Arsenic in Rice: Part 17 - The Ethical Considerations of a Threshold

Consumer Reports writes:

Consumers Union, the advocacy arm of Consumer Reports, urged the FDA to set a 3 ppb limit for total arsenic in apple and grape juice.

They are advocating for that level, which would then also be used for rice:

Using the 5-ppb [New Jersey] standard in our study, we found that a single serving of some rices could give an average adult almost one and a half times the inorganic arsenic he or she would get from a whole day’s consumption of water, about 1 liter. (CR)

Consumer Reports is advocating for a line to be drawn.  On one side the product will be "safe" - or - not  "troubling," "worrisome," "cause for concern," or "potentially harmful."  The question that needs to be asked is what will rice and apple juice that falls on the other side - more than 3 ppb - be called?

That's a question that seems to get brushed aside or, most likely, not even considered.  And here is where the ethical considerations of a threshold must be taken into consideration.

The reason that New Jersey decided that 5 ppb was "safe" for their water was because they could not effectively treat the water to anything below that.  Remember, their law demands a one in one million risk which means that the water would need to be treated to 0.003 ppb.  Not only is that not possible to treat down to, it is also not possible to analyze with any degree of precision and accuracy.

So New Jersey settled on 5 ppb as being reasonably able to attain:

This determination comports with the NJSDWA mandate to establish the MCL at the most protective level within the constraints of medical, scientific and technological feasibility. (NJ)

But that threshold is for water.  We can "waste" water if it cannot be treated, use it for non-consumption purposes.  That treatment option is not available for apple juice and rice that exceeds the threshold of 3 ppb.  So what would happen to it?  Would it need to be destroyed?  And if so, would the "wasting" of that apple juice, or more specifically rice, that contains 4 ppb inorganic arsenic be ethical?

First, let's settle on what I mean by "ethical":

Ethics refers to well-founded standards of right and wrong that prescribe what humans ought to do, usually in terms of rights, obligations, benefits to society, fairness, or specific virtues. (1)

The ethical consideration rears its ugly head when you draw that line in the sand.  If Consumer Reports wants a 3 ppb standard, what will be done with rice and apple juice that is found to contain 4 ppb?

If 3 ppb is "safe" then exceeding that number - appearing on the other side of that line is...what?

• We are not talking about water here.  We are talking about a food.  You cannot treat rice or apple juice that is found to contain 4 ppb of inorganic arsenic, so what do you do with it?

• Well we could blend it to dilute the total to below the 3 ppb - you know, the solution to pollution is dilution approach.  But that assumes that we have the capacity to store and blend this volume.

• We could just dispose of it, but that means that we take that rice out of the food supply thereby denying rice to citizens that can no longer afford it.  Economics 101 in play: supply and demand sets the price,

• We stop growing rice and apples in areas where the arsenic shows up in the samples.  Sounds good.  But you can't just plant an apple tree and start producing apples - it takes a long time to grow..  Nor can you grow rice anywhere - it take access to a lot of water.  Besides, look at the numbers for both apple juice and rice.  Arsenic is EVERYWHERE and in EVERY sample. It is ubiquitous with these two products because it is an element and it is in the water and soil cycle (see my previous post).

Well, that leaves us then with this.

• We could give it to poor people or starving people.  That's a better alternative for them.  If you are hungry, what difference does it make?  And in areas where food is short, those folks will die from starvation long before bladder cancer ever manifests itself.

If you draw a line in the sand at some ppb, you either dilute it, waste it, or give it to others when that threshold is exceeded.

You see the problem now with a line in the sand?  That line had better be bullet-proof or the ethical considerations that will come into play will rear their ugly head.  If you say 3 ppb is "safe" then wasting rice and apple juice when it contains 4 ppb will raise the cost of these two items and take them out of being consumed.  We can live without apple juice, but rice?

If you say that 4 ppb is not bad enough to waste, then where do you draw the line as to when it must be wasted?  And who gets to consume the 4 ppb product?  Do wealthy people get to eat the 3 ppb and less while the poor and hungry get the above threshold product?  Would that be fair?

Is that ethical?  Is that what we ought to do?

What will the rice and apple juice that exceeds the "3 ppb limit" be classified as?  Consumer Reports calls rice above 5 ppb "troubling," "worrisome," "cause for concern," or "potentially harmful."  If they push for a 3 ppb limit, as they are advocating for apple juice, then how can they justify a 5 ppb limit for rice?  Rice will therefore have to also meet the 3 ppb limit per serving to be "safe."

Here is what I want Consumer Reports to respond to:

1. What will rice and apple juice be considered if it exceeds the 3 ppb limit they urge the FDA to set?
2. What must be done to rice and apple juice that exceeds this threshold of 3 ppb?
3. Can rice and apple juice that exceeds 3 ppb be given to starving people and/or the poor, and, if so, how is that ethical?

And my final question:

• If exceeding the threshold is considered "potentially harmful" or to increase risk, how can we ethically allow anyone to consume this rice and apple juice?

The answer is you can't. Once you draw a line in the sand, anything that appears on the other side must be the opposite of what you want.  Safe: Unsafe, Healthy: Unhealthy, Toxic: Non-Toxic,  Okay: Not Okay, Good: Bad.

It is one or the other, it cannot be both.

So I'll end with this:

If you are going to draw a line in the sand, that line better represent a real risk if you step over it.  Does stepping over a 3 ppb limit represent a real risk?  Does eating a 1/4 cup serving of rice with 9.6 ppb inorganic arsenic represent a real risk?  If it does, then it is "potentially harmful."  If it does not, then it is safe.

It cannot be both.  This is why we must choose a threshold that represents a real potential for harm.  When you do, those ethical considerations become much more manageable when you exceed the threshold. We have an obligation to protect public health.  We have an obligation to feed people.  We have an obligation to look at the data and make sound decisions when setting a threshold of what is, and is not "safe."


Part 17 - Creating a Needless Concern.

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Arsenic in Rice: Part 16 - Rice Eaters and Bladder Cancer

Consumer Reports tells their readers:

Our resulting analysis of 3,633 study participants found that on average, people who reported eating one rice food item had total urinary arsenic levels 44 percent greater than those who had not, and people who reported consuming two or more rice products had levels 70 percent higher than those who had no rice.

This leads them to view the arsenic they detected in food products as such:

“Despite our taking into account other common sources of arsenic, and no matter which way we sliced the data, we see a very strong association between rice consumption and arsenic exposure,” says Stahlhut, who along with Navas-Acien led a similar analysis of NHANES data for our January 2012 article on arsenic in juice. That analysis found that study participants who reported drinking apple or grape juice had total urinary arsenic levels that were on average nearly 20 percent higher than those who didn't.

