Abstract
This study aimed to provide first data on the concentrations of different classes of organohalogenated contaminants (OHCs) in human serum from Pakistan, an area with limited information on environmental pollution. Serum samples (N=85) were collected from mothers (N=34; age ranged 23–51years), their children (N=34; age 3–10years) and general group (N=17; age 13–65years) with rural and urban residential settings. The concentrations of studied OHCs in serum decreased as follows: organochlorinated pesticides (OCPs)>polychlorinated biphenyls (PCBs)>polybrominated diphenyl ethers (PBDEs). Novel brominated flame retardants (NBFRs) were not detected, except for 1,2-bis(2,4,6-tribromophenoxy)-ethane (BTBPE)<0.2–8ng/g lipid weight (lw). Low levels of HO-PCBs (<0.2–20ng/glw) were detected, while HO-PBDEs were <0.2ng/glw. ∑PCBs (2–105ng/glw) together with ∑PBDEs (0.2–6.7ng/glw) contributed ~5% of the total OHCs body burden. The concentration(s) of major contributors (>80%) of OCPs ranged from <1–3645ng/glw for 1,1′-bis-(4-chlorophenyl)-2,2-dichloroethene (p,p′-DDE), <1–445ng/glw for β-hexachlorocyclohexane (β-HCH) and from 5 to 200ng/glw for pentachlorophenol (PCP). p,p′-DDE, the major OHC, was significantly higher (p<0.05) in rural children than in all other groups. In serum of rural children, the major OHCs were significantly higher (p<0.05) than the mothers. The current study indicates continuous exposure to humans with already regulated OHCs and highlights the need for further monitoring of these OHCs in the region.
•First data on the occurrence of OHCs in human serum from Pakistan•OHCs were investigated in mothers and children from urban and rural settings.•p,p′-DDE and β-HCH were the major contaminants in all studied groups.•∑DDTs were significantly higher in rural children than in the other groups.•Current Pakistani levels of OHCs are lower than those reported in the literature.