Secondly, irrigation is necessary in many sites due to the fact they are concentrated in warmer dryer climates. Therefore, runoff can create high levels of pollutants in the water supply and in the atmosphere itself. An 18 hole golf course requires 3 to 4 tons of various herbicides and pesticides every year to keep greens and fairways looking healthy, kill weeds, and control insects. Nitrogen and phosphorus in fertilizers will eventually flow into water supplies and could stimulate the growth of algae among other ecological impediments. It is known that golf courses use pesticides that contain organic phosphorus and after application, the pesticides evaporate into the air and can be absorbed into the bodies of animals, including humans.
Winds can carry chemicals to nearby neighborhoods and create many health problems.
In Canada soil samples and sediment from aquatic sites were taken from some test courses and shown to have exceeded Canadian environmental levels for mercury. Water life was also tested and shown to have higher mercury content than those some distance from the golf courses. Once again, when courses are built on scenic and natural sites as they so often are, there would be a negative impact on biodiversity in those regions. Golf courses in the Puget Sound region have their own unique set of environmental issues. First, is the immense population growth taking place, creating a demand for recreational sites, including golf courses.