Bouldin J L, Farris J L, Moore M T, Smith S, Stephens W W, Cooper C M
Arkansas State University, Environmental Sciences Program, Jonesboro, Arkansas, USA.
Environ Toxicol. 2005 Oct;20(5):487-98. doi: 10.1002/tox.20137.
Contaminants such as nutrients, metals, and pesticides can interact with constructed wetlands and existing drainage ditches used as agricultural best-management practices. Our research has shown that the presence of macrophytes and a hydrologic regime aid in the transfer and transformation of pesticides associated with agricultural runoff. This study consisted of application of both atrazine (triazine herbicide) and lambda-cyhalothrin (pyrethroid insecticide) to vegetated and unvegetated microcosms in order to measure the fate and effects of pesticides applied at suggested field application rates. Exposures focused on monocultures of Ludwigia peploides (water primrose) and Juncus effusus (soft rush). Pesticide sorption was evident through concentrations of atrazine and lambda-cyhalothrin in plant tissue as high as 2461.4 and 86.50 microg/kg, respectively. Toxicity was measured in water from unvegetated microcosms for 28 days and in Chironomus tentans (midge larvae) exposed to sediment collected from 3 h to 56 days in microcosms receiving the pesticide combination. The comparative survival of test organisms in this study suggests that effective mitigation of pesticides from runoff can depend on the macrophyte contact and vegetative attributes associated with ditches.
诸如养分、金属和农药等污染物会与人工湿地以及用作农业最佳管理措施的现有排水渠相互作用。我们的研究表明，大型植物和水文状况有助于与农业径流相关的农药的转移和转化。本研究包括将莠去津（三嗪类除草剂）和高效氯氟氰菊酯（拟除虫菊酯类杀虫剂）施用于有植被和无植被的微型生态系统，以测定按建议田间施用量施用农药后的归宿和影响。暴露试验集中于单一种植的黄花水龙和灯心草。通过植物组织中莠去津和高效氯氟氰菊酯的浓度分别高达2461.4和86.50微克/千克，可明显看出农药的吸附作用。在无植被微型生态系统的水中测量了28天的毒性，并在暴露于接受农药组合的微型生态系统中3小时至56天收集的沉积物中的摇蚊幼虫中测量了毒性。本研究中受试生物的相对存活率表明，有效减轻径流中的农药可能取决于与沟渠相关的大型植物接触和植被属性。
