Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310029, PR China.
Aquat Toxicol. 2010 Jun 1;98(1):83-90. doi: 10.1016/j.aquatox.2010.01.016. Epub 2010 Feb 1.
The availability of sorbed hydrophobic organic contaminants (HOCs) to benthic organisms is important for characterizing sediment toxicity. While many studies show a correlation between the rapid desorption HOC pool and bioavailability to benthic organisms, bioavailability of the slow or very slow desorption fraction is still poorly understood. In this study, Chironomus tentans were exposed to phenanthrene (PHE) or permethrin (PM) to derive biota-sediment accumulation factors (BSAFs) in a sediment that was sequentially desorbed with Tenax extraction or amended with a charcoal to modify the distribution of PHE and PM among the rapid (f(rapid)), slow (f(slow)) and very slow (f(vslow)) desorption pools. As the desorption interval was increased, the f(rapid) quickly decreased to zero and became negligible after 12h desorption for PHE and 48h desorption for PM. However, in samples with depleted f(rapid), BSAF values were substantially greater than zero, suggesting availability of f(slow) and f(vslow). A multivariate linear regression model was further used to estimate BSAFs specific to the different desorption pools, i.e., BSAF(rapid), BSAF(slow) or BSAF(vslow). The slow desorption pool was found to be readily available to C. tentans, with BSAF(slow) values ranging from 25.3 to 73.9% of BSAF(rapid). In comparison, BSAF(vslow) ranged from 0 to 5.9% of BSAF(rapid), suggesting a lack of availability. Therefore, the kinetically slow desorption fraction is relatively bioavailable and should not be ignored in sediment toxicity assessment.
被吸附的疏水性有机污染物（HOCs）对底栖生物的可用性对于描述沉积物毒性很重要。虽然许多研究表明快速解吸 HOC 池与底栖生物的生物可利用性之间存在相关性，但慢速或非常慢速解吸部分的生物可利用性仍知之甚少。在这项研究中，Chironomus tentans 被暴露于菲（PHE）或氯菊酯（PM）中，以在 Tenax 提取或用木炭修改其分配的沉积物中获得生物沉积物积累因子（BSAF） ，以改变 PHE 和 PM 在快速（f(rapid)）、慢速（f(slow)）和非常慢速（f(vslow)）解吸池之间的分布。随着解吸间隔的增加，f(rapid)迅速降低至零，并且在 12 小时解吸 PHE 和 48 小时解吸 PM 后变得可以忽略不计。然而，在耗尽 f(rapid)的样品中，BSAF 值大大大于零，表明 f(slow)和 f(vslow)的可用性。进一步使用多元线性回归模型来估计特定于不同解吸池的 BSAF，即 BSAF(rapid)、BSAF(slow)或 BSAF(vslow)。发现慢速解吸池容易被 C. tentans 利用，BSAF(slow)值范围为 BSAF(rapid)的 25.3%至 73.9%。相比之下，BSAF(vslow)范围为 BSAF(rapid)的 0%至 5.9%，表明缺乏可用性。因此，动力学上缓慢解吸的部分相对具有生物可利用性，不应在沉积物毒性评估中忽略。
