Combustion of crude oil during in-situ burning can introduce polycyclic aromatic compounds (PACs) into small-scale freshwater systems. (15th November 2022)

• Record Type: Journal Article
• Authors: Blandford, Nicholas C.; Peters, Lisa; Timlick, Lauren; Rodríguez-Gil, José Luis; Palace, Vince
• Is Part Of: Journal of environmental management. Volume 322(2022)
• Publication Date: 2022-11-15
• Subjects: Oil spill -- Slick thickness -- Heat transfer -- Remediation -- Aquatic toxicity; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.116078
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: In-situ burning (ISB) is the controlled combustion of an oil slick to remove large quantities of spilled oil from the aquatic environment. Prior to employing ISB as a remediation technique, an oil slick must often be corralled by physical or chemical means to achieve a sufficient thickness (typically >1 mm) for ignition. While ISB is an effective means to remove oil mass, less is known about the potential for ISB to mobilize polycyclic aromatic compounds (PACs) into the aquatic environment. The PACs are primary contaminants of concern in crude oil due to their environmental persistence and toxicity. We examined the potential for ISB to mobilize PACs into underlying waters in a series of small-scale burns conducted across a gradient of oil slick thicknesses (0–7 mm). Concentrations of PACs in underlying waters were evaluated and compared to reference conditions using an equivalent gradient of oil slick thicknesses that were not ignited. At thinner slick thicknesses (i.e. 0 – 4 mm) ISB enhanced the mobilization of total PACs, likely a result of heat transfer to underlying waters; this effect increased as slick thickness increased. Among thicker slicks (i.e. 4 – 7 mm), pyrogenic PACs became more prevalent and greater concentrations of 4-ring PACs were detected in underlying waters. The potential for PAC mobilization needs to be considered in scenarios where ISB may be the only viable oil spill remediation option (e.g. wetlands, marshes, or where oil is entrained) and in shallow systems susceptible to temperature changes. Graphical abstract: Image 1 Highlights: Total PAC transfer to underlying water was maximized at slick thicknesses of ∼4 mm 4-Ring PACs were increasingly produced by thicker oil slicks Burning introduced pyrogenic PACs into underlying water Shallow freshwater systems are particularly vulnerable to PAC contamination