Water FAQ 4

Table 1: General Chemistry Parameters

Alkalinity (as CaCO₃)
no numerical guideline
Alkalinity is a measure of the buffering capacity of water – its ability to resist sudden changes in pH. pH and alkalinity are factors in determining whether water is corrosive, scale-forming, or neutral. If water is corrosive, metals, such as lead or cadmium, may leach into the water and cause adverse health effects.

Ammonia (as Nitrogen)
no numerical guideline
The presence of ammonia (NH₃) may indicate improperly treated sewage or fertilizer or it may occur naturally. Ammonia may be converted to nitrate or nitrite. If the nitrate, nitrite, or the bacterial level is elevated, investigate the source.

Anion Sum
no numerical guideline
The anion sum is the sum of the negative ions (anions) present in water. It is used to calculate the ion balance. Major contributors to the anion sum are usually alkalinity, chloride, and sulphate. The anion sum is not an indicator of water quality. It is a check of the analytical accuracy of the data.

Bicarbonate and carbonate (as CaCO₃)
no numerical guideline
Bicarbonate and carbonate, as CaCO₃, are derived from carbonate rocks, carbon dioxide (CO₂) in the atmosphere, and the weathering of feldspars and other minerals. Both are major contributors to alkalinity. Bicarbonate and carbonate may combine with calcium and magnesium when water is heated, forming a scale on pipes and plumbing materials.

Calcium (Ca)
no numerical guideline
Calcium is present in all natural waters. It is a major contributor to drinking water hardness. Excessively hard water can affect the function and lifetime of plumbing systems and appliances.

Cation Sum
no numerical guideline
The cation sum is the sum of positive ions (cations) present in water. It is used to calculate the ion balance. Major contributors to the cation sum are usually calcium, magnesium, and sodium. The cation sum is not an indicator of water quality. It is a check of the analytical accuracy of the data.

Chloride (Cl¯)
AO of less than or equal to 250 milligrams per litre (mg/L)
Chloride is found naturally in groundwater. It can cause water to have a salty taste. Chloride may also be an indicator of saltwater intrusion or sewage contamination. Chloride is often the first sign of deteriorating groundwater quality.

Colour
AO of less than or equal to 15 true colour units (TCU)
Colour in drinking water may be aesthetically unappealing and is a possible indication of contamination.

Conductivity
no numerical guideline
Conductivity is a measure of the ability of water to carry an electrical current. It increases as the amount of dissolved minerals (ions) increases and can signal the presence of other contaminants in water. Conductivity is one of several parameters used to indicate overall water quality.

Copper (Cu)
AO of less than or equal to 1.0 milligrams per litre (mg/L)
Copper is naturally occurring, but the most common source of copper in drinking water is the corrosion of copper-containing plumbing materials. It is an essential element required in small amounts by all living organisms. Very high concentrations of copper can cause nausea and other gastrointestinal discomforts.

Dissolved Organic Carbon
no numerical guideline
Dissolved Organic Carbon (DOC) is used to measure dissolved compounds found in water derived from plant and animal (organic) materials. DOC is one of several parameters used to indicate overall water quality.

Fluoride (F)
MAC of 1.5 milligrams per litre (mg/L)
Fluoride is naturally occurring. It may be present naturally in dissolved form in groundwater through weathering and erosion of certain rock and soil types. It may also be present in groundwater due to septic and sewage treatment effluent from areas with fluoridated water. Exposure to excess fluoride in drinking water can cause dental fluorosis. Over the long term, it can cause skeletal fluorosis.

Hardness
no numerical guideline, but the optimum range of hardness in drinking water is an equivalent calcium carbonate (CaCO₃) concentration between 80 and 100 mg/L
Hard water is caused by the presence of minerals such as calcium and magnesium in water. Hard water causes scale formation in pipes, on plumbing fixtures, and in heating systems. Hardness is one of several parameters used to indicate overall water quality.

Ion Balance
no numerical guideline
The ion balance compares the negative ions (anion sum) to the positive ions (cation sum). They should theoretically be equal to each other, within plus or minus 5 per cent. Although unusual, if the ions are not balanced, it may indicate that an ion is present in the water that has not been accounted for. The ion balance is not an indicator of water quality. It is a check of the analytical accuracy of the data.

Iron (Fe)
AO of less than or equal to 0.3 milligrams per litre (mg/L)
Iron is a metallic element present in many types of rock. It is commonly found in water. It is an essential element required in small amounts by all living organisms. Iron can collect and block pipes or fixtures and break off as rust flakes or sediment, giving water an unpleasant appearance and taste. Health effects are not expected at levels normally found in drinking water.

Langelier Index
no numerical guideline
The Langelier Index is an approximate indicator of the degree of saturation of calcium carbonate (CaCO₃) in water. It is calculated using the pH, alkalinity, calcium concentration, total dissolved solids, and water temperature of a water sample. The Langelier Index was one of many indicators formerly used to assess the stability of water (whether it was corrosive or scale-forming water). It is no longer considered a good indicator of corrosion.

Magnesium (Mg)
no numerical guideline
Magnesium is present in all natural waters. It is an essential element required in small amounts by all living organisms. It is a major contributor to drinking water hardness. Excessively hard water can affect the function and lifetime of plumbing systems and appliances.

