Use of feathers to assess polychlorinated biphenyl and organochlorine pesticide exposure in top predatory bird species of Pakistan

Little is known about the levels of organochlorines (OCs) in predatory bird species from Asia or the factors governing their concentrations. This study is the first report on concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in predatory birds of Pakistan. The concentrations of PCBs and OCPs were investigated using tail feathers of ten different species of predatory birds. In addition, concentration differences among body, tail, primary and secondary feathers were investigated for six individuals of black kite (Milvus migrans). Ranges of concentrations were highest for dichlorodiphenyldichloroethylene (p,p′-DDE: 0.11–2163ngg−1 dry wt.) followed by dichlorodiphenyltrichloroethane (p,p′-DDT: 0.36–345ngg−1 dry wt.), hexachlorobenzene (HCB: 0.02–34ngg−1 dry wt.), ∑PCBs (0.03–16ngg−1 dry wt.) and trans-nonachlor (TN; 0.01–0.13ngg−1 dry wt.). CB 118, 153, 138, and 180 along with p,p′-DDE were found as the most prevalent compounds. ∑PCBs and ∑DDTs were significantly different among species (both p