School of Environmental Science and Engineering , Huazhong University of Science and Technology , Wuhan 430079 , P.R. China.
School of Resource and Environmental Sciences, Hubei Key Laboratory of Biomass-Resources Chemistry and Environmental Biotechnology , Wuhan University , Wuhan 430074 , P.R. China.
Environ Sci Technol. 2018 Nov 20;52(22):13457-13468. doi: 10.1021/acs.est.8b01405. Epub 2018 Oct 29.
Polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are predominant pollutants normally coexisting at electronic waste dumping sites or in agricultural soils irrigated with wastewater. The accumulation of PAHs and HMs in food crops has become a major concern for food security. This study explored the hydroponic uptake of 16 priority PAHs and 5 HMs (Cd, Cr, Cu, Pb, and Zn) by pak choi ( Brassica chinensis L.). PAHs exhibited stronger inhibition on pak choi growth and physiological features than HMs. Five HMs were categorized into high-impact HMs (Cr, Cu, and Pb) and low-impact HMs (Cd and Zn) with distinct behavior under the coexposure with PAHs, and low-impact HMs showed synergistic toxicity effects with PAHs. Coexposure to PAHs and HMs slightly decreased the uptake and translocation of PAHs by pak choi, possibly attributing to the commutative hindering effects on root adsorption or cation-π interactions. The bioconcentration factors in PAHs + HMs treatments were independent of the octanol-water partition coefficient ( K), owing to the cation-π interaction associated change of K and induced defective root system. This study provides new insights into the mechanisms and influential factors of PAHs uptake in Brassica chinensis L. and gives clues for reassessing the environmental risks of PAHs in food crops.
多环芳烃（PAHs）和重金属（HMs）是主要污染物，通常共存于电子废物倾倒场或用废水灌溉的农业土壤中。PAHs 和 HMs 在食用作物中的积累已成为食品安全的主要关注点。本研究探讨了水培小白菜（ Brassica chinensis L.）对 16 种优先 PAHs 和 5 种 HMs（Cd、Cr、Cu、Pb 和 Zn）的吸收。PAHs 对小白菜生长和生理特征的抑制作用强于 HMs。5 种 HMs 分为高影响 HMs（Cr、Cu 和 Pb）和低影响 HMs（Cd 和 Zn），在与 PAHs 共存时表现出不同的行为，低影响 HMs 与 PAHs 表现出协同毒性效应。PAHs 和 HMs 的共暴露略微降低了小白菜对 PAHs 的吸收和转运，这可能归因于对根部吸附或阳离子-π 相互作用的交换阻碍效应。PAHs+HMs 处理中的生物浓缩因子与辛醇-水分配系数（ K）无关，这是由于阳离子-π 相互作用导致 K 发生变化并诱导根系缺陷。本研究为 Brassica chinensis L. 中 PAHs 吸收的机制和影响因素提供了新的见解，并为重新评估食品中 PAHs 的环境风险提供了线索。
