Pesticide Residues in Fish - Pesticides: Evaluation of Environmental Pollution - page 375

much as 2000-fold over the concentration of the residue in water (Devi et al. 1981). The liver
has been shown to be the major organ for the metabolism of the residues in fish (Peterson
and Bately 1993).
Among the several freshwater fish species caught in two rivers in South Africa, the
African catfish showed highest concentrations of residues (Heath 1992) and can be used as
an indicator species for pollution. Grobler (1994) detected and measured pesticide residues
in the catfish caught in the Olifants River, South Africa, and dams in Zimbabwe, respec-
tively. They found that the catfish contained elevated levels of pesticide residues compared
with other freshwater fish species.
The bioaccumulation of carbofuran and endosulfan in tissues is demonstrated in several
other species of fish (Berbert et al. 1989; Ferrando et al. 1992; Kale et al. 1996; Singh and
Garg 1992). Of the tissues analyzed for residues, the liver contained the highest level of
carbofuran and endosulfan residues, followed by the intestines, gills, brain, and skeletal
muscle. The liver and gills of Clarias gariepinus caught in the Olifants River, South Africa,
were also found to accumulate high levels of heavy metals (Du Preez et al. 1997).
The levels of organochlorine pesticides were monitored in 18 fish species from Konya
markets, Turkey. These species were selected on the basis of their importance to local
human fish consumption. DDT and its metabolites and HCH were the predominant con-
taminants in fish muscles. The mean concentrations of summation operator DDT were in
the range between 0.0008 and 0.0828 μg/g. DDT was the predominant residue in Sparus
aurata . Detectable levels of HCH, aldrin, and heptachlor were found in most samples.
However, dieldrin, endrin, β-endosulfan, p,p′-DDT, and p,p′-DDD were not detected in
Salmo trutta . The mean of endrin ranged from 0.0040 μg/g ( Triglia lineate ) to 0.0326 μg/g
( Trachurus trachurus ) (Leyla et al. 2009).
A study was carried out between May 2002 and August 2003 in Meric Delta, Turkey,
which is located at a site where the Meric River falls into the Aegean Sea. Residues of OCPs
in fish ( Cyprinus carpio ) samples from Meric Delta were analyzed (Belda and Kolankaya
2006). The α- and β-HCH were the predominant HCH isomers in all analyzed fish samples
and ranged between 319.5 and 968.15 ng/g and between 397.5 and 876.4 ng/g, respectively.
The concentration levels of p,p′-DDT (ranging from 2.68 to 52.45 ng/g) were consistently
higher than its metabolite p,p′-DDE, indicating a recent use of this OCP in the area.
Residue levels of organochlorine pesticides in 13 commercially important fish spe-
cies collected from the NW Arabian Gulf were monitored. While most of the residues
were below the detection limit of 1 tg/kg wet weight, relatively low concentrations of
∑DDT, endrin, and dieldrin were detected in the edible tissue of these fish. The ∑DDT
residue levels ranged from 2 to 1 tg/kg weight, endrin ranged from none detected (rid) to
45 tg/kg, and dieldrin from ND to 5 tg/g. A definite correlation was established between
total organochlorine pesticide residues and lipid content (r = 0.6) for the NW Arabian
Gulf fish. A comparison with fish from Hor-al-Hammar Lake (an area that used to be
sprayed with pesticides) has shown that the latter contained significantly higher residue
levels. The ΣDDT residue levels ranged from 5 to 45 lig/kg wet weight, endrin from 3 to
83 tg/kg, and dieldrin from ND to 4 tg/kg. Based upon the observation that the original
DDT (p,p′-DDT) was identified in the NW Arabian Gulf fish, it has been concluded that
there was a recent input of DDT to this region. Since DDT application has been banned in
Iraq, consequently, it was assumed that DDT must originate from a more remote source.
Endrin is considered to be the most toxic of all commercial insecticides to fish (Johnson
and Finley 1980), and this was the second most dominant compound in fish from the
NW Arabian Gulf. Endrin residues were detected in approximately 90% of these fish,
with mean values ranging from 1 tg/kg in large-scale sole, croaker, and elongate ilisha