Manganese (Mn)
AO of less than or equal to 0.05 milligrams per litre (mg/L)
Manganese is a metallic element present in many types of rock. It is commonly found in water. It is an essential element required in small amounts by all living organisms. Manganese can collect and block pipes or fixtures and break off as black flakes or sediment, giving water an unpleasant appearance and taste. Health effects are not expected at levels normally found in drinking water.

Nitrate (NO₃^–)
The guideline depends on the method the laboratory uses to measure concentrations:
• nitrate measured directly – MAC of 45 milligrams per litre (mg/L)
• nitrate-nitrogen calculated from the total nitrogen concentration – MAC of 10 milligrams per litre (mg/L)
The presence of nitrate may indicate improperly treated sewage or fertilizer or it may occur naturally. Nitrate contamination is often one of the first signs of deteriorating groundwater quality and could indicate other problems with well water quality. Nitrate-nitrogen levels greater than 10 mg/L can pose a risk to infants up to six months old.

Nitrite (NO₂^–)
The guideline depends on the method the laboratory uses to measure concentrations:
• nitrite measured directly – MAC of 3.2 milligrams per litre (mg/L)
• nitrite-nitrogen calculated from the total nitrogen concentration – MAC of 1.0 milligram per litre (mg/L)
The presence of nitrite may indicate improperly treated sewage or fertilizer, or it may occur naturally. Nitrite contamination may be a sign of deteriorating groundwater quality and could indicate other problems with well water quality. Nitrite-nitrogen levels greater than 1.0 mg/L can pose a risk to infants up to six months old.

Orthophosphate as phosphorous (P)
no numerical guideline
Ortho-phosphate is a chemistry-based term that refers to an inorganic phosphate. The presence of ortho-phosphate in groundwater can indicate contamination from surface water sources. Investigate the source, as the presence of pathogens or other contaminants present in surface water may cause adverse health effects.

pH
AO of between 6.5 and 8.5
A pH less than 6.5 may contribute to the corrosion of pipes and fittings. A pH less than 6.5 is not a health-risk in itself, but corrosive water can dissolve metals, such as lead, cadmium, zinc, and copper present in pipes.
This may lead to increased concentrations of these metals in drinking water, which can cause health concerns.

A pH greater than 8.5 may contribute to scale build-up in plumbing materials. pH is one of several parameters used to indicate overall water quality.

Potassium (K)
no numerical guideline
Potassium is naturally occurring, but the most common source of potassium in drinking water are water treatment systems, such as ion exchangers (water softeners) that use potassium chloride. It is an essential element required in small amounts by all living organisms. Adverse health effects from exposure to increased potassium in drinking water are unlikely in healthy people. Potassium may cause health effects in people with certain conditions (for example, people taking certain medications for heart disease, kidney disease, pain, and HIV treatment). If water is softened by potassium ion exchange, you should use a separate, unsoftened supply of water for cooking and drinking.

Silica as SiO₂
no numerical guideline
Silica is an abundant compound, present in groundwater through erosion of rocks and minerals. Silica is much more common in groundwater than in surface water. Dissolved silica does not have any known health concerns for humans. However, the presence of high amounts of dissolved silica may interfere with water treatment systems designed to remove dissolved iron and manganese. Extremely high dissolved silica concentrations may produce scale in pipes and restrict water flow within piping systems.

Saturation pH
no numerical guideline
Saturation pH is a theoretical pH at which water is stable and will neither form a scale nor corrode. It is calculated using the temperature, total dissolved solids, and the calcium content and alkalinity of water.

Sodium (Na)
AO of less than or equal to 200 milligrams per litre (mg/L)
All groundwater naturally contains some sodium. It is an essential element required in small amounts by all living organisms. High levels of sodium can give water a salty taste. Sodium in drinking water may cause health concerns for those on sodium-restricted diets. If water is softened by sodium ion exchange, you should use a separate, unsoftened supply of water for cooking and drinking.

Sulphate (SO₄^2-)
AO of less than or equal to 500 milligrams per litre (mg/L)
Sulphate minerals in drinking water can increase corrosion of plumbing and water well materials. Sulphate is found naturally in groundwater through the weathering of rocks. At levels above 1000 mg/L, sulphate in drinking water can have a laxative effect.

Total Dissolved Solids
AO of less than or equal to 500 milligrams per litre (mg/L)
Total dissolved solids (TDS) is the calculated dissolved matter found in water comprised of mineral salts and small amounts of other inorganic and organic substances. It is related to the conductivity of water. TDS is one of several parameters used to indicate overall water quality. If the concentration of total dissolved solids is too high, the water is unsuitable for drinking or cooking.

Turbidity
varies, based on the source and the technology used to treat water
For surface water and groundwater under the direct influence of surface water, turbidity may indicate the presence of disease causing organisms, such as bacteria, viruses, and parasites that can cause nausea, cramps, diarrhea, and associated headaches. In secure groundwater sources, turbidity may be present due to the presence of clay, silt, and inorganic matter from natural sources. It is important to know and understand the source of turbidity.

Zinc (Zn)
AO of less than or equal to 5.0 milligrams per litre (mg/L)
Zinc is naturally occurring, but the most common source of zinc in drinking water is the corrosion of galvanized plumbing and well materials. Zinc is an essential element and is generally considered to be non-toxic at levels normally found in drinking water. Exposure to very high concentrations of zinc may result in nausea and diarrhea.