LIEC, UMR 7360 CNRS-Université de Lorraine, Bd des Aiguillettes, BP 70239, 54506, Vandœuvre-lès-Nancy, France.
Environ Sci Pollut Res Int. 2016 Jan;23(1):109-19. doi: 10.1007/s11356-015-4367-0. Epub 2015 Mar 27.
Constructed wetlands are an effective and practical option for removing pesticide pollution from runoff or subsurface drainage water. The objective of this study was to assess the efficiencies of a ditch with a bundle of straw placed in its centre and a vegetated pond installed in grass cover bands at downstream of a drained plot. The dissipation rates of three herbicides and three fungicides were monitored on four substrates commonly found in constructed wetlands (two soils, sediment and straw). The influence of water content was determined in a sequence of three steps (flooded-unsaturated-flooded) over 120 days. The pesticide dissipation rates observed during the 120 days of incubation ranged from 1.4 to 100%. Isoproturon and 2,4-MCPA (MCPA) showed the highest dissipation rates, which ranged from 61.0 to 100% of the applied quantities during the 120 days of incubation. In contrast, boscalid and tebuconazole showed the lowest dissipation rates, which ranged from 1.4 to 43.9% of the applied quantities during the 120 days of incubation. The estimated DT50 values ranged from 20.5 days to more than 1 year and were influenced by the substrate water content. The soil and straw substrates had the lowest DT50 values during the unsaturated conditions, whereas the sediments had the lowest DT50 values during the flooded conditions. These results could be explained by an adaptation of microbial communities to their environmental conditions. Thus, the most favourable conditions of dissipation for soils and straw are observable when the drainage ceases (spring and summer). However, favourable conditions occur all year for the sediments, except when the constructed wetlands are dry. The results suggest that the dissipation of pesticides in constructed wetlands contributes to the long-term effectiveness of these buffer zones for reducing water pollution.
人工湿地是去除径流水或地下排水农药污染的有效且实用的选择。本研究的目的是评估在排水区下游安装中心带一束稻草的沟渠和植被池塘的效率。在人工湿地中常见的四种基质（两种土壤、沉积物和稻草）上监测了三种除草剂和三种杀菌剂的消解速率。在 120 天内通过三个步骤（饱和-不饱和-饱和）确定水分含量的影响。在 120 天的培养期间观察到的农药消解速率范围为 1.4%至 100%。异丙隆和 2,4-MCPA（MCPA）表现出最高的消解速率，在 120 天的培养期间，其消解量占施用量的 61.0%至 100%。相比之下，肟菌酯和戊唑醇表现出最低的消解速率，在 120 天的培养期间，其消解量占施用量的 1.4%至 43.9%。估计的 DT50 值范围为 20.5 天至 1 年以上，受基质含水量的影响。在不饱和条件下，土壤和稻草基质的 DT50 值最低，而在饱和条件下，沉积物的 DT50 值最低。这些结果可以通过微生物群落对其环境条件的适应来解释。因此，土壤和稻草的最佳消解条件是在排水停止时（春季和夏季）观察到的。然而，除了人工湿地干燥之外，沉积物全年都处于有利条件。结果表明，农药在人工湿地中的消解有助于这些缓冲区减少水污染的长期有效性。
