Schuler Lance J, Wheeler Matthew, Bailer A John, Lydy Michael J
Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University at Carbondale, Carbondale, Illinois 62901, USA.
Environ Toxicol Chem. 2003 Feb;22(2):439-49.
This study investigated the effect of long-term sediment aging on the toxicokinetics of benzo[a]pyrene (BaP) and hexachlorobiphenyl (HCBP) using three freshwater benthic invertebrates. Hyalella azteca, Chironomus tentans, and Lumbriculus variegatus were exposed to BaP- and HCBP-spiked sediments that were aged for 7 d or 1.5 years. The toxicokinetics of the two compounds were determined for each test organism using a two-compartment model. The modeling of BaP was more complex because biotransformation was included within the model. The results of this study showed that the HCBP uptake clearance rates (k(s)) for each species were generally an order of magnitude greater than those determined for BaP and this difference was most likely due to preferential and rapid binding of BaP to sediment particles. Overall, the bioavailability of HCBP in spiked sediments tended to decrease with duration of aging, based on k(s) values and bioaccumulation factors (BAFs). However, the decreases in bioavailability appear to be species specific. Benzo[a]pyrene did not decline in bioavailability for the species tested because it may resist movement into the micropores of the sediment due to its large size. In addition to the bioassays, this article outlines a method for toxicokinetic modeling of biotransformed compounds and methods for statistical comparisons of kinetic parameters (i.e., k(s), k(d)...) and BAF values.
本研究使用三种淡水底栖无脊椎动物，调查了长期沉积物老化对苯并[a]芘（BaP）和六氯联苯（HCBP）毒代动力学的影响。将阿氏摇蚊、细蜉和颤蚓暴露于加标了BaP和HCBP且老化了7天或1.5年的沉积物中。使用双室模型确定了每种受试生物体内这两种化合物的毒代动力学。BaP的模型更为复杂，因为模型中包含了生物转化过程。本研究结果表明，每种物种对HCBP的摄取清除率（k(s)）通常比BaP的摄取清除率高一个数量级，这种差异很可能是由于BaP优先且快速地与沉积物颗粒结合。总体而言，基于k(s)值和生物累积因子（BAFs）可知，加标沉积物中HCBP的生物有效性往往会随着老化时间的延长而降低。然而，生物有效性的降低似乎具有物种特异性。受试物种中BaP的生物有效性并未下降，因为其分子较大，可能难以进入沉积物的微孔中。除了生物测定外，本文还概述了一种对生物转化化合物进行毒代动力学建模的方法，以及对动力学参数（即k(s)、k(d)……）和BAF值进行统计比较的方法。