 Which leads them to this conclusion:

Consumers Union, the advocacy arm of Consumer Reports, urged the FDA to set a 3 ppb limit for total arsenic in apple and grape juice.

I am going to come back to that...but right now we still need to look at what we know so far.

• Urinary arsenic concentrations give a good biomarker of the absorbed dose of arsenic, since about 70% is excreted in the urine. (AJE)
• Rice eaters had arsenic levels that were 44 percent greater than those that do not consume rice. (CR)
• The average amount of rice consumed is one cup. (EHP)
• Consumer reports measured the amount of inorganic arsenic in one serving of rice and found the highest level to be 9.6 μg per 1/4 cup. (CR)

In my last post I attempted to show what is in play:

• ...if a 1/4 cup serving size that exceeds the New Jersey drinking water standard of 5 ppb is considered by Consumer Reports to be "troubling," "worrisome," "cause for concern," or "potentially harmful." 
• ....consuming one full cup of this rice must therefore result in four times more "troubling," "worrisome," "cause for concern," or "potentially harmful."

In all my previous posts I have tried to show that "troubling," "worrisome," "cause for concern," or "potentially harmful," that results from consuming 1/4 cup of rice that exceeds the New Jersey drinking water standard of 5 ppb for arsenic must be because of some risk of harm.

Because Consumer Reports sees harm if a serving is above 5 ppb, that harm must therefore be based on bladder cancer since that is what the NRC based the slope factor on used to support New Jersey's 5 ppb drinking water standard.

And because bladder cancer is also what IRIS is using for the Cancer Slope Factor - potency - they propose for arsenic, exceeding any number above "0" for arsenic increase the risk of bladder cancer.  New Jersey accepts a one in one million risk as acceptable which means 0.003 μg/L would be considered "safe."  Understanding reality, NJ set on a limit of 5 μg/L as acceptable based on the ability to treat the water as well as accurately test for an amount that low.  Therefore 0.003 μg/L "safe" became "safe" at 5 μg/L.

I then looked at urinary total arsenic that was reported by the CDC.  This led me to write in my last post:

So...if Mexican Americans and Asians consume more rice than Whites...and rice eaters have more urinary total arsenic than non-rice eaters...and the Cancer Slope Factor assume a potency whereby consuming more increase the risk harm...and that potency was used to that justify the New Jersey drinking water level of 5 ppb...and that Cancer Slope Factor, now proposed by the IRIS, is based on bladder cancer in woman...

Which I concluded with this:

...we would, therefore, expect to see more bladder cancer in Mexican Americans and Asians, especially in women...shouldn't we?

I want to stress here that all of my sources are the same sources as used by Consumer Reports and their experts.  They are all from reputable sources.  I am looking at the same data, facts, and figures that they look at and I don not see "troubling," "worrisome," "cause for concern," or "potentially harmful," for any of the rice they tested.

We are missing a lot, and I do mean a lot, of data to conclude "troubling," "worrisome," "cause for concern," or "potentially harmful," when exceeding 5 ppb per serving up to a maximum of 10 ppb.

If rice eaters have more urinary total arsenic then non-rice eaters, should we see more bladder cancer in those groups that consume rice on a daily basis?  So back to this question I posed:

...we would, therefore, expect to see more bladder cancer in Mexican Americans and Asians, especially in women...shouldn't we?

I went to the National Cancer Institute and looked up the data on bladder cancer from the Surveillance and Epidemiology and End Result (SEER) database.  Here is what they say:

Source

Now, with those estimate numbers in mind, let's look at what the EPA's IRIS is basing the proposed arsenic Cancer Slope Factor on:

2010 Draft IRIS Page 150-151

The EPA is proposing a Cancer Slope Factor on women's risk for bladder cancer.  This means that women appear to be more susceptible to the harm of bladder cancer from exposure to arsenic.  The "potency" of arsenic as a bladder cancer carcinogen is based on women and bladder cancer.  All things considered, when consuming a cup of rice, women and men receive the same dose of arsenic.  Same with drinking water.  There is a slight difference in urinary total arsenic between men and women.

CDC

If women are more susceptible to bladder cancer - the life-time risk - then wouldn't we see a higher incidence in women since consumption of arsenic seems to be the same?  That Cancer Slope Factor is derived from a line drawn through data points that looked at arsenic dose and incidence of cancer.  It assumes that there is a linear relationship between what was seen at high doses (the Morales data) and what should - theoretically - be seen at low doses.  It assumes a line going all the way to zero.  Zero dose, Zero risk of bladder cancer.

Let's look at those numbers in terms of an incidence rate for bladder cancer:

Source

EPA's proposed IRIS Cancer Slope Factor assumes a "safe" concentration of arsenic for a risk of one in 10,000 to be 0.14 μg/L (which is based on a consumption of 2 liters of drinking water per day).

Let's look at the incidence of bladder cancer in rice eaters.  Notice how Asians and Hispanics, two groups we know consume rice, have lower bladder cancer incidence than whites for both men and women.

I don't know...the numbers just don't support the theoretical potency for arsenic and bladder cancer the EPA is proposing.  Dr. Honneycutt with the TCEQ elaborates the same observation:

For bladder cancer alone, the incidence risk calculated by USEPA based on final draft values for males/females is 3.1E-04 per μg/L. Therefore, based on 2 μg/L as an average drinking water concentration, the estimated bladder cancer risk for the US population would be 6.2 per 10,000 or 62 per 100,000. However, the actual occurrence of bladder cancer in the US is about 23 cases per 100,000 (males/females combined). It would take 3 times the actual bladder cancer incidence for US males/females combined to even make possible the 62 cases per 100,000 estimated due to arsenic exposure from drinking water alone. Thus, the incidence risk calculated by USEPA final draft values for bladder cancer appears to be inaccurate and overly conservative. (emphasis mine)

Which brings us to this point.

If the theoretical Cancer Slope Factor is based on bladder cancer, and the incidence of bladder cancer does not match the theoretical risk being calculated, should we accept the theoretical risk as the basis for determining a "safe" threshold or for "establishing health criteria?"

If that Cancer Slope Factor proposed by EPA does not estimate the bladder cancer risk correctly, exceeding the New Jersey 5 ppb threshold for a 1/4 serving of rice will not be "troubling," "worrisome," "cause for concern," or "potentially harmful."

And if that's true, advocating for a "3 ppb limit for total arsenic in apple and grape juice" - which would be carried over for rice - is not warranted.

