ASSESSING THE ACIDITY OF WATER DRAINING INTO RIVERS AND ESTUARIES
Effect of Acidity
ASSESSING THE ACIDITY OF WATER DRAINING INTO
RIVERS AND ESTUARIES
Introduction to acidity and pH
The acidity of water is usually measured with the pH scale. This is a number that varies between
1 and 14. A pH of 7 is said to be neutral. A pH value of more than 7 is said to be alkaline, and a
pH of less than 7 is said to be acidic. The degree of acidity increases as the pH value decreases
A drop of one pH unit means that the acidity increases ten times. For instance, a pH of 2 is ten
times more acidic that a pH of 3.
The following figure shows the pH of some common substances.