Stenalt E, Johansen B, Lillienskjold S, Hansen B W
Department of Life Sciences and Chemistry, Roskilde University, Denmark.
Ecotoxicol Environ Saf. 1998 Jul;40(3):212-25. doi: 10.1006/eesa.1998.1687.
In a mesocosm study, the effects of a gradient of tributylin (TBT) (nominal TBT concentrations of 0.3, 2.3, 18.5, 146, and 1150 ng Sn liter-1) on Mytilus edulis larvae and postlarvae, including the settlement phase, were investigated over 15 days. Effects of TBT on mortality, growth measured as increase in shell length, shell dimensions, and settlement were evaluated. In general, mortality was high in all mesocosms including the control; during the first 24 h of the experiment, mortality was 63% at the highest TBT concentration (26% in the control). An LC50 (24 h) of 254 ng Sn liter-1 was estimated. The mortality rate of larvae/postlarvae increased 40% at 18.5 ng Sn liter-1 (0.41 day-1) compared with the control (0.30 day-1). For postlarvae, the growth rate decreased with increasing TBT concentration. The mean shell length at 2.3 ng Sn liter-1 was significantly reduced in comparison to the control on Day 15. Then EC10 (15 days) for shell growth was estimated to be 5.4 ng Sn liter-1. This is the lowest effect concentration ever reported in the literature. For postlarvae, shell dimensions in terms of shell length-shell width relations were affected by TBT at 1150 ng Sn liter-1, because the reduced growth led to the failure of adult mussels to secret a dissochonch shell. During the first days of exposure, the settlement monitored on polyethylene settling strips was stimulated by TBT, after which the settlement decreased due to the high mortality. Only a small portion of the population survived to the end of the test period. By comparison of the biotic conditions (in terms of larval abundance and particle concentration reflecting larval food) in the control mesocosm with those in the cove where the experiment was conducted, it was concluded that the mesocosm had successfully simulated the field conditions.
在一项中宇宙研究中，研究了三丁基锡（TBT）浓度梯度（名义TBT浓度为0.3、2.3、18.5、146和1150 ng Sn·L⁻¹）对紫贻贝幼虫和后期幼虫（包括附着阶段）在15天内的影响。评估了TBT对死亡率、以壳长增加衡量的生长、壳尺寸和附着的影响。总体而言，包括对照组在内的所有中宇宙中的死亡率都很高；在实验的前24小时内，最高TBT浓度下的死亡率为63%（对照组为26%）。估计24小时半数致死浓度（LC50）为254 ng Sn·L⁻¹。与对照组（0.30天⁻¹）相比，在18.5 ng Sn·L⁻¹（0.41天⁻¹）时幼虫/后期幼虫的死亡率增加了40%。对于后期幼虫，生长速率随TBT浓度增加而降低。在第15天，2.3 ng Sn·L⁻¹时的平均壳长与对照组相比显著降低。然后估计壳生长的15天效应浓度（EC10）为5.4 ng Sn·L⁻¹。这是文献中报道的最低效应浓度。对于后期幼虫，在1150 ng Sn·L⁻¹时，壳长与壳宽关系方面的壳尺寸受到TBT影响，因为生长减少导致成年贻贝无法分泌解离壳。在暴露的最初几天，聚乙烯附着条上监测到的附着受到TBT刺激，之后由于高死亡率附着减少。只有一小部分种群存活到试验期结束。通过将对照中宇宙中的生物条件（根据幼虫丰度和反映幼虫食物的颗粒浓度）与进行实验的海湾中的生物条件进行比较，得出中宇宙成功模拟了野外条件的结论。
