Se, Sr and V exceeded MPCs and all sites were classified as highly polluted based upon WQI and Cd values. This, along with site-specific differences in the expression of genes associated with xenobiotic metabolism and oxidative stress in roach, indicates potential risks to the fishery. Though all HQs and HIs were below 1 indicating a lack of significant risk to consumers, Pb levels in roach exceeded MPCs for safe consumption indicating a potential risk. Given the potential risks to the fishery and consumers, the development of pollution monitoring and management programs are warranted. The work presented here provides initial monitoring data that can be used to aid such efforts and also underscores the need to identify environmental stressors that may thwart the anticipated growth of fisheries in this region.

A review of ecological effects and environmental fate of illicit drugs in aquatic ecosystems.

Although illicit drugs are detected in surface waters throughout the world, their environmental fate and ecological effects are not well understood. Many illicit drugs and their breakdown products have been detected in surface waters and temporal and spatial variability in use translates into "hot spots and hot moments" of occurrence. Illicit drug occurrence in regions of production and use and areas with insufficient wastewater treatment are not well studied and should be targeted for further study. Evidence suggests that illicit drugs may not be persistent, as their half-lives are relatively short, but may exhibit "pseudo-persistence" wherein continual use results in persistent occurrence. We reviewed the literature on the ecological effects of these compounds on aquatic organisms and although research is limited, a wide array of aquatic organisms, including bacteria, algae, invertebrates, and fishes, have receptors that make them potentially sensitive to these compounds. In summary, illicit drugs occur in surface waters and aquatic organisms may be affected by these compounds; research is needed that focuses on concentrations of illicit drugs in areas of production and high use, environmental fate of these compounds, and effects of these compounds on aquatic ecosystems at the concentrations that typically occur in the environment.