Department of Soil and Water Science, Indian River Research and Education Center, University of Florida/IFAS, Fort Pierce, FL 34945, USA.
Bull Environ Contam Toxicol. 2011 Oct;87(4):426-30. doi: 10.1007/s00128-011-0380-2. Epub 2011 Aug 11.
Norflurazon and simazine are pre-emergent herbicides detected frequently in surface water associated with South Florida agricultural canals and drainage water. This study investigated the potential use of a 1.34 ha constructed wetland for removing these herbicides from surface water. The total length of the wetland was 400 m and width was 35 m. A surface water flow rate of 740 L/min was maintained in the system using a pump. The plant community within the system consisted primarily of Panicum repens, Alternanthera philoxeroides, and Bacopa caroliniana. Norflurazon and simazine, derived from commercial formulations, were injected (51.1 g active ingredient each) directly into the water pumped into the wetland over a 2 h period. Water samples were collected from the wetland upstream of the dosing system at 3 h intervals from the beginning through 360 h and at the exit point at 1, 2, and 3 h intervals for the periods of 0-24, 25-48 and 49-360 h after dosing, respectively. The herbicides were extracted using C-18 cartridges and were analyzed by GC-TSD. The total mass of each herbicide discharged from the system was estimated by multiplying the concentration by the total volume discharged during the sampled period. Neither herbicide was detected in the inflow water during the entire study. Norflurazon was first detected at the exit 19 h after dosing and simazine after 23 h. Discharge patterns of the two herbicides differed dramatically. Norflurazon tended to bleed off from the wetland with no distinct peak concentration. However, the mobile fraction of simazine was discharged over a 58 h period. Mean/maximum/median detectable concentrations of the herbicides were 3.9 ± 1.7/8.1/3.4 μg L(-1) for norflurazon, and 11.9 ± 6.8/23.6/12.0 μg L(-1) for simazine, respectively. The total masses of norflurazon and simazine discharged from the exit during the 15 day study were 51.7 and 26.9 g, indicating 0% and 47.4% removal from the surface water by the system.
诺氟草酮和西玛津是在与南佛罗里达州农业运河和排水水有关的地表水经常检测到的前茬除草剂。本研究调查了使用 1.34 公顷人工湿地从地表水中去除这些除草剂的潜力。湿地的总长度为 400 米，宽度为 35 米。通过使用泵将系统中的地表水流速维持在 740 L/min。系统内的植物群落主要由 Panicum repens、Alternanthera philoxeroides 和 Bacopa caroliniana 组成。诺氟草酮和西玛津源自商业制剂，在 2 小时内直接注入（各 51.1 克有效成分）泵入湿地的水中。从开始到 360 小时，每隔 3 小时从投药系统上游的湿地采集水样，在投药后 0-24、25-48 和 49-360 小时期间，在 1、2 和 3 小时间隔从出口点采集水样。使用 C-18 筒提取除草剂，并通过 GC-TSD 进行分析。通过将浓度乘以采样期间排放的总量，估算出系统中排出的每种除草剂的总量。在整个研究过程中，流入水中都没有检测到这两种除草剂。投药后 19 小时在出口处首次检测到诺氟草酮，23 小时后检测到西玛津。两种除草剂的排放模式有很大差异。诺氟草酮从湿地中渗出，没有明显的峰值浓度。然而，西玛津的移动部分在 58 小时内排出。两种除草剂的检出浓度平均值/最大值/中位数分别为 3.9 ± 1.7/8.1/3.4 μg/L 对诺氟草酮，11.9 ± 6.8/23.6/12.0 μg/L 对西玛津。在 15 天的研究期间，从出口处排出的诺氟草酮和西玛津的总量分别为 51.7 和 26.9 克，表明系统对地表水的去除率分别为 0%和 47.4%。
