Agriculture Reference
In-Depth Information
als can be very susceptible to high nitrates and so should not drink water that has more than
10 mg/L of nitrate. Mature animals should not drink water with more than 100 mg/L of
nitrate.
Arsenic, selenium, barium, cadmium, and mercury above recommended limits must be
removed. Check with your county Extension agent and your veterinarian for specific limits
and suspected problems in your area.
pH
You should also have the pH of your water assessed. Absolutely pure water has a neutral
pH of 7.0, and wells usually range from 6.5 to 8.0. Some metals, such as lead and zinc, are
more soluble in acid water. If water with a pH of less than 5.0 (acidic) runs through lead
pipes, it may result in corrosion and subsequent ingestion by your horse of excess lead,
which can be toxic. Water that has been softened by an ion-exchange water-softening unit
and runs through lead pipes can pick up lead and result in lead poisoning. Today plastic
water pipes are used in most residential and agricultural applications, so lead leaching is
not a problem.
The calcium and magnesium in hard water with a pH greater than 8.5 (alkaline or basic)
tend to precipitate out, causing a white, crusty residue or film. The residue interferes with
washing and rinsing and can leave a scale on horses, blankets, and buckets.
HARD WATER
If hard water is used to bathe horses or wash blankets, it makes thorough cleaning difficult
and leaves behind a white residue from the precipitated calcium and magnesium. You can
overcome hardness in wash water by using water-softening equipment or adding a soften-
ing compound.
A popular water-softening device is the common household salt-filled water softener,
which exchanges sodium ions for the calcium and magnesium ions that cause water hard-
ness. Although the water is made suitable for cleaning purposes, it becomes very high in
sodium (salt) and is often not suitable for drinking water or for watering plants. Therefore,
water from such a softener and from some softened community water would be appropri-
ate for washing horses and blankets but not for drinking unless its sodium content does not
exceed the EPA recommendation of 20 ppm for people on sodium-restricted diets. You can
soften batches of water that are specifically going to be used for washing horses, blankets,
and equipment by adding, as needed, sodium hexametaphosphate, a water softener sold un-
der the trade name of Calgon. (Do not confuse Calgon with Calgonite; the latter is a cleaner
made specifically for automatic dishwashers and contains several harsh detergents.) Sodi-
