Title: Concentrations and chiral signatures of POPs in soils and sediments: A comparative urban versus rural study in Canada and UK
Abstract: Surface soils and sediments were collected in Toronto, Canada to investigate the concentrations and enantiomeric signatures of urban versus rural locations. Samples were analyzed for polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and organochlorine pesticides (OCs). In soils, the sum of 10 PCB congeners (∑PCB 28, 52, 95, 101, 118, 136, 138, 149, 153, 180) and 15 PAHs (∑PAHs) ranged from 0.76–58 to 58–3200 ng g−1, respectively. The most abundant OCs detected were DDTs, followed by chlordanes and endosulfans. ∑PAHs exhibited an urban–rural gradient of up to 60 times but a gradient was not observed for ∑PCBs and OCs which may reflect local sources of these chemicals. In sediments, ∑PCBs and ∑PAHs ranged from 0.03–23 ng g−1 to 42–3300 ng g−1, respectively. ∑PCBs, ∑PAHs, chlordanes and DDTs exhibited weak urban–rural gradients. Chiral signatures of PCB 95, 136, 149, trans-chlordane (TC), cis-chlordane (CC) and o,p-DDT were characterized to study the enantiomeric degradation in urban versus rural areas and its relation to contaminant levels. Supplementary to these data, we also report on the chiral signatures of PCBs in UK lake sediments from a variety of urban and rural locations. The extent of enantiomeric degradation was expressed as the enantiomeric excess (EE%) which is defined as 100 × (E1 − E2)/(E1 + E2), where E1 is always the most abundant enantiomer and E2 is the least abundant enantiomer. The EE% of PCB 149 in the UK sediments was negatively correlated (p < 0.05) with ∑PAHs suggesting either more recent emissions of this PCB congener in the more contaminated urban locations and hence a more racemic signature or less enantiomeric degradation of the congener in more contaminated urban soils. However, no significant correlation was observed between EE% of any of the chiral chemicals and contaminant levels in the Toronto soils.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 99
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