食物相暴露下三丁基锡(TBT)在疣荔枝螺(Thais clavigera)体内的吸收和代谢动力学

摘要

Oysters were respectively exposed to 1000 ng· L-1 and 100 ng·L-1 tributyltin (TBT) aqueous for 4 weeks, which was as dietary to feed the female and male Thais clavigera whelks for 45 days. Then these Thais clavigera were depurated for 30 days. The results show that TBT rapidly accumulated in their digestive and reproductive organs(ku = 0.004 -0.022 d-1). Moreover, elimination and biotransformation of TBT were also rapid (BDI = 5.6 -2330, ke = 0.024 -0.053 d-1). MBT was the dominant metabolite in each tissue. Therefore, bio-magnification of TBT did not occur during the trophic transfer process. Additionally, to females, the mobilization of TBT from digestive to reproductive organs and bioaccumulation of TBT (ku =0.006 -0.022 d-1, BMF =0.181 -0.664) were more obvious than that of the males. However, lower metabolism and elimination of TBT (BDI =5.6 - 10.5, ke =0.024 -0.025 d-1) in female reproductive organs, which indicated that the reproductive organs of females were the main targets of TBT accumulation. The results are important to the risk assessment of TBT contamination in coastal environments.%将牡蛎消化腺分别暴露在1000 ng·L-1和100 ng·L-1 TBT水溶液中4周,然后将染毒的牡蛎消化腺分别投喂疣荔枝螺(Thais clavigera).经过45 d的暴露和30 d的净化,我们发现雌雄疣荔枝螺的消化和生殖系统能较快地吸收TBT(吸收速率ku=0.004-0.022·d-1),并且其代谢(生物代谢系数BDI=5.59-2330)和排出速率(净化速率ke=0.024-0.053·d-1)也相对较快,各器官中TBT的代谢产物MBT占了相对较高的比例,因此TBT在食物链传递过程中没有出现生物放大的现象.此外,TBT有逐渐从雌螺消化系统向生殖系统转移的趋势,并且雌螺生殖系统对TBT的吸收和富集能力(ku=0.006-0.022·d-1,生物放大系数BMF=0.18l-0.664)要显著强于雄螺(ku=0.004-0.014·d-1,生物放大系数BMF=0.142-0.376),但其代谢和净化速率(BDI=5.59-10.50,ke=0.024-0.025·d-1)却显著低于雄螺(BDI=115-12.4,ke=0.031-0.050·d-1),雌螺的生殖系统被认为是TBT转移和富集的潜在靶器官,这对我们今后开展TBT污染的环境监测和评价具有重要的参考价值.