Fish Mercury Calculator
Free Fish mercury Calculator for marine ocean health. Enter variables to compute results with formulas and detailed steps.
Reviewed by Daniel Agrici, Founder & Lead Developer
Formula
Weekly Hg (ug) = Mercury_ppm x Serving_g x Servings/week
Mercury per serving = fish ppm x grams. Weekly limit = 0.1 ug/kg/day x body weight x 7 (halved for pregnancy). Compare weekly intake to limit.
Worked Examples
Example 1: Regular Tuna Consumer
Problem:Light tuna 0.128 ppm, 170g, 3x/week, 70 kg adult.
Solution:Per serving=21.8 ug\nWeekly=65.3 ug\nLimit=49.0 ug\n133% of limit
Result:65.3 ug/week (133% - Above Limit)
Example 2: Salmon Lover
Problem:Salmon 0.022 ppm, 170g, 4x/week, 65 kg.
Solution:Per serving=3.7 ug\nWeekly=15.0 ug\nLimit=45.5 ug\n33% of limit
Result:15.0 ug/week (33% - Low Risk)
Frequently Asked Questions
How does mercury get into fish?
Mercury enters aquatic ecosystems from industrial emissions coal-burning plants and natural geological sources. Atmospheric mercury deposits into water where bacteria convert it to methylmercury which is readily absorbed by organisms. Concentrations magnify through the food chain by roughly 10-fold at each trophic level. Large predatory fish like swordfish and shark have concentrations 10000 to 100000 times higher than surrounding water.
What is the EPA reference dose for mercury?
The EPA reference dose for methylmercury is 0.1 micrograms per kg body weight per day. For a 70 kg adult this means no more than 7 ug daily or 49 ug weekly. The dose includes a 10-fold safety factor below known adverse effect levels. This translates to roughly 2 to 3 servings weekly of low-mercury fish like salmon or about 1 serving of moderate-mercury albacore tuna for most adults.
Which fish have the highest mercury levels?
Swordfish averages 0.995 ppm shark 0.979 ppm king mackerel 0.730 ppm and bigeye tuna 0.689 ppm. Tilefish from Gulf of Mexico can exceed 1.4 ppm. The FDA advises pregnant women and children to completely avoid these four species. Orange roughy marlin and some grouper also have elevated levels above 0.3 ppm. These fish accumulate mercury over long lifespans exceeding 20 to 30 years.
Which fish are lowest in mercury?
Salmon at 0.022 ppm provides excellent omega-3 with minimal mercury risk. Shrimp at 0.009 ppm sardines at 0.013 ppm tilapia at 0.013 ppm pollock at 0.031 ppm and catfish at 0.025 ppm are all very low mercury options. Light canned tuna at 0.128 ppm is safe for moderate consumption. These low-mercury fish can be eaten 2 to 3 times weekly without approaching the EPA reference dose.
References
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy