Assessment of metal accumulation and ecological risk around Rize Harbor, Turkey (southeast black sea) affected by copper ore loading operations by using different sediment indexes.

The purpose of the study was to determine metal pollution and ecological risk in the sediments around Rize Harbor. Metal concentrations (Cu, Zn, Pb, Cd, As, Hg, Ni and Al), were determined in the sediments collected from 7 sites in November, 2010. Metal levels in the sediments were varied from 33.9 to 279.1 mg/kg for Cu, 82 to 383 mg/kg for Zn, 15.9 to 33 mg/kg for Pb, 4.9 to 12.3 mg/kg for As, 0.1 to 1.4 mg/kg for Cd, 0.01 to 0.07 mg/kg for Hg, 13.1 to 17.6 mg/kg for Ni, 1.5 % to 2.98 % for Al. Concentration of metals also was evaluated by enrichment factor, Sediment Quality Guideline (SQGs) of US EPA, and two sets of SQGs indices. A factor analysis was used to determine source of contamination. Two probable source types were identified as anthropogenic and crustal for metals, explaining 86.4 % of the total variance. Six sites were heavily polluted by Cu. Copper concentration in R1 station was found significant enrichment. Current concentration of copper would be expected to frequently be associated with the toxic effect on biota.

Effects of water quality and fish size on toxicity of methiocarb, a carbamate pesticide, to rainbow trout.

The acute toxicity of methiocarb in juvenile rainbow trout (Oncorhynchus mykiss, 3.25±0.79g) was evaluated in glass aquaria under static conditions. Nominal concentrations of methiocarb in the toxicity test ranged from 1.25 to 7.50mgL(-1). The concentrations of methiocarb that killed 50% of the rainbow trout within 24-h (24-h LC(50)), 48-h LC(50), 72-h LC(50), and 96-h LC(50) were 5.43±0.19, 5.04±0.18, 4.95±0.19, and 4.82±0.21mgL(-1) (95% confidence limits), respectively. Mortality of fish increased with increasing water temperature. Increasing alkalinity from 19mgL(-1) as CaCO(3) to 40, 60, or 90mgL(-1) as CaCO(3) significantly decreased mortality of fish. Total hardness ranging from 50mgL(-1) as CaCO(3) to 147mgL(-1) as CaCO(3) did not affect mortality of fish exposed to methiocarb. Fish exposed to methiocarb had histological alterations such as lamellar edema, separation of epidermis from lamellae, and lamellar fusion. Methiocarb exposed fish had necrosis between molecular and granular layer of cerebellum where Purkinje cells present. Results indicate that alkalinity, temperature, and fish size affect methiocarb toxicity of rainbow trout.