Institute of Wetland and Water Research, Faculty of Science, Radboud University Nijmegen, PO Box 9100, 6500GL Nijmegen, The Netherlands.
Integr Environ Assess Manag. 2010 Jan;6(1):135-44. doi: 10.1897/IEAM_2009-035.1.
Petroleum products may contain up to thousands of individual hydrocarbon compounds, which vary widely in environmental behavior and ecotoxicity. Environmental risk assessment of these complex substances is facilitated by use of the hydrocarbon block method (HBM). The HBM assigns similarly behaving hydrocarbons to the same blocks and then relates release rates of petroleum products to environmental concentrations and human intake rates by means of so-called environmental fate factors and human intake fractions of the hydrocarbon blocks. We have derived such fate factors and intake fractions and associated uncertainties with a library of representative hydrocarbon structures. Fate factors and intake fractions of over 1500 individual representative hydrocarbons have been modeled according to the EU Technical Guidance Documents. Fate factors and intake fractions for the chosen hydrocarbon blocks are then estimated from average values obtained for the individual compounds in the blocks. Fate factors and intake fractions of the hydrocarbon blocks vary by up to 10 orders of magnitude for the different emission scenarios and compartments/spatial scales. The highest fate factors are obtained for the exposure scenarios with the highest emission intensity (the local emission scenarios) and for the most direct exposure chain. Uncertainties introduced by the “blocking” method are typically smaller than 30% and rarely larger than a factor of 3. Various hydrocarbon blocking schemes of different resolution were tested, and all schemes investigated appeared to perform satisfactorily. The use of the library-based HBM was illustrated by assessing the aquatic ecological risk of gas oil, emitted to water. The aquatic risk characterization ratio of gas oil hydrocarbons in regional freshwater is estimated to be 6 × 10(−5) per unit of emission (1 kg/d released 1:10:100 to local, regional, and continental scales, respectively), with an uncertainty of 32%. In view of other uncertainties in environmental risk assessment, the precision achieved with the procedure presented here is judged to be reasonable.
石油产品可能含有多达数千种单独的碳氢化合物，这些化合物在环境行为和生态毒性方面差异很大。使用碳氢化合物分组法（HBM）可以促进对这些复杂物质的环境风险评估。HBM 将具有相似行为的碳氢化合物分配到相同的组中，然后通过所谓的环境归宿因子和碳氢化合物组的人体摄入分数，将石油产品的释放速率与环境浓度和人体摄入速率联系起来。我们使用代表性碳氢化合物结构库推导出了这些归宿因子和摄入分数以及相关的不确定性。已经根据欧盟技术指导文件对超过 1500 种代表性单个碳氢化合物的归宿因子和摄入分数进行了建模。然后，根据碳氢化合物组中各化合物的平均值，估算所选碳氢化合物组的归宿因子和摄入分数。对于不同的排放情景和隔室/空间尺度，碳氢化合物组的归宿因子和摄入分数相差可达 10 个数量级。对于排放强度最高（局部排放情景）和最直接暴露链的暴露情景，获得的归宿因子最高。“分组”方法引入的不确定性通常小于 30%，很少超过 3 倍。测试了不同分辨率的各种碳氢化合物分组方案，所有研究的方案似乎都表现良好。通过评估排放到水中的瓦斯油的水生生态风险，说明了基于库的 HBM 的使用。估计区域淡水中瓦斯油碳氢化合物的水生风险特征比为 6×10(−5)每单位排放（1 公斤/天分别以 1:10:100 的比例释放到局部、区域和大陆尺度），不确定性为 32%。鉴于环境风险评估中的其他不确定性，此处提出的方法所达到的精度被认为是合理的。
