油冬菜对水凝胶包裹^(14)C-多菌灵的吸收及其在土壤-油冬菜体系中的可提态残留和结合残留

Extractable Residue,Bound Residue of ^(14)C-carbendazim Loaded by Hydrogel in Soil as well as Its Uptake by Oil Spiced Cabbage

利用高吸水树脂(SAP)和农药解决干旱半干旱地区抗旱保水及虫害问题是行之有效的农业生产措施,研究并阐明SAP与农药共存下的农药环境行为规律以保障环境安全性具有重要的实际意义。本文以具有缓释特性的水凝胶包覆多菌灵(H-MBC)为研究对象,应用同位素示踪法研究14C标记H-MBC在水中的释放特性及其与原药(14C-MBC)在土壤-油冬菜体系中的结合残留、可提态残留、矿化及挥发物总量的异同性,同时考察油冬菜对14C标记H-MBC的吸收利用规律。结果表明,H-MBC可以实现多菌灵缓慢释放,48 h释放了总量的60%,至360 h时释放量达到了总量的96%;14C标记H-MBC及14CMBC在土壤中可提态残留均随着时间递减,至培养34 d时分别占引入量的10.70%和6.95%;14C标记H-MBC及14C-MBC在土壤中的结合残留随着时间先增后降,其拐点分别出现在28 d和14 d,其中14C标记H-MBC的结合残留约占引入量35.71%~52.51%,而对照14C-MBC的结合残留约为引入量的23.87%~43.26%;油冬菜对14C标记H-MBC和14C-MBC的吸收均较少,仅占引入量的0.08%~1.64%,表明2种施药方式下多菌灵均不会在植物中产生大量残留。根据质量平衡得到的14C标记HMBC和14C-MBC降解产生的挥发性物质(可能为14C-CO2和/或14C-甲酸)的量分别为30.17%~52.66%和32.26%~65.75%,凝胶的包覆减少了多菌灵挥发性物质的产生。本研究为干旱地区安全、科学使用SAP和农药提供了科学依据。

The application of super absorbent polymers（ SAP） to agriculture is one of the effective measures to solve the problems of drought resisting and water retention in arid-semiarid region and the use of agrochemicals is an indispensable part as well. So it is obviously important to study and clarify environmental behavior of agricultural chemicals when coexisted with SAP. In this study,explored the release profile of Carbendazim loaded by hydrogel（ H-MBC） in distilled water. Bound residue and extractable residue of H-MBC and Carbendazim（ MBC） in soil were investigated by14 Cisotope tracing,and the uptake of14 C labeled H-MBC and14C-MBC by Oil spiced cabbage（ Brassica chinensis L.） was also studied. The results showed as follows：^14C-Carbendaizm derived from14 C labeled H-MBC was slowly released in water,and the release longevity could be prolonged to more than 360 h. The extractable residue（ ER） for both14 C labeled H-MBC and14C-MBC decreased with time,reaching 10. 70% and 6. 95% of applied amount respectively after34 days of incubation. The bound residue（ BR） of14 C labeled H-MBC and14C-MBC in soil increased first then decreased after a certain time,and the inflection point occurred after 28 days and 14 days respectively. Around 35. 71%～ 52. 51% of applied H-MBC and 23. 87% ～ 43. 26% of MBC formed BR. The uptake of both14 C labeled H-MBC and ^14C-MBC by Oil spiced cabbage was limited,and about 0. 08% ～ 1. 64% of the applied amount,indicating that neither H-MBC nor MBC would lead to high residue in plant. The disappeared proportions（14C labeled carbon dioxide and / or14C-labeled methanoic acid） constitute 30. 17% ～ 52. 66% of applied14C-labeled H-MBC,32. 26% ～ 65. 75%of14C-MBC, demonstrating that the encapsulation of hydrogel decreased the volatilization and mineralization of carbendazim derived from H-MBC. The results were helpful to understand the environmental behavior and fate of H-MBC in soil-plant system and paved a way for safely-rational use of SAP and agrochemicals,as well as their environmentfriendly and development tendency.