Element/ Property |
Source |
Issues |
Treatment/Practices |
Maximum Concentrations |
|---|---|---|---|---|
Bicarbonate and Carbonate (HCO3- and CO32-) |
Dissolved limestone, dolomite, and atmospheric carbon dioxide. | Lime deposits may form in plumbing and irrigation systems with high bicarbonate and carbonate levels in the water when calcium and magnesium are also present. | Lower the pH through acid injection. | Household water: No standard has been set; see TDS section on page 10. Irrigation: Calcium carbonate may form on equipment or plants. Levels of 180-600 ppm can be severely hazardous. See Alkalinity section. Livestock: Current limit not established; see TDS section below. |
| Boron (B) | May be found naturally in groundwater, in surface water as an industrial pollutant or as a product grassof agricultural runoff and decaying plant materials. Generally, toxic boron concentrations in the soil are found only in arid regions of Texas. |
Boron can be toxic to some plants when the levels are too high. Sensitive crops may be affected at 0.33 ppm; semitolerant crops may be affected at 0.33-0.67 ppm; tolerant crops may be affected at 0.67 ppm or above. Note: If there is more than 1 ppm of boron in your water, boron levels may increase in your soil. Clay soils accumulate boron faster than do sandy soils. | Reverse osmosis and distillation. | Household water: No EPA drinking water standard set, see TDS section on page 10. Irrigation: Toxicity to many sensitive plants may occur at 1 ppm. Most perennial grasses are relatively tolerant at 210 ppm. Because crops vary in tolerance to boron, water that is marginal for sensitive plants may still be used for more tolerant crops. Livestock: CAST levels established at 5.0 ppm. |
| Bromate (BrO3) | By-product of drinking water disinfection | Increased risk of cancer. | Reverse osmosis. | Household water: 0.01 ppm, EPA Primary Drinking Water Standard. Irrigation: Current limit not established. Livestock: Current limit not established. |
| Cadmium (Cd) | Primarily found in surface water as a pollutant from industries such as electroplating. | Potential damage includes anemia, retarded growth and increased hypertension. | Reverse osmosis. | Household water: 0.05 ppm, EPA Primary Drinking Water Standard. Irrigation: 0.01 ppm for long-term use; 0.5 for short-term use. Livestock: 0.05 ppm — limit recommended by NAS; CAST established limits at 0.5 ppm. |
| Calcium (Ca) | Dissolved rock, limestone gypsum, salts and soil. | A component of water hardness, calcium can combine with bicarbonate and carbonates and cause “lime deposits,” scale, extremely hard water and salinity (see Hardness). | Add water softeners or use similar ion exchange methods. | Household water: No EPA drinking water standard has been set; see the TDS section on page 10. Irrigation: Current limit not established, see the TDS section on page 10. Livestock: Current limit not established; see TDS section; potential problems with dairy cattle >500 ppm. |
| Chloride (Cl) | In nature, chloride comes from dissolving minerals. May be found in large amounts in oilfield brine, sea water and industrial brine. In surface water, may be from road salt, fertilizers, industrial wastes or sewage. | When combined with sodium, chloride makes drinking water taste salty and may make the water more corrosive. May also blacken or pit stainless steel. | Reverse osmosis. | Household water: More than 250 ppm may cause the water to taste salty (EPA Secondary Drinking Water Standard). Irrigation: More than 900 ppm is considered unsuitable for all agronomic crops. Livestock: Current limit not established, see TDS section on page 10. Recommended maximum concentration 15,000 ppm. |