RfD and Consensus...Part 1

I recently added a section called "consensus" to the Wikipedia page on "Reference Dose."

Yeah, that's what I do for fun.

I was looking for some supporting information to help me put my AHMP presentation together and came across an EPA memo titled:

WASHINGTON STATE DEPARTMENT OF HEALTH’S EVALUATION OF EPA’S PERCHLORATE DRINKING WATER PRELIMINARY REMEDIATION GOAL (PRG).

Back to the question of "safe" is it?  Here is what the memo says about perchlorates found in the Deep Creek area in the state of Washington:

There are no federal or Washington State drinking water standards for perchlorate. However, EPA uses a 24.5 ug/l perchlorate drinking water equivalent level (DWEL) as a preliminary remediation goal (PRG). 

In looking at how perchlorates enter into the human receptor, EPA has decided that the predominate way would be through drinking Deep Creek water which has perchlorate contamination.

Though there is no MCL - "maximum contaminant level" - for perchlorates, the EPA uses the DWEL - "drinking water equivalent level" to establish a "safe level" of perchlorates in the water that may be consumed.

The DWEL is the basis for establishing the MCL, so this is a reasonable approach   The DWEL is calculated for non-carcinogens and uses the reference dose (RfD).

The DWEL, therefore, is defined by EPA as:

"a drinking water lifetime exposure level, assuming 100% exposure from that medium, at which adverse, noncarcinogenic health effects would not be expected to occur."

When the EPA establishes the "safe" level of a contaminant in drinking water it bases it on the "lifetime health advisory" derived as follows:

The Lifetime HA for the drinking water contaminant is calculated from its associated Drinking Water Equivalent Level (DWEL), obtained from its RfD, and incorporates a drinking water Relative Source Contribution (RSC) factor of contaminant-specific data or a default of 20% of total exposure from all sources. 

As you can see, the RfD is the foundation upon which all these "safe" levels are derived.

Where we have confusion is when we compare a concentration in one media - such as apple juice - with the regulatory level established for drinking water.  Without an understanding of the RfD for non-carcinogens and risk factors for carcinogens, comparing what is found in the apple juice to what is acceptable in drinking water will make the apple juice appear to be tainted.

Case in point.  From the Dr. Oz Website: 

In 2006, the Environmental Protection Agency (EPA) enacted a stringent health standard with respect to arsenic levels in drinking water, stating concentrations should not exceed 10 parts per billion (ppb). Interestingly, the actual goal for arsenic exposure from drinking water, what is termed the maximum contaminant level goal (MCLG), is zero ppb. That bears repeating – the goal is no arsenic in our drinking water. The 10 ppb level is simply as close as we can reasonably get considering our natural exposure to arsenic in the environment and other limitations. At that level, almost all experts agree our drinking water is quite safe.

So if our drinking water is "quite safe" why say this right after?

Shouldn't the same goal or, at the very least, similar science-based exposure guidelines, be in place for the juices we commonly give to our children?

It is, in my opinion, due to a disconnect in how a "safe" level is derived, a disconnect on how the the RfD is calculated, and a disconnect in how a "goal" and "risk" are different.

Let's look at benzene, for example. 

Source

Now benzene is kind of an odd bird, which makes it a good example on how this works.

Because benzene is considered a human carcinogen, there may be some degree of carcinogenic risk even below the MCL. Based upon EPA calculations, the EHP estimates that drinking water containing 5 ppb benzene would be associated with an increased lifetime risk of cancer in the range of between two and eight in one million (2 to 8 excess cancer cases in 1,000,000 people exposed). This estimate is based on a daily intake of two liters of water per day for 70 years. (1)

For this reason - carcinogenicity - benzene is given an MCLG of "0":

MCLG: Maximum Contaminant Level Goal. A non-enforceable health benchmark goal which is set at a level at which no known or anticipated adverse effect on the health of persons is expected to occur and which allows an adequate margin of safety. (2)

The EPA has also developed a toxicity value (Reference Dose or RfD) for non-cancer effects based on a human study.

A decrease in cells which are vital to immune system function (lymphocytes) was the most sensitive effect of several measured blood parameters. The adult drinking water equivalent level (DWEL) for this RfD is a benzene concentration in water of 140 ppb - 0.14 mg/L - ppm.

The benzene DWEL, which is the "lifetime exposure level assuming 100% exposure from that medium," is 0.1 mg/L.  This is based on the following formula:

Source

Plugging the RfD into the formula, we get:

DWEL (mg/L) = (0.001 x 70) / 2 = 0.14 mg/L = 0.1 mg/L or "ppm"

Because we know that there is a risk of cancer, the MCLG is set at zero.  Because we know that zero is unattainable, and we know that there is also a non-cancer risk, we can set the legally enforceable MCL for benzene at 0.005 mg/L or 5 ppb.

When Dr. Oz posts:

Interestingly, the actual goal for arsenic exposure from drinking water, what is termed the maximum contaminant level goal (MCLG), is zero ppb. That bears repeating – the goal is no arsenic in our drinking water. The 10 ppb level is simply as close as we can reasonably get considering our natural exposure to arsenic in the environment and other limitations. At that level, almost all experts agree our drinking water is quite safe.

He is acknowledging that the current standard for arsenic is safe even though the goal is zero.  This is the same with benzene and all the other carcinogens.  We want zero, it is safe at the MCL.  Why is it safe?  Because the MCL and MCLG is set lower than the DWEL:

The MCLG is then derived by considering other known or potential sources of exposure, using the relative source contribution (RSC) factor.

