By Ted Schettler, MD, MPH
Science and Environmental Health Network
NOTE: Dr. Schettler will speak on a webinar about this topic on March 22 at 2pm Eastern time, The Ohio Train Disaster: Impacts and Emerging Lessons.
Soil and Sediment Testing for Dioxins
The US EPA is requiring Norfolk Southern to test for dioxins at the East Palestine Ohio train derailment site. That’s welcome news. But the EPA also says “… so far, its monitoring in samples of air, soil, water and sediments for “indicator chemicals” like chlorobenzenes and chlorophenols has suggested a low probability for the release of dioxins.”
On the EPA data website where they are posting the results of air, soil, and sediment sampling you will see that the reporting limit (detect level, an indicator of test sensitivity) for chlorophenols (and dibenzofurans, a close relative of dioxins) is 53-65 mg/kg of soil or sediment. For chlorobenzenes, the reporting limit is much lower at 0.05-0.06 mg/kg.
Chlorobenzenes are much more volatile (more than 100 X) than chlorophenols or dibenzofurans (or dioxins). So we would expect that any chlorobenzenes that formed would have evaporated from soil exposed to air. Moreover, many furans and dioxins are toxic at parts per trillion levels so we need much more sensitive testing than 50-60 mg/kg in soil or sediment to determine whether worrisome concentrations may have formed.
This study of a European train carrying vinyl chloride that derailed and burned found background dioxin values measured in soils and plants generally in the background range of 20 ng TEQ/kg in the surrounding area but increased to 8300 ng at the fire site.
We need soil/sediment testing in East Palestine at much lower levels of detect (more sensitive) than 50-60 mg/kg. It should be at least 1000 times more sensitive. We can hope that any dioxins/furans formed are confined to the burn site and did not spread in the smoke plume. If truly low at the burn site, we can feel more confident that contaminated smoke plumes would not have deposited concerning levels farther away. If elevated at the burn site, then more extensive site characterization will be necessary.
Air testing in homes in East Palestine
Residents of East Palestine initially complained and some continue to complain of chemical smells, headaches, confusion, rashes, chest congestion, cough, nausea and vomiting. These are all symptoms of exposure to several of the volatile chemicals known to be released—butyl acrylate, ethylhexyl acrylate, ethylene glycol monobutyl ether, and vinyl chloride. Since then, elevated levels of acrolein have been detected in the air by a Texas A&M team, which probably formed during the burn and can cause similar symptoms.
In response, Norfolk and Southern contracted with CTEH, an environmental consulting firm that serves high-risk industries when they are in trouble. CTEH personnel are now doing the airm onitoring in residences in E Palestine, analyzing for volatile organic compounds (VOCs) that were released into the environment. The results of their testing are being used by Norfolk Southern to make financial decisions with regard to housing and reparations for residents.
So what has CTEH found? Every one of the approximately 500 homes tested are reported to show less than 0.1 ppm total VOCs (TVOCs) in all locations. This is implausible. One study of background TVOC levels in 58 homes nowhere near an environmental disaster showed average TVOC levels over 300 ppb (0.3 ppm) with variation depending on where they are measured, presence of smokers, air conditioning and so on. But readings of below 0.1 ppm are unusually low,
using the same technology that CTEH is using in East Palestine. So what’s going on here? Are East Palestine homes somehow free of background VOCs emanating from sources within the typical home? It’s unlikely.
CTEH must make publicly available their sampling protocols, instrument specifications, instrument calibration methods, and frequency of calibration. How is it possible that every single home tested in East Palestine has TVOC levels below 0.1 ppm?