Acid neutralizing capacity

Long-Term Trends in Acid Neutralizing Capacity under Increasing Acidic Deposition: A Special Example of Eutrophic Taihu Lake, China, Tao Yu, Qiujin Xu, Chengda He, Haibing Cong, Dan Dai, Fengchang Wu, and Wei Meng, Environ. Sci. Technol., 2016, 50 (23), pp 12660–12668.

In Chapter 11, acid neutralizing capacity (ANC) is defined in Section 11.3 on Alkalinity. This paper provides a unique case study in a region of the world still afflicted by serious and on-going acidic input. The authors describe the Taihu region in China as being seriously impacted by acid rain with an average rainfall pH of less than 5. However, the ANC and pH of Taihu Lake have increased over the past 60 years according to their calculations. Their analyses show that watershed neutralization by carbonates and algae activity were the two major processes responsible for this increase. However, future projections show that these neutralization processes will be depleted by the early 2040s at the current rate of acid input and urge an “integrated and balanced” recovery plan be implemented for this ecosystem.

Ocean acidification

Environment: Earth's acid test, Schiermeier, Q., Nature 471 (2011) 154-156 (Published by Nature, March 2011).

On pp 256-259 of Environmental Chemistry we examine some basic calculations related to aqueous carbon dioxide and its effect on the solubility of calcium carbonate (limestone). A later discussion, pp 360-362, follows up with a brief look at the same issues in the ocean environment. With increasing atmospheric carbon dioxide levels and therefore its greater accumulation in water through Henry’s Law, acidification of the oceans is occurring.  This paper presents some predictions showing how the increased atmospheric carbon dioxide bring changes in pH and how this is affecting not only sedimentary carbonate dissolution but also other important aspects of marine life.