Impact of endocrine disrupting compounds in sewage impacted coastal area on seabream.

The pollution of coastal regions worldwide has been of a great concern due to the presence of endocrine disrupting chemicals (EDCs). These chemicals find their way to the marine environment via the sewage treatment plants (STPs). Hence, this study was designed to investigate the status and sources of EDCs and their effect on fish in Kuwait's coastal areas, from the chemical and biological perspectives. The assessment of three STPs indicated the presence of significant levels of phthalates (19 and 31µg/l), alkylphenols (85 and 159ng/l), and estrogens (30 and 368ng/l) in both inflow and outflow samples. The analysis of samples from field exposure sites revealed significant levels of EDCs in seawater (phthalates: 2.1-4.6µg/l; alkylphenols: 1.2-16.4ng/l; estrogens: 0-36.2ng/l) and sediment (phthalates: 2.1-15.7mg/kg dry wt; alkyphenols: 2.5-15.1µg/kg dry wt.; estrogens: 4.1-214.2µg/kg dry wt.) samples. The biological perspective investigated through the exposure of fish to sewage outlets at five sites. The hepatosomatic index (HSI) revealed a higher level in winter samples 0.48-0.79%) in comparison to summer samples 1-1.5%). Histological observation of hepatic tissue of fish exposed during winter months in all sites, showed much less necrotic changes and hepatic vacuolation in the hepatic tissue of summer exposed fish. Imunnohistochemistry evidences revealed a significant level of positive signals and Vtg localization in the hepatic tissue as the results support the histopathological alterations observed. Results of enzyme-linked immunosorbent assay (ELISA) showed no significant difference between the plasma protein content of winter and summer samples. Overall, the study suggest that there is possible local source or a chronic input of untreated and/or partially treated water due to the significant levels of phthalates, alkyphenols, and estrogens detected in the Kuwait Bay. These levels were enough to initiate alteration in the hepatic tissue of fish exposed to the sewage outlets in Kuwait for two weeks.

Acute toxicity of some heavy metals to Lates calcarifer fry with a note on its histopathological manifestations.

Static bioassay tests for acute toxicity of four heavy metals to fry of the fish Lates calcarifer in brackishwater medium were conducted. The 96 h LC50 values of metals such as Hg, Cu, Cr, and Mn for two different size groups 11 +/- 3 mm and 24 +/- 4 mm were found to be 0.085, 1.3, 27.9, and 220 mg/L and 0.20, 1.8, 33, and 250 mg/L, respectively. The rank order of toxicity of metals was found to be Hg > Cu > Cr > Mn. Using the safe concentration factor of 0.01, the allowable safe concentration for Hg, Cu, Cr, and Mn in brackishwater are 0.00085-0.002, 0.013-0.018, 0.279-0.33, and 2.20-2.50 mg/L, respectively. The damage caused to different organ systems of the fish, exposed to the heavy metals, agrees with the rank order of the toxicity. Heavy nerve tissue necrosis was observed in fish exposed to mercury. Copper induced gill epithelial necrosis and kidney tubular degeneration. Chromium and manganese accounted for various histopathological manifestations involving vital organs such as liver and kidney.