沉积物中2,2',4,4'-四溴联苯醚(BDE-47)在铜锈环棱螺体内的毒代动力学及其繁殖毒性

多溴联苯醚(PBDEs)是一种全球性的新型持久性有毒污染物,沉积物中高浓度的PBDEs是水生态系统的巨大风险源,2,2’,4,4’-四溴联苯醚(BDE-47)在PBDEs同系物中,目前分布最广,生物毒性最强。为评价沉积物中BDE-47向底栖动物体内转移的潜力及其对底栖动物的潜在繁殖毒性,将实验室培养的铜锈环棱螺(Bellamya aeruginosa)暴露于BDE-47加标沉积物中,研究了BDE-47在铜锈环棱螺体内的毒代动力学特性及其对铜锈环棱螺潜在繁殖力的影响。结果表明,铜锈环棱螺对沉积物中BDE-47吸收较快,代谢速度相对较慢,BDE-47在铜锈环棱螺体内具有较强的生物积累性。生物积累达理论平衡时,铜锈环棱螺体内BDE-47浓度为1440.67ng·g-1(以样品干质量计)。BDE-47在铜锈环棱螺体内的生物积累和生物净化过程较好地符合一级动力学模型,摄入速率常数、清除速率常数和生物-沉积物累积因子分别为0.10、0.038和2.75,生物半衰期为18d。铜锈环棱螺体内BDE-47达到90%稳定状态所需的理论时间约为60d。低浓度BDE-47(160ng·g-1)暴露对铜锈环棱螺的潜在繁殖力没有影响,但当浓度≥640ng·g-1时,铜锈环棱螺的繁殖力下降50%,这表明BDE-47对铜锈环棱螺具有繁殖毒性。铜锈环棱螺可作为指示沉积物中底栖生物长期暴露于BDE-47的良好检测模型。

Toxicokinetics and Reproductive Effects of Sediment-Associated 2,2',4,4'-Tetrabromodiphenyl Ether (BDE-47) in Bellamya aeruginosa

Polybrominated diphenyl ethers(PBDEs) are a group of emerging and ubiquitous persistent organic pollutants.A high concentration of PBDEs accumulated in sediments poses a great threat to aquatic ecosystem.2,2’,4,4’-tetrabromodiphenyl ether(BDE-47) is a PBDEs congener with the most wide environmental distribution and the highest toxicity to wildlife and human.The aim of the present study was to assess the transfer capacity of BDE-47 from sediments to benthic organisms and the reproductive toxicity of BDE-47.The laboratory-cultured Bellamya aeruginosa were exposed to BDE-47-spiked sediments,the toxicokinetics of BDE-47 and its effects on potential fecundity of B.aeruginosa were investigated in details.Results showed that B.aeruginosa could rapidly absorb BDE-47 from sediments but slowly metabolize this chemical,leading to a relatively high bioaccumulation of BDE-47 in B.aeruginosa.The maximal content of bioaccumulated BDE-47 in the tested B.aeruginosa at theoretical equilibrium was 1 440.67 ng·g-1(calculated on a dry weight basis).The bioaccumulation and biodepuration process of BDE-47 in B.aeruginosa could be well fitted by the first-order kinetic model.The uptake rate coefficient,clearance rate coefficient,and biota-sediment accumulation factor of BDE-47 were 0.10,0.038 and 2.75,respectively.The biological half-life of BDE-47 in B.aeruginosa was 18 d.The estimated time to reach 90% of steady-state tissue concentration was 60 d.The chronic exposure to sediments contaminated by BDE-47 with relatively low concentration(160 ng·g-1) had little effect on potential fecundity of B.aeruginosa,but a significant decline(50%) of potential fecundity occurred when BDE-47 concentration was ≥ 640 ng·g-1,which was indicative of reproductive toxicity of BDE-47 to B.aeruginosa.It was demonstrated that B.aeruginosa can serve as a good test model for the indication of chronic exposure of benthic macroinvertebrates to BDE-47 in sediments.