Department of Agriculture, Crop Production and Rural Environment, University of Thessaly, Nea Ionia, Volos 38446, Greece.
Chemosphere. 2013 Sep;93(1):20-8. doi: 10.1016/j.chemosphere.2013.04.049. Epub 2013 May 18.
Biobed substrates commonly exhibit high degradation capacity. However, degradation does not always lead to detoxification and information on the metabolic pathways of pesticides in biobeds is scarce. We studied the degradation and metabolism of three pesticides in selected biomixtures and soil. Biomixtures stimulated degradation of terbuthylazine and metribuzin, whereas chlorpyrifos degraded faster in soil. The latter was attributed to the lipophilicity of chlorpyrifos which increased adsorption and limited biodegradation in organic-rich biomixtures. Although the same metabolites were detected in all substrates, qualitative and quantitative differences in the metabolic routes of pesticides in the various substrates were observed. Chlorpyrifos was hydrolyzed to 3,5,6-tricholorpyridinol (TCP) which was further degraded only in compost-biomixture CBX1. Metabolism of terbuthylazine in compost biomixtures (BX) and soil resulted in the formation of desethyl-terbuthylazine (DES) which was fully degraded only in the compost-biomixture CBX2, whereas peat-based biomixture (OBX) promoted the hydroxylation of terbuthylazine. Desamino- (DA) (dominant) and diketo- (DK) metribuzin appear as intermediate metabolites in all substrates and were further transformed to desamino-diketo-metribuzin (DADK) which was fully degraded only in compost-biomixture GSBX. Overall, lower amounts of metabolites were accumulated in biomixtures compared to soil stressing the higher depuration efficiency of biobeds.
生物床基质通常表现出较高的降解能力。然而，降解并不总是导致解毒，而且有关生物床中农药代谢途径的信息也很缺乏。我们研究了三种农药在选定的生物混合物和土壤中的降解和代谢。生物混合物刺激了特丁津和二甲戊灵的降解，而毒死蜱在土壤中降解更快。这归因于毒死蜱的亲脂性，它增加了在富含有机物的生物混合物中的吸附作用，限制了生物降解。尽管在所有基质中都检测到了相同的代谢物，但在不同基质中观察到了农药代谢途径的定性和定量差异。毒死蜱被水解为 3,5,6-三氯吡啶醇（TCP），仅在堆肥-生物混合物 CBX1 中进一步降解。在堆肥生物混合物（BX）和土壤中，特丁津的代谢导致去乙基-特丁津（DES）的形成，仅在堆肥-生物混合物 CBX2 中完全降解，而泥炭基生物混合物（OBX）促进了特丁津的羟基化。去氨基（DA）（主要）和二酮（DK）二甲戊灵作为中间代谢物出现在所有基质中，并进一步转化为去氨基二酮二甲戊灵（DADK），仅在堆肥-生物混合物 GSBX 中完全降解。总的来说，与土壤相比，生物混合物中积累的代谢物较少，这强调了生物床具有更高的净化效率。
