Purdue researchers develop faster hazardous spill response method

When responding to a hazardous spill, every second counts — and Purdue University researchers have found a way to maximize that time.

A research team led by Nusrat Jung, an assistant professor in the Lyles School of Civil and Construction Engineering, has developed a new rapid screening method to test for volatile chemicals. This new method, described in a paper published in the journal Science of The Total Environment, can be used in a variety of hazardous spill scenarios to provide responders faster results when checking for chemicals in the soil, water and air.

“The most crucial time after a hazardous spill are the moments immediately following the incident,” Jung said. “Our team wanted to develop a method that could provide first responders and researchers a swift and accurate assessment so that they may form a faster plan of action to better contain the spill and protect the surrounding communities and the environment.”

In the United States, hazardous chemical incidents — including fires, explosions and chemical releases — are a common occurrence. On average, these incidents occur once every two days as per the Coalition to Prevent Chemical Disasters. Between 2004 and 2014, there were approximately 172,000 chemical spills that affected bodies of water. Over the past 20 years, hundreds of thousands of chemical incidents have impacted drinking water sources.

“The increasing prevalence of hazardous chemical incidents in the United States necessitates the implementation of analytically robust, rapid and reliable screening techniques for toxicant mixture analysis to understand short- and long-term health impacts of environmental exposures,” Jung said. “In disaster situations like these, every extra second saved is invaluable.”

Depending on the complexity of an incident, experts from outside the area may be consulted, but response is always initiated by local emergency services. Should a disaster exceed local capabilities, assistance from state and federal agencies may be requested.

A recent major chemical disaster in East Palestine, Ohio, has underscored the importance of thorough contamination assessment, Jung said. On Feb. 3, 2023, a train derailment prompted a chemical spill and fires. An open burn involving over 100,000 gallons of vinyl chloride was conducted three days later. Hazardous compounds were released into air, water and soil.

“My fellow researchers and I saw a situation that will unfortunately happen again — likely in the near future,” Jung said. “It was clear that providing first responders with high-quality data as quickly as possible was the biggest asset we could provide, post-spill.”

To provide time-sensitive exposure data for emergency response, Jung’s team outlined a novel methodology for rapid characterization of chemical contamination of environmental media to support disaster response efforts. A controlled static headspace sampling system, in conjunction with a high-resolution proton transfer reaction time-of-flight mass spectrometer was developed to characterize volatile organic compounds (VOCs) in surface water samples collected near the East Palestine train derailment site.

Spatial variations were observed in the chemical composition of surface water samples collected at different locations. Hydrocarbons were found to be the most abundant chemical group of all surface water samples, contributing 50% to 97% to the total headspace VOC mass. Compounds commonly detected in surface water samples, including benzene, styrene, xylene and methyl tert-butyl ether, were also observed in most surface water samples, with aqueous concentrations typically at nanograms-per-liter levels.

“Rapid evaluation of air, water and soil contamination and human exposure risks is critical to decision-making,” Jung said. “This helps officials minimize population exposures and environmental harm. An effective and reliable approach to assess air, water and soil contamination, and subsequent human exposures, is urgently needed.”

Improving the screening method

Historically, several techniques have been used to monitor air and water composition after chemical incidents, Jung said. Photoionization detectors (PIDs) are sometimes used for volatile organic compound sampling due to their low cost, portability and relatively expansive range.

In Ohio, air sampling was conducted using PIDs by various environmental agencies. However, Jung said, PIDs do not provide reliable data on chemical loadings in an environment as they fail to speciate chemical compounds, can underestimate volatile chemical concentrations by one to two orders of magnitude and are prone to signal interferences due to ambient moisture. PIDs also respond to different VOCs with different sensitivities, and PID performance has only been evaluated for a limited number of VOCs.

A second approach to air sampling is to utilize sorbent tube and canister sampling, followed by offline analysis via thermal desorption gas chromatography (GC)-mass spectrometry or GC-flame ionization detection. Such techniques, Jung said, generally offer poor time resolution, can result in long delays in sample processing and analysis, and cannot be scaled to achieve multimedia environmental sampling in the field.

“To identify environmental and public health risks more rapidly at a chemical disaster site, improved sampling and analysis approaches are needed,” Jung said.

To improve the sample-taking, Jung’s team utilized novel online mass spectrometry for rapid characterization of the chemical contamination of surface water samples collected near the East Palestine train derailment site. Specifically, proton transfer reaction time-of-flight mass spectrometry with hydronium as the reagent ion was used — a form of chemical ionization mass spectrometry that has been used for online monitoring of VOC concentrations in outdoor and indoor atmospheric environments. Jung’s team conducted an extensive set of laboratory experiments to demonstrate the robustness of the new rapid screening approach, which is most sensitive for volatile compounds that readily partition from water to air.

From Feb. 27 to March 25, 2023, the research team collected 20 surface water samples from 16 sites alongside Sulphur Run, Leslie Run, Bull Creek, North Fork Little Beaver Creek and Little Beaver Creek near and around the train derailment site at East Palestine, all within 24 to 51 days after the train derailment. The samples were collected in headspace-free amber glass jars with polytetrafluoroethylene-lined caps. After collecting the samples, they were transported back to Purdue in a cooler and then stored until they were analyzed.

This study was supported by the National Science Foundation (grants CBET-2327139 and CBET-1847493).

Writer: Drew Stone, Purdue Lyles School of Civil and Construction Engineering