EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > WATER QUALITY/WATER CHEMISTRY > WATER CHARACTERISTICS > pH
A measure of the alkaline or acid strength of a substance. pH is defined as the logarithm of the reciprocal of the hydrogen ion concentration of a solution.
Adapted from: Porteous, A. 1996. Dictionary of Environmental Science and Technology, Second Edition. John Wiley and Sons. p. 413.