Usability 
All seafood contains mercury. Some is naturally occurring but about half of the mercury in the environment is the result of burning coal and natural gas, gold mining, smelting and cement production.
Eating fish high in mercury can be harmful to health, particularly for pregnant women, nursing mothers, women who might become pregnant, and children. The US EPA and FDA have published guidelines for safe levels of consumption.
This mobile friendly calculator from the Sea Turtle Restoration Project helps you monitor your mercury consumption on the go. Simply choose the fish type from a list and enter your weight and serving size and the calculator will show you how much mercury it contains and whether it exceeds the EPA/FDA limit. Source: Mobility.mobi