PAC-Risk

The urgent need of improved and applicable analytical methods for assessing the occurrence and likely impact of polycyclic aromatic compounds (PACs) on humans and the environment has been identified by both industry and academia. The current risk assessment method suffer from insufficient tools to give a comprehensive picture of the chemical risks of PACs in contaminated environments. Despite the highly complex mixtures of PACs, the current approach is based on chemical analysis of 16 priority polycyclic aromatic hydrocarbons (PAHs). Over the past 40 years, these 16 PAHs have become widely accepted as representatives for all PACs and routinely analyzed in environmental monitoring program and risk assessments. There are PACs that have considerably higher toxicity than the priority PAHs, but many of them have not been studied enough with respect to frequency of occurrence in the environment and toxic effects in different organisms to be included in routine measurements. Our previous works have shown that the observed bioreporter effects of samples from PAC-contaminated sites are considerably underestimated by chemical analysis of the priority PAHs. This project aims to identify those PACs that are the drivers of the mixture toxicity, i.e., that cause the observed effects in the bioreporters, and improve the existing knowledge about toxic mechanisms, environmental occurrence and compositions of PACs. The overall objective of this project is to establish robust and sensitive chemical and bioreporter methods to screen for polycyclic aromatic compounds (PACs) in contaminated sites, such as soil, sediment, water or buildings and in recycled materials such as pelleted recycled rubber tires. Specific objectives are to:

- Establish sensitive and selective chemical analytical methods of PACs in complex mixtures, which can discriminate among closely similar PAC isomers, including alkylated isomers.

- Establish relevant bioreporters to screen for PACs, which cover the most critical endpoints for human and ecological risks.

- Identify toxicity driving PACs in different matrices like soils, ashes or recycled materials and their possible toxic mechanisms by use of effect directed analysis (EDA).

- Determine which PACs are frequently present in samples from urban and industrial sites by use of chemical (target or non-target) analysis in combination with EDA, and define PAC mixture profiles associated with different sources.

- Determine changes in PAC composition, toxicity and mobility throughout remediation processes by use of effect directed analysis (EDA) in combination with chemical (target or non-target) analysis.

Accomplishing these objectives will provide improved tools to assess the actual chemical risks of PAC-contaminated sites and recycled materials, which will lead to better decision support for remediation actions and sustainable recycling of materials.