Vinturella Amy E, Burgess Robert M, Coull Brent A, Thompson Kimberly M, Shine James P
Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts 02115, USA.
Environ Toxicol Chem. 2004 Nov;23(11):2578-86. doi: 10.1897/03-358.
The roles and relative importance of nonpyrogenic organic carbon (NPOC) and black carbon (BC) as binding phases of polycyclic aromatic hydrocarbons (PAHs) were assessed by their ability to estimate pore water concentrations and biological uptake in various marine sediments. Sediment bioaccumulation tests were performed with the marine polychaete Nereis virens, using a polyethylene device to estimate pore water concentrations of PAHs. Using existing partitioning data for pyrene and phenanthrene, it was found that the traditional Equilibrium Partitioning model, which assumes all organic carbon is NPOC (EqP(OC)), overestimated the measured pore water concentrations in the test sediments by one to three orders of magnitude. Instead, the measured pore water concentrations were better predicted from a distribution scenario that uses both BC and NPOC (EqP(NPOc,BC)) When comparing actual worm body burdens of pyrene and phenanthrene with the two model estimates of worm tissue concentrations, the EqP(OC) model tended to overestimate actual body burdens by three orders of magnitude, while the EqP(NPOC,BC) model came much closer to the true body burden values. The observed distribution of PAHs in the test sediments was used to calculate BC partition coefficients for five PAHs, which were one to two orders of magnitude higher than their corresponding organic carbon-normalized distribution coefficients, or K(OC)s. Together, these results suggest that, in certain situations, adding black carbon to distribution models may be necessary to predict accurately the bioavailability of PAHs.
通过评估非致热有机碳（NPOC）和黑碳（BC）作为多环芳烃（PAHs）结合相的能力，来估计各种海洋沉积物中的孔隙水浓度和生物摄取情况，进而评估它们的作用和相对重要性。使用聚乙烯装置来估计PAHs的孔隙水浓度，对海洋多毛类动物沙蚕进行沉积物生物累积试验。利用芘和菲现有的分配数据发现，传统的平衡分配模型假设所有有机碳均为NPOC（EqP(OC)），该模型将试验沉积物中测得的孔隙水浓度高估了一到三个数量级。相反，使用同时包含BC和NPOC的分配方案（EqP(NPOc,BC)）能更好地预测测得的孔隙水浓度。当将芘和菲的实际虫体负荷与两种模型对虫体组织浓度的估计值进行比较时，EqP(OC)模型往往将实际虫体负荷高估三个数量级，而EqP(NPOC,BC)模型则更接近真实的虫体负荷值。利用试验沉积物中PAHs的观测分布来计算五种PAHs的BC分配系数，这些系数比其相应的有机碳归一化分配系数（即K(OC)s）高一个到两个数量级。总之，这些结果表明，在某些情况下，可能需要在分配模型中加入黑碳，才能准确预测PAHs的生物可利用性。
