Under most conditions ground water contains greater amounts of dissolved minerals than do surface supplies. But as water percolates through sand, rock and clay formations, it loses much of the suspended matter, colour and bacterial contamination it gathers at the surface.
That's why very deep wells are likely to provide water that is clear, colourless, low in bacteria and high in minerals. There are exceptions, however, that make generalizations somewhat difficult.
Springs also provide ground water. On the whole they contain significant amounts of dissolved minerals.
MAJOR CONSIDERATIONS IN TH E USE IF GROUND WATERS include:
• The presence of hardness and other minerals in larger amounts than in surface waters of the same locality as a rule.
• Iron and Manganese in many well supplies.
• Hydrogen Sulfide sometimes present
• The cost of pumping well water usually greater than pumping surface water.
• The mineral content of several wells may differ widely even though located close to each other.
• Occasional uncertainties of supply.
• Limited possibility of bacterial contamination as compared to surface waters.
• Generally more consistent in temperature, minerals, ect. than surface waters.
For example: we classify lakes, rivers, reservoirs and ponds as surface water. These bodies receive water directly from precipitation and from surface run-off. They also derive a portion of their supplies from underground springs connected with ground water sources.
While surface water, as a rule has the advantage of lower mineral content, there are certain disadvantages to be considered:
• The presence of much contaminated matter making water unfit for human consumption until properly treated.
• Industrial & Municipal Pollution of many supplies.
• Surface run-off bringing mud and decayed vegetation into the water.
• Possibility of animal and human wastes in the water.
• In many cases good environments for algae and bacteria.
GROUND WATER vs SURFACE WATER:
Regardless of the mineral and organic make-up of a water source, both deep wells and large lakes make available water that is more or less of consistent quality from season to season. In contrast, many small bodies of water, shallow wells and springs often reflect seasonal and even daily variations in their mineral content.
TIPS and ADVICE:
Water is our most amazing and precious natural resource. It has been called the "universal solvent" due to its ability to dissolve many different minerals, compounds and chemicals. Many of these dissolved materials are objectionable, cause property damage and can even health concerns in some cases. The following provides basic information on some of the most prevalent water problems and how to best deal with reducing or removing them from your water supply.
Hardness - Water hardness is derived from calcium and magnesium minerals that have been dissolved into water beneath the earth's surface. These minerals are found in limestone deposits and are the primary source of hard water. When the minerals dissolve, they become electrically charged particles call ions. The amount of hardness in any given water is dependent upon the amount of calcium and magnesium minerals present and the length of time the water stays in contact with them. The degree of hardness varies greatly from region to region and should, therefore, be checked and quantified by proper water testing. The degree of hardness is measured in Grains per Gallon (gpg). In order to protect plumbing, fixtures, clothing, etc., the hardness level should generally be adjusted to less than 3.0 gpg.
Iron & Manganese - Iron and manganese compounds are very common in rocks and soil. These compounds are easily leached into the water supply after coming into contact with ground water, particularly acidic water. Iron and manganese are well known for depositing red, orange and/or black stains on plumbing fixtures, laundry, and anything the water touches. These water constituents are measured by quality water testing and quantified in Parts per Million (PPMS) or Milligrams per Liter (mg/l). Serious damage to the entire water system may result if these compounds exceed the maximum contamination limit. The limit for iron is 0.3 mg/l and for manganese, 0.05 mg/l.
Iron/Manganese/Sulfur Bacteria - These are actually living organisms that are often found present in waters. They are not known to cause disease but can create a host of other problems. They feed on the minerals: iron, manganese and sulfur. In addition to the characteristic red, orange and/or black staining, they generally create slimy deposits in areas like toilet tanks. In order to rid a water supply of these problems, the organisms must be killed (usually by chlorine) and the source of their food must be eliminated. There is no defined "limit" allowable for these organisms since virtually any level will eventually cause problems.
Hydrogen Sulfide - This constituent is very easily identified by the awful "rotten egg" smell it releases. Hydrogen sulfide gas can permeate an entire home or building with its rank odor. In addition, it is extremely corrosive and can attack piping, tanks, water heater elements and any metallic surfaces it contacts. Since it is present as a gas in water, it usually must be tested at the source since it will dissipate quickly when released from the water system. Virtually any level of this gas can be offensive and destructive and often varies in concentration throughout the period of a year based on numerous factors including the amount of the rainfall and even barometric pressure. Amounts as minute as 0.05 mg/l can be detected by many individuals and cause property damage over a period of time.
Turbidity & Colour - These problems can originate from any number of sources. Obvious is the presence of light-to-heavy color or a fine "grit" in the water. Clay, sand and silt can be a source for turbidity, or the presence of tiny particles. These particles can cause serious damage to the moving parts of appliances like washing machines, dish washers, etc. The colours can cause staining in clothing. Proper water testing is usually required to best determine the real cause of such problems. Typically, a good quality mechanical filter will handle most of such problems.
