For me, it's now.
I have the same trouble as most people when it comes to realising how serious the dangers of Forever Chemicals are, visualising how these tiny things can create so much havoc.
At first I was "Meh, they are tiny what harm can they do" (although I feel all chemicals are harmful) only the word Bioaccumilate set off alarm bells, but the more research I did the more concerned I became. How about this?
I've been trying to think of a way to create a visualisation, but the Maths and Chemistry are way out of my league - something I am not ashamed to admit.
Problems, Patterns, thats where I excel seeing things that people don't always see.
So today I enlisted some help, a far greater Maths intelligence, being able to delve alot deeper than me.
Visulise this. This is one Gram of Flour.
This is made up of approximately 23.5 Million particles.
My question was "how many C8 String Particles in one gram"?
Imagine a pin head 1.5mm across.
Now to cover that pin head in flour it takes ~200 → 20,000 flour particles depending on particle size. A typical mid-estimate (50 µm particles) gives ~800 particles on the pin head
For PFAS You could fit ~3.5 trillion C8 molecules in a monolayer on a 1.5 mm pin head (only weighing 2.4 ng)
So if you take anything from this blog, take this away,
1. A single flour particle = something you can almost see under a microscope.`
2. A single C8 molecule = so tiny it makes a nanometer look enormous.
3.And then 412 million “pin heads” of C8 to equal just 1g of flour?
That’s mind-boggling.
Here is the working out for this blog.
(If there are any errors or corrections that need making please let me know).
Oh, before I forget, the answer is 1 g flour ≈ the mass of ~1.5 sextillion C8 molecules.(that's Twenty one zeros)
Comparison,
1,000,000 = 1 Million (23.5 Million Flour particles)
1,000,000,0000 = 1 Billion
1,000,000,000,000 = 1 Trillion ... ->
1,000,000,000,000,000,000,000 = 1 Sextillion (1.5 Sextillion PFAS molecules)
A second Question hit me this morning,
"which is larger a DNA strand or the PFAS string"
DNA strands:
- Human DNA is roughly 3 billion base pairs long.
- Each base pair is about 0.34 nanometres, so if you stretched it out, a single human DNA molecule would be about 1–2 meters long.
PFAS “strings”:
- PFAS (per- and polyfluoroalkyl substances) are molecules, not sequences of base pairs.
- Even long-chain PFAS molecules only have tens to hundreds of atoms, so they’re on the order of nanometres at most.
Comparison:
A DNA strand is astronomically larger than a PFAS molecule, both in length and complexity. Even the longest PFAS polymers are tiny compared to a single DNA molecule.
So, lets break this down more.
Step 1: Convert mass to moles
(A mole is a molecule not a subterranean creature in this instance)
We have:
m=0.04μg=4×10−8gm = 0.04\,\mu g = 4 \times 10^{-8}\,gm=0.04μg=4×10−8g
Take PFOA (a common PFAS) as an example:
- Molecular formula: C₈HF₁₅O₂
- Molar mass M≈414 g/molM \approx 414\,g/molM≈414g/mol
Moles of PFAS=MassMolar mass=4×10−8414≈9.66×10−11 mol\text{Moles of PFAS} = \frac{\text{Mass}}{\text{Molar mass}} = \frac{4 \times 10^{-8}}{414} \approx 9.66 \times 10^{-11}\, \text{mol}Moles of PFAS=Molar massMass=4144×10−8≈9.66×10−11mol
Step 2: Convert moles to number of molecules
Use Avogadro’s number: NA=6.022×1023N_A = 6.022 \times 10^{23}NA=6.022×1023 molecules/mol
Number of molecules=9.66×10−11×6.022×1023≈5.81×1013 molecules\text{Number of molecules} = 9.66 \times 10^{-11} \times 6.022 \times 10^{23} \approx 5.81 \times 10^{13} \text{ molecules}Number of molecules=9.66×10−11×6.022×1023≈5.81×1013 molecules
Step 3: Interpretation
- In 1 mL of water containing 0.04 µg of PFAS, there are roughly 58 trillion PFAS molecules.
- Even though their total volume is tiny (2×10−8 mL2 \times 10^{-8}\,mL2×10−8mL), the molecular count is huge because each molecule is so small.
The next question is what are the affects of these Trillions of molecules to our body, how many have to be in our bodies until they do affect us?
