The urban use of pyrethroids has been associated with the contamination and toxicity of urban surface water. A less considered phenomenon is that many pyrethroids may be transformed to a common intermediate, 3-phenoxybenzoic acid (3-PBA), that is an endocrine-disrupting compound. Here we examined the conversion of five common pyrethroids, permethrin, λ-cyhalothrin, deltamethrin, fenpropathrin, and esfenvalerate, to 3-PBA on concrete. Formation of 3-PBA was almost instantaneous, reaching up to 3% of the initial level of pyrethroids within hours of exposure, and was caused mainly by hydrolysis, likely enhanced by the strong alkalinity of concrete. The accumulation of 3-PBA on concrete was transient, with half-lives of 4.2–6.7 h depending on the treatment. Low levels (nanograms per liter) of 3-PBA were frequently found in urban streams draining residential neighborhoods, validating the off-site transport potential of 3-PBA from urban hard surfaces. Findings from this study suggested that urban hardscapes such as concrete pavement are reactive surfaces, conducive to the formation of biologically active transformation products.

中文翻译：

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拟除虫菊酯类农药在城市硬表面上的转化为3-苯氧基苯甲酸

拟除虫菊酯在城市的使用与城市地表水的污染和毒性有关。较少考虑的现象是许多拟除虫菊酯可转化为常见的中间体3-苯氧基苯甲酸（3-PBA），这是一种破坏内分泌的化合物。在这里，我们研究了在混凝土上将5种常见的拟除虫菊酯，苄氯菊酯，λ-氯氟氰菊酯，溴氰菊酯，苯丙酸菊酯和esfenvalerate转化为3-PBA的方法。3-PBA的形成几乎是瞬时的，在暴露后数小时内达到拟除虫菊酯初始水平的3％，并且主要是由水解引起的，而强碱可能会增强这种水解。3-PBA在混凝土上的积累是短暂的，根据处理的不同，其半衰期为4.2–6.7小时。在排泄居民区的城市溪流中经常发现低水平的3-PBA（纳升每升），这验证了3-PBA从城市坚硬表面的异地运输潜力。这项研究的发现表明，诸如混凝土路面之类的城市硬景观是反应性表面，有助于形成具有生物活性的转化产物。