The information below is just a small amount of what can be found in water systems and wells. It also shows the importance of doing a mineral sample as well as a bacteria sample for potential home buyers as the minerals that can be found in the water supply can be just as much of a health risk as well as bacteria. One of the important reasons for doing mineral and bacteria samples on a property is the potential unexpected costs for treatment.
Information included on this page is from Health Canada Web Site
Search under Guidelines for Drinking Water.
Canadian drinking water supplies are generally of excellent quality. However, water in nature is never “pure.” It picks up pieces of everything it comes into contact with, including minerals, silt, vegetation, fertilizers, and agricultural run-off. While most of these substances are harmless, some may pose a health risk. To address this risk, Health Canada works with the provincial and territorial governments to develop guidelines that set out the maximum acceptable concentrations of these substances in drinking water. These drinking water guidelines are designed to protect the health of the most vulnerable members of society, such as children and the elderly. The guidelines set out the basic parameters that every water system should strive to achieve in order to provide the cleanest, safest and most reliable drinking water possible.
The Guidelines for Canadian Drinking Water Quality deal with microbiological, chemical and radiological contaminants. They also address concerns with physical characteristics of water, such as taste and odour.
**See water test sample pages for limits.
The most significant risks to people’s health from drinking water come from microscopic organisms such as disease-causing bacteria, protozoa and viruses. The guidelines that relate to these microorganisms are stringent because the associated health effects can be quite severe and effect health over the long term.
There are three main types of microorganisms that can be found in drinking water: bacteria, viruses, and protozoa. These can exist naturally or can occur as a result of contamination from human or animal waste. Some of these are capable of causing illness in humans. Surface water sources, such as lakes, rivers, and reservoirs, are more likely to contain microorganisms than groundwater sources, unless the groundwater sources are under the direct influence of surface water.
The main goal of drinking water treatment is to remove or kill these organisms to reduce the risk of illness. Although it is impossible to completely eliminate the risk of waterborne disease, adopting a multi-barrier, source-to-tap approach to safe drinking water will reduce the numbers of microorganisms in drinking water. This approach includes the protection of source water (where possible), the use of appropriate and effective treatment methods, well-maintained distribution systems, and routine verification of drinking water safety.
All drinking water supplies should be disinfected, unless specifically exempted by the responsible authority. In addition, surface water sources and groundwater sources under the direct influence of surface water should be filtered.
Chemical and radiological substances may also be found in some drinking water supplies but these are generally only a concern if they are present above guideline levels.
E. coli is a member of the total coliform group of bacteria and is the only member that is found exclusively in the feces of humans and other animals. Its presence in water indicates not only recent fecal contamination of the water but also the possible presence of intestinal disease-causing bacteria, viruses, and protozoa. The detection of E. coli should lead to the immediate issue of a boil water advisory and to corrective actions being taken. Conversely, the absence of E. coli in drinking water generally indicates that the water is free of intestinal disease-causing bacteria. However, because E. coli is not as resistant to disinfection as intestinal viruses and protozoa, its absence does not necessarily indicate that intestinal viruses and protozoa are also absent. Although it is impossible to completely eliminate the risk of waterborne disease, adopting a multi-barrier approach to safe drinking water will minimize the presence of disease-causing microorganisms, reducing the levels in drinking water to none detectable or to levels that have not been associated with disease.
Other members of the coliform group are found naturally in water, soil, and vegetation, as well as in feces. Total coliform bacteria are easily destroyed during disinfection.
In semi-public and private drinking water systems, such as rural schools and homes, total coliforms can provide clues to areas of system vulnerability, indicating source contamination, as well as bacterial re growth and/or inadequate treatment (if used). Coliforms can be in a distribution system from inadequately treated source water, or contamination of the water after treatment from pipe leaks with negative pressure, pipe breaks, inadequate cleaning and disinfection after repairs, cross connections. Surges in water pressure could result in sloughing of the biofilm, increasing TC counts. TC in biofilms may result in resistance to disinfection and other measures such as flushing.
If found in non-disinfected wells, it could indicate surface water infiltration or regrowth in the well or plumbing system. Shock-Chlorination and flushing should get rid of TC although it might need to be repeated a few times. If this solves the problem then the issue is regrowth. If not the system is vulnerable to contamination. In the absence of E-Coli, the presence of TC in the distribution system is of no immediate public health significance, however, their presence should prompt further investigation and action. As they are a indicator bacteria.
The health effects of exposure to disease-causing bacteria, viruses, and protozoa in drinking water are varied. The most common manifestation of waterborne illness is gastrointestinal upset (nausea, vomiting, and diarrhea), and this is usually of short duration. However, in individuals such as infants, the elderly, and immune compromised individuals, the effects may be more severe, chronic (e.g., kidney damage) or even fatal. Bacteria (e.g., Shigella and Campylobacter), viruses (e.g., norovirus and hepatitis A virus), and protozoa (e.g., Giardia and Cryptosporidium) can be responsible for severe gastrointestinal illness. Other pathogens may infect the lungs, skin, eyes, central nervous system, or liver.
From Guidelines for Canadian Drinking Water Quality.
Boron compounds are rapidly and completely absorbed from the gastrointestinal tract, through mucous membranes and through damaged or abraded skin. Boron concentrations in the liver, kidney, brain and blood. In human tissues, the following mean boron concentrations have been reported (µg/g wet weight): kidney, 0.6; lung, 0.6; lymph nodes, 0.6; blood, 0.4; liver, 0.2; muscle, 0.1; testes, 0.09; and brain, 0.06. Boron is eliminated from the body mainly by the kidney, with minor amounts being excreted in feces, sweat and saliva; it is also excreted in cow’s milk. More than 92% elimination has been reported to occur within 96 hours of ingestion of 750 mg of boric acid in water or up to 50 mg in a water-emulsifying ointment by human volunteers. Symptoms of acute boron poisoning include nausea, vomiting, diarrhea, headache, skin rashes, desquamation and evidence of central nervous system stimulation followed by depression. In severe cases, death usually results in five days as a result of circulatory collapse and shock. The acute lethal dose of boric acid has been estimated to be 15 to 20 g for adults, 5 to 6 g for infants and 1 to 3 g for newborns. Children, the elderly and individuals with kidney problems are most susceptible to the acute toxic effects of boron.
