摘要:
蓝藻藻泥好氧堆肥腐熟后还田是其打捞后资源化利用的主要途径。堆肥后仍有一定数量的微囊藻毒素(microcystin, MC)残留,大量还田是否会对作物生长和人类健康产生安全风险尚不明确。将青菜(Brassica chinensis)暴露于不同MC含量的石英砂和菜地土壤,观测植株生长状况及体内MC含量,并观测不同含量的MC在菜地土壤中的降解速率。结果发现:砂培实验结束时,青菜成株的株高和生物量随着MC暴露浓度的增加而显著降低,而植株地上部MC的含量则显著增加。在 MC浓度为0.386mg·kg-1的处理中,青菜地上部MC-LR(L为亮氨酸)和MC-RR(R为精氨酸)的浓度分别达到27.45μg· kg-1(鲜质量)和1.35μg·kg-1(鲜质量)。MC-LR和MC-RR在青菜地上部的富集系数都随着砂培基质中MC浓度的增加而显著降低,且前者显著高于后者。土培青菜生长过程中吸收和累积的MC数量显著小于砂培实验。MC在菜地土壤中降解56d 后,MC-LR和MC-RR的降解率均达90%以上。按普通有机肥的一般用量(2.5kg·m-2)施用充分腐熟的蓝藻堆肥成品种植青菜,食用后每人每天摄入的MC含量远低于WHO制定的饮用水中MC的指导值。研究为评估现行蓝藻堆肥工艺中残留的 MC对作物生长和生物安全风险提供了科学依据。
关键词:
-
微囊藻毒素
/
-
青菜
/
-
生物累积
/
-
降解
Abstract:
The collection of cyanobacteria is an effective way to reduce the amount of cyanobacteria and its risk of bloom. Aerobic composting of dewatered cyanobacteria after collection can change waste into resources. However, the residue of microcystins (MC) after aerobic composting should be considered in view of its application safety to plants and human health. To explore the application safety of the composted cyanobacteria, the MC exposure test of green vegetable (Brassica chinensis) cultivated in sand and vegetable soil, and the degradation test of MC in vegetable soil were conducted. Results showed that the height and biomass of Brassica chinensis cultivated in sand significantly declined with the increase of MC concentration, while the content of MC in the above-ground part of the green vegetable increased with the increase of MC concentration at harvest. When being exposed to 0.386mg·kg-1 of MC, the contents of MC-LR (L indicated leucine) and MC-RR (R indicated arginine) in edible part of the green vegetable were 27.45μg·kg-1 (fresh mass) and 1.35μg·kg-1 (fresh mass), respectively. The bio-concentration factor of MC-LR was significantly higher than that of MC-RR. Both of bio-concentration factors of MC-LR and MCRR decreased with the increase of MC concentration in sand culture test. Because of the degradation of MC in soils, the accumulation of MC detected in the green vegetable cultivated in soils was less than that cultivated in sand. The degradations of MC-LR and MC-RR in vegetable soils were more than 90% after 56 days. The application of composted cyanobacteria with the amount of 2.5kg·m-2 would not influence the growth of Brassica chinensis. The content of MC taken into human bodies via the edible part of the green vegetable was much lower than the standard in drinking water established by WHO. Those results could provide the scientific basis for evaluating the effect of residual MC in composted cynaobacteria on vegetable growth and its biosecurity after farmland application.
点击查看大图
下载:
