Laboratory of Ecotoxicology, Institute of Environmental Science (ICAM), University of Castilla-La Mancha, 45071 Toledo, Spain.
Laboratory of Ecotoxicology, Institute of Environmental Science (ICAM), University of Castilla-La Mancha, 45071 Toledo, Spain.
Sci Total Environ. 2019 Jun 1;667:761-768. doi: 10.1016/j.scitotenv.2019.02.402. Epub 2019 Feb 27.
Herein, we examined whether synergistic effects of earthworms (Lumbricus terrestris) and pine needle-derived biochar result in biochar-coated burrows with enhanced carboxylesterase (CE) activity (a pesticide-detoxifying enzyme). Biochar was placed at the top of soil columns at two doses (2.5 and 5% w/w dry mass), with an additional biochar-free treatment as control. Carboxylesterase and dehydrogenase activities were measured in the burrow walls sampled at three depths (0-4, 8-12, and 18-22 cm). Biochar was recovered from these samples to confirm its vertical transport and enzymatic activation. We tested whether biochar protected CE activity against desiccation stress of burrow wall samples. Likewise, the role of earthworm mucus in stabilizing CE onto biochar surface was also investigated by measuring the enzyme activity in fresh biochar particles previously incubated in the presence of earthworm mucus and purified esterase. Finally, we checked for the sensitivity of biochar-bound CE activity against selected organophosphorus pesticides. The main results were: i) co-application of earthworms and biochar caused a significant increase of CE activity in the first 12 cm of the soil column, ii) recovered biochar particles displayed CE activity which was significantly higher in the particles collected from the bottom of columns, iii) soil desiccation decreased the enzymatic activity, although such effect depended on biochar treatment and column depth (22-77% inhibition). Nevertheless, CE activity still was higher in the samples from the 5%-biochar treatment than activity in control and 2.5%-biochar treatments, iv) earthworm mucus favored the retention of CE onto the biochar surface, and v) the activity of biochar-bound CE was sensitive to inhibition by chlorpyrifos-oxon. These results suggest that the joint application of L. terrestris and biochar may be a suitable vermiremediation strategy to inactivate OP pesticides.
在此，我们研究了蚯蚓（Lumbricus terrestris）和松针衍生生物炭的协同作用是否会导致生物炭涂覆的洞穴具有增强的羧酸酯酶（CE）活性（一种农药解毒酶）。生物炭以两种剂量（干质量的 2.5%和 5%）放置在土壤柱的顶部，另外还有一个无生物炭的处理作为对照。在三个深度（0-4、8-12 和 18-22cm）处取样的洞穴壁中测量羧酸酯酶和脱氢酶活性。从这些样品中回收生物炭以确认其垂直迁移和酶的激活。我们测试了生物炭是否能保护 CE 活性免受洞穴壁样品的干燥胁迫。同样，通过测量先前在蚯蚓粘液存在下孵育的新鲜生物炭颗粒和纯化酯酶中的酶活性，研究了蚯蚓粘液在稳定 CE 到生物炭表面的作用。最后，我们检查了生物炭结合的 CE 活性对选定有机磷农药的敏感性。主要结果是：i）蚯蚓和生物炭的共同应用导致土壤柱前 12cm 处 CE 活性显著增加，ii）回收的生物炭颗粒在柱底收集的颗粒中显示出显著更高的 CE 活性，iii）土壤干燥降低了酶活性，尽管这种效果取决于生物炭处理和柱深（22-77%抑制）。然而，5%生物炭处理的样品中的 CE 活性仍高于对照和 2.5%生物炭处理的活性，iv）蚯蚓粘液有利于 CE 保留在生物炭表面，v）生物炭结合的 CE 活性对氯吡硫磷-氧的抑制敏感。这些结果表明，L. terrestris 和生物炭的联合应用可能是一种合适的蚯蚓修复策略，可使 OP 农药失活。
