Technical Bulletin No. 0935: Water Column Chlorophyll A Patterns in the Long-Term Receiving Water Study Rivers

Concerns over nutrient enrichment in the nation’s water systems have led EPA to require the states to develop numeric nutrient and algal biomass criteria, including water column chlorophyll a (chl a) concentrations, for restoring and maintaining the chemical, physical, and biological integrity of aquatic systems. In response, water column chl a was collected from the Long-Term Receiving Water Study (LTRWS) rivers as part of the suite of water quality and biological variables used to assess patterns related to pulp and paper mill effluent in four mill effluent receiving waters representing three EPA subecoregions. Overall, water column chl a concentrations were low and largely unrelated to mill location in all LTRWS rivers.