• MCLG (mg/L) = DWEL x RSC

The RSC from drinking water is based on actual exposure data, or, if data are not available, a value of 20% is assumed for effects based on lifetime exposure. This allows 80% of the total exposure to come from sources other than drinking water, such as exposure from food, inhalation, or dermal contact. For the few MCLGs based on adverse effects related to exposure in children, an RSC of 100% was usually applied because the source of exposure for the critical study was drinking water. However, in more recent assessments, even when actual data from other sources are available, EPA uses a maximum RSC value of 80% to allow for potential unidentified sources. (3)

In other words, for a chemical such as benzene, a non-cancer RfD is established that generates a DWEL of 0.14 mg/L.  That DWEL is then multiplied by about 0.8 (80%) to compensate for all the other ways the chemical gets into the receptor.  For benzene, however, the MCLG is set at zero and the MCL - the value set as close to the MCLG as feasible using the best available analytical and treatment technologies and taking cost into consideration - is set at 0.005 mg/L.

• We consider the DWEL safe because it is based on the RfD.
• We consider the RfD acceptable because it is based on "an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime." (3)
• The MCL is less than the DWEL
• The MCLG can be less than the MCL and is set at "zero" for carcinogens.

How low can you go (/queue music)

All the way to zero.

Which brings me back to my original question of the RfD.  If the RfD is the foundation, how confident are we in the number we are using?  As the EPA writes:

A change in the RfD could lead to a change in the MCLG and thus possibly also in the MCL. (3)

A good read on all of this can be found here.

Next post: RfD and Consensus...Part 2


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Reference Dose: The foundation of Risk

I am getting ready to prepare my presentation "Apples, Arsenic, and Risk" for the upcoming 2012 AHMP conference in Alaska September 9 -13 in Anchorage. I wrote a lot on this topic in previous posts and need to pare it down (pun intended).

One of the most difficult parts of preparing a presentation is finding the starting point from which to tell your story. I can't just stand up there and whine about Dr. Oz and Chuck Norris. Nor can I present a bunch of facts and figures to prove my case. Boring. I get one shot at this, and I need to make it work.

So, where to start and what to build is where I am in July. I know the story's end, I know the moral, how do I tell it for Environmental Health Safety Professionals who depend on the very information I am going to present but know little about how it works without being condescending, preachy, or uninteresting.

Sure they understand risk, and regulatory compliance concentrations, and clean up levels, but do they understand why other than that is what they are told - or - what some formula spits out?  Why do we set the limit at 10µg/L for arsenic in our drinking water, 5 mg/L for the level of arsenic in our waste, 0.018 µg/L for ambient water quality criteria, 0.3 mg/L for arsenic in storm water, and 23 µg/L for arsenic in our fruit juice?

We are dealing with the same chemical, yet depending on where we find it, the values assigning the risk change.  As well it should. It is deemed "safe" if it is below the threshold depending on where we find it and what receptor (animal/plant/human) will be exposed to the arsenic, how much (dose), and length of time exposed (acute/chronic).

We draw a line in the sand and say "safe" or "presents a risk."  That line in the sand is drawn from a formula that looks at the length of time exposed as well as how the chemical will enter into the receptor. Since I am interested in protecting human health, the receptor will be based on that.

That formula - for humans - is based on the concept that there is a daily level at which we do not expect harm to take place over a lifetime.  This is what we call the "reference dose" or "RfD."

RfD: An EPA estimate, with uncertainty or safety factors built in, of the daily lifetime dose of a substance that is unlikely to cause harm in humans.

The foundation for risk for all chemicals that are suspected to cause harm to human health are based on this concept.  You must accept that concept - that there is an amount that we can consume every day for a lifetime - of a risk that is unlikely to cause harm in humans.

I've discussed this concept a number of times in previous posts.  This is how we do it in the United States. We set thresholds based on a formula of what we think might take place using a value that we have determined is a "safe" level if there is uptake into the receptor.

When the FDA says that 23 µg/L for arsenic is the maximum "safe" level in our fruit juice it is basing that level on the amount of juice to be consumed that would be put into the human receptor.  Therefore, if consuming juice - normally - over a lifetime, it would be “unlikely” to cause harm from arsenic.

When folks like Dr. Oz, Consumer Reports, and Chuck Norris compare the amount of arsenic found in apple juice to the amount of arsenic deemed safe for drinking water - the MCL - they are forgetting that the MCL and FDA concentration deemed "safe" are based on the same foundation; the RfD.  What is different in these two values is what is considered to be "normal" uptake. We drink more water than apple juice therefore we can consume more arsenic in the apple juice and remain safe.

Why are the two values different?

Because the RfD states that there is "daily lifetime dose of a substance that is unlikely to cause harm in humans."  Consume less than the RfD and there will "unlikely" be harm.  It is all about the RfD and the dose that delivers that RfD, and the length of time you will be exposed to that dose.

Chemical Exposure is similar to wealth, only the inverse.  If it takes $2.00 to buy a cup of coffee and you have no money or $1.99, you are in the same predicament - you will have no coffee.  Same goes with chemicals.  If the RfD concept is to be our foundation, then we have to move away from "less is better" and move toward a threshold based on uptake into the receptor.  Below that concentration in the matrix we are exposed to, we are fine.

Which brings us to another question.  If the foundation is the RfD, then how confident are we in the RfDs we have established?


Next Post: RfD and Consensus


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Apples, Arsenic, and Risk - Part 20: It is - and always will be - about the dose.

"All substances are poisons; there is none which is not a poison. The right dose differentiates a poison…." Paracelsus (1493-1541).

I hate to keep whipp'n that dead horse, but that's what is missing in these discussions on the arsenic that has been found in apple juice.  Let's look at what Russell H. Greenfield, MD says on the Dr. Oz website regarding arsenic in apple juice:

The 10 ppb level [arsenic MCL for drinking water] is simply as close as we can reasonably get considering our natural exposure to arsenic in the environment and other limitations. At that level, almost all experts agree our drinking water is quite safe.

