Today's question: We used to hear a lot about acid rain. What is acid rain? Is it still a problem, and does it affect water supplies?

Plain Talk answer: Acid rain forms when particles from natural sources, such as volcanoes and decaying vegetation, and man-made sources, primarily sulfur dioxide and nitrogen oxides, are released into the atmosphere. Most emissions come from burning fossil fuels such as coal to generate electrical power and gas-burning vehicles. The rain falls on surface waters and land that runs into surface waters, increasing acidity in the water. Natural aquatic and plant life have a hard time surviving in these conditions.

Because of the Clean Air Act and other environmental regulations, these types of emissions have declined in recent years and acid rain is not the threat it used to be, but it does remain in some areas.

Scientists have predicted that further emission reductions are necessary to prevent increasing damage to North American ecosystems, particularly in New England, some parts of the Rocky Mountains and much of Eastern Canada.

Water treatment plants can adjust the pH levels and balance the water between acid and alkaline, so it isn’t a problem with the water you receive at the tap.

For more information on this and many other water-related topics, check out Plain Talk About Drinking Water by Dr. James M. Symons.