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Water: Total Maximum Daily Loads (303d)

EPA Decision on Whether to Re-evaluate and Revise its Recommended Marine pH Water Quality Criterion

On April 15, 2010, EPA sent a letter to the Center for Biological Diversity (CBD) describing its decision to not revise the existing Clean Water Act section 304(a)(1) marine water quality criterion for pH at this time.  On April 15, 2009, EPA published in the Federal Register a Notice of Data Availability (NODA) containing data and information provided by CBD and others regarding the potential effects of ocean acidification on aquatic life, and simultaneously solicited data and information from the public to inform the Agency's decision on whether to re-evaluate and revise its marine pH criterion.  Ocean acidification refers to the decrease in the pH of the oceans caused by the uptake of carbon dioxide from the atmosphere. 

In making its decision to not revise the criterion, EPA carefully reviewed all of the information received from the public during the NODA process as well as additional information from the National Oceanic and Atmospheric Administration (NOAA).  Currently, there is not sufficient data to revise the National recommended criteria for marine pH to appropriately address the natural variability in pH across coastal regions.

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