Lu Xiaoxia, Reible Danny D, Fleeger John W
Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
Environ Toxicol Chem. 2004 Jan;23(1):57-64. doi: 10.1897/03-39.
Benzo[a]pyrene (BaP)-amended sediment was desorbed by a sequential batch method using an isopropanol solution wash. The observed isotherm showed no evidence of desorption resistance, as indicated by increased partitioning to the solid phase at low concentrations. This was consistent with the prediction of minimal desorption resistance for highly hydrophobic compounds using a biphasic model. Bioavailability of BaP in desorbed sediments was assessed by toxicokinetic measures of uptake, bioaccumulation, and elimination in the deposit-feeding, freshwater tubificid oligochaete Ilyodrilus templetoni. Worms were exposed to sediments with BaP concentrations of approximately 26 and 11 microg/g dry weight sediment after desorption for one and three batches, respectively. The I. templetoni tissue concentration attained an apparent steady state after approximately one month and resulted in a biota-sediment accumulation factor of approximately 1.3 for both sediments. This is consistent with the paradigm that pore-water concentration predicts the uptake of organic contaminants into lipids despite the literature data showing that the major uptake route for BaP is likely from the ingestion of sediment particles. Ilyodrilus templetoni exhibited a high assimilation efficiency (80%) during a single-gut passage, a low elimination rate (k(c) = 0.0032 h(-1)), and negligible biotransformation of sediment-associated BaP.
采用异丙醇溶液洗涤的序批式方法对苯并[a]芘（BaP）污染的沉积物进行解吸。观察到的等温线未显示出解吸阻力的迹象，低浓度下向固相中分配的增加表明了这一点。这与使用双相模型预测的高疏水性化合物的最小解吸阻力一致。通过沉积食性淡水颤蚓Ilyodrilus templetoni的吸收、生物累积和消除的毒代动力学测量来评估解吸后沉积物中BaP的生物有效性。分别在解吸1批和3批后将蠕虫暴露于BaP浓度约为26和11μg/g干重沉积物的沉积物中。大约一个月后，I. templetoni组织浓度达到明显的稳态，两种沉积物的生物群-沉积物累积因子约为1.3。这与孔隙水浓度预测有机污染物向脂质中吸收的范式一致，尽管文献数据表明BaP的主要吸收途径可能是通过摄取沉积物颗粒。Ilyodrilus templetoni在单次肠道通过期间表现出高同化效率（80%）、低消除率（k(c)=0.0032 h(-1)）以及沉积物相关BaP的生物转化可忽略不计。
