Ability of a material to allow the passage of a liquid, such as water through rocks. Permeable materials, such as gravel and sand, allow water to move quickly through them, whereas impermeable material, such as clay, don't allow water to flow freely.
Glossary » P
PERMEABILITY
PESTICIDE
Any substance or mixture of substances used to prevent, destroy, repel or mitigate any pest. A pesticide may be a chemical substance, biological agent (such as a virus or bacterium), antimicrobial, disinfectant or device used against any pest. Pests include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, spread disease or are a vector for disease or cause a nuisance
pH
A measure of the acidity or basicity of a solution. The pH value of a body of water expresses its tendency to donate or accept hydrogen ions on a scale of 0 (very acidic) to 14 (very basic). Natural waters range from pH 6.5 to pH 8.5 and are often slightly basic.
PHOSPHORUS
Biologically available phosphorus is found in lakes, waterways and wastewater in the form of phosphates. The discharge of treated wastewater and agricultural drainage into a lake will increase a lake’s phosphate levels. Lawn and landscape fertilizer runoff is another major source of phosphate in lakes and their use should be avoided near the water. Phosphate increase is the most common cause of undesirable growth of aquatic weeds and algae
PLANKTON
Small organisms that float or drift in great numbers in bodies of salt or fresh water. Plankton is a primary food source for many animals, and consists of bacteria, protozoans, certain algae, cnidarians, tiny crustaceans, and many other organisms.
POINT SOURCE POLLUTION
Water pollution coming from a single point, such as a pipe.