That's an important point to acknowledge.  It is the whole reason I spend time writing these posts.  If we are going to draw a line in the sand and claim "safe" on one side, then we will need to address what will it mean for the products that have concentrations above that threshold and fall on the other side of the line?



Not only does the science behind toxicology demand that we get this right, there are ethical considerations that need to be made as well.


Next Post: Arsenic in Rice: Part 17 - The Ethical Considerations of a Threshold


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Apples, Arsenic, and Risk - Part 7: Who the heck is Sharyn Duffy of Geneseo, N.Y.?

Okay, so if cancer at these low levels is not the concern the EPA says it is, would there be anything else that would cause Consumer Reports concern regarding the finding of inorganic arsenic in apple juice?  Here is what they report:

• Mounting scientific evidence suggests that chronic exposure to arsenic...even at levels below water standards can result in serious health problems.
• But the many diseases likely to be increased by exposure even at relatively low levels are so common already that its effects are overlooked simply because no one has looked carefully for the connection,” says Joshua Hamilton, Ph.D., a toxicologist specializing in arsenic research and the chief academic and scientific officer at the Marine Biological Laboratory in Woods Hole, Mass.
• It’s a carcinogen known to cause bladder, lung, and skin cancer in people and to increase risks of cardiovascular disease, immunodeficiencies, and type 2 diabetes.
• A 2004 study of children in Bangladesh (PDF) suggested diminished intelligence based on test scores in children exposed to arsenic in drinking water at levels above 5 ppb, says study author Joseph Graziano, Ph.D., a professor of environmental health sciences and pharmacology at Columbia University.
• And a study published in 2011 (PDF) in the International Journal of Environmental Research and Public Health examined the long-term effects of low-level exposure on more than 300 rural Texans whose groundwater was estimated to have arsenic at median levels below the federal drinking-water standard. It found that exposure was related to poor scores in language, memory, and other brain functions.
• Chronic arsenic exposure can initially cause gastrointestinal problems and skin discoloration or lesions. Exposure over time, which the World Health Organization says could be five to 20 years, could increase the risk of various cancers and high blood pressure, diabetes, and reproductive problems.
• Signs of chronic low-level arsenic exposure can be mistaken for other ailments such as chronic fatigue syndrome.
• “Given what we know about the wide range of arsenic exposure sources we have in this country, I suspect there is an awful lot of chronic, low-level arsenic poisoning going on that’s never properly diagnosed.”
• ...but also can cause lasting harm to children’s developing brains and endocrine and immune systems, leading to other diseases, too.
• “Recent studies have shown that early-childhood exposure to arsenic carries the most serious long-term risk,”
• Evidence of arsenic's ability to cause cancer and other life-threatening illnesses has surged because some of the diseases linked to it have latency periods of several decades.

So, what we come away with when reading the Consumer Report's article on Apples and Arsenic is this:

• Mounting scientific evidence...serious health problems
• Many diseases likely to be increased by exposure even at relatively low levels...overlooked
• Increase risks of cardiovascular disease, immunodeficiencies, and type 2 diabetes
• Diminished intelligence based on test scores in children exposed to arsenic in drinking water at levels above 5 ppb.
• Exposure was related to poor scores in language, memory, and other brain functions.
• Increase the risk of various cancers and high blood pressure, diabetes, and reproductive problems.
• Low-level arsenic exposure can be mistaken for other ailments such as chronic fatigue syndrome.
• Low-level arsenic poisoning...that’s never properly diagnosed.
• Lasting harm to children’s developing brains and endocrine and immune systems, leading to other diseases.
• Early-childhood exposure to arsenic carries the most serious long-term risk.
• Ability to cause cancer and other life-threatening illnesses has surged...latency periods of several decades.

Wow!  All that from drinking apple juice?

Not so fast, I'm thinking.  Let's look at it objectively, and ask two questions:

1. Is drinking apple juice unsafe because of arsenic?
2. Is drinking water with the 10 ug/L (ppb) of arsenic unsafe?

Now go back and read the bullets above, what answers to those two questions is being conveyed by Consumer Reports?

Is their report an accurate description of the dangers posed by drinking apple juice that they found had a mean (average) inorganic arsenic concentration of 3.14 ug/L (95%UCL = 3.53) and a median of 2.51 ug/L. (I took all 84 values and ran them using Excel's statistical formulas.  These values exclude three grape juice samples included in their data.)

Some of Consumer Reports' claims of serious health problems they support with a citation link, others are quotes for medical/science professionals, but one in particular is a testimony:

Signs of chronic low-level arsenic exposure can be mistaken for other ailments such as chronic fatigue syndrome. Usually the connection to arsenic exposure is not made immediately, as Sharyn Duffy of Geneseo, N.Y., discovered.

Okay, a real person affected by arsenic...

She visited a doctor in 2007 about pain and skin changes on the sole of her left foot. She was referred to a podiatrist and eventually received a diagnosis of hyperkeratosis, in which lesions develop or thick skin forms on the palms or soles of the feet. It can be among the earliest symptoms of chronic arsenic poisoning. But she says it was roughly two years before she was finally referred to a neurologist, who suggested testing for arsenic. She had double the typical levels.

Okay...she had hyperkeratosis...a skin lesion that's associated with arsenic exposure...she had double the typical levels...  Double?  Typical?

Okay....they named a real person, surely Consumer Reports checked out her story...where did they find her?  What do we know about Sharyn Duffy of Geneseo, N.Y.?  Aha! Google search...nothing.

What support do we have to show that a.) Sharyn Duffy was diagnosed with hyperkeratosis, and b.) she had double the typical levels?  Should we accept the diagnosis and quantification of arsenic presented in the Consumer Reports article as valid?  I tried - as much as I am willing to spend my free time on trying - to find any reference to her case.  Nothing.

I could discount it as "unsubstantiated" but where's the fun in that?

Here is what we know (if you can believe the EPA and ATSDR) about arsenic and skin lesions, such as hyperkeratosis:

[I]n a study with detailed exposure assessment, all confirmed cases of skin lesions ingested water containing >100 μg/L arsenic (approximately 0.0037 mg As/kg/day).

Another large study reported increased incidence of skin lesions associated with estimated doses of 0.0012 mg As/kg/day (0.023 mg As/L drinking water).

Several epidemiological studies of moderately sized populations (20–200 people) exposed to arsenic through drinking water have detected no dermal or other effects at average chronic doses of 0.0004–0.01 mg As/kg/day, and one very large study detected no effects in any person at an average total daily intake (from water plus food) of 0.0008 mg As/kg/day.

Notice how the intake of arsenic is reported in "mg" per liter?  Consumer Reports claims that Sharyn Duffy had "double the typical levels."  The plot thickens (no pun intended...you know...hyperkeratosis...oh, never mind...).

