Increasingly, the concentration of phosphorus and its anionic forms (phosphates) in Ohio rivers has caused great concern among the environmental community. Phosphorous, often the limiting nutrient, is a crucial element in stimulating plant growth. Before phosphorus can be readily used by plants, it is converted to its orthophosphate form (PO43-) by the bacteria present in surrounding soil. As soil enters the water due to stormwater runoff, the presence of excess phosphorus and the bacteria capable of producing orthophosphate galvanizes the growth of algae and other nuisance fungi detrimental to river ecosystems (EPA.ohio.gov). This process of eutrophication, the natural aging of a lake or bay which can take thousands of years, occurs at a much faster and environmentally alarming rate in the presence of increased concentrations of phosphates (water-research.net). This accelerated aging causes an abnormality in the natural cycle of water systems. As rivers, lakes and bays age over long periods of time, new bodies of water are able to form and host similar ecosystems thereby continuing the natural development process. Consequently, high concentrations of phosphates are causing an imbalance in the natural geological order of Ohio’s rivers.
In combination with super-eutrophication, phosphates are responsible for the death of aquatic life by the “choking” of a waterway or the decrease of oxygen concentrations to levels that can no longer support aquatic life.
While stormwater runoff is one source of phosphorus discharge, there are many other point sources that cause phosphates to reach water systems. These include septic tanks, animal waste and runoff from feedlots, cleaning products with phosphates, industrial effluents and waste water treatment plants.
The following criteria for total phosphorus were recommended by US EPA (1986):
1. no more than 0.1 mg/L for streams which do not empty into reservoirs,
2. no more than 0.05 mg/L for streams discharging into reservoirs, and
3. no more than 0.025 mg/L for reservoirs.
Content on this web page authored by Dimitry Grinevich, Daniel Beckett, Meaghan Novi, Matt Van Avermaete & Andrew La Rosa