Changes in Ca2+, alkalinity, dissolved inorganic carbon (DIC) and pH have occurred in the epilimnion of Onondaga Lake over a 10-yr period, in response to a major reduction in external Ca2+ loading that resulted from the closure of an adjoining soda ash manufacturer. These changes included reduced Ca2+ concentrations, diminished depletion of DIC and alkalinity in the upper waters in the summer, and a shift to higher pH values. Results of analyses from sediment trap collections before and after closure of the facility indicate approximately 3-fold reductions in particulate inorganic carbon (PIC), and suspended solids deposition have occurred as a result of the closure. Despite these changes, the water column remains oversaturated with respect to the solubility of CaCO3. Moreover, there was no apparent relationship between the degree of CaCO3 saturation and PIC deposition. Changes in the extent of CaCO3 precipitation have altered the acid-base chemistry of the lake which, in turn, affects prevailing pollution problems associated with inputs of domestic waste, such as NH3 toxicity.
ASJC Scopus subject areas
- Environmental Chemistry