Here is a bit of interesting trivia we also read in the Consumer Reports article:

Because most ingested arsenic is excreted in urine, the best measure of recent exposure is a urine test.

Why's that important?  Because we can measure and get a pretty good estimate of how much total arsenic is being consumed on average - or typical.  And if we know that, we can then double it to find out how much arsenic Sharyn Duffy was exposed to.

In the Consumer Reports article they tell us:

[w]e commissioned an analysis of data from the National Health and Nutrition Examination Survey (NHANES), conducted annually by the National Center for Health Statistics. Information is collected on the health and nutrition of a nationally representative sample of the U.S. population, based on interviews and physical exams that may include a blood or urine test. 

It would have been nice of them to report these values, but nevertheless, we can get a good idea of what they are by looking at NHANES research that has been published.  Here is what I found:

Source Table has been revised since posting)

I am going to assume that Sharyn Duffy of Geneseo, N.Y. is > 20 years of age.  If "most ingested arsenic is excreted in urine" we can assume that the amount of arsenic that Sharyn Duffy was exposed to, if it was "double the typical levels" was approximately 20 ug.  What goes in goes out...

Remember those studies on skin lesions the EPA looked at?  Well here is what they concluded from those studies:

This value [0.0008 mg As/kg/day] has been used to calculate a chronic oral MRL for inorganic arsenic of 0.0003 mg/kg/day.  

EPA considers 0.0003 mg/kg/day "safe" but reports that 0.0008 mg/kg/day "detected no effects in any person at an average total daily intake (from water plus food)."

Let's assume that Sharyn Duffy of Geneseo, N.Y. is a petite woman who weighs 110 pounds or 50 kg.  At 20 ug total intake, she would be consuming 0.4 ug/kg/day or 0.0004 mg/kg/day to get "double the typical levels."

Okay, so she is being exposed to more than the EPA's "safe" dose, but it is way under the 0.0008 mg/kg/day where "no effects in any person at an average total daily intake (from water plus food)" were seen in "one very large study."

So maybe poor Sharyn Duffy of Geneseo, N.Y. is very susceptible to arsenic and the little bit she consumed (if we can trust that it was only enough to "double the typical levels") gave her the disease associated with much higher doses of arsenic.  How does Sharyn Duffy's experience with arsenic affect my answer to the questions I posed earlier:

1. Is drinking apple juice unsafe because of arsenic?
2. Is drinking water with the 10 ug/L (ppb) of arsenic unsafe?

It doesn't.  At worse, Consumer Reports got it wrong, and she was exposed to much more arsenic then "double the typical levels."  At best, Sharyn Duffy of Geneseo, N.Y. is an anomaly...an outlier...and we can ignore her encounter with arsenic because that's not what we would see in the public at large.

Onward....

Next Post: Apples, Arsenic, and Risk - Part 8: Arsenic and type 2 diabetes

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Apples, Arsenic, and Risk - Part 1: One in 500

In the January 2012 Consumer Report's article "Arsenic in your juice," they write:

Our analysis was led by Richard Stahlhut, M.D., M.P.H., an environmental health researcher at the University of Rochester with expertise in NHANES data, working with Consumer Reports statisticians. Ana Navas-Acien, M.D., Ph.D., a physician—epidemiologist at Johns Hopkins University’s Bloomberg School of Public Health, also provided guidance. She was the lead author of a 2008 study in the Journal of the American Medical Association (PDF) that first linked low-level arsenic exposure with the prevalence of type 2 diabetes in the United States.

So Consumer Reports accepts that there is a "link" between type 2 diabetes and low levels of arsenic...which is most likely one of the contributing factors for support of this statement that is also in their report:

But chronic toxicity can result from long-term exposure to much lower levels in food, and even to water that meets the 10-ppb [EPA] drinking-water limit.

as well as printing this quote...

“I suspect there is an awful lot of chronic, low-level arsenic poisoning going on that’s never properly diagnosed.” - Michael Harbut, M.D.

leading to this...

Consumers Union urges federal officials to set a standard for total arsenic in apple and grape juice. Our research suggests that the standard should be 3 ppb. 

Such standards would better protect children, who are most vulnerable to the effects of arsenic... 

Moreover, the EPA should impose stricter drinking-water standards for arsenic...

Ignoring the desire to have zero arsenic in the food and drink we consume, would lowering the level of arsenic to 3 ppb or less make a difference?  Would lowering the amount of arsenic in drinking water to a level less than 10 ppb (as the EPA is proposing) make a difference in preventing chronic toxicity?

Consumer Reports believes it would:

For known human carcinogens such as inorganic arsenic, the EPA assumes there's actually no "safe" level of exposure, so it normally sets exposure limits that include a margin of safety to ideally allow for only one additional case of cancer in a million people, or at worst, no more than one in 10,000. For water with 10 ppb of arsenic, the excess cancer risk is one in 500.

Public Health, especially those that look at chemical exposure risk, have been pigeon-holed by the "no safe level of exposure" for carcinogens statement.  Why?  because it always leads to the "risk of cancer" discussion of one in a million .

How do you think the general public - including medical professionals - understand the statement:

For water with 10 ppb of arsenic, the excess cancer risk is one in 500.

That statement is only true if you accept EPA's model that generated that risk.  And even if you accept their model, there is this little thing called reality that can nullify it.

But the damage has been done.  Drinking water with 10 ppb will bring about one more cancer for every 500 persons according to the EPA.

No...no it will not.  That's what the model predicts, and because the "people demand a number" we have made the model's output sacrosanct.  However, the prediction of one excess cancer risk in 500 for 10 ppb arsenic is nothing more than an answer spit out of an equation:

Source

That risk level - "R" is what we want to see, one in a million, one in 100,000... and that along with the "Cancer Potency" or "q" for the carcinogen in question will tell us how much of that chemical a 70 kg person can be exposed to over a lifetime (70 years) so that out of 1 million or 100,000, or 500 we should not see more than one additional cancer.

Sounds reasonable, until you look at how simple that formula is. The lifetime cancer risk - R - is whatever number we want to put in there.  Same with body weight.  Those numbers are not going to ever come into dispute.  So the "safe" intake, or in this case, the intake that would reduce your lifetime risk to one out of something, is predicated solely on the "theoretical cancer potency estimate for humans" which is also called the "cancer slope factor."

When the EPA produce data that shows arsenic at 10 ppb resulting in "male bladder cancer model outputs" for a "Lifetime Risk" of 3.20E-03 (3.2 per 1000) it is stating that their model's cancer slope factor (CSF) is accurate.  And to know if it is accurate, we need to compare the projected incidence to the actual incidence of bladder cancer in males.