Shouldn't the same goal or, at the very least, similar science-based exposure guidelines, be in place for the juices we commonly give to our children?

What goal would Dr. Greenfield want to see?  Consumer Reports thinks "the standard should be 3 ppb" and the FDA, on December 15, 2008, issued a memo on research they had done regarding arsenic in the juice:

In conclusion, the chronic consumption of apple juice products containing over 23 µg/L (ppb) inorganic arsenic would represent a potential health risk.

The FDA in 2008 says 23 ug/L is the maximum total arsenic in apple juice that would not pose a potential health risk.  That 23 ug/L is based on the actual dose a child would take in (uptake) based on how much apple juice is normally consumed.  That's the way it is supposed to be done, that's the way the FDA did it in 2008, so why does Consumer Reports, Dr. Oz, Dr. Greenfeild, and good ol' Chuck Norris think the FDA has dropped the ball on this?

Let's look at how the FDA came up with that:

Consumption estimates were based on average consumption over two days for individuals who consumed apple juice (eaters only) and were calculated for two population groups: Males and females (MF) from birth to 2 years of age and MF 2 years of age and older.  

The estimates included foods codes for products that were 100% apple juice, including infant apple juice; juice blends that included apple juice as an ingredient were not included.

Relying on results of the more recent 2003-04 NHANES, consumption of apple juice by MF birth to 2 years was estimated to be 16.7 and 36.2 g/kg body weight/day at the mean and 90th percentile, respectively, compared with previous estimates of consumption for all juices of 19.1 and 43.4 g/kg body weight/day.  

For MF 2+ years, consumption of apple juice was 6.0 and 12.9 g/kg body weight/day at the mean and 90th percentile, respectively, compared with the previous estimates for all juices of 6.0 and 13.0 g/kg body weight/day. 

Since consumption estimates from both surveys are similar, the level of concern (LOC) that was calculated for the previous assessment (23 ug/L, or ppb) can be applied in the case of apple juice. 

The 23 ug/L is for inorganic arsenic and is based on the dose a child would take in drinking apple juice.  The reason that number is higher than the 10 ug/L for arsenic in drinking water is that the dose from drinking water is estimated to be 20 ug at the 10 ug/L MCL.  This is because the MCL is based on drinking 2 liters of water per day.

What that means is this:

A 30 kg child (66 pounds) drinking 36.2 grams of apple juice per kilogram of body weight consumes 1086 grams of apple juice which is 1.1 liter.  That's the amount that will deliver the dose of arsenic.  That quantity of apple juice is the 90th percentile highest amount of apple juice estimated to be consumed.  A child drinking that much apple juice would receive 25.3 ug of total arsenic at a maximum FDA acceptable concentration of 23 ug/L.  The highest anticipated "daily dose" for this 30 kg child is 25.3 total arsenic from drinking apple juice.

For drinking water, that same child would consume 2 liters of water at the MCL of 10ug/L for a total daily dose of 20 ug.  That's what the EPA considers a safe dose.

So normal apple juice consumption will see less than 25.3 which is equivalent to what would be consumed if drinking two liters of water at the MCL for arsenic of 10 ug/L.

Drinking apple juice at a total arsenic concentration of less than 23 ug/L is the same as drinking water at the MCL 10 ug/L for arsenic.  The dose is based on the amount consumed per unit of fluid.  You drink less apple juice per day then water so apple juice can contain more ug/L of arsenic and still be considered safe.

Sounds counter intuitive, especially when you are talking about toxicity. We are concerned with the amount of the toxin - dose - received not the amount of the toxin found.  This is why you cannot compare the MCL for drinking water to the concentration of arsenic found in apple juice.  The MCL has been established for a dose based on consuming 2 liters per day.  You therefore need to compare the dose the receptor is anticipated to receive with the maximum dose - mg/kg body weight - established as "safe."

This is how it works.   It is - and always will be - about the dose when describing toxicity.

23 ug/L of total arsenic presents less dose than a drinking water MCL of 10 ug/L and is based on the assumptions of how much of each is consumed.  As long as the daily dose does not exceed 20 ug for a 70 kg person - or - 0.28 ug arsenic/kg body weight - we will not expect to see any short term or long term potential health risks over a 70 year lifetime!

That's why Dr. Greenfield states on the Dr. Oz website:

At that level [10 ug/L], almost all experts agree our drinking water is quite safe.

Even ol' Chuck Norris agrees with that, although I am pretty sure he has no idea that he does:

At the very least, the FDA should not allow more arsenic in apple juice than it allows in Americans' drinking water.

"Not so fast!" Yells our hero Chuck Norris, "tell them about the cover-up!"  No, Chuck, you tell them:

Tragically teetering on a huge U.S. health cover-up, the FDA posted eight "previously undisclosed test results" for apple juice samples from across the country that had arsenic levels that superseded even its own "level of concern" for inorganic arsenic. Two of those eight samples had an arsenic level of 27 ppb. One had a level of 42 ppb, and two others were at 45 ppb.

Tragically teetering?  Oh chuck, you are such the drama queen!  Here is what the FDA discloses in another memo dated November 21, 2011:

In July 2011, we issued an Import Bulletin to significantly increase the number of juice products sampled and analyzed for arsenic under the Toxic Elements program. Importantly, of the 74 samples collected as a result of this import bulletin, all were from China. Of these:

• 1 sample was above 23 ug/L total arsenic
• 1 sample was 10 ug/L total arsenic
• 2 samples were 11 ug/L total arsenic
• The remainder, (almost 95 percent), were below 10 ug/L total arsenic.

