What are the permissible levels of trace elements (such as arsenic, copper, iron, lead, and zinc) in water for the water to still be considered safe for exposure/bioaccumulation by people and aquatic life?
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Question:
What are the permissible levels of trace elements (such as arsenic, copper, iron, lead, and zinc) in water for the water to still be considered safe for exposure/bioaccumulation by people and aquatic life?
Answer:
Several of these trace elements are regulated by the EPA and are on their list of primary drinking
water standards. These include arsenic, copper, and lead, as well as cadmium,
chromium, mercury, and selenium. Iron is not a regulated contaminant because it
is not known to cause health problems, but there is a secondary drinking water
standard based on its tendency to stain laundry and plumbing fixtures.
Manganese, copper (again), silver, and zinc are also included in the secondary
standards. The primary and secondary standards are available on the EPA Web
page Current Drinking Water Standards.
The above standards are national drinking water standards. Other water-quality
standards are set by states to protect aquatic life. You can check with your
state environmental or natural resources agency to see what aquatic life
water-quality standards are in effect in your state. EPA is currently reviewing
its recommendations for aquatic life criteria. The existing criteria are found
at http://www.epa.gov/OST/standards/wqcriteria.html
and more information on the current review of standards is available on Aquatic Life Water Quality Criteria.
The USGS National Analysis of Trace Elements also has current information on trace elements across the United States, including links to specific studies and current items in the news.