That's reasonable, isn't it?  Well you would think so, but somehow that little bit of common sense seems to be missing.  You know, if the model predicts x is x what we are seeing.  Instead we have a system that has developed a methodology devoid of conformation.

And to top it off, we have lost sight of just what "for water with 10 ppb of arsenic, the excess cancer risk is one in 500" actually means.  That it is based on a theoretical cancer slope factor for one particular type of cancer.

Next post: Apples, Arsenic, and Risk - Part 2: EPA's Proposed Cancer Slope Factor.


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Laundered Shop Towels: 14 - Should you believe them?

In my first post on this topic I asked:

Should we accept it based on the reputation of Gradient and the credentials of the three authors?  Or should we look deeper into the study to see how they came up with data that affords Kimberly-Clark the ability to ask workers: Why risk it?  Who's counting on you?

I then went on to say:

Well I have looked into it.  I can support my conclusion that there is no additional risk to a worker using a laundered shop towel.  Period.  Should you believe me?  No, not until you read what I am putting forth as my reasons why this study is flawed and their conclusion false.

So here we are after 13 posts on this topic.  I have presented how Gradient came to conclude that there is a risk

Kimberly-Clark sure wants to take Gradient's findings at face value.  What business wouldn't want to show how bad the other option is by claiming:

"Two studies conducted during the last 8 years show that laundered shop towels contain toxic heavy metals even after laundering." (1)

And they get to do that with unabashed glee simply because of a study prepared interdependently by:

"an environmental and risk science consulting firm renowned for their expertise in Toxicology, epidemiology, Risk Assessment, Product Safety, Contaminant Fate and Transport, and Environmental/Forensic Chemistry." (1)

But those ratios Gradient reports in Table 8a have a much different meaning when you look at how they were generated as well as what the comparison is made to:

(Gradient 2011 Report)

Let's look at each one of my issues with their model, calculation, and assumptions.  If there is an increase in risk high enough to warrant discontinuing the use of laundered shop towels, it must be supported by the science presented in Gradient's reports.

Gradient claims that the average concentration of lead (the metal with the highest exceedance ratios -Table 8a) in laundered shop towels is 100 mg/kg.  If that average is not correct, then none of the intake values they calculated are correct.

Based on the minimum and maximum concentrations they present in Table 4 of their study, and the standard deviation reported, it is evident that the average Loads they use are skewed to represent a higher concentration of metals than would naturally be found.

The calculated mean - or average - is supposed to represent the true mean of the population.  Based on the high variability in the concentrations they report (as shown by the standard deviation exceeding the mean) it is highly unlikely that the averages they used to determine the Load represent what is actually found on a laundered shop towel.  It is, in most likelihood, magnitudes higher than what would normally be found.

Let's look at an example to illustrate this:

Here are 25 values representing the lowest concentration detected (1.7) and the highest (600) for lead.  All the other numbers are just numbers I came up with.  The numbers in blue represent all the values less than the mean, the numbers in red represent concentrations higher than the mean.  Using these numbers I was able to get close to the mean and standard deviation reported by Gradient.

Since 100 mg/kg is the number Gradient uses to estimate the lead Load on the laundered shop towel, if these were the actual values detected, 22 towels encountered would have a concentration of lead on them less than 100 and three would be above.

In a normal distribution, "100" would be the average encountered. so at the end of the day, after handling 12 shop towels, the load encountered would be around 100.  That's based on a normal distribution, where 100 is in the middle, half lower and half higher.  In my example 92% of the towels encountered have a lead concentration lower than 100.  See previous post on this topic.

I don't know what the actual concentrations for lead are, but I do know that the average of 100 is not a true representation of what is normally found on laundered shop towels.  It is too high based on the standard deviation reported.  This means that the Load for the towel they calculated is too high as well.

Even if the mean concentrations Gradient reports were correct, there is still the issue on whether or not the metals can be dislodged from the towel and onto the hand.  That's the whole purpose of calculating a Load, to see what is available to enter the mouth from the hand.  I discussed that issue in this post, and it is extremely relevant in determining the validity of their intake values.

The fact that an object may contain a high concentration of metals does not warrant concern if those metals can not be transported into the receptor, in this case from the hand into the worker's mouth.  In order for Gradient's model to hold true, metals must come off the towel and onto the hand - Tt/h.  Why Gradient did not look at what, if any, metals could dislodge from the towels is beyond me.  Even Adam and Jamie of the Mythbusters could have figured out a sound way to determine this.  And they're not PhDs!

So I'll call the "Load" and "Tt/h" part of Gradient's calculation:

But let's look at Load from a different angle.  Gradient claims that the intake of lead a worker might encounter on laundered shop towels is "11" times higher than the CalEPA NSRL for lead.  That is, the lead Load is significant enough to bring about 10 additional cancers for every 100,000 workers using laundered shop towels. (We would expect one cancer at the NSRL).  See previous post.

As I showed in that post, 100,000 workers would use 11.8 billion laundered shop towels.  Are you willing to contend that the 25 shop towels Gradient tested represent the Load on 11.8 billion towels?

Not only are the Load values Gradient used in question, but the intake they calculated requires the worker to place their hand to their mouth each time a laundered shop towel is used.  For these exceedance values to be true, a worker must bring their hand (single) to their mouth 117,600 times (12 towels, 245 day, 40 years).  And each time they bring their hand to their mouth, 13% of what is on the hand comes off the hand and is consumed.

Where did Gradient come up with that number of 13%? That number is half the amount of soil a child consumes if all of the soil consumed came from the hands.  Read my post on this for more information on how Gradient derived this.

Why Gradient chose to use a child's hand and not an adults when calculating this transfer efficiency can only be answered by them.  Had they used an adult's hand, the HTE would have been 6%.  But that's still based on a faulty premise that all of the soil consumed by the adult came solely from the hands.

A better - or more sound - method would have been to use CalEPA's hand to mouth calculation (see post). Once again, why Gradient made up their own method for deriving an HTE can only be answered by them.  It does seem odd though, that they would use CalEPA's MADL and NSRL thresholds and not their methodology.  Peculiar.

Based on this, I'll call the "HTE" part of Gradient's calculation "Busted" as well:

And what about Kimberly-Clark's claim:

"Just how far did they exceed these limits? Here’s one example: the study found that a worker using a typical number of shop towels per day can be exposed to up to 3,600 times the health-based exposure limit set for lead." (4th page)

What does that mean, "3600 times?"  That health based exposure limit is the CalEPA MADL for lead, and had Kimberly-Clark been more forthcoming, they would have let the worker know that the value CalEPA uses is based on health of the fetus and is set 1000 times lower than the no observable health effects level described in the literature.  See this post and this post.

