pH Sampling

pH is a measure of the alkalinity or acidity of a substance. This is measured on a scale from 1 to 14. Lower pH values indicate more acidic conditions while higher pH values indicate more alkaline (or basic) conditions. Factors such as bedrock type or influence from other sources such as sewage treatment waste can affect this. pH can be affected by chemicals in the water and can therefore change many chemical and biological processes in the aquatic ecosystem. Low pH can allow toxic elements in the water to become mobile. This can produce conditions that are toxic to aquatic life, particularly to sensitive species. Most aquatic animals prefer a range of 6.5 – 8.0. pH outside of this range reduces the biodiversity in the watercourse.

When macrophyte/ algal growth is high photosynthesis raises pH levels in rivers.