Pesticide Residues in Fish - Pesticides: Evaluation of Environmental Pollution - page 374

in the species Clarias gariepinus , Clarias gariepinus , and Channa obscura , respectively. The
metabolites, namely p,p′-DDE and endosulfan sulfate, were also detected in six of the eight
fish species used for the investigation. From the results of this work, organochlorine pes-
ticide residues in the Densu river basin are likely to have originated from various sources,
such as the use of pesticide products for agricultural purposes by farmers along the Densu
river basin (Afful et al. 2010).
The distribution and residue levels of BHC, lindane, endrin, o,p′-DDT, p,p′-DDE, and
p,p′-DDD in Mugil and Tilapia species collected from Egyptian Delta lakes were evaluated.
Residues of BHC and p,p′-DDT were found in most fish samples obtained from El-Manzala,
El-Burullus, Edku, and Maryut lakes. Fish samples from Lake Edku showed the highest
residue levels of the studied pesticides. Residues of BHC and p,p′-DDT in Mugil and Tilapia
species are within the range found in fish from the northwest Atlantic but lower than
the levels reported for other fish species in the United States. Mugil and Tilapia species
could be used as indicator organisms for monitoring the residue levels of OCPs and their
distribution.
A great deal of domestic, agricultural, and industrial wastes is thrown in Bahr El-Bakar
drainage canal. This drain finally pours its water in Manzala Lake, north of Egypt, where
extensive fishing activities exist. Fish is considered an important source of food to a great
portion of the human population. As large as a total of 400 ng/L of chlorinated organic pes-
ticides in water samples and 364 ng/g in the sediment samples were estimated, whereas,
the concentration of these compounds in fish samples was as high as 137 ng/g.
A National Pesticide Monitoring Program was initiated by the Biological Research
Centre, Baghdad in 1981 to determine the residue levels of persistent compounds in
the environment and biota. The purpose of the present work was to find out the OC
residue levels in different fish species collected from a polluted region in Diyala River
(Rustamiya, Baghdad), where the largest sewage treatment plant in Baghdad discharges
treated water. Seventy fish, 1-3 years old, of 11 different species were collected in 30 dif-
ferent collections from October 1983 until July 1984 from the same sampling station on
the lower part of Diyala River at Rustamiya. Among the 30 composite samples collected,
12 consisted of only one species (one fish), which was mostly Chondrostoma regium , and
others consisted of 2-5 species; however, only one composite consisted of 6 species. The
numbers of fish caught for each species were as follows: Chondrostoma regium: 19, Liza abu:
11, Barbus grypus: 11, B. xanthopterus: 6, B. luteus: 6, B. belaweyi: 4, Mystus pelusius: 4, Aspius
vorax: 2, Heteropneustes fossilis: 3, Cyprinus carpio: 2, and Garra rufa: 2 . All the freshwater
fish showed a high percentage of OCs (90-100%). Generally speaking, higher levels of
all insecticide residues were detected in low-fat content fish of all species. Chlordane,
including cis- and trans-chlordane, and hydroxychlordane showed the highest average
residue level of 73.495 ppm (fat basis) in low-fat content group of the species B. xanthop-
terus, and 68.816 ppm (fat basis) in high-fat content group of the same species. The con-
centration of the pesticides was higher in low-fat content groups of all species than in
high-fat content groups.
It was reported that, following endosulfan application for tsetse fly control in Botswana,
an increased fatality in freshwater fish was observed and endosulfan residues were
detected in the tissues (Mathlessen et al. 1982). This is an example of nontarget organisms
being affected by applications of insecticides in vector control. A high concentration of
pesticide residues was detected in the liver of the indigenous fish sampled for the study
followed by the intestines, gills, brain, and skeletal muscles (Heath 1992). The pesticide
residues were rapidly absorbed into the body through the gills of freshwater fish species
(Lloyd 1992) and accumulated in the various organs, sometimes bioconcentrated by as