What Gradient should have done was calculate potential exposure risk using EPA's method for determining the clean up level of lead in soil, which is also based on the health of he fetus (post).  EPA's "preliminary remediation goals (PRG) are based on the amount of lead intake from soil that would bring about a level of lead in the blood harmful to the fetus. At that blood level concentration of lead, Gradient's intake value exceeds the EPA 'safe" level by 3 times.  Using the more appropriate 6% HTE (based on an adult hand), the exceedance ratio is 1.3 - using all the other assumptions and values used by Gradient.  3600 times higher refers to a value used to determine when signage and notification is not required by a business.

So I'll call Kimberly-Clark's claim in their brochure:

There you have it.  I've shown you theirs...and I've shown you mine.

Should you believe Kimberly-Clark when they state:

Heavy metals have been found in laundered shop towels in amounts that exceed health-based exposure guidelines related to cancer and non-cancer related health issues, like reproductive and developmental effects.

Should we still conclude that laundered shop towels pose a risk to workers?

You have read my posts and can easily check my sources and work my calculations.  Here is what I think, based on what my research into this matter has shown me:

Which leads me to only one conclusion - Gradient's study and conclusion is....

Next post: Laundered Shop Towels: 15 - Why I spend the effort


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Laundered Shop Towels: 13 - 100,000 workers using 12 laundered shop towels per day

If 100,000 workers using 12 laundered shop towels for 245 days per year for 40 years consumed 15 ug of lead each and every time the 12 towels were handled, we would expect to see one additional cancer as a result of that exposure.

If 100,000 worker using 12 laundered shop towels for 245 days per year for 40 years consumed 168 ug of lead each and every time the 12 towels were handled, we would expect to see how many additional cancers as a result of that exposure?

In my last post, I showed the formula CalEPA uses to calculate the NSRL - No Significant Risk Level - value of 15 ug/day of lead.  Here is how the CalEPA calculates that risk of one in 100,000 for the NSRL:

Source  Page 15

Doing a bit of algebra - I think that's what it's called - we switch the variables around so we can solve for "R"-  which is the cancer risk.

• R = (0.168 mg * 0.047 mg/kg-day-1) / 70 kg = 1.1E-04 or 1.1 in 10,000 or 11 in 100,000.

See!  11 times, just like Gradient said in Table 8a!

(Gradient 2011 Report)

Yes, but think about it for a minute....

What that ratio of "11" represents is this situation:

• 100,000 workers using 12 laundered shop towels per day for 9,800 days (245 * 40)
• 11,760,000,000 laundered shop towels containing an average of 100 mg/kg of lead
• 100,000 workers placing their hand to their mouth 11,760,000,000 times

Let those numbers sink in...check my math, I could have made a calculation error.

Notice what it would take to get 11 additional cancers in 100,000 workers for 100 mg/kg of lead?  11.8 billion laundered shop towels used, 11.8 billion times the worker's hand contacts the mouth.

Here is what ATSDR says about exposure and cancer, just so you can see that my logic is sound on this.

ATSDR extensively reviews literature linking exposure to compounds with cancer. The lowest level of exposure documented to cause any form of cancer in humans or animals is reduced by a safety factor of 100,000, which simply means if 100,000 people were exposed to this amount ofcompound 24 hours, everyday of their lives for 70 years, 1 extra cancer case might be expected above the normal rate of cancer in that population, i.e. 1 case in 100,000 above normal. (1)

The population here is workers.  So if you can honestly envision 11.8 billion laundered shop towels containing and average of 100 mg/kg of lead after being washed in soap and hot water, then dried under heat, a plausible situation, well I've got a bridge for you to buy!  And if you can see each of these 100,000 worker's bringing their hand to their mouth 11.8 billion times, well I've got land in Florida to sell you as well!

That ratio of "11" times higher than the NSRL uses Gradient's values and equation!

What happens if I use lead intakes calculated using more sound values?   In a previous post I made a case for throwing Gradient's equation out...

...and replacing it with CalEPAs hand to mouth equation.

Guideline for Hand-to-Mouth Transfer of Lead through Exposure to Consumer Products: 2011

The CalEPA equation calculates the daily total intake.  The intake is divided by 70 kg (weight of an adult) to derive a mg/kg-day intake value. (See post)

• Intake = 0.0013 mg/cm2 x 19 cm2 x 0.5 x 1.5/hour x 8 hours =  0.148 mg per work day
• 0.148 mg per day = 0.148 / 70 kg =  0.0022 mg/kg-day Intake or 2.2E-03 mg/kg-day

Using Gradient's EF of 245 days, an ED of 40 years, and an AT of 25,550 days (70 years) we would modify the CalEPA calculation as follows:

• (0.0022 mg/kg-day * 245 days/year * 40 years) / 25550 days = 8.4E-04 mg/kg-day
• 0.00084 mg/kg-day * 70 kg = 0.06 mg-day

Using CalEPA's hand to mouth intake formula, a worker using twelve laundered shop towels per day for 40 years would have a lead intake of 0.00084 mg/kg-day over a 70 year period of time.

Placing that intake into CalEPA's cancer risk calculation, the "R" cancer risk would be:

• R = (0.06 mg * 0.047 mg/kg-day-1) / 70 kg =  4 in 100,000.

Using Gradient's values - with the exception of the hand to mouth transfer rate - the excess cancer risk from using 12 towels per day containing 100 mg/kg of lead for 40 years is 4 additional cancers per 100,000 workers.

So whatcha think?  

Is 11.8 billion shop towels with 100 mg/kg lead a plausible scenario?  Will 100,000 workers place their hand to their mouth 11.8 billion times?  Is this really an exposure situation where one would ask a worker who is using a laundered shop towel:  "Why risk it?"

Source

As I stare into that baby's eyes I have no problem telling that dad, go ahead and use laundered shop towels. If lead is the baddest metal they found, go ahead and use a laundered shop towel all you want.  Heck, you can even use it while drinking apple juice!

Next post: Laundered Shop Towels: 14 - Should you believe them?

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Laundered Shop Towels: 2 - A flaw in the model

Here is what Gradient concludes in their 2011 Study:

Metals on shop towels can get onto hands and then potentially be ingested, as evaluated in the 2003 report and as developed in this evaluation.

For typical use of 12 towels a day per person, exceedances of Proposition 65 limits, and US EPA and ATSDR toxicity criteria may occur for antimony, beryllium, cadmium, cobalt, copper, lead, and molybdenum.  Calculated intakes for these metals were up to 3,600-fold higher (based on maximum intake concentration for lead) than their respective toxicity criterion.

