Researchers involved in the independent, taxpayer-funded testing project known as WV TAP say results from a single expert panel show that Crude MCHM can be detected by an expert human nose when analytical methods used in testing the water indicate non-detect levels.
The WV TAP program was established in response to lingering concerns over water quality and testing after the January 9 spill by Freedom Industries. The spill fouled the drinking water supply of 300,000 West Virginians for up to 10 days.
In a summary of the documents disclosed Monday afternoon, WV TAP researchers said the “ability of the expert human nose” to detect Crude MCHM is “far greater than any analytical method available today.” According to the summary, “the estimated OTC for the Expert Panel is in the realm of parts per trillion (ppt), a very low concentration.”
The National Guard and state officials tested the water at a threshold of 2 parts per billion (ppb). Officials with the Centers for Disease Control and Prevention deemed the water “safe” for drinking at levels below 1 part per million (ppm).
Odor threshold values reported from the WV TAP study show:
- Odor Threshold Concentration: 0.15 ppb [The actual OTC for the experts is likely less than 0.15 ppb]
- Odor Recognition Concentration: 2.2 ppb [15 times greater than OTC]
- Odor Objection Concentration based on degree of liking: 4.0 ppb [27 times greater than OTC]
- Odor Objection Concentration (OOC) based on complaint: 4.0 ppb [27 times greater than OTC]
The summary states that estimated thresholds determined in the Expert Panel study “support consumer observations” that “people recognized and objected to the licorice odor caused by Crude MCHM in their drinking water even though the analytical reports were showing non-detect at a minimum reporting level of 10 ppb.”
On Monday, the WV TAP project also released a literature review of studies on health effects of MCHM.