Dogs and Phosphoric Acid...one more time.

In the words of Peter Griffin "You know what really grinds my gears?"  How we describe the hazards of a chemical when it is found to be present in the environment.

All chemicals pose a hazard at a particular dose.  If it is under that dose, then the hazard seen at a higher dose does not apply.

Yes, it is that simple.

In two previous posts I tried to explain this concept using dogs and phosphoric acid found in a can of Coke.  To summarize:

If you are describing a dog that you will come in contact with that looks like this:




Don't make it sound like it looks like this:

Which brings me to the EPA's "Imminent and Substantial Endangerment Order to Protect Drinking Water in Southern Parker County." (1)  In the Order, the EPA states:

The EPA says that contaminants are present in the aquifer.  The term "contaminant" means:

[A]ny physical, chemical, biological, or radiological substance or matter in water. (2)

What the EPA is claiming is that they found "substances" in the water.  That definition does not require that the concentration - dose - be at any particular level, only that "any" amount was found to be present. "Any" means any.

The EPA goes on to say in the order:

These substances, according to the EPA, are in an "any" amount that may present an "imminent and substantial endangerment to the health of persons."

Notice what it says about the ingestion of benzene - one of the contaminants found:

[B]enzene if ingested or inhaled could cause cancer, anemia, neurological impairment and other adverse health impacts."

In other words, the EPA is telling us is that if you walk into this kennel (drink water from this aquifer) you will run into this dog:

What type of dog did the EPA actually find:

And:

Benzene - a "contaminant" - was found to be present in the water at the following concentrations:

3.1 ppb or 0.0031 ppm
6.12 ppb or 0.00612 ppm
4.55 ppb or 0.00455 ppm

The average benzene concentration is:

4.59 ppb or 0.00459 ppm

I wonder if the EPA has anything to say about how much of a "contaminant" can be found in drinking water before it is considered unsafe?  You know, like is there a maximum amount of certain chemicals that determine if the water is safe to drink?  Like maybe something called a "maximum contaminant level" or "MCL?"

Well by golly, there is!  Here is what the EPA has established under the SDWA:

Maximum Contaminant Level (MCL) - The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.

Maximum Contaminant Level Goal (MCLG) - The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals. (3)

So an MCL is the "highest level" of a contaminant allowed in drinking water below which "there is no known or expected risk to health."

In other words, if the concentration of the contaminant found in the drinking water is below the MCL or MCLG, there would be "no known or expected risk to health" according to the EPA.

I wonder if the EPA has established an MCL for benzene?  By golly, they have!

http://water.epa.gov/drink/contaminants/index.cfm

The MCL for benzene is 0.005 ppm.  What was the benzene concentration in the three samples:

3.1 ppb or 0.0031 ppm
6.12 ppb or 0.00612 ppm
4.55 ppb or 0.00455 ppm

The average benzene concentration is:

4.59 ppb or 0.00459 ppm

Only one of the three samples had a concentration above the MCL of 0.005 ppm with the average benzene concentration below it.  Based on this, the EPA should have said that there is no known or expected risk to health associated with the benzene.  Instead the EPA states:

There is no MCL for hexane, propane, or ethane.  The MCL for toluene is 1 ppm.  All three samples were well below this.

This is the same thing as telling a Coke drinker about the phosphoric acid in their drink:

Phosphoric acid is corrosive.  Ingestion may produce burns to the lips, oral cavity, upper airway, esophagus and  possibly the digestive tract. Circulatory collapse. Unconsciousness, possibly death. (post)

Did the water pose an "Imminent and Substantial Endangerment" to public health?  Possibly.  Maybe because of the flammability of the methane, propane, and ethane found.  Flammability - based on flash point, flammable range, or percent LEL - was not determined by the EPA.

Is it possible that enough gas could form in the well?  I'm not sure about that.  The flammable range of methane is 5-15% in the air. (3).  Sampling of the air for LEL within the well would be required to make a flammability determination at the concentrations found.  The fact that the pumps locked up and effervescence was noticed makes further review necessary.

Flammability is the only potential "Imminent and Substantial Endangerment" situation that may be present.  The presence of "any" contaminants found fall below EPA's MCLs and should not have been mentioned as their level in the water presents "no known or expected risk to health."

Rule number 1:  If the contaminants fall below the MCL do not identify them as a possible health concern, or as a health concern greater than what the dose would manifest. (Dogs)

Rule number 2: Do not describe health hazards associated with a chemical at a dose that is higher than what is actually found. (phosphoric acid)


Now, where was I?  Oh yeah, the Seven Deadly Sins...

Next Post: Seven Deadly Sins: I'm not seeing it.


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