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Feasibility of lettuce cultivation in sophoroliplid-enhanced washed soil originally polluted with Cd, antibiotics, and antibiotic-resistant genes

Ye, Mao, Sun, Mingming, Wan, Jinzhong, Feng, Yanfang, Zhao, Yu, Tian, Da, Hu, Feng, Jiang, Xin
Ecotoxicology and environmental safety 2016 v.124 pp. 344-350
antibiotic resistance, cadmium, chlorophyll, endophytes, food chain, food security, genes, heavy metals, human health, lettuce, protein content, roxithromycin, soil, soil remediation, sulfadiazine, surface area, sustainable technology, tissues, ultrasonic treatment, vegetable growing
Vegetable cultivation in soils polluted with heavy metals, antibiotics and a high abundance of antibiotic-resistance genes (ARGs) can seriously threaten human health through the food chain. Therefore, novel techniques that not only remediate soil, but also ensure food security are urgently required. In the present study, two successive washings with 20gL−1 of sophoroliplid solution plus ultrasonication (35kHz) were effective in extracting 71.2% Cd, 88.2% tetracycline, 96.6% sulfadiazine, and 100% roxithromycin. Simultaneously, relative abundance of ARGs (tetM, tetX, sulI, and sulII) was decreased to 10−7–10−8 (ARG copies/16S copies). Further, lettuce cultivation in the 2nd washed soil showed significant improvement in vegetable growth indices (fresh/dry weight, root surface area, chlorophyll content and soluble protein content) and a decrease in isolate counts for antibiotic-resistant bacterial endophytes and ARG abundance in lettuce tissues. This combined cleanup strategy provides an environmentally friendly technology for ensuring vegetable security in washed soils.