 Compare that to the arsenic levels reported by Consumer Reports.  But wait, there is more:

[we] now have a total of 160 apple juice samples collected from 2005 to 2011. These include 70 samples posted by FDA on September 27, 2011 and an additional eight samples that were part of this data set. These eight samples, which had not been previously posted, all have total arsenic levels greater than 23 ppb and were in the process of being further verified.

The data set also includes 82 new samples collected in the latter part of 2011 for which the data have just now become available. Of these 160 apple juice samples:

• Almost 88 percent had fewer than 10 ppb total arsenic
• 95 percent had total arsenic levels below 23 ppb total arsenic.

Okay...anything else from the lyin' stinkin' covern' up FDA?

Similarly, from the Total Diet Study program:

• Nearly 77 percent of the 134 composite apple juice samples tested from 1991 to 2009 (including baby food and general consumption samples) had total arsenic levels below 10 ppb.
• 95 percent had total arsenic levels below 23 ppb.

Cover-up?  C'mon Chuck, this ain't nothin' different than what Consumer Reports found.  How many samples do you need to have analyzed to get you to understand that we're not in any danger.  I mean, really Chuck?

Until then, tides of arsenic will continue to flow from foreign produce fields into American bloodstreams.

Tides of arsenic?  Chuck, Chuck, Chuck...

I have written 20 posts on this topic.  I have tried to show how many of these statements from Consumer Reports, Dr. Oz, and Chuck Norris are not substantiated.

As much as I believe we should consume food that is grown locally and with little to no pesticides, I cannot say that the reason for doing so is because foreign grown apple juice contains more arsenic than American. The Consumer Reports data shows that it does not.

I cannot support lowering the inorganic arsenic level to 3 ug/L.  There is no evidence to support that.  None.  Period.  The FDA's level of concern of 23 ug/L appears to be prudent, justified, and can be supported by the same data used to produce the drinking water MCL for arsenic at 10 ug/L.  And at that level, one more time courtesy of Dr. Greenfield:

"almost all experts agree our drinking water is quite safe."

It is - and always will be - about the dose received and not the amount detected.  You cannot compare the ug/L established for water with the ug/L found in apple juice.  This is no different than comparing a one pound ingot of lead with a one pound feather pillow.  They both weigh the same but one of them you would not want dropped on your head.

Let me sum it all up.  Here is how it works, it only works this way.

If little 2 year old Johnny weighs 66 pounds (30 kg) and he drinks the upper most amount of apple juice the FDA research found, 1.1 liters (36.2 g/kg body weight/day), and that apple juice contains the highest amount of total arsenic the FDA says is safe - 23 ug/L - he would consume 25.3 ug of total arsenic each day he drank 1.1 liters of apple juice.

That's a pretty big two year old and that's a lot of apple juice to drink, but that's a potential and I'm trying to force a "worst-case" scenario to illustrate my point.

25.3 ug for a 30 kg child comes out to 0.84 ug arsenic/kg body weight.  0.84 ug is 8.4E-4 mg/kg.

The IRIS reference dose (RfD) for inorganic arsenic is 3.0E-4 mg/kg-day.  Now before you say "whoa! That's more than double" remember this:

In general, the RfD is an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime.

Little Johnny will not drink more apple juice per body weight when he gets older, in fact, the FDA reports that after two years of age, a child drinks about half of that amount per body weight.  And as their body weight increase towards 70 kg, the dose of arsenic received per body weight gets less and less each day they consume apple juice.  So that at the end of 70 years, the dose of arsenic is around 3.0E-4 mg/kg-day based on a max of 23 ug/L.

Oh, and that worst-case amount of arsenic, 8.4E-4 mg/kg-day, is for total arsenic.  Looking at the Consumer Reports data, inorganic arsenic is about 30% less than that.

Nevertheless you may say, this worst case mega-heavy-baby little Johnny is consuming more than the IRIS RfD of 3.0E-4 mg/kg-day of inorganic arsenic based on these FDA estimates and calculations.

True that, but I have another little bit of information that will let me know everything will come out OK.  Even if little Johnny were to drink 1.1 liters of apple juice with 23 ug arsenic every day and never weigh more than 30 kg, the estimated dose of total arsenic - 8.4 mg/kg-day - is just barely above the NOAEL (No Observable Adverse Effect Level) of 8.0E-4 mg/kg-day listed by IRIS for inorganic arsenic and well below the LOAEL (Lowest Observable Adverse Effect Level) of 1.4E-2!

So is the FDA correct in identifying 23 ug/L arsenic in apple juice as a level of concern?  Yes.

Can the FDA substantiate their claim that:

...the chronic consumption of apple juice products containing over 23 µg/L (ppb) inorganic arsenic would represent a potential health risk.

Yes.

Is Dr. Russell H. Greenfield, MD correct when he says:

It remains very unlikely that you have done any harm to yourself or to your children through the drinking of apple juice. 

Yes.

Can you and your kids drink apple juice despite all of the misinformation and assumptions made by Consumer Reports, Dr. Oz, and Chuck Norris?

Yes.

Everything in moderation.

Now, how do you like them apples!


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Apples, Arsenic, and Risk - Part 16: The Great and Powerful Oz

Dorothy: Oh, apple juice! Oh - look! Oh!

Scarecrow: Come along, Dorothy - you don't want any of that apple juice. Hmm!

Apple Tree: Are you hinting my apple juice aren't what they ought to be?

Scarecrow: Oh, no! It's just that she doesn't like arsenic in her apple juice!

Apple Tree: Oh, you!  Have you been listening to Dr. Oz and Chuck Norris?

Scarecrow: Yeah.  But I also read about it in Consumer Reports...

