Anything that has been shown to, or suspected of, causing ill health or disease if consumed.
For example, a high level of lead in water is “pathogenic”, leading to brain damage.
The measuring standard for the degree of acidity of a liquid or soil. High pH means the liquid or soil is acidic; low pH means the soil or liquid is more alkaline. The pH of the human body usually in a range of 7.2 to 7.8 – not too acidic and no too alkaline. Water should be in a similar range.