Acidic Water - Water is defined as alkaline (basic) or acidic depending on the pH. If water is acidic, it will have values from 0 to 6.9; if alkaline, from 7.1 to 14. Water with a pH of 7 is considered "Neutral." Corrosion is usually associated with acidic water. Corrosion can release toxic metals such as lead, zinc, copper and cadmium from pipes or plumbing fixtures. The corrosion associated with low pH can literally destroy all types of metal plumbing and fixtures. Fixtures can have blue-green stains caused by the corrosion of copper or brass plumbing or red stains caused by the corrosion of iron plumbing. If not corrected, the corrosion will eventually cause pin holes in piping and necessitate extensive plumbing repairs. Waters with a pH below 6.8 should be corrected to avoid such problems. Other problems can occur in water with a high pH. For example, when the pH exceeds 8.5, water may have an alkali taste, scale may form in pipes and equipment, the germicidal activity of chlorine is reduced, and trihalomethane formation is accelerated.
Taste & Odour - These problems can be caused by any number of sources. A "rotten egg" odor is typically caused by the presence of hydrogen sulfide gas. There can be various other objectionable tastes and odors in water caused by the presence of underground organic chemicals, naturally occurring decomposition like humic matter, etc. Problems of this nature are often difficult to trace to a specific source. Of course, any water with a "chemical" smell should be tested for the presence of industrial chemical, herbicides or industrial waste due to potential health consequences. Normally, however, a simple carbon filter can deal with most "general" tastes and odours.
Tannins/Humic Acid - These naturally-occurring compounds result from water coming into contact with decaying leaves and various other types of vegetation. Some of the problems will be slight odors, odd tastes, yellow color and possible staining of fixtures and clothing. Another major problem is the fact that these compounds can seriously affect the proper performance of other types of water treatment equipment like softeners and filters. These organic compounds tend to "coat" ion exchange resins, filtration media and synthetic membranes. Specialized resins used in a softener-type system can effectively deal with such problems.
Coliform Bacteria - The presence of these living organisms in a water supply for human/animal consumption and use can be VERY DANGEROUS! This group of organisms originate from human and animal wastes. They can enter a water system through cracks in well casings, improper well construction or directly from areas of waste like sewage leach beds and septic systems. The possible presence of such dangerous organisms is why every water system should be tested on a regular basis by the local health authority. Should such organisms be found, the source of such contamination must be determined and corrections made. Local health authorities should always be consulted for proper testing and correction methods.
Organic Chemicals - Many organic compounds resulting from the decay of decomposing natural matter can occur in water (such as tannins, lignin's, etc.) and, although troublesome, are not generally a concern from a health standpoint. However, there are cases where industrial chemicals, herbicides, pesticides and byproducts of chlorination (like THM's) can exist in a water supply and should be considered a POTENTIAL HEALTH HAZARD unless testing proves otherwise. Many have been related to cancers and other diseases. Proper testing for such contaminants is always recommended. If the source of such problems cannot be determined or corrected, carbon filters of various designs have often been found to reduce such problems. Local health authorities should always be consulted for proper testing and correction methods.
Nitrates/Chlorides/Sulfates - These water constituents can sometimes be present in water supplies. Usually occurring in rural and private water supplies, nitrates are of most concern due to the possibility SERIOUS HEALTH EFFECTS, especially for young children. Nitrates can enter a water system from such possible sources as manure, fertilizers and some types of waste. A condition known as "Blue Baby Syndrome" can occur in young children as a result of the intake of nitrates. Local health authorities should always be consulted for proper testing and correction methods. Chlorides and sulfates can also enter a water supply from various sources but, in low concentrations, are not generally a serious health concern. Intestinal upset and diarrhea in some individuals have been reported where high levels are present. Maximum levels are: 10 mg/l for nitrates (as nitrogen), 1 mg/l for nitrites (as nitrogen); 250 mg/l for chlorides; and 250 mg/l for sulfates. All of these contaminants can typically be reduced or removed with specialized water treatment equipment or, preferably, elimination of the source cause.
Sodium Salts - These simply result from the presence of "sodium" compounds. They are often naturally-occurring in certain water supplies. In other cases, the ion exchange process of water treatment will introduce sodium compounds. In either case, high levels of sodium compounds can cause a salty, soda or alkaline taste in the water. Excess sodium compounds in water are easily reduced or removed by deionization or reverse osmosis systems.
Any questions or comments email us at: firstname.lastname@example.org
Hydrologic Cycle image source: www.online.wvu.edu/Faculty/demo/Module_2/hydrologic.html