ALUMINIUM
(total)
ug/l
Aluminium is the most abundant metal in the earth's crust - the third most abundant element.
It is used in the building industry, utensils, aircraft, cars, explosives , pigments, paints and in coagulation process in water treatment.
Health implications
Aluminium has been considered non toxic, though large oral doses may induce gastro-enteritis. In recent years circumstantial epidemiological evidence has linked aluminium to Alzheimer's disease (a form of pre senile dementia).
Renal patients are at particular risk from aluminium and the company is obliged to inform the local health Authority when levels rise above 30
ug/l. Most dialysis patients use an inline reverse osmosis unit to deionise the water before use.
The guide level set by WHO and the PCV ( both 0.2mg/l) are based on aesthetic criteria.
ANTIMONY (total) ug/l
Usually occurs in the form of stibnite which is its sulphide.
Used in alloys in the semiconductor industry, in rubber, textiles, paint
and glass industry.
Health implications
A limiting standard for antimony in water has not been issued as its occurrence is unlikely to reach toxic levels in raw or treated water.
BARIUM (total) ug/l
This metal is always present at low levels. Its compounds are used in paper manufacture, paint production,ceramic glazes etc. In fresh water higher levels indicate some ingress from an industrial/municipal source. Used medicinally.
Health implications
Acutely toxic when soluble salts are ingested in excess of 600mg. However it is unlikely to reach these levels in raw or treated water unless very peculiar conditions occur.
BERYLLIUM
The primary source of beryllium in the environment is the burning of fossil fuels, although contamination is slight. It can enter water ways through weathering of rocks, atmospheric fall out and industrial/municipal discharges. In fresh water the levels are usually low (<1ug/l).
BORON (total) ug/l
Boron may occur naturally in some waters or may find its way into a water course through cleaning compounds and industrial waste effluents.
Health implications
Concentrations normally found in drinking water are below 1000ug/l, typically 100ug/l, concentrations normally considered innocuous for human consumption. (Note: may effect plants at 1000ug/l, even lower if green housed).
CADMIUM (total) ug/l
Normally produced as a by-product of zinc production; the principal uses are in fabrication of alloys, solders, metal plating and batteries. The solubility of cadmium is influenced by the nature of the source and the acidity of water. In surface water if more than a few ug are found, indicate contamination by industrial process or landfill
leachate.
In distribution cadmium levels are low, and when elevated levels are found, especially in customer premesis it may be associated with plated plumbing fittings, silver based solders or galvanised iron piping associated material.
Health implications
It is a non essential non beneficial element recognised to be of high toxic potential. Prolonged exposure to it at toxic levels from drinking water is unusual, but fatalities have been recorded in remote a Japanese valley with an excessive cadmium level in the local drinking water.
At levels of 15mg/l nausea and vomiting has been reported. Cadmium impairs gut absorption of essential trace metals such as iron and promotes kidney
disorders.
CALCIUM (total)
ug/l
See HARDNESS
CHROMIUM (total) ug/l
Chromium occurring in its natural state is highly insoluble, however weathering or bacterial action can make it more soluble. Found in surface waters it is usually due to industrial emissions. Chromium containing sludge applied to land may wash into water courses.
The major use of chromium are for chrome alloys, plating, oxidising agents, corrision inhibitors and manufacture of pigments, ceramics and photographic wares.
The valency of the chemical form in natural waters is influenced by the acidity of the water. There is a tendency for naturally occurring higher levels of chromium to be associated with waters of the greatest hardness.
Health implications
Chromium is an essential element for glucose and lipid metabolism and in several amino acids.
Chromium has a range of oxidation states. The most common being 3+, which is the essential one for man. The hexavalent form (6+) is highly toxic and causes irritation to the gut linings, and has a deleterious effect on the liver and kidneys.
COBALT
Used in alloys, metal electroplating, glass, porcelin and enamel industries.
COPPER (total) ug/l
Copper can find its way into surface water from smelting, refining, copper wire mills, coal burning industries, electroplating, tanning, engraving, photography, fungicides, insecticides as well as iron and steel works.
Health implications
Copper is an essential element for human metabolism. Copper is not a cumulative poison. Poisoning from copper is normally avoidable because the taste threshold makes the water undrinkable at below levels which are toxic.
