Hunter Wesley, Yang Yu, Reichenberg Fredrik, Mayer Philipp, Gan Jianying
Department of Environmental Sciences, University of California, 2258 Geology, Riverside, California 92521, USA.
Environ Toxicol Chem. 2009 Jan;28(1):36-43. doi: 10.1897/08-209.1.
Pyrethroids are hydrophobic insecticides commonly used in both agricultural and urban environments. Their high toxicity to aquatic organisms, including benthic invertebrates, and detection in the sediment at many locations in California, U.S.A., have spawned interest in understanding their bioavailability in bed sediments. A recent study showed good correlation between uptake of 14C-permethrin in Chironomus tentans and solid-phase microextraction (SPME) fibers in sediments. The present study was directed at the development of an SPME technique applicable to trace levels of nonlabeled pyrethroids in sediment. Disposable polydimethylsiloxane fibers were used to detect freely dissolved pore-water concentrations of bifenthrin, fenpropathrin, cis-permethrin, trans-permethrin, cyfluthrin, cypermethrin, and esfenvalerate under agitated and static conditions. Partition equilibrium between fiber and sediment was reached in <5 d when the samples were agitated on a shaker at low speed, while much longer times (>23 d) were needed without agitation. Polydimethylsiloxane to water partition ratios (K(PDMS)) of the seven pyrethroids were measured separately and ranged from 2.83 x 10(5) to 1.89 x 10(6). When applied to field-contaminated sediments, agitated matrix-SPME was able to detect pore-water concentrations as low as 0.1 ng/L. The method developed in the present study may be coupled with bioassays to gain mechanistic understanding of factors affecting pyrethroid toxicities, and applied to field samples to better predict sediment toxicities from pyrethroid contamination.
拟除虫菊酯是常用于农业和城市环境的疏水性杀虫剂。它们对包括底栖无脊椎动物在内的水生生物具有高毒性，并且在美国加利福尼亚州的许多地点的沉积物中都有检测到，这引发了人们对了解它们在河床沉积物中的生物可利用性的兴趣。最近的一项研究表明，摇蚊对14C-氯菊酯的摄取与沉积物中的固相微萃取（SPME）纤维之间具有良好的相关性。本研究旨在开发一种适用于沉积物中痕量非标记拟除虫菊酯的SPME技术。使用一次性聚二甲基硅氧烷纤维在搅拌和静态条件下检测联苯菊酯、甲氰菊酯、顺式氯菊酯、反式氯菊酯、氟氯氰菊酯、氯氰菊酯和乙氰菊酯的自由溶解孔隙水浓度。当样品在低速振荡器上搅拌时，纤维与沉积物之间的分配平衡在<5天内达到，而在不搅拌的情况下需要更长的时间（>23天）。分别测量了七种拟除虫菊酯的聚二甲基硅氧烷与水的分配比（K(PDMS)），范围为2.83×10(5)至1.89×10(6)。当应用于受现场污染的沉积物时，搅拌基质-SPME能够检测到低至0.1 ng/L的孔隙水浓度。本研究中开发的方法可以与生物测定相结合，以获得对影响拟除虫菊酯毒性的因素的机理理解，并应用于现场样品，以更好地预测拟除虫菊酯污染造成的沉积物毒性。
