Pesticide Residues in Fish - Pesticides: Evaluation of Environmental Pollution - page 369

wetlands in Karnataka, India, and their suitability for human consumption. Among
the OCPs tested, isomers of hexachlorocyclohexane (HCH) were the most frequently
detected with β- and γ-HCH as the main pollutants. The average concentration of ∑HCH
and ∑DDT ranged from 2.1 to 51.7 μg/kg and below detection level to 12.3 μg/kg,
respectively. Other OCPs such as heptachlor epoxide, dieldrin, and endosulfan were
found at lower levels. Among various fish species tested, the higher pesticide burden
was recorded in Anguilla bicolor bicolor (77.9 μg/kg) and the lower was in Heteropneustes
fossilis (2.1 μg/kg). OCPs detected in this study were well below the tolerance limits rec-
ommended for fish. The calculated daily dietary intake of OCPs in all the species exam-
ined was lower than the maximum acceptable dietary intake (ADI) limits prescribed for
human consumption.
The level and distribution patterns of some OCPs were monitored in fish samples of the
Gomti River, India, collected from three sites. In the fish muscles, OCPs ranged between
2.58-22.56 ng/g (mean value: 9.66 ± 5.60 ng/g). Neither spatial nor temporal trends could
be observed in the distribution of the OCPs. Aldrin was the predominant OCP, whereas
HCB and methoxychlor could not be detected. α-HCH and β-HCH among the isomers
of HCH and p,p′-DDE among the metabolites of DDT were the most frequently detected
OCPs. The results revealed that the fish of the Gomti River are contaminated with various
OCPs (Malik et al. 2007).
OCP residues were determined in 10 species of fish caught at Cochin and Rameshwaram
coast and sold in Coimbatore, Tamil Nadu, India. Species were selected on the basis of
their regular availability throughout the year and commercial value (Muralidharan et al.
2009). A total of 389 fish were analyzed for organochlorine residues and their suitability
for human consumption was evaluated. Results showed varying levels of residues of hexa-
chlorocyclohexane (HCH), DDT, heptachlor epoxide, endosulfan, and dieldrin. Among the
10 species, a high concentration of pesticide residues was recorded in Sardinella longiceps ,
Carangoides malabaricus , Chlorophthalmus agassizi , Saurida tumbil , and Rastrelliger kanagurta .
The variation in total organochlorine residues among species and between places was not
significant (p >0.05). Only five species of fish showed monthly variation in residue levels
and there was no significant correlation between the body size and residue levels in the
tissue. About 22% of the fish exceeded the maximum residue limits (MRL) of total HCH
prescribed by FAO/WHO for fish products. The calculated dietary intake of total HCH
through consumption of C. malabaricus, C. agassizi, and S. longiceps exceeded the maximum
acceptable dietary intake (ADI) limits prescribed for human consumption. The present
study recommends continuous monitoring of environmental contaminants in marine fish
to assess the possible impact on human health.
A number of studies have indicated that the residues of organochlorine pesticides includ-
ing HCH , DDT, endosulfan, and their metabolites are commonly occurring substances in
water of the river and its estuary. Unusual content of the pesticides was reported by Nayak
et al. (1995) in the middle stretch (Varanasi) of the river ( Table 13.3 ). Moderate content of
HCH compounds was recorded by Kumari et al. (2001). DDT and its analogs were noticed
at moderate levels by Ray (1992), and Halder et al. (1989). Ray (1992) also reported moderate
content of endosulfan.
Bojakowska and Gliwicz (2005) showed that river sediments in Poland are commonly
contaminated with OCPs. They were found in 97.5% of the analyzed sediments from dif-
ferent rivers. The dominant compound was β-HCH in roach ( Rutilus rutilus ) and bream
(Abramis brama ) muscles and endrin in the muscle tissue of ide ( Leuciscus idus ). Mean con-
centrations of OCPs in the gonads ranged from 0.385 to 0.544 ng/g ww for α-HCH, 0.745 to
0.832 ng/g ww for γ-HCH, 0.479 to 0.576 ng/g ww for dieldrin, and 0.381 to 0.684 ng/g ww