Apple Tree: Sigh...Them too?  What did they have to say about my apple juice?

Scarecrow: Stuff like "mounting scientific evidence suggests that chronic exposure to arsenic and lead even at levels below water standards can result in serious health problems."

Apple Tree:  Really, and how much arsenic did they find in my apple juice?

Scarecrow: 3 ug/L...4 if you want to high-side it.

Apple Tree:  And Consumer Reports told you that at that level it could result in serious health problems.

Scarecrow:  Yeah.  And Dr. Oz said the same thing on his web site...that "the findings raise significant health concerns for us and for our children, and have generated incredulousness that this could happen in our country."

Dr. Oz: I am the great and powerful Oz!

Apple Tree: Yeah, so I've been told.

Scarecrow: Chuck Norris said "Poisonous apples are definitely not just being offered in fictional Snow White adventures."
 
Apple Tree:  So my apple juice is poisonous?

Dorothy:  Oh my goodness!  And I've been drinking it.  And Toto too!

Scarecrow:  Consumer Reports says that "arsenic has been notoriously used as a poison since ancient times. A fatal poisoning would require a single dose of inorganic arsenic about the weight of a postage stamp."  A postage stamp!  Do you know how small a postage stamp is!?!

Dorothy: Oh my!

Apple Tree: And how much did they find in my apple juice?

Scarecrow: 4 ug/L.

Apple Tree. How much do you weigh scarecrow?

Scarecrow:  About 70 kilograms

Apple Tree:  Do you know how much Arsenic in a liter of water it would take to kill you or Dorothy?

Doroethy: Oh my, leave me out of this...

Apple Tree:  Well I looked up on the Google and found the weight of a postage stamp.  0.0533 grams.  Do you know how much that is in micrograms?

Scarecrow:  Nope (points to head).  Haven't got a brain, remember?

Apple Tree:  Okay, work with me here.  There are 1000 milligrams in a gram and 1000 micrograms in a milligram.

Dorothy:  This is why Barbie hated math too!

Apple Tree:  Yeah, but this is important.  Everyone is sayin' my apple juice aren't what they ought to be because of arsenic.  They are trying to compare what 0.0533 grams of arsenic will do to you with the 4 micrograms found in my juice.  0.0533 grams is 53,300 micrograms.  The amount needed to kill you is 13,325 times higher than what one liter of my apple juice contains.

Dorothy: Lions, and Tigers, and inorganic arsenic, oh my!

Scarecrow:  Well on the Dr. Oz web page, it does have a Clinical Assistant Professor of Medicine, some guy by the name of Russell H. Greenfield, MD, that tells us:

Arsenic is naturally abundant in our environment in such places as rock formations, minerals and soil, and is also a byproduct of human agricultural and industrial pursuits. Keep this in mind, because it’s important to understand we are all exposed to small, background amounts of arsenic on a regular basis from the food we eat, the water we drink, and the air we breathe. Concerns only arise when considering the type of arsenic (organic or inorganic) we are exposed to, and especially the degree of exposure.

Apple Tree:  Precisely!  Now you're catching on.  Look at the NHAMES study Consumer Reports reviewed.  The average total urinary arsenic is about 8 ug/L.  Now some of that is organic and some inorganic, but that fact is, Americans are exposed to arsenic without drinking apple juice.  It's the dose that's important.  My apple juice has about 4 ug/L of arsenic.  A juice box holds about 8 ounces - or about 0.25 Liters...so that's about 1 ug of arsenic consumed.

Scarecrow: So what your really telling us is that if arsenic exposure is so bad, why don’t you see more people sick or dying from it?’

Apple Tree:  No.  What I'm saying is to consider the dose...the amount of arsenic being consumed from my apple juice in comparison to the total.  The reason you don't see more people getting sick or dying is that the dose we take in is small.

Scarecrow:  Yeah, I thought that would be your argument.  So did Consumer Reports.  They say "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.”

Apple Tree: So if no one has looked for a connection, does that mean a connection is there?

Scarecrow: Yer' givin' me a headache Apple Tree!  Consumer Reports says that when they did look, "the connections they've found underscore the need to protect public health by reducing Americans’ exposure to this potent toxin."

Apple Tree:  Once again with the potent toxin....

Scarecrow:  Well it is...a postage stamp amount can kill you.

Apple Tree:  We're not dealing with anything near that amount in my apple juice.  Why bring up a potential harm that's not present?  Let's stick to the arsenic in my apple juice, not what's found elsewhere.

Scarecrow: Well...still, they found connections....

Apple Tree:  You mean the type 2 diabetes study and the study showing poorer scores in global cognition, processing speed and immediate memory?

Scarecrow:  Yeah...and Sharyn Duffy's hyperkeratosis...

Apple Tree:  Okay, and even if there was a connection, was that connection based on 4 ug/L in one juice box...or even two juice boxes a day?

Scarecrow: Ahhh...well, even without a brain, consuming more arsenic can't be good.  Isn't it additive?

Apple Tree:  Yes it is.  But were talking 1.4 ug/L more arsenic in apple juice drinkers.  Does 1.4 ug/L create any additional risk for these apple juice drinkers?  Not based on any of the studies Consumer Reports or Dr. Oz presented.

Dorothy: But what if I don't want to consume any more arsenic than I have to?  What if I want to limit Toto's exposure just in case?  If it is a carcinogen there is some risk right?

Apple Tree:  Yes.  And it is perfectly fine for you to choose not to drink my apple juice.  There is no such thing as zero risk, so if reducing the amount of arsenic you take in is something you think prudent, then by all means stop drinking my apple juice.

Dorothy:  And you won't be mad at me?  You won't throw apples at me?

Apple Tree:  Nope.  All I ask is that you don't tell folks that my apple juice aren't what they ought to be.

