Water Quality

Impacts of deicing salt use on metal and radionuclide mobilization – implications for ground and surface water quality

Farmers complying with the Food Safety Modernization Act Produce Safety Rule are required to take many water samples on their farms. This document reviews environmental factors that affect surface water quality test results and how farmers can reduce the impacts of these factors.

Until recently, the point-of-use water treatment industry focused on improving the aesthetic quality of drinking water. The industry has lately been thrust into the forefront of treatment of contaminated drinking waters that pose a serious health hazard. The response has been a plethora of companies and products promising to render the consumer’s drinking water safe and contaminant free. The individual is left to sift through advertising claims and technical data to select the appropriate treatment method.

Water is often called the universal solvent. As water moves underground or over land, it dissolves a variety of compounds including minerals, salts, and organic compounds. The concentration of “total dissolved solids” (TDS) in a water sample is a measure of the dissolved compounds in the water small enough to pass through a 2-micrometer sieve. For comparison, one human hair is approximately 100 micrometers in diameter. A TDS test measures the amount, but does not identify the individual compounds or their sources.

Sodium and chloride, which together compose common table salt, often occur naturally in groundwater as it dissolves minerals underground. Higher levels of sodium and chloride in household water, however, often come from manmade sources such as road salt, industrial wastes, sewage, fertilizers, or water softeners. In coastal areas, sodium and chloride can also enter groundwater via salt water intrusion into fresh water aquifers. In high enough concentrations, salt water intrusion can render groundwater unsuitable for drinking, cooking, or irrigating.

Iron and manganese are naturally occurring minerals found in certain rocks and soils that can be dissolved by groundwater. Corroding iron or galvanized steel pipes may also be a source of iron in household water. Typically, neither iron nor manganese presents a health risk to humans when present in a household water supply; however, a portion of the population suffering from hemochromatosis (excess iron in the body) may be especially sensitive to iron in drinking water. Iron and manganese are primarily associated with nuisance problems such as staining of clothes and plumbing fixtures or objectionable taste. Iron and manganese are similar chemically and therefore produce similar problems. Iron and manganese are usually either dissolved (in solution) in water or found in particulate form.

Heavy metals such as lead, copper, cadmium, arsenic, and mercury may be present in water supplies for a variety of reasons. Lead and copper most commonly leach into water supplies through corrosion of household plumbing fixtures, pipes, fittings, and solder, and cadmium contamination may occur as a result of impurities in the zinc of galvanized pipes or fittings. Water supplies that are corrosive are more likely to leach lead, copper, and possibly cadmium from pipes and fittings, if these metals are present in plumbing systems. Some factors that can indicate corrosive water include low pH, high temperature, low total dissolved solids content, and high amounts of dissolved oxygen or carbon dioxide.

Hard water contains high levels of calcium and magnesium ions. These ions, among others, are naturally dissolved into groundwater as it comes in contact with soluble limestone and other rocks and minerals. While consuming hard water does not present a health risk, it may cause aesthetic or nuisance problems such as bitter taste or mineral deposits (scale) on dishes, utensils, and plumbing fixtures. Hard water can also reduce the efficiency and life span of water heaters.

Concerns about personal and family health may lead you to question the safety of the water used in your household. Perhaps you have been alarmed by recent publicity about water pollution problems and their effect on water used in the home for drinking, cooking, and many other purposes. You may be particularly uncertain about the quality of your household water if you rely on your own well or other private water supply. With the availability of modern water treatment equipment and the aggressive marketing of these devices, you may wonder about the need to install such equipment in your home.

Knowing the amount of sodium in your drinking water is important for your health, especially if you have high blood pressure. Sodium is an essential mineral for maintaining a healthy fluid balance and is important for brain function and muscle contractions but consuming too much sodium can elevate your blood pressure.