Mercury's Health Effects | Oceana

Mercury’s Health Effects


Mercury exposure in humans results primarily from eating fish that contain methylmercury.

Mercury is primarily a neurotoxin, which means it attacks the central nervous system. Its effects are often subtle enough not to be recognized immediately, but more and more people are learning that their health problems could be due to mercury exposure.

Nervous system problems can include impaired coordination, tremors, irritability, memory loss, depression, blurred vision and a tingling sensation in the skin. Other symptoms include fatigue, headache, decreased concentration and muscle or joint pain.

Adverse health effects from mercury in fish diets can range from subtle nervous system effects to more serious mercury poisoning, depending on how much and how often fish is eaten and how much mercury is in the fish.

Particular Concerns for Children

An EPA scientist estimated that one in ten pregnant women has enough mercury in her blood to pose neurological risks to her developing baby. This means that hundreds of thousands of newborns each year in the United States may be exposed to enough mercury to hinder nervous system development.

Perhaps the greatest concern about mercury is its effect on the early development of the fetus and later effects on childhood development.

Methylmercury can travel across the placenta from the mother to the fetus, meaning exposure to the dangerous poison often begins in the womb during a baby’s most vulnerable developmental period. Children and fetuses are also harmed by lower concentrations of mercury than it takes to hurt adults.

  • Mercury can cause irreversible impairment to brain function in children in the womb and as they grow.
  • Infants and children exposed to toxic doses of mercury have problems with attention span, language, visual-spatial skills, memory and coordination.
  • Very high exposure levels in children can lead to brain damage, mental retardation, blindness, seizures and speech problems.
  • Exposure also appears to weaken the heartbeat and the developing immune system.

Problems for Adults

Cardiovascular Disease
At least 12 scientific studies have linked mercury to cardiovascular diseases including increased blood pressure, irregular and increased heart rate and increased rates of death from heart attacks.

Mercury is among a group of chemicals that can cause infertility according to the National Research Council. It is believed that mercury exposure can lead to spontaneous abortions.

Kidney Damage and Cancer
Mercury causes kidney damage and is classified as a “Possible Human Carcinogen” by the EPA and IARC. While there is inadequate information to draw a conclusion based on human studies, it has been shown to cause kidney tumors in male laboratory mice.


  • Check out these mercury testimonials of real people affected by mercury pollution.
  • You can find more stories in Dr. Jane Hightower’s book Diagnosis Mercury