Dr. Oz: I am the great and powerful Oz.  Pay not attention to that apple tree!

Chuck Norris:  He's part of a government cover-up, chop him down and buy local!

Apple Tree:  I am local you ignorant munchkin!

Dorothy: Oh my!

Apple Tree: Un-tether that balloon and get those two fear-mongers out of here.

Dorothy:  Well I better be going, but which way is the correct way forward?

Apple Tree:  Follow the path the data leads you down, not where the hype sends you.

Dorothy:  But it's all so confusing and scary!  How will I know when there really is a connection?

Apple Tree:  Be objective.  And when you read something that says there is a correlation, click your heals three times and repeat:

Correlation does not imply causation...

Correlation does not imply causation...

Correlation does not imply causation...

Next Post: Apples, Arsenic, and Risk - Part 17: Generated Incredulousness


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Playing the part of Dale Gribble...Chuck Norris!

Whoa! Hold on, son! I want you to keep an open mind so you can make an informed decision! If you want, you can read a bloated government report on smoking, or go straight to the horse's mouth and get the facts from the tobacco industry.  Dale Gribble

_____________________

According to Chuck Norris in his Nov 4, 2011 C-Force article:

Many attribute the increase in the rate of ASDs to children's being exposed to significant quantities of thimerosal, a mercury-based compound that has been used since the 1930s as a preservative in certain vaccines and pharmaceutical products to prevent bacterial and fungal contamination.

What Chuck bases this on is information he obtained from two websites, The National Autism Association (NAA) and the Coalition for Mercury-free Drugs (CoMeD).  That's as far as his "research" apparently went on this topic.

Chuck, like many others in this camp, seem to be convinced that the spike in Autism cases we saw in the 1990s was the result of the preservative - thimerosal - a mercury-based compound.  Here is what Chuck has to say about thimerosal:

Since 2001 in the U.S., no new vaccine licensed by the Food and Drug Administration for use in children has contained thimerosal, except for ones to prevent influenza. Nevertheless, the CDC [Centers for Disease Control] continues to recommend some routine vaccines with "trace amounts of thimerosal" for children younger than 6.

A reasonably intelligent person might be wondering why Chuck would find it necessary to tell his reader who posed the question...:

Chuck, I keep hearing conflicting reports that certain vaccines are dangerous and even can cause autism in children. What do you know? – Cheryl M., Charlotte, N.C.

 ...about a material that is no longer used.

Here is what the CDC states, according to Chuck:

According to the CDC's website, however, "to date, the studies continue to show that vaccines are not associated with ASDs. ... The most recent and rigorous scientific research does not support the argument that thimerosal-containing vaccines are harmful. ... Is thimerosal in vaccines safe? Yes."

So if thimerosal is no longer used and if it is used it is "safe," why is Chuck bringing this issue back up?  You will have to ask him on that, all I can do is speculate as to his reasoning.

What I can reasonably speculate on is this:  Chuck and his anti-vaccine cohorts do not trust the CDC.  Not only that, they don't trust "the nation's bastion of authoritative health advice" - the Institute of Medicine.

They don't trust them, but they do trust those who agree with them.  Guys like Dr. Boyd Haley - the one who the NAA attributes the claim that "recent studies have confirmed the association between the use of thimerosal and autism has moved from "biologically plausible" to a "biological certainty." (see previous post)

Let's look at what Chuck says in his C-Force article.

Nevertheless, the CDC [Centers for Disease Control] continues to recommend some routine vaccines with "trace amounts of thimerosal" for children younger than 6.

Here is what the FDA - the agency with authority over vaccines - says about thimerosal:

Thimerosal has been removed from or reduced to trace amounts in all vaccines routinely recommended for children 6 years of age and younger, with the exception of inactivated influenza vaccine (see Table 1). A preservative-free version of the inactivated influenza vaccine (contains trace amounts of thimerosal) is available in limited supply at this time for use in infants, children and pregnant women. Some vaccines such as Td, which is indicated for older children (≥ 7 years of age) and adults, are also now available in formulations that are free of thimerosal or contain only trace amounts. Vaccines with trace amounts of thimerosal contain 1 microgram or less of mercury per dose.

If you are interested in this topic, you should spend time looking at Table 1.  Of the 30 different manufactured vaccines on the list, only 5 contain trace amounts of thimerosal, four of those are for Seasonal Trivalent Influenza (for which three manufactures do not use thimerosal) and one is for Tetanus "which is indicated for older children (≥ 7 years of age) and adults."

Had Chuck done his own research he would have been able to accurately report this which would have allowed him to correctly inform his reader that one; vaccines are safe, and two; she and other concerned parents can request thimerosal-free vaccines.

My question is why Chuck, the NAA, and CoMeD continue to present vaccines as a likely culprit for autism?  Since January 2003 thimerosal has been out of the vaccines we routinely give children.

There is little current data that I could easily find showing the trend of autism over time.  What I did find looks at California and is based on how California schools must report.

Source

Source

If you look at these graphs you will see an increase in Autism since 2002.  The California data is based on "The disability categories and enrollment breakdown in California for individuals (newborn through twenty-two years of age)."  One would assume that as time progressed from 2002, more and more children entering into California Schools would have received vaccines without thimerosal.  Even factoring in new autism cases in 7 & 8 year olds - who may have received thimerosal - the number of children vaccinated without it would far exceed this group.  Even accounting for a lag in time from thimerosal vaccination to diagnosis, there would be a dip in the number of cases around 2007 as five year olds entered the school system who were vaccinated after 2002.

No matter how you look at it, these two graphs show an increase in the number of autism cases after thimerosal was removed.  Interesting...  So how come Chuck and his fellow anti-vaccine folks still want to tie thimerosal to autism?