Krasovskii et al. examined the sexual function of men (determined by questionnaire) living in areas with varying concentrations of boron in water supplies (“0.015, 0.05 or 0.3 mg/kg”). It was reported that there was a tendency towards a reduction of function in men consuming water with a boron content of “0.3 mg/kg.” However, the validity of the results could not be assessed owing to the lack of information included in the published account of the study.
The aesthetic objective for sodium in drinking water is ≤200 mg/L. Sodium is not considered a toxic element; up to 5 g/day of sodium is consumed by normal adults. Although the average intake of sodium from drinking water is only a small fraction of that consumed in a normal diet, the intake from this source could be significant for persons suffering from hypertension or congestive heart failure who may require a sodium-restricted diet.
An estimated 25 to 50 percent of salt used on roads for snow and ice control enters the ground water and can elevate levels of sodium in public water supplies. Other potential sources of sodium contamination of water supplies are sewage and industrial effluents, seawater intrusion in coastal areas, and the use of sodium compounds for corrosion control and water-softening processes. Smaller quantities are introduced through leaching of sodium compounds from “normal” soils and the use of sodium hypochlorite for disinfection and sodium fluoride for control of tooth decay.
Fluid volume controls sodium retention, and sodium concentration controls the amount of water in the body. The distribution of water across blood vessel walls depends upon the balance between the effective osmotic pressure of the plasma and the net outward hydrostatic pressures. Disturbances in this balance may occur for various reasons in some forms of hypertension, congestive cardiac failure, renal disease, cirrhosis, toxaemia of pregnancy, and Meniere’s disease.
Because the body has very effective methods to control sodium levels, sodium is not an acutely toxic element in the normal range of environmental or dietary concentrations, (One gram of salt per kilogram body weight can be lethal in small children.) Toxic symptoms of sodium poisoning include general involvement of the central nervous system with increase in sensitivity, muscle twitching, tremors, cerebral and pulmonary oedema, and stupor.
In a study of 348 children aged 7 to 12 years, some positive correlation was found between sodium levels in drinking water and an increase in blood pressure. When fourth-grade children consumed a low-sodium drinking water, blood pressure levels decreased with sodium concentrations in girls but not in boys. Another study of 216 female teenagers showed no correlation between sodium levels in drinking water and blood pressure.
An acceptable range for drinking water pH is from 6.5 to 8.5. Corrosion effects may become significant below pH 6.5, and the frequency of incrustation and scaling problems may be increased above pH 8.5. With increasing pH levels, there is also a progressive decrease in the efficiency of chlorine disinfection processes.
Copper is markedly affected by pH. In aggressive waters, slight corrosion occurs, and the small amount of copper in solution may cause staining of fabrics and plumbing fixtures. In addition, redeposition of copper on aluminum or galvanized surfaces sets up electrochemical cells resulting in pitting of these metals. In most waters, the critical pH value is about 7.0, but in soft waters containing organic acid Waters that are excessively hard do not usually lead to severe corrosion problems, but they are prone to excessive incrustation and also reduce the effectiveness of soaps. Hardness is usually removed in water with softeners.
Because pH is related to a variety of other parameters, it is not possible to determine whether pH has a direct relationship with human health. Insofar as pH affects the unit processes in water treatment that contribute to the removal of viruses, bacteria and other harmful organisms, it could be argued that pH has an indirect effect on health. The destruction of viruses by the high pH levels encountered in water softening by the lime/soda ash process could also be considered beneficial. On the other hand, the increased yield of trihalomethanes at high pH values may be detrimental.
There are no specific health effects on which to base limits for the pH of drinking water. The main purpose in controlling pH is to produce water in which corrosion and incrustation are minimized. These processes, which can cause considerable damage to the water supply system, result from complex interactions between pH and other parameters such as dissolved solids, dissolved gases, hardness, alkalinity and temperature. As a generalization, metal corrosion may become significant below a pH of about 6.5; incrustation and scaling problems are most commonly encountered above about pH 8.5. The acceptable range for drinking water pH is therefore from 6.5 to 8.5.
An aesthetic objective of ≤500 mg/L has been established for total dissolved solids (TDS) in drinking water. At higher levels, excessive hardness, unpalatability, mineral deposition and corrosion may occur. At low levels, however, TDS contributes to the palatability of water. Total dissolved solids (TDS) comprise inorganic salts and small amounts of organic matter that are dissolved in water. The principal constituents are usually the cations calcium, magnesium, sodium and potassium and the anions carbonate, bicarbonate, chloride, sulphate and, particularly in groundwater, nitrate (from agricultural use).
Total dissolved solids in water supplies originate from natural sources, sewage, urban and agricultural runoff and industrial wastewater. In Canada, salts used for road deicing can contribute significantly to the TDS loading of water supplies. Concentrations of TDS in water vary owing to different mineral solubilities in different geological regions.
In addition to palatability, certain components of TDS such as chlorides, sulphates, magnesium, calcium and carbonates also affect corrosion or encrustation in water distribution systems. High TDS levels (above 500 mg/L) result in excessive scaling in water pipes, water heaters, boilers and household appliances such as tea kettles and steam irons. Such scaling can shorten the service life of these appliances.