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Nasty NitratesW

eutrophication

Nasty Nitrates

We start off the new month of February with the second in our new series of Wise Water Words from OSFR about how we can all help our water, whether it be on the surface or down in the ground/limestone.  For those of us in a rural area, especially those in a high aquifer recharge area, we need to be very observant as to our use of  lawn fertilizers and septic tanks, as they, along with agriculture,  are the primary sources of excessive nitrogen and phosphorous in our water.

Our thanks go to Media Committee Chair Patty Street of OSFR who provided the following information.

Comments by OSFR historian Jim Tatum.
-A river is like a life:  once taken, it cannot be brought back-


We all need nitrogen.  Animals get nitrogen by eating plants and other animals.  Plants get nitrogen from water and the soil.  They absorb it in the form of nitrates and ammonium.  Nitrates are the major source of nitrogen for aquatic plants. (Fish and aquatic insects do not utilize nitrates.)

Nitrates occur naturally in soil and water, and, as long as this balance goes undisturbed, all is well.  However, excess levels of nitrates, which contaminate ground and surface waters, are occurring at alarming rates.  These excess levels can be traced to human activity:

  • agricultural practices
  • human wastes
  • industrial pollution

Nitrogen fertilizers are used on yards, field, and golf courses.  If too much is used (plants can absorb only so much), the excess is washed away into streams, rivers, and ground waters.  The same happens with animal waste and manure.

In addition, untreated human sewage also contributes to nitrate levels in surface and ground waters.  Leaky or poorly functioning septic tanks contribute to these levels, as well as city treatment plants.  Although these plants treat sewage to make it non-hazardous to humans, they still release nitrates into the waterways.  Industrial plants and agricultural processing operations are also sources of nitrate pollution.

Here is an illustration of how too many nitrates affect our water quality:

eutrophication

Eutrophication is the process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates.  These nutrients promote excessive growth of algae, which, when it decomposes, depletes the water of available oxygen.   This causes the death of other organisms, notably, fish.

Too many nitrates can also harm humans.  Nitrates can interfere with the ability of our red blood cells to carry oxygen.  This can be especially harmful to children, with the possibility of brain damage.  If you live in a rural area and your primary source of drinking water is from your well, you might want to have your water tested.  Nitrates are colorless and odorless and can’t be detected without special equipment.

What can we, as individuals, do to reduce the presence of nitrates in our groundwater?  The list is long:

  • Do not fertilize plants or yard during the winter months of December, January and February. Roots are dormant during these months, so any nitrogen won’t be used by the plants and, therefore, will leach into the groundwater.
  • When you do fertilize, purchase fertilizer with a low nitrogen number, preferably less than 10. It should also contain a MINIMUM of 50% slow release nitrogen.  Slow release nitrogen is not water soluble, meaning it does not leach into the groundwater.  It will remain in the soil longer (where you want it) and stay out of the watershed.
  • GO NATIVE! Use native plants in your landscape, and you won’t need as much fertilizer or water.  Natives are acclimated to Florida’s climate, it’s ups and downs in temperature and rainfall.  They will thrive with very little attention.
  • Instead of a yard full of grass that must be constantly maintained as a lawn, try Xeriscaping, or planting ground covers, or even a mixture of native plants and vegetables!
  • Get your soil tested. If the soil is too acidic, it is keeping nitrogen from getting to your grass/plants.  When pH is balanced, your lawn will use nitrogen more efficiently, keeping applications to a minimum.
  • Try not fertilizing. Nitrogen occurs naturally in the soil, so you may have enough already.

The idea is to use as little fertilizer as possible, to keep excess from leaching into our groundwater.  Every little bit counts.

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2 Comments

  1. I have always wondered why a leaky septic tank can cause problems. In a “healthy” septic tank the liquid is dispersed in a drainage field and goes into the aquifer. Can anyone explain to me why a leaky septic tank changes this equation?

    1. and, just for the record, the majority of my yard is comprised of edible native plants which need no watering or fertilizing:)

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