Phosphorus is one of the most important components in the ongoing struggle to balance agricultural prosperity with water quality. When farmers fertilize their fields with this essential nutrient, plants use some, with precipitation carrying excess amounts into nearby bodies of water, fueling algal blooms that can kill fish and and endanger drinking water quality.
But phosphorus that lingers in the soil, sometimes for decades, is troublesome as well.
What scientists call “legacy phosphorus” — or “legacy P,” a common abbreviation — exists in a sort of nutrient limbo.
Phosphorus can easily bind to soil particles, a state in which plants don’t usually access it. The nutrient generally must be in water plants take up in order for them to use it. Moreover, as farmers spread more fertilizer, new quantities of phosphorus are made available to crops. But as land erodes or heavy rains hit fields, some of that older phosphorus will make its way into streams, rivers, lakes and ultimately groundwater. In coming decades, greater quantities of legacy phosphorus could get flushed into water sources due to climate change, which is projected to increase heavy precipitation events in the Midwest.
Portland’s first snowstorm of the winter storm season hit mid-day prompting thousands of people to head home early. Unfortunately, roadways were clogged for hours leaving many to abandon their cars. Cautious motorists decided to stay home from work when the second snowstorm that left roadways icy for days. Portland is now looking at adding road salt to their arsenal to make road ways safer.
The city is concerned with the damaging effects of road salt. It would ultimately get washed into storm drains which flow to a sewer treatment plant. Will the salt corrode old metro-area pipes? It affects the roads, the steel in the bridges and the concrete and it affects your car. And, the salt that stays on the roads will eventually get washed into the environment.
Minnesota is beginning to see some of the environmental effects of road salt use. In the Twin Cities metro area, the level of salt (chloride) in 39 surface waters now exceeds water quality standards. An additional 38 surface waters are almost above the standard and many others remain untested. Data shows that salt concentrations are continuing to increase in both surface waters and groundwater across the state.
The fact is that it only takes one teaspoon of road salt to permanently pollute 5 gallons of water. Once in the water, there is no way to remove the chloride. At high concentrations, chloride can harm fish, aquatic plant life, groundwater and drinking water supplies.
The Environmental Protection Agency reports that 40% of the nation’s waterways suffer water quality problems. Water systems are often interlinked and the dangers of runoff from agriculture, forestry, construction and people’s personal yards are numerous.
Did you know that a typical city block generates more than five times as much rainwater runoff as a forested area of the same size? This is because rooftops and pavement don’t allow water to soak into the ground like forests, wetlands and grasslands do. Instead, rainwater runs off pavement into the nearest storm drain, where it’s transported to local streams, rivers and eventually the ocean. On its way to the storm drain, rainwater picks up pollutants like oil, antifreeze, pet waste, fertilizers and pesticides. In most places, storm water does not get treated, so all of those pollutants end up in local waters.
Using non-toxic house products, not dumping things other than water down storm drains, and not flushing medication down the toilet or sink are just a few things you can do to keep the water in your area clean.