基于Tenax脱附动力学的沉积物中菊酯类农药生物有效性研究

Research on Bioavailability of Pyrethroids in Sediments Based on Tenax Desorption Kinetics

菊酯类农药已被广泛应用于农业、林业和渔业生产中,因其高疏水和亲脂性使其更易残留在沉积物中,因此研究其生物有效性对沉积物的环境质量和风险评价具有重要意义.采用强吸附性树脂（Tenax）连续萃取法研究洋山港潮间带表层沉积物中4 种代表性菊酯类农药（高效氯氟氰菊酯、联苯菊酯、氯菊酯和甲氰菊酯）的脱附动力学,评价菊酯类农药在沉积物中的生物有效性,并将Tenax 萃取结果与海洋经济底栖生物菲律宾蛤仔（Ruditapesphilippinarum）的累积试验进行比较.结果表明,在有机碳（OC）含量较低的洋山港潮间带表层沉积物中,菊酯类农药的快速解吸组分比例（Frap）高达50%以上,快速、慢速和极慢速解吸速率常数数量级分别为10-1、10-2 和10-5 ～10-3.与Frap 相比,Tenax 单点萃取结果可用于评价沉积物中菊酯类农药的生物有效性,并且在应用上更加快速、经济有效.与菲律宾蛤仔体内菊酯类浓度（Cb）之间相关性研究表明,Tenax 24 h 萃取结果（Cs,24 h ）更适用于生物体内污染物累积的预测（lg Cb =4.03 lg Cs,24 h -17.02,R2 =0.88,P〈0.05）.该研究结果不仅可以简单、快速地评价沉积物中菊酯类污染物的生物有效性,为海洋沉积物的环境质量和风险评价提供可靠依据;还可以有效地预测经济双壳类底栖动物体内菊酯类污染物的生物累积,为养殖领域沉积物环境风险评价及相关水产品的食品风险评价提供更为简单快捷的方法.

Pyrethroids have been widely used in agriculture, forestry and fisheries as pesticide, and frequently detected insediment because of their high hydrophobicity and lipotrophy. It is, therefore, of great significance to the assessment of en.vironmental quality and risk to study bioavailability of these compounds in sediments. Tenax desorption kinetics of four py.rethroids （cyhalothrin, bifenthrin, permethrin and fenpropathrin） were analyzed to evaluate bioavailability of the pyre.throids in sediments of the tidal zone in the Yangshan Port, meanwhile results of the Tenax extraction were compared withthose of the experiment on bioaccumulation of pyrethroids in Ruditapes philippinarum. Results show that the fraction ofreadily desorbable pyrethroids （Frap ） accounted for over 50% in the surface sediments low in organic carbon（OC）content, and the desorption rate of the fractions of readily, slowly and very slowly desorbable pyrethroids varied in magni.tude order, being 10-1, 10-2 and 10-5 -10-3, respectively. Compared with Frap, single time.point Tenax extraction can beused to evaluate bioavailability of pyrethroid pesticides in sediments, rapidly, economically and effectively. Correlation a.nalysis shows that 24 h Tenax （Cs,24 h） extraction is more suitable to application to the prediction of pyrethroid accumula.tion concentrations in Ruditapes philippinarum （Cb） （lg Cb =4.03 lg Cs,24 h -17.02,R2 =0.88,P〈0.05）. The findings ofthis study may not only provide reliable scientific basis for simple rapid evaluation of bioavailability of pyrethroids in sedi.ments and assessment of environmental quality and risk of marine sediments, but also be used to predict bioaccumulationof permethrin pesticides in bivalve oobenthos, and furthermore, as a simpler and easier method for environmental risk as.sessment of aquaculture sediments and food risk assessment of relevant aquatic products.