Publication Date:
2021-05-19
Description:
This study was conducted to determine some heavy metals concentrations (in water and sediments) and oil
pollution (in sediments) in the southern Caspian Sea (Mazandaran Coast-Kelarabad). Surface sediments samples
were collected at three stations from autumn 2011 to winter 2012. In addition, water samples were collected
from autumn 2014 to summer 2015. All samples were perpaired by digesting and extracting processes and then
determined using Atomic Absortion Spectroscopy and High Performance Liquid Chromatography instruments.
Results of current study showed that annual mean contents of Zn, Cu, Cr, Ni, Pb, Cd, Hg and standard error
(±SE) of water were registered as 8.38 (±5.69), 10.90 (±4.95), 7.17 (±1.20), 4.50 (±0.90), 22.29 (±7.10), 4.83
(±2.30) and 0.131 (±0.07) µg/l, respectively. The mean values of the examined heavy metals in water samples
were obtained in order of Pb〉Cu〉Zn〉Cr〉Cd〉Ni〉Hg. The annual mean contents and standard errors (±SE) of
surface sediments were observed 59 (±3), 25 (±1), 42 (±2), 28 (±1), 14 (±1), 0.16 (±0.06) and 0.020 (±0.005)
µg/g.dw for Zn, Cu, Cr, Ni, Pb, Cd and Hg, respectively. Also, the mean values of the examined heavy metals in
surface sediment samples were noted in this rank Zn〉Cr〉Ni〉Cu〉Pb〉Cd〉Hg. The mean values of Igeo were
ranked as IgeoPb〉 IgeoZn〉 IgeoCu〉 IgeoCr〉 IgeoNi〉 IgeoCd and for enrichment factor were
EFPb〉EFZn〉EFCu〉EFCr〉EFNi〉EFCd〉EFHg. The mean values of the contamination factor were recorded as CFCd〉
CFPb〉 CFZn〉 CFCu〉 CFCr〉 CFNi〉 CFHg.
The annual mean contents of PAHs and standard errors (±SE) of surface sediments were registered as 2.81
(±0.73) µg/g.dw; among 16 compounds of PAHs, Fluranthene was contained maximum values (2.79±0.96
µg/g.dw). In addition, the concentration of naphthalene was below limit of detection. The Hazard Quotations
(HQs) of all PAHs were calculated higher than unit in surface sediments.
In conclusion, the results revealed that the mean concentrations of all heavy metals (except Cu) of water were
below the threshold levels but maximum concentrations of Cu, Pb and Cd were above of the regulatory limits
associated with toxicological effects, which repersented polluted condition in this area. Concentation of Cd in
sampled sediments based on geoaccumulation index (Igeo) showed modrated polluted conditions for this
regions, but other heavy metals were in unpolluted status. Cu, Cr, Ni and Cd contents of sediments in the
samples based on enrichment factor (EF) showed no enrichment conditions for this region, but other heavy
metals (Zn and Pb) were in minor enrichment status. The Caspian Sea sediments were classified as low polluted
based on CF, Cd and PLI. The results revealed that the 16PAHs concentrations of sediments were below the
threshold levels (except TEL) and mostly of pyrogenic (85%) sources, which represented unpolluted condition in
this area. According to results of the evaluation of risks to the health of 16PAHs suggest that there is risk for the
existing biota. Also, the Caspian Sea sediments were classified in Class 3 (Poor). According to anthropogenic
sources of some heavy metals and PAHs of sediment, it is essential that the management and development of the
cage aquaculture industry in the Caspian Sea to be made with environmental considerations and cautions.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Pollutants
;
Water
;
Sediments
;
Aquaculture
;
Heavy metals
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
52pp.
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