Overview
Selenium is an essential element in diets. But too much selenium can decrease thyroid hormone production and cause hair loss, skin lesions and brittle fingernails.
State, National, and Health Guidelines for Drinking Water
EWG Health Guideline: 30 ppb
The EWG Health Guideline of 30 ppb for selenium was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against hair loss and nail damage.
EPA Maximum Contaminant
Level (MCL): 50 ppb
The legal limit for selenium, established in 1991, was based on human epidemiological studies of populations exposed to naturally occurring selenium in drinking water. This limit does not include any additional consideration of children’s health.
ppb = parts per billion
National Standard Exists
Health Concerns:
Hormone disruption
Harm to child development
Harm to the brain and nervous system
Skin damage