Notice the word "can."  Let's look at how that word is defined by Websters:

"be physically able to."

That word "can" is important because it is the basis behind their model, which is as follows:

• Laundered shop towels contain heavy metals - even after they have been washed.
• The heavy metals in/on the shop towels can get onto the hands.
• The heavy metals on the hand can get into the mouth.
• The amount of heavy metals entering the mouth may exceed California Proposition 65 limits, and EPA & ATSDR toxicity criteria.

Here is the graphic from the 2003 Gradient Study on laundered shop towels - their model:

2003 Gradient Study

There are two important assumptions made here by gradient.

1. The metals on/in the towel can be dislodged onto the hand
2. The metals on the hand will be transferred to the mouth each and every time a towel is handled.

These two assumptions are very important in evaluating the validity of the intake values used to determine the exceedance with Proposition 65, EPA, and ATSDR toxicity criteria.

For these posts I am only going to focus on lead since that is the one heavy metal with the greatest exceedance.

Let's look at the first assumption: The metals on/in the towel can be dislodged onto the hand.  Gradient is basing this on the findings from their 2003 Study on the same topic.  Here is what they base this transfer from the towel to the hand on:

For ingestion exposure via hand contact with the laundered shop towels, we estimated transfer of metals from laundered shop towels to hands based on empirical data regarding transfer of pesticide residues from surfaces to hands, data regarding the number of laundered shop towels used daily per person, as well as an estimate of the percentage of the towel surface area that would contact the hand.

The amount of metal transferred to the hand that could ultimately be ingested was based on a hand-to-mouth transfer efficiency, using methodology developed by the U.S. Consumer Products Safety Commission (CPSC) for evaluating exposure to dislodgeable residues on treated wood surfaces

Gradient is basing their intake values on a model that assumes the lead concentration they determined to be present in shop towels can be dislodged from the towel onto the hand.

It is reasonable here to challenge this assumption based on the following:

Is it reasonable to assume that a shop towel that has been washed in hot water, with a detergent, then dried under heat, can dislodge lead onto the hand?

Gradient is basing their model on a CPSC study that looked a dislodgeable reside and used the same value of dislodgement in their calculation for the "Towel to Hand" transfer rate.  You can read how Gradient justifies their value of "13%" by reading the paragraph on towel to hand transfer on page 9 of the 2011 Study.  Here are the studies they looked at:

2011 Gradient Study

The question is (and I think it appropriate) should a comparison be made using transfer rates involving pesticide residue and dislodgeable residues with what could come off of a towel that has been washed with soap, rinsed, and heat dried?

The basis of their model is that heavy metals on the rag can get onto the hand and into the mouth.  If the heavy metals are not transferred to the hand, exposure took place but transport into the worker did not.

Without the ability to show that a towel - washed in soap and dried under heat - can transfer the lead onto the hand, the model is not appropriate and the intake values calculated are erroneous.

This could have, with relative simplicity, been evaluated by Gradient.  If we are looking at the lead coming off the towel, soaking the towel in water or a saline solution would give some idea of the amount of lead that could be dislodged onto a wet hand.  Additionally, the towels could have been handled aggressively by a test subject and the hands swabbed to see what, if any, residue came off the towel.  Both of these methods would have derived a value of lead that would be available to be transferred to the mouth.

Just because you have exposure does not mean you will have a health risk. There must be intake.  In order for the Gradient model to be valid, the lead must be transported from the towel to the hand.  They have not shown this to take place, only showing that dust and pesticide reside can be transported from a soft surface to the hand.

I cannot agree with their findings based on this one condition alone.  But that would make for a pretty short series of posts if I stopped now.  And besides, where's the fun in that?

So let's assume that the necessary assumption that the metals can be transported from the towel to the hand does, indeed, take place.  The next question becomes" Is the transfer rate of 13% of the lead from the towel to the hand valid?

Once again we are back to square one.  If we assume that the towel can transfer the lead to the hand, then we also have to assume that the transfer rate is similar to that found with dust and residue based on the studies Gradient looked at (see Attachment A graphic above).  The value of "13%" was based on:

Several studies looked at multiple compounds and found different transfer efficiencies depending on the compound being evaluated.  Within each study, we averaged the various relevant transfer percentages; they were averaged separately for studies conducted with dry vs. wet hands.  In reviewing the current literature, transfer to moist hands (average 20%) is four times higher than transfer to dry hands average 5%).  Workers are likely to come into contact with RSTs with both dry and moist hands.  Therefore, we averaged the transfers to moist hands and dry hands separately before averaging the two averages, to equally weight the results from both categories.  This value (13%) is more than double the transfer efficiency used in the 2003 evaluation (5%). (1)

In order to move on, one must agree with Gradient's assumption that 13% of what ever is on the washed towel's surface can be transported onto the hand - based on the surface area of the towel the hand comes in contact with.  If you can live with this assumption, then their model holds and a "Towel to Hand" transfer rate (Tt/h) holds true as well.  If you find this particular assumption a bit hard to accept, well you can ignore the rest of these posts and throw their study into the trashcan.  In order for the assertion that lead exceeds an amount by 3600 times, the lead MUST leave the towel and attach to the hand.

That 13% transfer rate is critical in determining the intake they use to compare against Proposition 65, EPA, and ATSDR toxicity criteria.

I contend that the laundered shop towels will not transfer any heavy metals to the skin under normal shop towel use.  Additionally, I contend that any dislodgeable heavy metals, such as lead, that remains on the towel after washing in soap and drying would transfer onto the skin at a rate well below 1%.

Of course I have nothing to prove that contention with.  So it's Bowman "0", Gradient "1"

But not for long.  I have this little thing called "statistics" to help me out in my contention that there is no additional risk to a worker who uses a laundered shop towel.  Unless they were to maybe eat twelve towels a day....but that's for another blog post.

Next post: Laundered Shop Towels:  Is it mean to ask for a median?

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Seven Deadly Sins: I'm not seeing it.

It starts like this...

Source

Which leads to this...

Source

Which leads folks to conclude that there must be something wrong since a warning has been issued.

"How in god’s name can the oil industry dump sh*t in our drinking water and not tell us what it is?" shouted Alan Hofer, who lives near the center of the sites being investigated by the EPA. (1)

Which causes this to happen...

Source

1000 cases of contamination have been documented in Colorado alone?  In the week that I started writing on this topic, I have found two cases, one in the Barnett Shale (see post) and one in Pavillion, Wyoming, for which sampling data is available, and that was with a bit of effort to locate.

