Phosphates are an important nutrient for aquatic plants and algae, but too many nutrients can lead to unchecked growth and low oxygen conditions (see Nitrates section). Sources of phosphates include urban landscape runoff such as fertilizer and detergents, as well as human and animal wastes. In a healthy creek, levels shouldn’t surpass 0.5 mg/L.
Phosphate levels in San Pablo Creek are a concern, more than any of the other tested parameters. We routinely get readings of more than 2mg/L.
What can you do?
Pick up after your pets
Go to car washes that treat their soapy runoff
Never discharge water from your washing machine directly to the gutter (which drains to the creek)