Department of Integrative Biology, University of California, Berkeley, California, USA.
Environ Toxicol Chem. 2014 Apr;33(4):920-9. doi: 10.1002/etc.2512. Epub 2014 Feb 26.
The Cache Slough complex is an area of tidal sloughs in the Sacramento-San Joaquin River Delta of California (USA), and is surrounding by irrigated agricultural lands. Among the species of concern in the area is the delta smelt (Hypomesus transpacificus), a federally listed threatened species. Releases of the organophosphate insecticide chlorpyrifos and pyrethroid insecticides were examined to determine whether they represented a threat to the copepods on which delta smelt feed (Eurytemora affinis and Pseudodiaptomus forbesi) and to aquatic life in general, represented by the standard testing organism, Hyalella azteca. There was a single incident of toxicity to H. azteca as a result of discharge of agricultural irrigation water containing chlorpyrifos. Pyrethroids were not found in samples collected during the dry season. Following rain events, however, the waters of western Cache Slough repeatedly became toxic to H. azteca because of the pyrethroids bifenthrin and cyhalothrin. The 96-h median lethal concentrations (LC50s) for E. affinis and P. forbesi for the pyrethroids bifenthrin and cyhalothrin were 16.7 ng/L to 19.4 ng/L when tested at 20 °C. However, their LC50s may be 5 mg/L to 10 ng/L at in situ temperatures of the Cache Slough, comparable to the peak bifenthrin concentration observed. The dominant pyrethroid source appeared to be urban runoff entering a creek 21 km upstream of Cache Slough. Pyrethroids of urban origin were supplemented by agricultural inputs of pyrethroids and chlorpyrifos as the creek flowed toward Cache Slough.
卡奇沼泽复合体是美国加利福尼亚州萨克拉门托-圣华金河三角洲的一个潮汐沼泽区，周围是灌溉农田。该地区受关注的物种之一是代氏银汉鱼（Hypomesus transpacificus），这是一种受联邦威胁的物种。检查了有机磷杀虫剂毒死蜱和拟除虫菊酯杀虫剂的释放情况，以确定它们是否对代氏银汉鱼（Eurytemora affinis 和 Pseudodiaptomus forbesi）的浮游动物以及以标准测试生物南海鱵（Hyalella azteca）为代表的水生生物构成威胁。由于含有毒死蜱的农业灌溉水的排放，南海鱵发生了一次单一的毒性事件。在旱季采集的样本中未发现拟除虫菊酯。然而，在雨后，由于拟除虫菊酯联苯菊酯和氯氟氰菊酯，西部卡奇沼泽的水域多次对南海鱵产生毒性。当在 20°C 下测试时，联苯菊酯和氯氟氰菊酯对 E. affinis 和 P. forbesi 的 96 小时中位数致死浓度（LC50）分别为 16.7 ng/L 至 19.4 ng/L。然而，它们的 LC50 可能在卡奇沼泽的原位温度下为 5 mg/L 至 10 ng/L，与观察到的联苯菊酯峰值浓度相当。主要的拟除虫菊酯来源似乎是进入卡奇沼泽上游 21 公里的小溪的城市径流。随着小溪流向卡奇沼泽，城市来源的拟除虫菊酯与农业输入的拟除虫菊酯和毒死蜱一起补充。
