Coffee, Acrylamide, and Proposition 65 - Part 7

Eight posts on this. Well if you are still reading we are getting close to the end.

Let's go back to this graphic:



If you will recall, I told y'all to pay attention to the writing in blue. The forcing of the line to have zero dose = zero risk is what sets the cancer slope (aka cancer potency).

To determine the concentration whereby you do not need to be concerned - the Not Significant Risk Level (NSRL) - and therefore are not required to notify the public that you have a substance "known to the state to cause cancer," you take the cancer slope value and you plug it into the formula below:

q(human) = cancer potency = cancer slope factor

Let's see how this works for a chemical called 4-methylimidazole. California has a nice document that spells out the Cancer Slope Factor (Cancer Potency) and the NSRL that was calculated using the formula I showed above.

California was nice enough to show their work for 4-methylimidazole so you can see how the NSRL was determined:

Source

You see that value of 16 micrograms in Table 1. You see the Cancer Potency in Table 1. You see the calculation for the NSRL in Table 1. You see the work, the formula, the values.

Can we agree on this as this is how you calculate the NSRL? 

You may be wondering why I am not using the same snip graphics from the California document for acrylamide.Well, that's because they don't show the work. Here is Table 1 for acrylamide:

Source

This looks just like Table 1 for 4-methylimidazole. You will notice that they give the NSRL for acrylamide as 1.0 micrograms per day.

Wait, I have been telling y'all that the NSRL for acrylamide is 0.2 micrograms per day. Where did that 0.2 number come form? It came from their webpage:

Source

I want y'all to know I don't make these numbers up. One of the reasons it take 7 to 10 posts is because I want to make sure the numbers presented are the numbers given.

So what is the NSRL for acrylamide? Is it 1.0 micrograms per day or 0.2 micrograms per day? What does the calculation for the NSRL show?

Source

Oh look! They did not show their work. Okay, I'll just calculate it myself using Excel:

Well, according to my calculation using their formula and their Cancer Potency value, the NSRL is 1.0 micrograms per day.


Let me make sure my calculation is calculating correctly. Ill use the values for 4-methylimidazole to see if I get what they got:

Okay, so my Excel formula works correctly. So where did a an NSRL of 0.2 micrograms per day for acrylamide come from?

The document from which these number came from that I plugged into my Excel formula is dated March 2005. These documents are how the state supports the numbers for the chemicals "known to the state...."  The "INITIAL STATEMENT OF REASONS" - also dated March 2005 gives the same cancer potency and NSRL of 1 microgram per day.

According to Title 27 for the California Code of Regulations §25705 "Specific Regulatory Levels Posing No Significant Risk" the NSRL is 0.2 micrograms per day.

It appears that, by citing 25705(c):

NSRLs may be based on: an assessment conducted by another state or federal agency (Section 25705(c)). (source)

Okay, then what is the March 2005 document all about? If they calculated the NSRL using a different Cancer Slope Factor (aka Cancer Potency), then where is the supporting data? Where did 0.2 micrograms per day come from?

Show your work!

Everything involving this court case, all the news articles, all the bloggers talking about it use 0.2 micrograms per day for the NSRL. Why? because that's the number that appears on the California Proposition 65 website for NSRL values.

Way back in 1992 this document had the Cancer Potency for acrylamide as follows:

Maybe they changed the Cancer Slope Factor (aka Cancer Potency) from 0.7 in 2005 to something else in 2018? Let's check the California Website for acrylamide to see:

Source

Wait...that oral slope factor is the one they used in 1992. Ahhh...I think I may know what happened. I think they got their apples mixed up with their oranges. Is it possible to have the same Cancer Slope for an inhalation dose and an ingestion dose? My thinking seems to be supported by this:

Historically, toxicity concerns over acrylamide centered on worker health and safety, primarily for neurological, male reproductive and cancer effects. However, in 2002 it was discovered that acrylamide can form during the cooking of starchy foods at high temperatures. This unexpected discovery shifted the concern for health risks to the public from acrylamide in the diet. Since 2002, acrylamide has been discovered in many plant-based foods that have been baked or fried at high temperatures. (source)

It appears though that this new look, March 2005, was not adopted into regulation so it still stands that the NSRL for acrylamide is 0.2. It should be, based on data - no lower than 1 micrograms per day as pointed out at the beginning of this post.

Now we can go all the way back to my first post on this. Is 0.2 micrograms a "real" number? Again, ya' gotta know that number because what ever that number is, above it presents a significant cancer risk according to California.

If 1 micrograms per day is a "real" number - or closer to the real number for a risk above one in 100,000 - then that Short cup of coffee - at 0.66 micrograms of acrylamide per cup - no longer poses a "significant risk" for cancer...based on how California looks at it.

This is why that writing in blue in the graphic at the top of the page is so critical to remember. millions of dollars are wasted over these NSRLs. It appears to me that the 0.2 micrograms per day established for acrylamide is wrong. legally it is correct, but calculation wise it is wrong.

Now add in the fact that the Cancer Slope Factor is derived by forcing the line from which the slope is determined mathematically, is assumed to begin at 0 risk and 0 dose.

Having fun yet?

Next Post: Coffee, Acrylamide, and Proposition 65 - Part 8