Chemical standards

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These standards are normally based on a life time's consumption and also take into account the intake from food and other sources.

Many of the chemicals listed below are not normally found in drinking water, or only occur in local circumstances.

 

 

Chemical standards

 
 

Parameter

Description

Standard

1,2- dichloroethane

Found in industrial solvents and can be detected in trace amounts in some source waters. They are removed by water treatment.

3µg/l

Acrylamide

Monomer is found in polyacrylamide which can be used in the treatment of water to remove impurities. Use of polyacrylamide is tightly controlled.

0.1µg/l

Aluminium

Occurs as a natural constituent of many waters. During the treatment process aluminium salts are used to remove impurities.

200µg/l

Ammonium

Ions are found naturally in most waters and removed by treatment.

0.3mg/l

Antimony

Rarely found in water and when this does occur it is likely to be due to the water being in contact with brass fittings or lead free solder.

5µg/l

Arsenic

Specific treatments can be used but it is not normally found in the Dublin Region.

10µg/l

Benzene

Used in the petrochemical and plastics industry. Occasionally it is found in source water but is removed by treatment.

1µg/l

Benzo(a)pyrene

One of several compounds known as polycyclic aromatic hydrocarbons. Trace levels can be found in drinking water where coal tar lining of mains was historically practiced to prevent corrosion.

0.01µg/l

Boron

Occurs naturally at low levels in all waters. Some industrial discharge and detergents can increase the concentrations in river water. Boron is not removed by normal water treatment.

1mg/l

Bromate

Formed during the disinfection of drinking water though the reaction with natural bromide. It can also occasionally be detected in water through industrial pollution.

10µg/l

Cadmium

Specific treatments can be used but it is not normally found in the Dublin Region water supplies.

5µg/l

Chloride

Found as natural salts in all waters. It is not removed during normal treatment. Concentrations depend on the local water source. 

250mg/l

Chromium

Very rarely found in drinking water.

50µg/l

Colour

Occurs naturally in many water sources. It is readily removed by treatment.

Acceptable to customers, no abnormal change.

Conductivity

Measure of the dissolved inorganic substances.

2500µS/cm at 20°C

Copper

Rarely found in source waters but can leach into drinking water as it passes through domestic copper pipes and fittings.

2mg/l

Cyanide

Very rarely found in drinking water.

50µg/l

Epichlorohydrin

Found in polyamines which can be used in the treatment of water to remove impurities. The use of polyamines is tightly controlled.

0.1µg/l

Fluoride

Occurs naturally is many water sources. Fluoride is added to the water supply to prevent tooth decay at the request of the Department of Health and Children.

0.6 – 0.8mg/l

Hydrogen Ion (pH)

Measure of the acidity of the water. pH values above 7 indicate alkaline conditions, pH 7 is neutral and below pH 7 is acidic.

≥6.5 - ≤9.5 pH

Iron

Naturally present in most water sources. Iron can also be present in drinking water through corrosion of iron water mains.  

200µg/l

Lead

Rarely found in source waters but can be found in drinking water due to pick up from lead pipes and fittings in domestic properties.

10µg/l

Manganese

Occurs naturally in many water sources. It is readily removed by treatment.

50µg/l

Mercury

Very rarely found in drinking water.

1µg/l

Nickel

Rarely found in source water.

20µg/l

Nitrate

Occurs naturally in most source waters but concentrations can be increased as a result of fertiliser use.

50mg/l

Nitrite

Occurs naturally at low levels in some waters but is removed by treatment.

0.5mg/l at consumers' tap 0.1mg/l at water treatment works

Oxidisability

The oxidisability parameter provides an indication of changes in water quality and allows an estimate of the organics removal during water treatment.

5.0 mg/l O2

Pesticides

Diverse group of organic compounds that include herbicides, insecticides, fungicides. Many water sources contain traces of one or more pesticides as a result of both agricultural and non-agricultural uses.

0.03µg/l for aldrin, dieldrin, heptachlor and heptachlor epoxide. 0.1µg/l for other individual pesticides. 0.5µg/l for the total of all pesticides detected

Polycyclic aromatic hydrocarbons

Found in drinking water where coal tar lining of mains was historically practiced to prevent corrosion. The standard is a measure of  benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(ghi)perylene and indeno(1,2,3-cd)pyrene.

0.1µg/l

Radioactivity-Tritium

Found naturally in water at very low concentrations. Elevated levels may indicate the presence of other artificial radionuclides.

100Bq/l

Radioactivity- total indicative dose

Measure of radiation exposure through drinking water. Radioactivity is naturally present in all water sources. Levels of radioactivity are normally monitored by measuring gross alpha or beta activities. 

0.1 mSv/year

Selenium

Very rarely found in drinking water.

10µg/l

Sodium

Naturally present in many water sources.

200mg/l

Sulphate

Naturally present in many water sources..

250mg/l

Taste & odour

Measure of the aesthetic quality of drinking water. Unusual tastes or odours may indicate a problem that requires investigation.

Acceptable to customers, no abnormal change.

Tetrachloroethane & trichloroethane

These are solvents which are very occasionally found in water sources. The standard is a measure of the combined concentrations.

10µg/l

Total organic carbon

Measure of the amount of organic material in the water, most of which comes from natural sources.

No abnormal change (mg/l)

Trihalomethanes total

Formed by the reaction of chlorine with natural organic substances in water. The standard is a measure of chloroform, bromoform, dibromochloromethane and bromodichloromethane. 

100µg/l

Turbidity

Measure of the clarity of water.

Acceptable to consumers, no abnormal change.

Vinyl chloride

Found in water pipes containing polyvinyl chloride (PVC). Concentrations are strictly controlled by product specification.

0.50µg/l

Key

 
 

Code/Units

Description

°C

Degrees Centigrade

µS/cm

Micro Siemens per Centimetre

Bq/l

Becquerels per Litre

mSv/year

Millisieverts per Year

mg/l

Milligrammes per Litre (one part per million)

µg/l

Microgrammes per Litre (one part per billion)

 

 

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