Fish Mercury Calculator
Methylmercury bioaccumulates in fish. FDA/EPA reference dose: 0.1 μg/kg body weight/day. High-mercury fish (swordfish, shark, king mackerel) should be limited; low-mercury options (salmon, shrimp, tilapia) are safe for frequent consumption. Pregnant women and children are most at risk—use the stricter 0.05 μg/kg/day limit.
🌍 Why This Matters for the Planet
Why It Matters
Methylmercury in fish can harm the nervous system, especially in fetuses and young children. Large predatory fish accumulate the most mercury. The FDA and EPA set safe limits to help you enjoy fish's benefits (omega-3s, protein) while minimizing mercury risk.
How You Can Help
Select your fish type, servings per week, and serving size. The calculator computes mercury per serving and weekly intake, compares to the FDA/EPA reference dose, and shows margin of safety. If pregnant or nursing, the reference dose is halved to 0.05 μg/kg/day.
Key Insights
- ●Swordfish and shark have ~45x more mercury than salmon
- ●Light canned tuna has ~3x less mercury than albacore
- ●Pregnant women should avoid high-mercury fish and limit albacore to 6 oz/week
- ●Margin of safety >2x indicates safe intake; <1x means you exceed the limit
📋 Quick Examples — Click to Load
📊 Mercury by Fish Type
Mercury concentration (ppm) across fish species
📊 Intake Breakdown
Per serving vs weekly total mercury
📊 Weekly Accumulation
Cumulative mercury over weeks at current intake
📊 Safe Servings by Fish
Max safe servings per week for your body weight & serving size
For educational and informational purposes only. Verify with a qualified professional.
🌎 Planet Impact Facts
Methylmercury bioaccumulates in fish; top predators have the highest levels
— FDA
FDA/EPA reference dose: 0.1 μg/kg body weight per day
— EPA
Pregnant women should use 0.05 μg/kg/day and avoid swordfish, shark, king mackerel
— FDA
Salmon, shrimp, tilapia, and cod are low-mercury choices for frequent consumption
— NOAA
Swordfish has 0.995 ppm mercury—about 45x higher than salmon
— FDA
Mercury enters oceans from coal burning and converts to methylmercury in sediments
— EPA
Methylmercury bioaccumulates in fish, especially large predatory species. The FDA/EPA reference dose is 0.1 μg/kg body weight/day for adults; pregnant and nursing women should use 0.05 μg/kg/day. High-mercury fish: swordfish (0.995 ppm), shark (0.979 ppm), king mackerel (0.73 ppm). Low-mercury: salmon (0.022 ppm), shrimp (0.009 ppm). This calculator estimates your weekly mercury intake and compares it to safe limits.
Key Takeaways
- • Pregnant women and young children are most at risk from mercury; use the stricter 0.05 μg/kg/day limit
- • Avoid or limit swordfish, shark, and king mackerel; choose salmon, shrimp, tilapia, or cod for frequent consumption
- • Margin of safety >2x = safe; 1-2x = caution; <1x = exceeds limit
- • A 170g (6 oz) serving is the standard FDA reference; adjust for your typical portion size
Did You Know?
How Mercury Intake Is Calculated
Mercury per Serving
Mercury (μg) = serving size (g) × mercury ppm ÷ 1000 × 1000. PPM = mg per kg fish; converting to μg gives serving_g × ppm.
Weekly Intake
Weekly mercury = servings per week × mercury per serving. For multiple people, divide by number of people for per-person intake.
Reference Dose & Margin
Reference dose (weekly) = 0.1 μg/kg/day × body weight × 7. Margin of safety = reference ÷ your intake. Safe servings = reference ÷ mercury per serving.
Expert Tips on Safe Fish Consumption
Mercury PPM by Fish Type
| Fish | Mercury (ppm) | Risk Level |
|---|---|---|
| Swordfish | 0.995 | High |
| Shark | 0.979 | High |
| King Mackerel | 0.730 | High |
| Tuna (Albacore) | 0.350 | Moderate |
| Bass | 0.152 | Low |
| Tuna (Light) | 0.126 | Low |
| Cod | 0.111 | Low |
| Catfish | 0.025 | Low |
| Salmon | 0.022 | Low |
| Tilapia | 0.013 | Low |
| Shrimp | 0.009 | Low |
Frequently Asked Questions
What is the FDA/EPA reference dose for mercury?
The FDA and EPA set a reference dose of 0.1 μg methylmercury per kg body weight per day for adults. For pregnant and nursing women, many health agencies recommend a more conservative limit of 0.05 μg/kg/day due to fetal and infant neurodevelopmental sensitivity.
Which fish have the highest mercury levels?
Swordfish (0.995 ppm), shark (0.979 ppm), and king mackerel (0.73 ppm) have the highest mercury. These large predatory fish bioaccumulate methylmercury from their prey. FDA advises pregnant women and young children to avoid these species.
Which fish are safest to eat frequently?
Low-mercury options include salmon (0.022 ppm), shrimp (0.009 ppm), tilapia (0.013 ppm), and catfish (0.025 ppm). These can be eaten 2-3 times per week by most people, including pregnant women, within serving guidelines.
How does mercury bioaccumulate in fish?
Methylmercury enters water from industrial sources and natural processes. Small fish absorb it; larger predatory fish eat many small fish and accumulate mercury in their tissues. Top predators like swordfish and shark have the highest levels.
Should I avoid tuna during pregnancy?
Light canned tuna (0.126 ppm) is lower in mercury than albacore (0.35 ppm). FDA recommends pregnant women limit albacore to 6 oz/week and light tuna to 12 oz/week. This calculator helps you stay within safe limits.
What is margin of safety for mercury intake?
Margin of safety = reference dose ÷ your weekly intake. >2x means safe; 1-2x means caution; <1x means you exceed the limit. Staying below 50% of the reference dose provides extra buffer, especially for children and pregnant women.
Key Statistics
Official Data Sources
⚠️ Disclaimer: This calculator is for educational purposes. Mercury levels vary by fish size, location, and species. FDA/EPA guidelines are general; consult your healthcare provider for personalized advice, especially if pregnant, nursing, or feeding young children.
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