摘要
拟除虫菊酯农药是一种广谱、高效、低毒、低残留的亲脂性杀虫剂,它会随农田排水、降雨淋洗进入水体,最终进入沉积环境,故沉积物是其最终归宿之一。本研究针对珠江河口沉积物中菊酯类农药的污染状况进行调查,研究它们的含量、组成比例、污染来源及其潜在毒性,为珠江渔业水生生态环境管理及掌握环境中有机污染情况提供依据,对保护渔业环境安全有十分重要的意义。2012年5月采集珠江河口表层沉积物,采用气相色谱法-电子捕获法(GC-ECD)对表层沉积物中联苯菊酯、甲氰菊酯、高效氯氟氰菊酯、氯菊酯、氯氰菊酯、氰戊菊酯、溴氰菊酯进行残留检测,并利用其对钩虾的生物毒性来评价沉积物的潜在毒性。结果显示,表层沉积物(以干质量计)中7种菊酯类农药质量分数介于ND^6.59μg·kg-1(ND表示未检出),平均值为0.75μg·kg-1,其总质量分数与有机碳质量分数呈现一定的正相关性;组成比例表明,氯菊酯最多,占总量的57.63%,它的检出率为61.90%,甲氰菊酯其次,约占总量的16.39%,检出率为28.57%,氯菊酯占主要组成部分,可能与其在珠江三角洲居民生活中被大量使用及其降解速率有关;珠江桥采样点高浓度的菊酯类农药的检出(6.59μg·kg-1),可能与其靠近人口密集和经济发达的广州有关;与国内外其他地区相比,珠江河口沉积物中菊酯农药处于较低水平;采用毒性单元TU(选用钩虾Hyallela Azteca的LC50)进行毒性评估,∑TU值范围为0~0.09,远远低于1,表明珠江河口拟除虫菊酯不存在生态风险。
Pyrethroids are synthetic insecticides commonly applied to many crops due to their efficacy at low doses, high degradation rate in the environment and relatively low toxicity with regard to non-target organisms. Pyrethroids used in agriculture may finally enter the aquatic environment and accumulate in the food chain and may cause serious ecological and health problems. The Pearl River Estuary is a unique ecological environment, yet little research has been conducted on pyrethroids in this area. This study aimed to determine if pyrethroids were detectable and widespread in the Pearl River Estuary and if concentrations were high enough to cause associated aquatic toxicity. Samples of surface sediments were collected in the Pearl River Estuary in May 2012 for analysis of pyrethroid residues using gas chromatograph-electron capture （GC-ECD）, with Hyalella azteca used to evaluate the potential toxicity of sediment. Results showed that total mass fraction of the pyrethroids in the surface sediments ranged from ND to 6.59 ~g＇kg1, with an average of 0.75 ~tg＇kg-1, and exhibited a positive correlation with organic carbon. The highest content of pyrethroids was found at the Pearl River Bridge. The proportions of permethrin were highest in the Pearl River Estuary, accounting for 57.63% of total pyrethroids, with detections in 61.90% sediment samples, followed by fenvalerate, accounting for 16.39% of total pyrethroids, with detections in 28.57% sediment samples. Permethrin was the most abundant pyrethroid due to its wide-spread use in the Pearl River Delta and its degradation. The Pearl River Bridge site showed a pyrethroid sediment concentration of 6.59 pg＇kg-1, which was probably due to it close proximity to Guangzhou, one of the most densely populated and economically developed cities in China. Toxic units （TUs） based on the LCs0 ofHyalella azteca were calculated to estimate toxicity risk. The TUs in the Pearl River Estuary was in the range of 0-0.09, suggesting there were no obvious toxic effects of pyrethroids on Hyalella azteca, and no ecological risk of pyrethroids in the Pearl River Estuary. Results from this study will provide a basis for controlling organic pollution and managing the aquatic environment in local fisheries.
出处
《生态环境学报》
CSCD
北大核心
2013年第8期1408-1413,1413+1411-1413,共6页
Ecology and Environmental Sciences
基金
公益性行业(农业)科研专项"珠江及其河口渔业资源评价和增殖养护技术研究与示范(201303048)"
广东省海洋渔业科技推广专项(A2011009)
关键词
拟除虫菊酯
沉积物
珠江河口
毒性评价
pyrethroids
sediments
Pearl River Estuary
toxic assessment
