Seasonal variations in concentrations, distributions, and air–soil exchange fluxes of dioxin-like polychlorinated biphenyls in Shanghai, China

Abstract

Dioxin-like polychlorinated biphenyl (dl-PCB) concentrations in ambient air and soil in Shanghai, China, were measured to allow seasonal and spatial differences in the dl-PCB concentrations, profiles, distributions, fugacity fractions, and air-soil fluxes to be determined. The toxic equivalent (TEQ) DL-PCB concentrations in the air were higher in summer (mean 9.46 fg m(-3), range 1.32-26.3 fg m(-3)) than in winter (mean 4.57 fg m(-3), range 1.55-10.9 fg m(-3)). The DL-PCB concentrations in air were different in different areas, and the concentrations decreased in the order industrial areas > commercial and residential areas > suburban areas > rural area. The mean DL-PCB concentration in soil was 0.25 pg TEQ g(-1) dry weight (dw) and the range was 0.05-0.90 pg TEQ g(-1) dw. The highest DL-PCB concentration in soil was found in a sample from a commercial/residential area. The DL-PCB fluxes were negative (-216 pg m(-2) h(-1) in summer and -41.1 pg m(-2) h(-1) in winter), and the fugacity fractions were below 0.5, indicating that dl-PCBs in Shanghai are deposited from the air to the soil in all seasons. The net fluxes were higher in summer than in winter, and the deposition fluxes were higher in industrial areas than in other areas in both summer and winter.

Air-soil diffusive exchange of PAHs in an urban park of Shanghai based on polyethylene passive sampling: Vertical distribution, vegetation influence and diffusive flux

“…Many studies focused only on assessing transport direction of air-soil diffusive exchange based on fugacity ratio of air and soil (Cetin et al, 2017a;Cetin et al, 2017b;Degrendele et al, 2016;Tian et al, 2016;Wang et al, 2015;Zhu et al, 2017). However, only in few studies exchange fluxes were calculated based on fugacity gradients between soil and air, following the Mackay fugacity approach (Koblizkova et al, 2009;Pokhrel et al, 2018;Tasdemir et al, 2012;Wang et al, 2017;Zhang et al, 2011) or Fick's law of diffusion (Donald and Anderson, 2017).…”

Toxicidade equivalente da atmosfera por dioxinas, furanos e bifenilas policloradas,com uso de duas técnicas de coleta, passiva e ativa

“…Em termos de toxicidade o congênere PCB-126 apresentou a maior contribuição entre os 12 dl-PCBs em todas as amostras desta pesquisa, cerca de 90%, corroborando resultados de outros estudos (YU et al, 2006;. TIAN et al, 2016).…”