How does excess fertilizer products affect a groundwater source?
Excess fertilizer products affect ground water in two ways. One way is when excess fertilizer products dissolve in rainwater and gradually seep into the ground and mix with the ground water thereby contaminating it.
Another way the the excess fertilizers in the soil enter the ground water is when they get carried off with rain water and enter into streams as run off. When the water in streams replenish ground water the fertilizers mix with the ground water thereby contaminating it.
It depends on the source of the groundwater. Excess fertilizer that is carried by run-off into a lake could destroy water quality. Fertilizer causes rapid growth of plants and algae, rapidly depleting available nutrients. Eventually, a large portion of biomass die off to be decomposed by aerobic bacteria. Decomposition of biomass consumes dissolved oxygen, creating a hypoxic crisis. The lack of oxygen kills the remaining aerobic organisms. Anaerobic bacteria/Facultative anaerobic bacteria will remain, further decomposing dead biomass, potentially creating toxins that spread into ground water.
