Water analysis parameters
The color
Norm : Aesthetic < 15 UCV
The color can come for mineral or organic sources. Iron (reddish color) and manganese (blackish color) are examples of mineral coloured water. There are many organic sources that can color water : algae, plant decomposition, tannins and lignins.
Turbidity
Norm : < 5 UTN
Turbidity is the cloudiness of water caused by the reflection of light on suspended particles (silt, clay, organic and inorganic matter). Turbidity can also be influenced by meteorological conditions such as high temperatures, torrential rains and lake overturns in the fall and spring.
Le pH
Norm : between 6,5 and 8,5
pH measures the activity of hydrogen ions (H+) in the water. It corresponds to the concentration logarithm of H+ ions. The pH scale varies between 0 (acidic) and 14 (base or alkaline). A slightly acidic water will have a reading between 6,5 and 7. A slightly alkaline water will have a reading between 7,2 and 8,3. Therefore, the pH value indicates the alkalinity and CO2 concentrations of the water. If the pH level is 7, water can become aggressive if the hardness and alkalinity are weak.
Iron (Fe) and manganese (Mn)
Norm : Aesthetic; Iron 0,3 mg/L and Mn 0,05 mg/L
Iron and manganese are frequently found in water in varying quantities depending on the regions and the source of the water. They are not toxic substances but do give a disagreeable color and taste to the water and can stain clothes and plumbing accessories.
The total hardness
Norm : Aesthetic < 120 mg/L
Since natural water is rich in CO2 and oxygen, it can easily dissolve any minerals ( calcite, gypsum, dolomite) it comes in contact with. Water can dissolve them and acquire a hardness of many thousands of mg/L depending where it has been.
Multivalent cations are responsible for the hardness. Total hardness is composed of about 80% calcite hardness and 20% magnesium hardness.
Only calcium is found in the calcite hardness. Magnesium hardness is composed of the other multivalent cations. In certain cases, hardness can be a problem.
For example, a high level of hardness can have an affect on soap, stain dishes, leave deposits in the hot water tank or the kettle. However, if there isn't enough hardness in the water, the water can become aggressive and corrode pipes and other accessories
|
Hardness level |
Concentration in mg/L of CaCO3 |
|
Soft |
0-60 |
|
Moderately soft |
60-120 |
|
Hard |
120-180 |
|
Very hard |
180 et plus |
Chlorides
Norm : Proposition < 250 mg/L
Chlorides are present in almost all waters. Concentrations can vary from multiples of ten mg/L to more then a thousand mg/L. Chlorides can come from water moving through sedimentary rock percolations, salted water intrusions or the spreading of sodium chloride and calcium on the roads. The maximum chlorides concentration is 250 mg/L, since water can taste salty at a higher concentration. Chlorides at high levels are also corrosion agents.
Alkalinity
Norm : Proposition between 30 and 500 mg/L
Alkalinity is the content level of carbonate (CO3), bicarbonate (HCO3) and alkali (OH-) in water. There are no applicable norms for alkalinity. However, water alkalinity between 30 and 500 mg/L of CaCO3 is considered acceptable and water alkalinity between 100 and 200 mg/L of CaCO3 is considered good. Alkalinity is the main control factor for the aggressiveness of the water and it's incrusting power. Aggressive water will have a tendency to react with metal pipes and corrode them. Incrusting water will have a tendency to clog pipes with salt and reduce their useful diameter.
Conductivity
Norm : Proposition < 1650 ms/cm
Water conductivity is based on ion content, especially when it comes to electricity. Water conductivity is directly linked to the concentration of the ionic impurities in the water. Conductivity measurements are influenced by pH levels and the temperature. It is possible to deduce the dry residue that can be filtered from conductivity.
Nitrates (No3)
Norm : < 10 mg/L
Nitrates are found just about everywhere in nature. Nitrates are a product of nitrogen oxidation. Nitrate concentration in water should not be greater then 10 mg/L, mainly because it can cause methemoglobinemia in young infants and lead to death.
Sulphates
Norm : < 500 mg/L
Sulphates come from gypsum rocks and sulphur oxidation found in rocks like pyrites. Sodium, ammonium and magnesium sulphates are the most common. In Quebec, the maximum concentration of sulphates allowed is 500 mg/L. Even though the sulphate ion is one of the least toxic, a concentration of 250 mg/L can cause gastro-intestine problems in children and a concentration of 300 mg/L will have a laxative effect on adults. In Europe, water is considered undrinkable if the sulphate concentration is higher then 250 mg/L.
Fecal coliforms
Coliforms exist in the intestinal system and grow at a temperature of 37 degrees Celsius. The presence of fecal coliforms usually indicate recent fecal pollution. The contamination source is near the water. E.Colis is the indicator.
Fecal streptococci
The presence of fecal streptococci confirms fecal pollution even in the absence of fecal coliforms. Fecal streptococci can survive a long time in the water. This means that the source of the pollution is far away.
Total coliforms
The presence of total coliforms does not confirm a fecal pollution. These coliforms can come from plant decomposition.