Sixty-six percent of rivers from New Hampshire to Florida and east of the Appalachians have a growing basic (alkaline) problem according to new research conducted by geologist Sujay Kaushal of the University of Maryland that was published in the Aug. 26, 2013, issue of the journal Environmental Science and Technology.
The researchers looked at records of pH trends in 97 major rivers in the Eastern United States and found a general increase in pH over the last 60 years. No rivers were found to have experienced changes that made the water more acidic.
The increasing alkalinity was traced to the burning of fossil fuels to produce electrical power and acid runoff from mining. The two sources of acid increase the rate of erosion of alkaline minerals in the carbonate rock that makes up a large portion of the Appalachians. The thinness of the soil layer on the mountains also speeds up the process. Similar erosion of concrete surfaces adds to the problem.
Despite the Clean Air Act and more recent laws designed to reduce air pollution, acid rain and the effects of acid rain are still a player in the river system of the Eastern United States.
Higher alkalinity increases the costs of cleaning water before people can use it safely, changes the types of algae that grow in rivers, and can kill fish and other aquatic wildlife that cannot cope with an increasingly basic environment. Using alkaline water to in the production of crops for humans may have as yet unknown health effects.
This is the first time scientists have found that acid rain has produced a basic change in the majority of rivers in such a large area.