Regional distribution of organochlorinated pesticides in pine needles and its indication for socioeconomic development

The regional distribution of 10 potentially harmful organochlorinated pesticides (OCPs) was investigated in pine needles from 18 sites in six Chinese regions. The OCPs concentrations in six regions were as follows: ∑HCH (∑HCH=α-+β-+γ-+δ-HCH), 4.7–51.5 ng/g; ∑DDT (p,p′-DDT+p,p′-DDE+p,p′-DDD), 0.9–30.9 ng/g; hexachlorobenzene (HCB), 1.1–5.3 ng/g; ∑chlordane (cis-chlordane + trans-chlordane), no detected–4.3 ng/g, on dry weight basis. Samples from southeast Chinese area contained the highest concentrations of ∑HCH, ∑DDT and ∑chlordane, while the contamination levels of most OCPs in southwest Chinese area were the lowest. The ratios of α/γ-HCH (ranged from 1.7 to 5) were observed to be noticeable increase from north to south China, and the ratio of 1.7 revealed the presence of the recent use of lindane in north Chinese area. The significant decrease of the sum concentrations of α- + γ-HCH from mid-1980s to the present and the strong correlation between α-, β-, γ-, δ-HCH (r=0.87–0.98, n=18, p<0.05) indicated the main usage of the technical HCH in history in China. The p,p′-DDE/p,p′-DDT ratios of <1 revealed the new input of p,p′-DDT in south, southeast and southwest Chinese areas, which could be partly contributed to the new use of impure dicofol. Economic development will leave its mark in the environment, however, its impact on the input and distribution of OCPs on a regional scale is unknown. We attempted to use the socioeconomic index (gross domestic product (GDP) per capita) to explain the distribution and input of OCPs and found that HCB and ∑DDT seemed to be linked to the economic development, while no relationship of HCH was observed. DDE% of ∑DDT also showed a negative correlation with the GDP per capita.