Abstract

Conventional analytical methods determine the concentration of compounds used to estimate the presence of environmental contamination capable of posing risk to human and ecological receptors. While these target analytes help regulators and environmental professional identify and manage potentially harmful conditions, these compounds can be generated by many natural and anthropogenic (man-made) sources and conventional methods alone fail to compositionally differentiate subsurface sources of contamination in complex environments. This case study demonstrates the advantage of using both conventional and forensic testing methods to accurately identify the source(s) of volatile hydrocarbon contamination in soil vapor samples for the development of an accurate conceptual site model in a neighbourhood near industrial facilities in Rio de Janeiro State, Brazil. The goal of this study was to differentiate potential impacts from a local steelmaking plant from fugitive hydrocarbons associated with more generic human activity in urban settings. This case study demonstrated the advantage of constructing chemical fingerprints from conventional volatile organic compound (VOC) method TO 15 and a forensic volatile hydrocarbon method using an enhanced version of method TO 15 (PIANO). The chemical fingerprints of vapor samples collected from subsurface soil gas and sewers were analysed and compared to laboratory reference samples. These data determined that the VOCs detected in neighbourhood soil vapor samples were associated with fugitive petroleum products migrating in the sewer pipelines and not with the steelmaking wastes emplaced near the residential area. This article discusses the forensic data and chemical signatures that support these findings, and the use of environmental forensic techniques to evaluate environmental data associated with complex scenarios, involving multiple contamination sources.

摘要

传统的分析方法确定化合物的浓度，用于估计可能对人类和生态受体构成风险的环境污染的存在。虽然这些目标分析物有助于监管机构和环境专业人士识别和管理潜在的有害条件，但这些化合物可以由许多自然和人为（人造）来源产生，仅靠传统方法无法在复杂环境中从成分上区分地下污染源。本案例研究展示了使用传统和法医检测方法准确识别土壤蒸气样品中挥发性碳氢化合物污染源的优势，以便在里约热内卢州工业设施附近的社区开发准确的概念场地模型, 巴西。本研究的目的是区分当地炼钢厂的潜在影响与与城市环境中更普遍的人类活动相关的逃逸碳氢化合物。本案例研究展示了从传统挥发性有机化合物 (VOC) 方法 TO 15 和法医挥发性烃方法使用增强版 TO 15 (PIANO) 构建化学指纹图谱的优势。分析了从地下土壤气体和下水道收集的蒸汽样品的化学指纹，并与实验室参考样品进行了比较。这些数据确定，在附近土壤蒸气样本中检测到的 VOC 与在下水道管道中迁移的逃逸石油产品有关，而不是与居民区附近的炼钢废物有关。