California Department of Pesticide Regulation, 1001 I St., Sacramento, CA 95814, United States of America.
California Department of Pesticide Regulation, 1001 I St., Sacramento, CA 95814, United States of America.
Sci Total Environ. 2020 May 20;718:137402. doi: 10.1016/j.scitotenv.2020.137402. Epub 2020 Feb 19.
Pyrethroid insecticides are frequently detected in urban surface waters at levels that are deleterious to sensitive aquatic species. The California Department of Pesticide Regulation (CDPR) Surface Water Protection Program collected 717 water and 191 sediment samples from 2009 to 2018 throughout California, providing a large dataset to conduct spatial and temporal trend analysis of pyrethroid concentrations. The pyrethroid bifenthrin accounted for 72% of average sample concentrations, and a strong relationship between whole water bifenthrin concentrations and the observed toxicity to the test species Hyallela azteca was established. To help mitigate runoff concentrations, CDPR adopted regulations in 2012 intended to limit the mass of pyrethroids applied to structures by professional pest control operators. A statistical analysis of CDPR statewide monitoring data collected at storm drain outfall and receiving water sites was conducted to determine if any significant trends in pyrethroid concentrations exist. Nonparametric statistical analysis of monitoring data revealed significant regional differences. In Northern California, decreasing trends in bifenthrin and cypermethrin concentrations may be counterbalanced by a potential switch to deltamethrin-containing products. Conversely, the few observed trends in concentrations at Southern California monitoring stations could be a result of regional hydrological and pest pressure differences. To evaluate the effects of structural applications on pyrethroid concentrations in urban runoff, CDPR conducted field trials using a tracer pyrethroid that was applied in accordance with the regulations. Detectable levels in runoff were observed, with an estimated 0.004-0.005% mass transport offsite per storm. Using field-derived sediment, the observed half-lives (514 days+) highlight the potential for contaminant laden sediment to serve as a long-term source of pyrethroids within waterways. Both chemistry and observed toxicity data identify storm water runoff as a primary transport mechanism. However, the presence of pyrethroids in dry-weather runoff suggests that significant loading can occur under various hydrologic conditions.
拟除虫菊酯类杀虫剂经常在城市地表水中被检测到，其浓度对敏感水生生物具有危害性。加利福尼亚州农药监管部门（CDPR）的地表水保护计划于 2009 年至 2018 年在加利福尼亚州各地采集了 717 个水样和 191 个沉积物样本，为进行拟除虫菊酯浓度的时空趋势分析提供了大量数据集。拟除虫菊酯类杀虫剂中的联苯菊酯占平均样本浓度的 72%，并且建立了全水样联苯菊酯浓度与观察到的对测试物种 Hyallela azteca 的毒性之间的强关系。为了帮助减轻径流浓度，CDPR 于 2012 年通过了旨在限制专业害虫防治操作人员在建筑物上施用拟除虫菊酯类杀虫剂的法规。对 CDPR 在暴雨排水口和受纳水体站点收集的全州监测数据进行了统计分析，以确定拟除虫菊酯类杀虫剂浓度是否存在任何显著趋势。对监测数据的非参数统计分析显示出明显的区域差异。在北加利福尼亚，联苯菊酯和氯菊酯浓度的下降趋势可能被潜在的改用含氯菊酯的产品所抵消。相反，在南加利福尼亚监测站观察到的浓度趋势可能是由于区域水文和害虫压力的差异造成的。为了评估结构应用对城市径流中拟除虫菊酯类杀虫剂浓度的影响，CDPR 按照法规使用示踪拟除虫菊酯进行了现场试验。在径流中观察到可检测水平，每个暴雨事件有约 0.004-0.005%的质量迁移到场外。使用现场衍生的沉积物，观察到的半衰期（514 天以上）突出表明，受污染的沉积物可能成为水道中拟除虫菊酯类杀虫剂的长期来源。化学和观察到的毒性数据都将雨水径流确定为主要的传输机制。然而，在旱季径流中存在拟除虫菊酯表明，在各种水文条件下可能会发生大量的负荷。
