A study on environmental pollutants (Organochlorine pesticides (OCPs), heavy metals, hydrocarbons and surfactants) in the southern part of Caspian Sea

At the present study, the environmental pollutants such as organochlorine pesticides (OCPs), heavy metals, hydrocarbons and surfactants were done during 22 months (Sept. 2009 through May 2011) located in southern part of Caspian Sea with longitude and latitude 48°-54° N and 36°-39° E, respectively. The aims of this study were to determine the seasonal pollutants matters in water layers and bed sediments of eight transect (24 stations) and the results are as follow: The maximum seasonal percentage range of OCPs were detected in spring water samples from 10, 50, and 50m depths such as (DDD, δ-BHC, heptachlor epoxide, endrin aldehyde),(DDD) and (aldrin, β-endosulfan) compounds about 62.5, 75 and 100%, respectively. The maximum seasonal residues fluctuation of OCPs were determined in spring water samples from 10, 50, and 50m depths such as aldrin (Babolsar station), aldrin (Tonekabon station) and heptachlor epoxide (Astara station) compounds about 5.03, 3.08 and 31.43 µg/l, respectively. The maximum percentage range of OCPs were detected in sediments samples from 10, 50, and 50m depths such as aldrin and α-BHC (winter), α-BHC (summer and winter) and aldrin (summer) compounds about 100, 75 and 87.5%, respectively. The maximum residues fluctuation of OCPs were determined in sediments samples from 10, 50, and 50m depths such as α-BHC (summer in Nushahr station), α-BHC (summer in Sefidroud station) and α-BHC (winter in Tonekabon station) and compounds about 5.96, 3.77 and 3.07 µg/l, respectively. The fluctuation and distribution of Total Petroleum Hydrocarbons (TPHs) concentration in different water layers samples were reduced from summer>spring> fall > winter, respectively. Also this trend occurred for bed sediments and reduced from winter > summer, respectively. The mean concentrations of TPHs in water samples of all seasons, regions, depths and transects were less than maximum permissible concentration (MPC). In this research, a comparison of TPHs with EPA standards shown that the desile range organic (DRO) was close to EPA standards such as TPHs and also 95 percent of water data were less than MPC. But gasoline range organic (GRO) concentrations in all stations were less than the amount of EPA standard. A comparison of TPHs concentration in sediments shown that the concentration of all stations were less than of national research council (NRC) range except west part. The maximum annual mean concentrations of Hg and Pb elements were detected in surface station (50m) at Nushahr and Amirabad transects. The most water data of Cd, Pb and Hg elements in comparison with critical concentrations with Europe, the USA and Japan standards were less than amounts of those standards. The distribution and abundance of Cd, Pb, Hg and Ni elements in water samples were detected 98, 96, 77 and 6%, respectively less than the ISQGs (Interim marine sediment quality guidelines) standards. In sediments samples, the mean and maximum concentration of Hg element detected in winter in comparison with ISQGs standards was more. But the concentrations of Cd and Pb in sediments samples of all stations were low and less than of ISQGs standards. The maximum concentration of linear alkyl benzene sulfonate (LAS) from spring through winter in Anzali (spring), Tonekabon (summer), Anzali (fall) and Nushahr (winter) were 0.07, 0.45, 0.145 and 0.087 mg/l, respectively. The maximum concentrations of LSA were detected in spring and fall in west part and summer and winter in middle part. But the lower concentration was occurred in west of southern part of Caspian Sea. According to standards of surfactants and comparison with LAS concentration of this study were less than the critical points

Study on physic-chemical parameters of waters for fish cage culture site selection in the southern of Caspian Sea

Marine aquacultures growth require good quality water is leading to high efficiency and low risk to human health. In other words, the water quality is a critical factor to success and failure of the aquaculture industry. The aim of this project is to study water quality and the trophic status at the different depths and layers in the southern Caspian Sea based on environmental parameters and nutrients during three periods (2008, 2009 and 2010-2011) in order the feasibility of fish cage. Results showed that water temperature, transparency, pH, dissolved oxygen were varied 5.50-32.60 ̊C, 3.50- 10.00 m, 7.15-8.80 and 3.18-12.00 mg/l at the different depths and layers, respectively. In addition, The values of NH4^+, NH3, NO^2-, NO3^- and PO4^-3 were 0.001-0.140 mg/l, 0.01-22.63 µg/l, 0.1-21.2 µg/l, 0.001-0.423 mg/l and 0.008-0.071 mg/l, respectively. Inorganic nitrogen (DIN/N), inorganic phosphorous (DIP/P) and total phosphorous (TP) were registerd 0.68-14.75, 0.07-0.68 and 0.01-2.67 µM, respectively. Thermal startification are more important for fish-breeding. Thermal stratification was occurred from depths greater than 20 m in late spring to early fall in the Caspian Sea. Optimum transparency for fish farming cage was considered less than 5 meter which in this study were recorded from 20 to 50 meter depths. The range of the standard of pH and dissolved oxygen for fish farming cage were 7.80-8.50 and >5 mg /l that in current study results of pH and dissolved oxygen were consistent.Various forms of nitrogen (ammonium, nitrite and nitrate ) at the different layers were acceptable and less than the threshold limit of Australia and New Zealand. But, phosphate value was more than threshold limit of Australia and New Zealand at some layers depth during years of 2009 and 2010- 2011. The results of the nutrients compared with data from the reference year (1996-1996 ) in the Caspian Sea was shown that this ecosystem passed oligotrophic status and shifted to mezotrophic and eutrophic condition. In addition, the values of NH4/N, NO3/N and DIP/P compared with eutrophic condition of reference year (2005) showed that Caspian ecosystem was not passed euotrophic condition and it still under mezotrophic status. As a conclusion, it seems that offshore of the Caspian Sea (depths between 20 to 50 meter) were suitable for different species of fish for cage culture. But, since 2000 decayds the Caspian Sea has experienced four times algal bloom (toxic and harmful species) and in recent years a number of other species also has reached to bloom potential and also mezotrophic condition of this ecosystem, it is appropriate that the establishment of fish farming cages carried out as a pilot to more precautionary approach which not lead to environmental disaster