Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
Toxins (Basel). 2020 Aug 14;12(8):523. doi: 10.3390/toxins12080523.
Microcystin-LR (MC-LR) is prevalent in water and can be translocated into soil-crop ecosystem via irrigation, overflow (pollution accident), and cyanobacterial manure applications, threatening agricultural production and human health. However, the effects of various input pathways on the bioaccumulation and toxicity of MCs in terrestrial plants have been hardly reported so far. In the present study, pot experiments were performed to compare the bioaccumulation, toxicity, and health risk of MC-LR as well as its degradation in soils among various treatments with the same total amount of added MC-LR (150 μg/kg). The treatments included irrigation with polluted water (IPW), cultivation with polluted soil (CPS), and application of cyanobacterial manure (ACM). Three common leaf-vegetables in southern China were used in the pot experiments, including L., L., and L. All leaf vegetables could bioaccumulate MC-LR under the three treatments, with much higher MC-LR bioaccumulation, especially root bioconcentration observed in ACM treatment than IPW and CPS treatments. An opposite trend in MC-LR degradation in soils of these treatments indicated that ACM could limit MC-LR degradation in soils and thus promote its bioaccumulation in the vegetables. MC-LR bioaccumulation could cause toxicity to the vegetables, with the highest toxic effects observed in ACM treatment. Similarly, bioaccumulation of MC-LR in the edible parts of the leaf-vegetables posed 1.1~4.8 fold higher human health risks in ACM treatment than in IPW and CPS treatments. The findings of this study highlighted a great concern on applications of cyanobacterial manure.
微囊藻毒素-LR（MC-LR）广泛存在于水体中，可通过灌溉、溢流（污染事故）和蓝藻粪便施用来转移到土壤-作物生态系统中，对农业生产和人类健康构成威胁。然而，到目前为止，还很少有研究报道各种输入途径对陆生植物中 MCs 的生物积累和毒性的影响。在本研究中，进行了盆栽实验，比较了用相同总量添加的 MC-LR（150μg/kg）进行污染水灌溉（IPW）、污染土壤栽培（CPS）和蓝藻粪便施用（ACM）三种处理方式下，土壤中 MC-LR 的生物积累、毒性和健康风险及其降解情况。实验中选用了中国南方三种常见的叶菜类蔬菜，包括 L.、 L. 和 L.。在三种处理方式下，所有叶菜类蔬菜都可以生物积累 MC-LR，ACM 处理的 MC-LR 生物积累量更高，尤其是根部的浓缩倍数比 IPW 和 CPS 处理更高。这些处理方式中 MC-LR 在土壤中的降解呈相反趋势，表明 ACM 可能限制了土壤中 MC-LR 的降解，从而促进了其在蔬菜中的生物积累。MC-LR 的生物积累会对蔬菜造成毒性，在 ACM 处理中观察到的毒性最大。同样，ACM 处理中叶菜类蔬菜可食用部分中 MC-LR 的生物积累对人体健康的风险比 IPW 和 CPS 处理高 1.1~4.8 倍。本研究结果表明，蓝藻粪便的应用值得关注。
