Colonization of polycyclic aromatic hydrocarbon-degrading bacteria on roots reduces the risk of PAH contamination in vegetables

• Published in: Environment international 2019-11, Vol.132, p.105081, Article 105081
• Main Authors: Chen, Shuang, Ma, Zhao, Li, Shunyao, Waigi, Michael Gatheru, Jiang, Jiandong, Liu, Juan, Ling, Wanting
• Format: Article
• Language: English
• Subjects: Bacteria; Bacteria - metabolism; Biodegradation, Environmental; Brassica - chemistry; Brassica - microbiology; Colonization; Degradation; Food Contamination - prevention & control; Health risk; Humans; Phenanthrene; Phenanthrenes - metabolism; Plant Roots - chemistry; Plant Roots - microbiology; Soil Pollutants - metabolism; Vegetable; Vegetables - chemistry; Vegetables - microbiology
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/j.envint.2019.105081

This is a primary investigation on the mitigation of polycyclic aromatic hydrocarbon (phenanthrene as a model PAH) contamination in vegetables including water spinach (Ipomoea aquatica Forsk), pakchoi (Brassica campestris) and Chinese cabbage (Brassica chinensis) using a gfp-labeled PAH-degrading bacterium (RS1-gfp). Effective root colonization led to dense RS1-gfp populations inhabiting the rhizosphere and endosphere of the vegetables, which subsequently led to a reduction in phenanthrene accumulation and risk in vegetables. When compared with the controls without RS1-gfp, the amount of phenanthrene accumulation due to strain RS1-gfp colonization reduced by up to ~93.7% in roots and ~75.2% in shoots of vegetables, respectively. The estimated incremental lifetime cancer risk (ILCR) for adults due to phenanthrene in vegetables was reduced by 24.6%–48% through RS1-gfp inoculation. The proposed method was developed to circumvent the risk of phenanthrene contamination in vegetables by inoculating PAH-degrading bacteria. The findings provide an in-depth understanding of PAH detoxification in agricultural plants grown on contaminated sites by exploiting bacteria like RS1-gfp, which portray both rhizo- and endophytic lifestyles. [Display omitted] •The isolated strain RS1-gfp is capable of degrading phenanthrene.•Root colonization led to dense populations of RS1-gfp on roots and internal vegetable tissues.•RS1-gfp colonization reduced the concentration and accumulation of phenanthrene in vegetables.•RS1-gfp can effectively mitigate the risks of vegetable phenanthrene contamination.