Details

Autor(en) / Beteiligte

• Ding, Yang
• Li, Li
• Wania, Frank
• Huang, Huanfang
• Zhang, Yuan
• Peng, Bo
• Chen, Yingjie
• Qi, Shihua

Titel

Do dissipation and transformation of γ-HCH and p,p’-DDT in soil respond to a proxy for climate change? Insights from a field study on the eastern Tibetan Plateau

Ist Teil von

• Environmental pollution (1987), 2021-06, Vol.278, p.116824, Article 116824

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2021

Quelle

MEDLINE

Beschreibungen/Notizen

• While the influence of climate change on the fate of persistent organic pollutants (POPs) is becoming a topic of global concern, it has yet to be demonstrated how POPs and their transformation products in soil respond to a changing climate at the local scale. We conducted a year-long field experiment with spiked soils to investigate the impact of climate on the dissipation of γ-hexachlorocyclohexane (γ-HCH) and p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT) as well as the formation of their products. Four sites along an elevational gradient on the eastern Tibetan Plateau were selected to represent four scenarios ranging from a dry and cold to a warm and humid climate. Based on the measured concentrations of the two pesticides and their transformation products, we calculated the dissipation rates of γ-HCH and p,p’-DDT in soil using two biphasic kinetic models, and the formation rates of transformation products using a mid-point rectangular approximation method. The spiked γ-HCH generally showed the expected decrease in dissipation from soils with increasing altitudes, and therefore decreasing temperature and precipitation, whereas dissipation of p,p’-DDT was influenced more by photolysis and sequestration in soil. The formation rates of the primary products of γ-HCH (i.e. γ-HCH→PeCCH and γ-HCH→TeCCH) and p,p’-DDT (i.e. p,p’-DDT→p,p’-DDE and p,p’-DDT→p,p’-DDD) indicate that a warmer and wetter climate favors dechloroelimination (anaerobic biodegradation) over dehydrochlorination (aerobic biodegradation). The significantly longer dissipation half-lives of γ-HCH at the coldest site suggests that the fate of POPs in frozen regions (e.g. polar regions) needs more attention. Overall, the fate of more volatile chemicals (e.g. γ-HCH) might be more responsive to the climate change. [Display omitted] •Altitudinal climate gradient is used as proxy for a climate changing over time.•Rates of dissipation from soil diverge between γ-HCH and p,p’-DDT.•Warmer wetter climate favors dechloroelimination over dehydrochlorination.•Dissipation and product formation change non-monotonically with altitude.•Empirical ratios aid in the identification of HCH- and DDT-type pesticide sources.