The present study was designed to analyze organochlorine pesticide residues in the blood samples of the residents of Karachi. Biochemical and hematological parameters were tested thoroughly for changes as a result of organochlorine residues. In the blood samples which were drawn from both genders, organochlorine compounds like α-endosulfan (1.565 mg/kg) and β-endosulfan (1.233 mg/kg) were found in higher quantities and were the most frequently detected compounds. Average concentrations of the detected compounds (mg/kg) were: HCH (0.819); Cyclodienes (2.839); Diphenylaliphatics (0.240). An evident finding was the alteration in enzyme activity in higher residue samples. Levels of GPT, GOT, ALP, Choline-esterase and γ-GT were tested in all samples and observed major shifts in the upper and lower limits in high residue samples as compared with the normal values. Analysis of the blood parameters were carried out thoroughly and checked the levels of TLC, RBC, Hb, Hct, MCV, MCH, MCHC, Platelets and differential leucocytes (Neutrophils, Lymphocytes, Eosinophils and Monocytes) but found no distinct changes and hence no convincing relation was observed. Results of the present investigation of OCs in different blood sera indicated that bioconcentration and biomagnification of these chemicals were common phenomena in the population of Karachi city and this may be accountable for a variety of diseases and health hazards.

Impact of PCBs was studied as a major source of physiological effects even very low concentration of PCBs transferred to the infants by mother's milk. Milk samples were collected from primipara and multipara women. A significant variation pattern was observed in the level of PCB congeners, as PCBs are lipophilic in nature, another possibility arises that great deals of residues are passed on to infants through mother's milk. A technique was developed to find out polychlorinated biphenyls (PCB) in breast milk. PCBs were extracted by Matrix Solid-Phase Dispersion (MSPD) and analyzed by Gas Chromatography with Electron Capture Detector. The precision (RSD < 10%, n = 125), recovery (85% to 110%) and limit of quantification (between 0.50 and 3.00 µg•L −1), the chi square analysis at p ≤ 0.05 has shown that the PCB level was higher in multipara as compared to primipara. The analysis of the thirty samples revealed PCB levels above 6.85 µg•L −1 in breast milk samples by analyses of a mixture of PCB congeners.