Department of Applied Chemistry, China Agricultural University, Beijing, 100193, P. R. China.
Chirality. 2014 Jan;26(1):33-8. doi: 10.1002/chir.22261. Epub 2013 Oct 31.
Many pesticides are chiral compounds and stereochemistry is an important factor for any reaction of chiral structures in biological systems. In this study, experiment about bioaccumulation of the two metalaxyl enantiomers in Tubifex (Oligochaeta, Tubificida) was conducted in laboratory aquatic ecosystems. Terrestrial soil spiked with two dose levels of metalaxyl was employed as the artificial bottom substrate. A method of determination of metalaxyl enantiomers in tubifex tissue, soil and overlying water were developed by HPLC. During a 14-day exposure, concentrations of metalaxyl in tubifex increased with the of soil concentration, however, the enantioselective bioaccumulation was only detected at high-dose exposure group, with the preferential accumulation of (-)-(R)-metalaxyl. The bioturbation activity of tubifex decreased water clarity and released soil-associated metalaxyl to overlying water. In those experiments where tubifex was exposed to metalaxyl from soil, pore water and overlying water, each route contributed to the total body burden, and our results indicated the pore water and soil are the primary exposure routes for high-dose exposure concentration treatment.
许多农药是手性化合物，立体化学是生物系统中手性结构任何反应的重要因素。在这项研究中，在实验室水生生态系统中进行了两种金属axyl 对映体在水丝蚓（寡毛纲，水丝蚓目）体内生物累积的实验。用两种剂量水平的金属 axyl 污染的陆地土壤作为人工底层基质。建立了高效液相色谱法测定水丝蚓组织、土壤和上覆水中金属 axyl 对映体的方法。在 14 天的暴露期间，水丝蚓体内金属 axyl 的浓度随着土壤浓度的增加而增加，但仅在高剂量暴露组中检测到对映体选择性生物累积，（-）-（R）-金属 axyl 优先累积。水丝蚓的生物搅动活动降低了水的清澈度，并将与土壤相关的金属 axyl 释放到上覆水中。在那些水丝蚓暴露于土壤、孔隙水和上覆水中金属 axyl 的实验中，每种途径都导致了总体内负荷，我们的结果表明孔隙水和土壤是高剂量暴露浓度处理的主要暴露途径。
