• 关键词：增温  锌  复合污染  多环芳烃  植物富集  风险评价

• 基金项目：国家重点研发计划（No.2017YFA0605001）；国家创新研究群体科学基金（No.51721093）

• 陈建
• 北京师范大学环境学院, 水环境模拟国家重点实验室, 北京 100875

• 夏星辉
• 北京师范大学环境学院, 水环境模拟国家重点实验室, 北京 100875

• 张真瑞
• 北京师范大学环境学院, 水环境模拟国家重点实验室, 北京 100875

• 席楠楠
• 北京师范大学环境学院, 水环境模拟国家重点实验室, 北京 100875

• 摘要：目前有关增温和重金属复合作用对植物富集疏水性有机物的影响研究还鲜有报道.本文通过构建土壤-大气-植物密闭微宇宙，分析土壤、大气和植物中多环芳烃（Polycyclic aromatic hydrocarbons，PAHs）的浓度及土壤中PAHs降解菌基因的拷贝数，进而探究增温（+6℃）和锌胁迫（100~600 mg·kg^-1）及两者复合作用对菠菜富集4种氘代PAHs及其致癌风险的影响.结果表明，增温使菠菜根部中PAHs的浓度降低了1.5%~20.4%，这是由于增温促进了土壤中PAHs的生物降解，进而导致PAHs自由溶解态浓度降低；另外，增温也降低了根部脂肪的含量，从而降低PAHs在根部的富集作用.然而，菠菜根部中PAHs的浓度随土壤中锌浓度的增加而增加，且增加比例为1.2%~91.7%，这主要是因为锌抑制了土壤中PAHs的降解，进而增加了PAHs的自由溶解态浓度；另外，锌胁迫还增加了菠菜根部细胞膜的通透性，进而促进根部吸收PAHs.增温和锌胁迫条件下，菠菜茎叶中PAHs的浓度分别降低了7.3%~51.1%和增加了3.0%~76.9%，与对根部富集PAHs的影响一致，这归因于茎叶中的PAHs主要来源于根部的向顶运输而非大气的茎叶吸收.增温和锌复合作用对菠菜富集PAHs具有拮抗作用，这是因为两者对土壤中PAHs的生物降解具有相反的影响.在无外源PAHs输入下，增温和锌胁迫分别会降低和增加PAHs的总致癌风险.

• Abstract：To date, few information is available on effects of elevated temperature and heavy metals on accumulation of hydrophobic organic compounds in plants. In this study, effects of elevated temperature (+6 ℃), zinc (100~600 mg·kg^-1) and their combination on the accumulation of four deuterated polycyclic aromatic hydrocarbons (PAHs) in spinach (Spinacia oleracea L.) and PAH-associated cancer risk were explored by measuring the PAH concentrations in soil, air and plant, and copy numbers of PAH-degrading gene in soil in an enclosed soil-air-plant microcosm. Results showed that PAH concentration in root decreased by 1.5%~20.4% under the elevated temperature. This was because elevated temperature promoted biodegradation of PAHs in soil and consequently decreased the concentration of freely dissolved PAHs. Additionally, elevated temperature decreased lipid concentration in roots, contributing to the root uptake of PAHs. In comparison, zinc addition increased the PAH concentrations in roots by 1.2%~91.7%, which is attributed to increases in concentration of freely dissolved PAHs and root electrolyte leakages. Additionally, PAH concentration in shoot was lower by 7.3%~51.1% under high temperature, while higher by 3.0%~76.9% under increased zinc concentrations. These results are in consistence with variations of PAH concentration in root under elevated temperature and zinc. This is because PAH accumulated in shoot originated mainly from acropetal translocation in root rather than foliage uptake from air. Elevated temperature and zinc combination had an antagonistic effect on the uptake of PAHs by spinach, attributing to their opposite influence on PAH biodegradation in soil. As a result, elevated temperature decreased total cancer risk of PAHs, whereas zinc increased the risk in the systems without PAH inputs.

• Key words：elevated temperature  zinc  co-contamination  polycyclic aromatic hydrocarbons  plant accumulation  risk assessment

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