By Vance Bennett
Not everything you were taught is necessarily 100% true.
Do meters lie? They don’t exactly “lie” but sometimes they don’t give us the whole truth and nothing but the truth.
All of our monitoring instruments have limitations. Sometimes, though, Mother Nature can create situations where our meters won’t give us information that is completely 100% accurate. To paraphrase a quote from General Honore: “People need to be cautious because anything built by man can be tricked by Mother Nature.” (You may remember another of his famous quotes, “Don’t get stuck on stupid.”)
One of these situations happens with meters that measure pH.
Also Read: pHinding the Meaning of pH
If you take a hazmat class that covers basic chemistry you will no doubt learn about the pH scale. We were all told it goes from 0 to 14. When you learn how to use hazmat monitoring equipment the scales on the instruments that measure pH go from 0 to 14. The scale on pH paper also goes from 0 to 14.
But what if it’s possible for a liquid to have a pH outside of those limits? Were we lied to?
Not really.
What exactly is pH? It is a property that specifies whether an aqueous solution is acidic or basic. The pH scale is logarithmic and inversely indicates the activity of hydrogen ions in the solution.
In many hazmat applications we use a linear scale not a logarithmic scale. In a linear scale each unit of distance on a plot corresponds to the same increment. For example, explosive (or flammable) limits (LEL/UEL) measure the amount of a flammable vapor in a given atmosphere. The LEL/UEL is expressed as a percentage. The size of the unit of measure doesn’t change as the percentage changes. If the amount of a flammable vapor doubles then the percent of vapor in the atmosphere will double.
Also Read: How to Effectively Train Leaders for Large-Scale Incidents
A logarithmic scale, on the other hand, is nonlinear. In that type of scale, numbers with equal distance between them such as 1, 2, 3, 4, and 5 are not equally spaced. The differences between the magnitudes of the numbers involved will increase or decrease significantly as you move up or down the scale.
If you live in California you are familiar with what is commonly called the Richter scale used to measure the intensity of earthquakes. This type of magnitude scale measures the energy released by an earthquake. If the Richter measurement of an earthquake goes from 1 to 2, the intensity isn’t twice as much, it’s 100 times worse. If the Richter magnitude number is 8 the quake will cause major damage to buildings. If it increases to 9 the quake will cause near total destruction.
The pH scale shares that attribute.
One thing to know about logarithmic scales: they are open ended. Therefore, the pH scale can go below zero and above 14.
There are two known locations that have negative pH solutions present. One is in California and the other is in Russia.
The site in California is in Shasta County, a little more than 8 miles northwest of Redding. The extremely low pH solutions are in what used to be a copper mine called the Iron Mountain copper mine.
Iron Mountain is actually a complex of mines. Mining in the complex dates back to 1879. The environmental problems with the mines were first discovered in 1939 when high runoff from the mine complex caused a massive fish kill in the Sacrament River downstream of the mine.
In 1983 the mine was placed on the Superfund National Priority list. The US EPA ranked it as the third-most heavily polluted site in California. Three years later, EPA began a site remediation study. In 1990 as a part of that study, investigators collected samples of various minerals in the mine. When they analyzed those samples they found the pH was -3.6. It’s the most acidic water naturally found on Earth.
The site in Russia is in hot springs near the Ebeko volcano. This volcano is located on Paramushir Island, a volcanic island in the northern portion of the Kuril Islands chain in the Sea of Okhotsk in the northwest Pacific Ocean. Researchers have found hot springs in this volcano with a pH as low as -1.7.
Naturally occurring negative pH does exist, but it can’t be measured with existing field instruments. It’s measured with laboratory equipment and requires special correction factors to give an accurate measurement. It exists in those two places (that we know of). The odds of a hazmat team responding to either location? Do we have to ask?
Are there more such locations? No one knows. Should your hazmat team respond to a report of one? You can respond but all you’ll be able to do when you get there is stand around and look concerned. Your instruments will work but they won’t detect anything.
My recommendation: call EPA. They like challenges like that.
About the Author
Vance Bennett is retired from California Specialized Training Institute, the training branch of the Governor’s Office of Emergency Services. During his 30 years at CSTI he was an Emergency Management coordinator and instructor in the Hazardous Materials Section. He was the course manager for several CSTI courses including Hazmat Incident Commander, First Responder Operations and CSTI Instructor Certification. As the CSTI representative to the FIRESCOPE Hazardous Materials Subcommittee, he helped develop hazmat team typing and equipment standards for California hazmat teams. Vance was also a regular presenter at the Hazmat Continuing Challenge Workshop.
Prior to coming to work for CSTI, he was on active duty in the U. S. Coast Guard specializing in marine safety and pollution response. During that time he was involved in responses to hazmat incidents and oil spills including the EXXON Valdez and American Trader spills. He served in a variety of USCG units including the Pacific Strike Team before retiring in 2009.
