Organohalogenated compounds in pine needles from Beijing city, China

Abstract

Pine needles collected from 22 sites of six areas in Beijing city, China, were analyzed by instrumental neutron activation analysis (INAA) combined with organic extraction for extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX). The concentrations of EOX (EOX = EOCl + EOBr + EOI) were in the order of EOCl ≫ EOBr > EOI. About 1.6–34% of EOCl remained as extractable persistent organochlorine (EPOCl) after treatment with concentrated sulfuric acid, which suggested that major fractions of EOCl in pine needles were an acid-liable or acid-soluble fraction. The fact that pine needle contained higher EOCl contents in chemical industrial and traffic hub areas indicated that chemical industries and exhaust emission from vehicle were the main sources of organochlorines in the Beijing’s air. The relative proportions of the known organochlorines (such as HCHs, DDTs, chlordanes, HCB and PCBs) to total EOCl and EPOCl were 0.32–0.76% and 2.5–11.4%, respectively, which implied that a major portion of the EOCl and EPOCl measured in pine needles was unknown. The organochlorinated pesticides (OCPs) and PCBs concentrations in six areas were as follows: ∑HCH (∑HCH = α- + β- + γ- + δ-HCH), 11.7–20.8 ng/g; ∑DDT ( p, p′-DDT + p, p′-DDE + p, p′-DDD), 12.5–113.3 ng/g; hexachlorobenzene (HCB), 1.1–5.3 ng/g; ∑chlordane ( cis-chlordane + trans-chlordane + heptachlor), 1.7–9.5 ng/g, ∑PCB, 41.8–270.5 ng/g, on dry weight basis. The samples from chemical industrial area and residential area nearby chemical industries contained the highest concentrations of ∑DDT, HCB, ∑chlordane and ∑PCB, while the contamination levels of most OCPs and PCBs in iron–steel industrial area were the lowest. The ratios of α/γ-HCH (ranged from 0.9–1.5) and p, p′-DDT/DDTs (ranged from 72.1% to 91.0%) revealed the presence of the recent use of lindane and DDTs or impure dicofol in Beijing.