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STANDARD CRITERIA
Sodium: Sodium is an essential nutrient. The 200 mg/L guideline for sodium in water has been set based on taste.
Individuals on a medically supervised sodium restricted diet should limit their intake of water that exceeds 20 mg/L of sodium.
The consumer should consult with their physician in such matters. If a water softener is used, it removes the Calcium and
Magnesium from the raw water and replaces it with Sodium. This increase in the natural Sodium level should be checked.
Major sources of Sodium are from water softeners, salt-water intrusion, road salt, and geological formations.
Potassium: Potassium is an essential element. There is no guideline but concentrations > 2000 mg/L may be
harmful to the nervous and digestive systems. The concentration in natural surface waters seldom reaches 20 mg/L.
Calcium: Calcium is an essential element. Calcium and Magnesium contribute to a water's hardness causing taste,
scale and excessive soap consumption. The major sources are geological, however road salting and dust control also contribute
calcium to waters. Calcium can be easily removed with a water softener.
Magnesium: Magnesium is an essential element. Magnesium may have a laxative effect when found in association
with the sulphate ion. High levels may contribute to undesirable taste. Magnesium along with Calcium contributes to a water's
hardness. The major sources are geological.
Hardness (as CaCOJ): Hardness is caused primarily by Calcium and Magnesium. The main concerns with hardness
are incrustation on pipes, kitchen utensils and tubs as well as excessive soap consumption. Hard waters when heated have a
tendency to form scale deposits; soft water, on the other hand, may result in corrosion of water pipes. Depending on pH and
alkalinity, hardness levels between 80 and 100 mg/L are considered to provide an acceptable balance between corrosion and
incrustation. Water softening will reduce the hardness of most waters but replace it with sodium which may be a health problem.
It is recommended that a separate, unsoftened supply be retained for culinary purposes.
Alkalinity (as CaCOJ): Alkalinity in the range of 30 to 500 mg/L is generally acceptable. Alkalinity is a measure of
water's capacity to neutralize an acid. Waters with high alkalinity when boiled over an extended period of time form a deposit or
unpleasant taste. Waters with very low alkalinity corrode pipes and plumbing.
Sulphate: The guideline of 500 mg/L for Sulphate has been established for health as well as aesthetic reasons. The
major physiological effect from ingestion of water containing sulfate at concentrations in excess of this limit is catharsis (laxative
effect) and gastrointestinal irritation. The presence of sulphate in drinking water may also result in noticeable taste. Major sources
are geological formations (e.g. gypsum) and industrial discharge; wet and dry deposition contains sulphates from burning fossil
fuels (e.g. coal).
Individuals who complain of a sulfur or rotten egg like odor from their water often have a hydrogen sulfide problem. Such water
is usually low in sulfate. The problem occurs when the groundwater exists in either low or negligible oxygen conditions and any
sulfur present tends to be reduced to hydrogen sulfide gas. As this water is piped into the house, the gas separates from the water
and as the tap is opened, the gas releases into the air causing a foul odor. Because this gas has been released into the air,
laboratory measurement is almost meaningless. Hydrogen Sulfide can also be generated in a fouled water treatment device as well
as in a domestic hot water heater.
Chloride: Chloride above the guideline of 250 mg/L imparts an undesirable taste to the water. The normal range in
drinking water is 5 to 20 mg/L. Levels above this may be an early indicator of contamination. Chloride also makes water more
corrosive towards the distribution system. Major sources are natural salt deposits, salt-water intrusion, and road salt and septic
tank systems.
Fluoride: The presence of fluoride in the 1.0 to 1.2 mg/L leads to a substantial reduction in dental caries. Fluoride is
added to many municipal water supplies. Fluoride levels in excess of 1.5 mg/L may produce dental fluorosis, a condition
characterized by mottling of tooth enamel. In certain areas of N.S. fluoride may be found naturally at levels near or above the
guideline.
Ortho - Phosphorus: Not commonly toxic but may produce taste or odor. A guideline of 0.2 mg/L usually recommended
to reduce eutrophication of water system (e.g. algae blooms). Major sources are municipal/industrial effluent, agricultural runoff
and domestic sewage (e.g. septic tank seepage).
Nitrate + Nitrite (N): The guideline of 10 mg/L (as N) has been established for health reasons. Excess nitrate can be
acutely toxic in infants, producing a blood disorder called methaemoglobinaemia (blue baby syndrome) which limits the amount
of oxygen the blood stream can carry. One major source of nitrate is fertilizers used in agricultural areas; other sources are
decaying plant or animal material, manure, and domestic sewage.
Ammonia (N): There seems to be little risk from ingestion of ammonia in drinking water at levels normally encountered.
Therefore, no guideline has been established. However, the presence of ammonia in water at concentrations above 0.2 mg/L is
often an early indicator of contamination, either surface water or domestic wastewater. If ammonia is high, the possibility and type
of contamination should be investigated.
Iron: The guideline of 300 ug/L has been established on the basis of aesthetic considerations. At concentrations above
300 ug/L iron can stain laundry and plumbing fixtures, and cause undesirable tastes in beverages. When exposed to the air, iron
precipitates and imparts an objectionable reddish-brown colour to the water. Iron may promote the growth of certain microorganisms,
leading to the deposition of a slimy coat in pipes. Iron is a major problem to many consumers in Nova Scotia.
