Abstract:
There are large masses of coal tar asphalt present in old roads, containing high concentrations of polycyclic aromatic hydrocarbons (PAHs). Uncertainty surrounding the risk they pose causes problems during road reconstruction and for the reuse of the asphalt present. To help elucidate potential risks, a parsimonious linear equilibrium partitioning model for the bioavailability of PAHs in soils contaminated by tar asphalt particles was developed. Furthermore, a set of partitioning coefficients for PAHs between sampled coal tar binders and water were determined experimentally, as well as measurements of freely dissolved concentrations using polyoxymethylene samplers in batch tests and column recirculation experiments with various mixtures of different soils (peat and sandy loam) and tar asphalts. The model predictions of freely dissolved concentrations were conservative and within an order of magnitude of measurements in both batch and column tests. The model presented here only relies on soil organic carbon content and the fraction coal tar binder in the soil to model PAH partitioning. This model could be used for more realistic. Low tier risk assessments towards rational prioritization of sensitive areas for risk reduction efforts.
摘要:
旧道路中存在大量煤焦油沥青,含有高浓度的多环芳烃(PAHs)。围绕它们带来的风险的不确定性会在道路重建和现有沥青的再利用过程中引起问题。为了帮助阐明潜在的风险,建立了焦油沥青颗粒污染土壤中多环芳烃生物有效性的简约线性平衡分配模型。此外,实验确定了一组PAHs在采样煤焦油粘合剂和水之间的分配系数,以及在批量测试和色谱柱再循环实验中使用聚甲醛采样器对自由溶解的浓度进行测量,其中包括不同土壤(泥炭和砂壤土)和焦油沥青的各种混合物。自由溶解浓度的模型预测是保守的,并且在分批和柱测试中都在一个数量级的测量范围内。此处提出的模型仅依靠土壤有机碳含量和土壤中的煤焦油粘合剂来模拟PAH分配。这个模型可以用于更现实的。低级风险评估,以合理地优先考虑减少风险的敏感区域。