Tracking the fate of polycyclic aromatic hydrocarbons in contaminated soils during windrow bioremediation pilot project

Petrochemical contamination of soils leads to adverse effects for human health and local ecology. Of particular concern are sixteen polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by the EPA for their... [ view full abstract ]

Petrochemical contamination of soils leads to adverse effects for human health and local ecology. Of particular concern are sixteen polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by the EPA for their known toxic and carcinogenic properties. Bioremediation strategies including aerobic composting have shown promise for degrading PAHs; however studies of the optimal composting conditions for this purpose are limited. Moreover, few open air studies have been undertaken in conditions comparable to the Irish climate, and few simultaneously track these contaminants in the leachate fraction. In this study, we investigate the attenuation of PAHs in a heavily contaminated soil throughout an open air windrow composting pilot project in Ireland. This study supports improved decision making for sites targeted for remediation projects where groundwater or surface water contamination is of concern.

Five windrows were constructed and subjected to the following treatments: four control treatments – 1. no further treatment, 2. aeration only, 3. addition of 10% wood shavings and aeration, 4. addition of 5% green waste and aeration - and one test treatment – 5. addition of 10% wood shavings, 5% green material, and aeration. Soil and leachate samples were analysed throughout the project for PAHs using GC-MS. We report on contaminant attenuation of this soil and discuss the conditions which may favour remediation of PAHs during the composting process. Methods for improving the quantification of PAHs in solid phase and aqueous phase extracts via GC-MS analysis are also investigated and discussed here.