Manganese: The guideline of 50 ug/L has been established for aesthetic reasons. Manganese at levels exceeding
150 ug/L can stain plumbing fixtures and laundry, and causes undesirable tastes in beverages and will form coatings on pipes,
which may slough off as a black precipitate. As with iron, manganese tends to be a general problem in Nova Scotia's surface and
groundwater. Major sources are soils/sediments, geological, industrial and agricultural.
Lead: The guideline of 10 ug/L has been established on the basis of toxicological considerations. Lead has long been
recognized as a general metabolic poison which causes a variety of human disorders. Children are more susceptible to the effects
of lead poisoning. The primary source of lead in water is from the corrosion of lead pipes within the consumer's water distribution
system and lead solder used to join pipes. In order to minimize exposure to lead introduced into drinking water from plumbing
systems, it is recommended that only the cold water supply be used after an appropriate period of flushing to rid the system of
standing water, for drinking, beverage preparation, and cooking.
Copper: The guideline of 1000 ug/L for copper is based on considerations of its taste and staining characteristics. The
most common source of copper in drinking water is from corrosion of copper pipes within the home. When copper remains in
contact with the pipes for long periods of time, the copper from the pipes dissolves in the water. When this water comes in contact
with soaps or detergents, the copper precipitates from the water forming a turquoise-blue sediment. Flushing the lines prior to
using the water will help to minimize the problems associates with copper.
Zinc: The guideline of 5000 ug/L has been established on the basis of aesthetic considerations. Zinc is an essential
element and is generally considered to be nontoxic. Water containing zinc at levels above 5000 ug/L tends to be opalescent,
develops a greasy film when boiled and has an undesirable astringent taste. The most likely source of zinc in water is from
corrosion of the distribution system.
Arsenic: The guideline of 25 ug/L has been established on the basis of toxicological considerations. Once ingested;
arsenic bioaccumulates and causes poisoning over a long period of time. The primary source of arsenic in Nova Scotia
groundwater is from mineral dissolution.
Uranium: The guideline of 20 ug/L has been established based on considerations of its chemical toxicity. Ingestion of
uranium may result in damage to the kidneys. Uranium may also produce objectionable taste and color in water, but the
concentrations at which this happens are much higher than the maximum acceptable concentration. The primary source of
uranium in Nova Scotian groundwater is from the dissolution of minerals and ores.
Cadmium: The guideline of 5 ug/L has been established on the basis of health considerations. The major source of
cadmium in water is from the corrosion of one's distribution system.
Colour, true: The guideline is 15 TCU (true colour units). Below this level there is no noticeable colour, at 100 TCU
water appears to be the color of tea. High color is a possible indication of pollution, aesthetically unpleasant, and stains clothing,
food, plumbing fixtures. It is caused primarily by dissolved organic matter (humic substances, tannins, lignins) and inorganic
material (iron, manganese). Apparent color in addition to the above includes color due to suspended matter (turbidity).
Turbidity: The guideline of 5 NTU (nephelometric turbidity units) is based on both health and aesthetic reasons. It is
usually caused by suspended particles e.g. silt, clay, algae. Surface waters range from 0-100 NTU, groundwater near 0 NTU.
Turbidity reduces the-effectiveness of chlorination tr-eatment by shielding microorganisms which may reach the consumer.
Conductivity: (uSiemens/cm = umho/cm) - no guideline. A measure of a waters ability to conduct an electrical current;
it increases as the amount of dissolved minerals (ions) increases. The umho is the reciprocal of the measure of resistance, the
ohm. Conductivity is used as a check on the accuracy of other chemistry analyses. Surface waters are generally
50-1500 uSiemens/cm.
pH : An acceptable range for drinking water pH is 6.5 to 8.5. One of the main objectives in controlling pH is to
produce water that minimizes corrosion or encrustation. Low pH causes corrosion of water distribution systems, while high pH
causes encrustation and scaling (e.g. CaC03).
MICROBIOLOGICAL PARAMETERS
Bacteria (Under Review): The maximum acceptable concentration (MAC) for bacteriological quality of public,
semi-public and private drinking water systems is no coliforms detectable per 100 mL. However, because coliforms are not
uniformly distributed in water and are subject to considerable variation in public health significance, drinking water the following
conditions is considered to conform to this MAC.
1. No sample should contain E. coli. E. coli indicates fecal contamination and the possible presence of enteric pathogens;
therefore the water is unsafe to drink. If E. coli is detected, corrective action
should be taken.
2. No sample should contain total coliform bacteria. In non-disinfected well water, the presence of total coliform bacteria in
the absence of E. coli indicates the well is prone to surface water infiltration and therefore at risk of fecal contamination. Total
coliform may also indicate the presence ofbiofilm in the well or plumbirig system. The presence of total coliform in the absense
of E. coli may require different different responses in different jurisdictions, but in Nova Scotia corrective action is required similar
to that required for the treatment of E. coli.
WATER TREATMENT
Should a consumer be confronted with a water quality problem, the first action should be to isolate the type of problem and
try to eliminate this problem by the appropriate corrective action. Your Department of Environment may be of assistance. Failing
corrective action, an alternative water source or water treatment should be considered. For specifics on water treatment, the
consumer should consult with GCS Water System specialists for their advice and
recommendation.
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