Environmental Science
R. Alijani Ardeshir; H. Zolgharnein; A.A. Movahedinia; N. Salamat; E. Zabihi; J. Regenstein
Abstract
Fipronil is a relatively new insecticide in agriculture with health and environmental effects. This is the first report studying effect of fipronil on fish administered via intraperitoneal route. Intraperitoneal LD50 of fipronil in 16.3 g Caspian kutum, Rutilus frisii kutum, fingerlings was determined ...
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Fipronil is a relatively new insecticide in agriculture with health and environmental effects. This is the first report studying effect of fipronil on fish administered via intraperitoneal route. Intraperitoneal LD50 of fipronil in 16.3 g Caspian kutum, Rutilus frisii kutum, fingerlings was determined using a total of 133 fish in 19 tanks (7 fish/tank) including one control and 6 treatment groups (300, 450, 550, 650, 750, 850 mg/kg). Fish were injected intraperitoneally and monitored at 96 h. The LD50 of fipronil was 632 mg/kg in Caspian kutum. Sub-lethal test doses of 10, 20, and 30% of the LD50 at 96 h were used to assess the effect of fipronil on the fish’s liver. The blood plasma of 90 fish were used (18 at each test dose and in controls) on days 7 and 14 for biochemistry. The hepatosomatic index (HSI) of the livers were obtained and histopathology done on the same days. Pyknosis, sinusoid dilation and vacuolization were common histological changes, and these changes became more severe in a time and dose dependent manner. This dependence was also observed for HSI and the liver biochemical test (alanine and aspartate transaminase). Liver histological alterations showed that fipronil can be a potential factor in liver carcinoma.
Environmental Science
S. Hassani; A.R. Karbassi; M. Ardestani
Abstract
The flocculation of dissolved heavy metals is a process which has an important effect on decreasing the concentration of the colloidal elements during estuarine mixing of river water and sea or ocean water. During this important process, a large amount of colloidal elements change into particles in ...
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The flocculation of dissolved heavy metals is a process which has an important effect on decreasing the concentration of the colloidal elements during estuarine mixing of river water and sea or ocean water. During this important process, a large amount of colloidal elements change into particles in the form of flock and the dissolved loads decline. This study is performed to evaluate the mechanism of self-purification of heavy metals in Sardabroud's estuary. For this purpose, the effect of salinity (varying from 1 to 8.5‰) on the removal efficiency of colloidal metals (copper, zinc, lead, nickel and magnesium) by flocculation process during mixing of Sardabroud River water and the Caspian Sea water was explored. The flocculation rate of Ni (25%) > Zn (18.59%) > Cu (16.67%) > Mn(5.83%) > Pb(4.86%) indicates that lead and manganese have relatively conservative behavior but nickel, zinc and copper have non-conservative behavior during Sardabroud River’s estuarine mixing. The highest removal efficiencies were obtained between salinities of 1 to 2.5%. Due to flocculation process, annual discharge of dissolved zinc, copper, lead, manganese and nickel release into the Caspian Sea via Sardabroud River would reduce from 44.30 to 36.06 ton/yr, 3.41 to 2.84 ton/yr, 10.22 to 9.7 ton/yr, 8.52 to 7.8 ton/yr and 3.41 to 2.56 ton/yr, respectively. Statistical analysis shows that the flocculation rate of Nickel is highly controlled by redox potential and dissolved oxygen. Moreover, it is found that total dissolved solid, salinity, electrical conductivity and potential of hydrogen do not have a significant influence in flocculation of studied metals.