So it starts with a complaint, an investigation, and then a recommendation.  In the process it leads to this:

"It starts to finger-point stronger and stronger to the source being somehow related to the gas development, including, but not necessarily conclusively, hydraulic fracturing itself," said Nathan Wiser, an EPA scientist and hydraulic fracturing expert who oversees enforcement for the underground injection control program under the Safe Drinking Water Act in the Rocky Mountain region. The investigation "could certainly have a focusing effect on a lot of folks in the Pavillion area as a nexus between hydraulic fracturing and water contamination." (2)

On the surface, it would appear that contamination found in the well water used for drinking by the good folks in Pavillion, Wyoming, is proof that the oil and gas drilling and fracturing has caused harm.  But I have been in this business for a long time to know that contaminated groundwater comes from a number of sources, all of which are present in the town of Pavillion.

• Underground fuel tanks
• Septic tanks
• Spills
• Open pits
• Natural

When investigating contamination a "Conceptual Site Model" is produced to look at all the possible sources.

Source

"Pointing fingers" is what we try to avoid.  It is easy to blame oil & gas wells since there are so many of them in the area (211 active gas wells, 30 plugged and abandoned wells, and 20 wells identified as “shut-in.” [2])

Again, though, on the surface it looks pretty evident as to who the culprit is, which is why anti-gas drilling folks like to use reports such as this and this, as evidence to prove how bad hydraulic fracturing is to public health and the environment.

I have read all of the reports issued by the EPA on their findings regarding groundwater contamination in Pavillion, Wyoming. I've tried to be as objective as I could in all of this but I am just not seeing the problem with hydraulic fracturing that is being put forward by groups like Earthworks and ProPublica.

Here is why.

First:  Without knowing the condition of the water before fracing has occurred it is impossible to say what contaminants were introduced by the procedure.

Second: With over 211 active wells in the Pavillion area, if hydraulic fracturing was introducing chemicals into the groundwater you would see a whole bunch of chemicals in the groundwater.  Look at this map of the wells in Pavillion.

Those blue dots are oil and gas wells.  The yellow/orange dots are where the wells where samples were collected.  If hydraulic fracturing was by its nature dangerous to groundwater you would see contamination of fracturing fluids in the groundwater.

This is not to say that drilling could - or does not - contribute to contamination.  Any activity involving chemicals has that potential.  Just like any airplane has the potential to crash, airplanes by their nature fly and continue to fly day in and day out.  Would we condemn all air travel as unsafe because a plane crashes?  Same can be said with hydraulic fracturing.  The hydraulic fracturing procedure, when performed correctly ("best practices"), does not pose a threat to public health through contamination of groundwater.

That's kind of a bold statement to make.  But like the title of this post says, I'm not seeing it.

But what about the contamination found in the wells of Pavillion?  There are a number of reasons possible, with the most likely being oil and gas operations in the area.  Huh?  Let me be clear on this.  Hydraulic fracturing by itself does not appear to cause or contribute to groundwater contamination.  Drilling operations using industry best practices appear to be keeping contaminants out of ground and surface water.  Operators who use industry best practices are not the concern.  It's the companies who left the "37 pits (which formerly held drilling fluids) [that] have been identified in the area" who are most likely responsible for contaminating the shallow surface water that mixes with the drinking water source.  Those, along with septic tanks and storm water runoff, have contaminated the drinking water aquifer - not hydraulic fracturing fluids.

The current operator, Encana, is now responsible for these pits.  Older properties, especially those with environmental concerns are referred to as "legacy properties" and are cleaned up and closed to meet state, federal, and industry standards.

So yes, there is contamination in the drinking water wells, but not to any significant health concern other than taste and odor.  And no, in spite of what ProPublica contends, will not "have a focusing effect on a lot of folks in the Pavillion area as a nexus between hydraulic fracturing and water contamination (3)."  Go up and read the ATSDR recommendations.

In spite of the anecdotal evidence presented by Earthworks and ProPublica, I'm not seeing it.  I'm being as objective here as I can.  Here, in a nutshell, is why:

If hydraulic fracturing was causing contamination to drinking water at any significant frequency, then the more wells drilled would mean the more drinking water wells contaminated and/or the higher the concentration of chemicals.  The fact that:

TIC analyses indicate two compound types that occur in several wells and might not be attributable to well components: adamantanes and 2-butoxyethanol phosphate. Adamantanes are hydrocarbons that occur naturally in crude and gas condensate; they could be used in hydrocarbon fingerprinting analyses to determine if oil and gas production is impacting wells.  2-butoxyethanol is found on the EPA Study List of Drilling Fluid Compounds (EPA 2008) and could react with naturally occurring phosphates to create 2-butoxyethanol phosphate.  (4)  

Would also mean that it, and other fracturing fluids would show up in water wells where drilling takes place. In simple terms, the level of contaminants and/or number of contaminated drinking water wells would be proportional to the number of hydraulic fracturing that has taken place in an area if drilling was inherently harmful to underground sources of drinking water.

I'm not seeing it.

Here is what ProPublica states: (5)

Thanks in large part to hydraulic fracturing, natural gas drilling has vastly expanded across the United States. In 2007, there were 449,000 gas wells in 32 states, thirty percent more than in 2000.

Almost half a million gas wells and yet ProPublica reports:

The [Pavillion] study, which is being conducted under the Environmental Protection Agency’s Superfund program, is the first time the EPA has undertaken its own water analysis in response to complaints of contamination in drilling areas, and it could be pivotal in the national debate over the role of natural gas in America’s energy policy.

Almost half a million gas wells and only one study. Now go back up to the top of this post and read the ATSDR recommendations.  Now go read the ATSDR report.  Why are they recommending not drinking the water?  Because of the contaminants of concern found in the 41 Pavillion drinking water wells sampled.  And what were those CoCs?

Source

 
That's right, the COCs are sodium, fluoride, sulfate, magnesium, selenium, nitrate, and one well with TPH.

I'm not seeing it because there is nothing to see.

But ProPublica says:

Of particular concern were compounds called adamantanes, a natural hydrocarbon found in gas that can be used to fingerprint its origin, and 2-BE, listed as a common fracturing fluid in the EPA’s 2004 research report on hydraulic fracturing. (6)

I'll cover that in a future post, right now I'm going to switch gears and talk about a recent paper that was presented at the 2011 AHMP Conference in Austin.



Next post: Laundered Shop Towels: Making a mountain out of a pile of clean rags.




http://www.epa.gov/region8/superfund/wy/pavillion/

http://www.epa.gov/region8/superfund/wy/pavillion/PavillionAllTables.pdf


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