Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Department of Crop and Soil Sciences, University of Georgia, Griffin, GA 30223, USA.
Sci Total Environ. 2017 Nov 15;598:471-478. doi: 10.1016/j.scitotenv.2017.04.126. Epub 2017 Apr 25.
Vegetables accumulate polycyclic aromatic hydrocarbons (PAHs) at high concentrations when grown in contaminated sites. Inoculation with PAH-degrading endophytic bacteria (EB) has been recognized as one of the most promising ways to remove PAHs from plant bodies; however, the performance of single endophytic bacteria is generally limited. This investigation used a composite of eight EB to reduce the contamination and health risk posed by 16 EPA priority PAHs in vegetables including Chinese cabbage (Brassica chinensis L.) and pakchoi (Brassica campestris L.). Composite EB have strong PAH degradation abilities, and more than 65% of ∑PAH were degraded after 10-day insuspension with composite EB. Vegetable were contacted with composite EB by seed soaking (SS) and leaf painting (LP) with an EB cell incubation at OD=0.2-1.5. Compared with those in non-inoculated controls, the ∑PAH concentrations in edible parts of Chinese cabbage and pakchoi colonized by composite EB via SS and LP with bacterial suspension at OD=0.2-1.5 were 42.07-70.77% and 15.79-53.20% lower, and the incremental lifetime cancer risk (ILCR) values for males and females were 31.78-84.08% and 26.60-83.40% smaller, respectively. SS was the optimal inoculation method for reducing PAH concentrations and ILCR values. Our results indicate that inoculating plants with composite EB can lower the health risk posed by vegetables contaminated with PAHs, and may be used to mitigate plant PAH contamination.
蔬菜在受污染的场地中生长时会高度积累多环芳烃 (PAHs)。接种能降解多环芳烃的内生细菌 (EB) 已被认为是从植物体内去除多环芳烃的最有前途的方法之一；然而，单一内生细菌的性能通常有限。本研究使用了八种 EB 的混合物，以降低包括白菜（ Brassica chinensis L.）和小白菜（ Brassica campestris L.）在内的蔬菜中 16 种 EPA 优先多环芳烃的污染和健康风险。复合 EB 具有很强的多环芳烃降解能力，经过 10 天悬浮培养复合 EB 后，超过 65%的∑PAH 被降解。通过种子浸泡 (SS) 和叶片涂抹 (LP) 将复合 EB 与蔬菜接触，并用 EB 细胞在 OD=0.2-1.5 孵育。与未接种对照相比，通过 SS 和 LP 用悬浮液 OD=0.2-1.5 接种复合 EB 后的白菜和小白菜可食部分的∑PAH 浓度分别降低了 42.07-70.77%和 15.79-53.20%，男性和女性的增量终生癌症风险 (ILCR) 值分别降低了 31.78-84.08%和 26.60-83.40%。SS 是降低 PAH 浓度和 ILCR 值的最佳接种方法。我们的结果表明，用复合 EB 接种植物可以降低受多环芳烃污染的蔬菜带来的健康风险，并且可能用于减轻植物多环芳烃污染。