You will notice I used two different data sources (albeit they most likely used the same data) to show an increase in autism since 2002.  You see, Chuck and company believe that a

Here is what Chuck wrote:

The deliberate avoidance and falsification of medical data to support CDC bias is heinous enough, but the fact that such information is manipulated to practice medicine on our nation's children is monstrous malpractice and even premeditated malevolence.  I agree wholeheartedly with Lisa Sykes, president of CoMeD, who summarized the CDC cover-up: "This type of malfeasance should not be tolerated by those who are entrusted with our children's health and well-being."

Cover-up?  Wow, that's a pretty strong accusation to make.  I bet Chuck must have some real powerful evidence to show this.  He must have come across a smoking gun that would unequivocally show that the CDC "ignored certain data and misled the medical community and public by insinuating that thimerosal in vaccines does not increase the risk of autism."

Exhibit A "Chuck's smoking gun"

...the Coalition for Mercury-free Drugs exposed a federal cover-up between the CDC and vaccine researchers. Despite the fact that the CDC received an email from CoMeD in 2002 that revealed a causal relationship between the removal of thimerosal from vaccines and a decline in the rate of autism, the CDC encouraged the publication of a study in Pediatrics...

Almost inconceivably, the study in Pediatrics actually purported that autism rates increased after thimerosal was removed.

...one coauthor, from Aarhus University, Denmark, was aware of the omission and alerted CDC officials in a 2002 email, stating, 'Attached I send you the short and long manuscript about Thimerosal and autism in Denmark ... I need to tell you that the figures do not include the latest data from 2001 ... but the incidence and prevalence are still decreasing in 2001.'

Exhibit B "The Actual Pediatrics Publication"

Thimerosal and the Occurrence of Autism: Negative Ecological Evidence From Danish Population-Based Data (1)  Note: This publication is copyrighted and may not be available online.  According to this paper:

The incidence of autism remained fairly constant during the period of use of thimerosal in Denmark, and the rise in incidence beginning in 1991 continued even in the group of children born after the discontinuation of thimerosal.

This was shown with the following graph:

 Notice that vertical line at year 1992?  Here is what the authors conclude:

The discontinuation of thimerosal-containing vaccines in Denmark in 1992 was followed by an increase in the incidence of autism. Our ecological data do not support a correlation between thimerosal-containing vaccines and the incidence of autism. 

Denmark removed thimerosal from its vaccines in 1992, 10 years before the United States.  Notice how the graph shows an increase in autism for all age groups.  If thimerosal was the culprit, there would be a downward trend.  There wasn't one seen in Denmark and there isn't one seen in the United States after 2002.

Notice, however, that there is a dip in the 5-6 and 7-9 age groups.  That dip takes place a full 7 years after the thimerosal was removed.

Cue music....

Enter Exhibit C "The Email"

Chuck went to CoMeD's website and found this:

Documents obtained via the Freedom of Information Act (FOIA) show that CDC officials were aware of Danish data indicating a connection between removing Thimerosal (49.55% mercury) and a decline in autism rates.  Despite this knowledge, these officials allowed a 2003 article to be published in Pediatrics that excluded this information, misrepresented the decline as an increase, and led to the mistaken conclusion that Thimerosal in vaccines does not cause autism.

And what is this "knowledge" that the CDC officials were aware of:

One coauthor, from Aarhus University, Denmark, was aware of the omission and alerted CDC officials in a  2002 email, stating "Attached I send you the short and long manuscript about Thimerosal and autism in Denmark … I need to tell you that the figures do not include the latest data from 2001 … but the incidence and prevalence are still decreasing in 2001"

You can read the email on CoMeD's website.   Why is this an issue for CoMeD and Chuck?

Nevertheless, in the final draft version of the publication submitted to Pediatrics, the data from 2001 showing a decline in autism was not mentioned.  Ignoring this omission, the CDC continued to endorse the article and, in a December 10, 2002  recommendation letter to the editor of Pediatrics, encouraged expedited review and publication of the article. The misleading Danish article was published by Pediatrics in 2003.

I am unsure if any of the the CoMed folks or Chuck bothered to ask the email writer or the authors why that 2001 information was not relevant to the conclusion.  It's an interesting bit of data because it begs the question as to what may be causing that decline in 2001.  It also begs the question why there is a decline in Denmark but not in California.  What it does not do is give any additional information to the paper's conclusion:

The discontinuation of thimerosal-containing vaccines in Denmark in 1992 was followed by an increase in the incidence of autism.

A decline in 2001, even one starting in 1999, would have nothing whatsoever to do with the removal of thimerosal.  That decline is nine years after removal, so diagnosis of children with Autism would have taken place during that time frame and there would be no connection to thimerosal in children born after 1992.  If thimerosal was the culprit, there would be a decrease as less children developed autism.  That's not what the graph shows, and including this smoking gun email data does not change that.

But...

Yeah, I know.  In 1994 they changed the way autism is diagnosed.

The increase in the incidence of autism from 1990 on may be attributable to more attention being drawn to the syndrome of autism and to a change in the diagnostic criteria from the ICD-8 to the ICD-10 in 1994.

So if more children were diagnosed with autism because of this change, you would still see a decrease over time (5 years) as less children developed autism if thimerosal was a factor.  In addition, the data from California shows Autism on the rise after it was removed from united States vaccines.

So what's behind all this?  Possibly nothing more than an increase in attention as the author's state.  That's not universally shared, however:

A study by researchers at the UC Davis M.I.N.D. Institute has found that the seven- to eight-fold increase in the number children born in California with autism since 1990 cannot be explained by either changes in how the condition is diagnosed or counted — and the trend shows no sign of abating.

