When mercury builds up to toxic levels in the human body, it can cause permanent neurological damage. If you are pregnant, mercury is dangerous to your developing fetus and later to your breast-feeding baby. A fetus exposed to mercury during pregnancy is especially likely to suffer mild to severe nervous system damage. Similarly, young children who eat a lot of fish containing mercury can suffer permanent brain damage.

Mercury occurs naturally in the environment and also as a result of industrial pollution. It is in our water, air, soil, and food. Fish are the most common source of mercury in the human diet. You can best protect your child from mercury exposure by avoiding high-mercury fish before and during pregnancy and when breast-feeding and choosing foods for your young child.

Health Canada advises that most people should not eat more than 150 g (5 oz) per week of fish that are known to have higher mercury levels. These include fresh or frozen tuna (not canned "light" tuna), shark, swordfish, marlin, orange roughy, and escolar. Some people need to restrict high-mercury fish even more:¹

• Nursing mothers or women who are or may become pregnant should limit high mercury fish intake to no more than 150 g (5.3 oz) a month.
• Children 5 to 11 years of age should limit high mercury fish intake to no more than 125 g (4.4 oz) a month.
• Children 1 to 4 years of age should limit high mercury fish intake to no more than 75 g (2.7 oz) a month.

Most Canadians don't need to limit how much canned albacore tuna they eat each week. But women who are or may become pregnant, nursing mothers, and children need to limit canned albacore tuna intake to no more than:¹

• 300 g (10.6 oz) each week for women who are or may become pregnant, or who are nursing.
• 150 g (5.3 oz) each week for children 5 to 11 years of age.
• 75 g (2.7 oz) each week for children 1 to 4 years of age.

Health Canada has no restrictions on eating fish and shellfish that are lower in mercury. These include salmon, rainbow trout, pollock, herring, shrimp, mussels, clams, oysters, and canned "light" tuna.

Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas.

Mercury will slowly leave the body over time in the urine, feces, and breast milk. If you are concerned about your own or your child's mercury level, talk to your doctor or local health unit about testing.