This app shows that when PFAS is present in your drinking water, the dose you get simply by drinking enough to stay alive, can exceed your immune-safe limit — even before eating any food. Based upon the logic of a weekly dietary maximum tolerable intake, before you exceed the safe weekly limit, set out by the European Food Safety Authority. It uses the EFSA scientific safety standard: 4.4 ng per kg body weight per week. No spin. Just maths.
PFAS are industrial chemicals that accumulate in your blood for years. Once inside you, they stay. EFSA examined animal studies, human biomonitoring, and vaccine-response data in children. Their scientists found one critical effect: children exposed to higher PFAS had weaker antibody responses to vaccines. They traced this back using PBPK modelling and set a strict weekly limit — the Tolerable Weekly Intake (TWI). This limit is the scientific safe-dose.
• EFSA TWI: 4.4 nanograms per kilogram of body weight per week
• Based on immune suppression in children
Everything in this app is built on that number.
What this calculator does:
1. Takes your body weight
2. Calculates your weekly PFAS “budget” using EFSA’s formula
3. Uses your water’s PFAS level
4. Shows how much water you can drink before you exceed that dose
The logic is simple:
• If you exceed the EFSA limit, your immune system is under strain
• If you do that every week, PFAS builds up in your blood
• If you do that for years, you’re at chronic risk
This app exposes that risk with clarity.
No distractions. No spin. Just the numbers.
Let them speak.