Gaseous emissions from herding agent-mediated in-situ burning for Arctic oil spills

Abstract

If a crude oil spill were to occur in partially ice-covered waters, many of the response tactics typically utilized in either open water or completely ice-covered conditions would become inefficient. In such situations, in-situ burning (ISB) can prove to be an efficient response tool; herding agent application is one available approach to thicken an oil slick. This study assessed the impacts on air quality following ISB tests on crude oil, in combination with herding agents, in partially ice-infested waters. The research focused on measuring downwind concentrations of respirable particulate matter (PM₂.₅) and seven different combustion gasses (CO, CO₂, NO, NO₂, NOx, SO₂, and VOCs) during five ISB events, with sampling instruments placed in-plume and 6-12 m away from the source area. The study also investigated if the utilized herding agent was detectable in the airborne plume. Findings include: 1) Concentrations of particulate matter (<2.5μm in diameter), SO₂, and CO were found to significantly (P <0.01) exceed various exposure limits and air quality standards, while the remaining compounds measured were significantly (P <0.01) below established exposure limits. Also, downwind, in the smoke plume, measured concentrations of SO₂, NOx, and total VOCs were higher than found in previous studies. It should be noted that instrument and methods not specifically approved by the U.S. Environmental Protection Agency, Occupational Safety and Health Administration, and the National Institute for Occupational Safety and Health were utilized during this study; 2) GC/MS analysis of aerosol samples collected utilizing a flow meter and carbon sorbent tubes in the smoke plume; the Siltech OP-40 silicone based functional group of the applied herding agent was not detected in the collected samples analyzed using GC/MS. Future research should include additional scalability studies where the concentrations of particulate matter and various combustion gasses are compared to modeled concentrations using computer software. Additional research is also needed to find a cost-effective method to decrease the amount of particulate matter during an in-situ burn. It is also recommended that guidance specific for conducting in-situ burns of crude oil or refined petroleum products in the Arctic is written and published by regulatory agencies, so the industry can rapidly make plans and propose such tactics if an incident did occur where mechanical or other non-mechanical response tactics are not feasible.