So what's the cause of this increase?  Here is what the UC Davis M.I.N.D. folks think:

Published in the January 2009 issue of the journal Epidemiology, results from the study also suggest that research should shift from genetics to the host of chemicals and infectious microbes in the environment that are likely at the root of changes in the neurodevelopment of California’s children.

“It’s time to start looking for the environmental culprits responsible for the remarkable increase in the rate of autism in California,” said UC Davis M.I.N.D. Institute researcher Irva Hertz-Picciotto, a professor of environmental and occupational health and epidemiology and an internationally respected autism researcher.

One "environmental culprit" we can stop looking at?  Thimerosal and vaccines.

As Dale Gribble might say.

Vaccines don't kill people, Chuck Norris does!

A less scientific- but informative - blog on this topic can be found here



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Six degrees of irresponsibility from Chuck Norris

Our Wednesday edition of The Eagle newspaper ran a syndicated piece of nonsense by Chuck Norris.

Chuck - who I would not take acting lessons from. let alone listen to him about public health issues - was asked by a reader:

Chuck, I keep hearing conflicting reports that certain vaccines are dangerous and even can cause autism in children. What do you know? – Cheryl M., Charlotte, N.C.

Chuck's response in his commentary called "C-Force" was titled:

Link between autism, vaccines 'biological certainty'

What Chuck doesn't understand is that "biological certainty" is only one of the nine Hill's Criteria of Causation "minimal conditions needed to establish a causal relationship between two items." (1) (2)

But what do you expect from a guy who's research into this topic was gleaned from two anti-vaccine websites. In fact, if you read what ol' Chuck writes, and then read what's on these two websites (3) (4), you would swear it was plagiarism, but that's for another post I suppose.

If you have read any of my previous blogs, you know that the anti-vaccine rhetoric really gets to me.  It's not good science supporting it, it's dangerous to children who go un-immunized, and it creates unnecessary concern and stress for parents who want to do what is best for their children.

Chuck Norris should know better than to print something as fact that is not thoroughly researched.  His editors should have fact checked his writing, and my newspaper should have done so as well.

There is no credible evidence linking vaccines to autism.  Yes, both these two websites Chuck regurgitated "fact" from claim to have evidence showing a "CDC cover-up" and "biological certainty" are easily explained and do nothing to advance the thimerosal-autism correlation other than make a general connection that both can be present.

I'll write more on the "cover-up" in a later post, for now, I want to show you how six degrees of irresponsibility from Chuck Norris works:

1. Chuck Norris writes an article titled: Link between autism, vaccines 'biological certainty'

2. The "biological certainty" claim comes from the National Autism Association website (3) which states:"Recent studies have confirmed the association between the use of thimerosal and autism has moved from "biologically plausible" to a "biological certainty" and attributes this to a scientist named "Boyd Haley."

3. Boyd Haley is a co-author on a paper titled:   "Mercury and autism: Accelerating Evidence?" in Activitas Nervosa Superior; Jul 2007; 49, 1/2; ProQuest Central pg. 22.  In this paper the authors state:

Source: Mercury and autism: Accelerating Evidence?

4. This paper is critical of the paper "Thimerosal and the Occurrence of Autism: Negative Ecological Evidence From Danish Population-Based Data" in Pediatrics 2003;112;604.  This is the paper that the other website claims there was a "CDC cover-up."

The plot now thickens....

Doing a Texas A&M Library search for journal articles attributed to Dr. Boyd Haley, I find nothing written by him stating or using the term "biological certainty."  I did a Google search using the words:  "biological certainty Boyd Haley"  Nothing pops up except page after page quoting the National Autism Association's claim that Dr. Haley made this claim.

So I do a Google search using the words "Boyd Haley"

....which brings up the 5th degree of irresponsibility from Chuck Norris:

5. Clicking on the third link I read this: "OSR was developed and patented by Dr. Boyd Haley PhD, who has said that his OSR product will permanently bind with Mercury 1 million times better than either DMSA, DMPS, or EDTA."(5)

According to this website:

"Boyd Haley is highly respected and well known throughout the community of holistic Mercury-free dentists and "Defeat Autism Now!" (DAN!) medical doctors. Boyd Haley is a vigorous opponent of the use of Mercury in vaccines and dental fillings, and he is very active in the Defeat Autism Now (DAN!) community. DAN! is a nationwide association of medical doctors who believe that Autism can be treated primarily with Mercury chelation, anti-Candida medications, and diet. The DAN doctors are in the process now of transitioning away from DMSA, towards OSR, as their Mercury chelator of choice. 

Which brings me to the 6th degree of irresponsibility

6. According to the first website on the search page , the Chicago Tribune reports the following:

Source

The problem with folks like Chuck Norris and the National Autism Association and The Coalition for Mercury-free Drugs (CoMeD) is that they want so badly to find a cause that they are willing to latch on to anyone that supports their thinking.  Even snake oil salesmen.

Chuck Norris wrote this irresponsible piece of nonsense without spending anytime asking the question, are these statements valid?  Why would the National Autism Association still use anything attributed to Boyd Haley?  Why would website after website regurgitate the same National Autism Association claim of "biological certainty" without looking up to see who and what the guy is involved with?

Good science demands objectivity.

If you don't want thimerosal in your kid's vaccination ask your Doctor to provide thimerosal free vaccines and boosters (yeah, I know its no longer used....I'm trying to get folks past this reason not to vaccinate).

And Chuck, stick to writing about exercise and a good diet.  Leave science to those who are willing to do the research.

For a recent scientific journal article on the topic of Thimerosal and Autism click here.


Edit.  Notes
http://www.ncbi.nlm.nih.gov/pubmed/11111798


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