WHO recommend a guideline value of 1 mg/l, above this concentration copper may interfere with domestic use of water e.g., staining of laundry and plumbing fixtures. Above 3mg/l
(PCV) emetic effects are possible in susceptible people and the water will taste astringent.
IRON (total) ug/l
It is the fourth most abundant element by weight in the earth's crust. It is used in steel and is cast.
In the Thames region some underground sources are rich in ferrous, iron (ii) salts which are soluble. Removal can be accomplished by oxidation to the ferric, iron (iii) state e.g., by aeration or prechlorination which makes them insoluble and then filtration. Iron (ii) salts can be or sequestered with silica to remove them.
Surface waters tend not to be so rich in iron in the Thames catchment. Some surface water works use iron based coagulants and the company is moving towards these.
Iron deposits can build up in the distribution system as a result of settlement of rust. These can cause problems when stirred up by pressure or flow direction changes as they can be encountered by the customer. It is usually possible to flush these problems away.
Health implications
Iron is an essential element forming the basis of porphyrin haemoglobin.
Finding an iron level at alert in a customer's house the internal plumbing configuration may be suspected. Determine if the iron found is derived from the main or from the customer's premises.
When arranged in the sequence Galvanised iron, unprotected iron , lead, copper no galvanic action will occur, any contravention of this order is likely to promote galvanic action.
Galvanic action is the displacement of one metal by another metal of greater electrode
(redox) potential e.g. Copper (+0.153) displaces Zinc (-0.763) > Iron (-0.44) > lead (-0.126). This sequence can easily remembered by the useful mnemonic
"G.U.L.C." -Galvanised iron - Unprotected iron - Lead -Copper.
An inspection of the pipework should be made and samples taken. A bylaws inspection at this stage in the proceedings is recommended.
Confirmation of a problem existing should be passed onto the householder and advice given to help the customer understand the reasons why he should invest in new plumbing.
At pHs < 7.2 iron may come out into solution. To prevent formation of black deposits due to the action of iron bacteria, oxygen should be maintained higher than 2 mg/l and a free chlorine of greater than 0.2 mg/l.
LEAD (total) ug/l
Used primarily in storage batteries, cable covering, plumbing, ammunition, tetra ethyl lead (in petrol to prevent "knocking") as a radiation shield, in the paint and glass industries an of course on church roofs.
Health implications
There are serious neurotoxic effects including irreversible brain damage associate with lead at blood levels of 100-120 micro grams per
decilitre. It is a cumulative poison, acute poisoning being rare. It is not required by the body for metabolism and exposure to it should be kept as low as possible.
The WHO guidelevel and PCV are set at 50ug/l.
MANGANESE (total) ug/l
It is found as a salt usually in association with iron in drinking water. It is used in metal alloys, drycell batteries and as a micronutrient in some
fertilisers.
Anaerobic groundwater often contains elevated levels of manganese.
Health implications
It is an essential element for human physiology. There are no known cases of manganese intoxication attributable to drinking water. The alert level is set not for health but aesthetic reasons.
MAGNESIUM (total) ug/l
See Hardness and Calcium.
MERCURY (total) ug/l
Burning of fossil fuels, smelting of various metals, cement manufacture and waste disposal are sources of it in the environment. Mercury based compounds are also used in chloroalkali plants, paints, thermometers and agriculture.
Mercury can exist in the environment as a metal, as monovalent and divalent salts, and as organomercurials which are more toxic, the most important of which is methyl mercury.
The major source of mercury in the environment is the natural degassing of the earths
crust (25000-150000 tonnes). Other sources are burning of fossil fuels, smelting of various metals, cement manufacture and waste disposal. Mercury and compounds are also used in
chloro-alkali plants, paints, and agriculture.
Mercury can exist in the environmentas a metal, as monovalent and divalent salts, and as
organomercurials, the most important of which is methyl mercury.
Inorganic mercury can be controlled in water in treatment by iron and alum coagulation. Organic mercury can be reduced by the action of Granular Activated Carbon.
Health implications
Methyl mercury compounds are highly toxic to the central nervous system whilst inorganic mercury compounds effect the kidneys. It has no beneficial function in the human physiology.
The PCV and WHO guidelevel are set at 1 ug/l.
NICKEL
Nickel is ubiquitous. The chief ores are arsenides and sulphides. It is a hared silvery-white ductile metallic element. It is used for plating, making stainless steel, and other corrosion resistant alloys. Also used in ceramics, batteries and space applications. Nickel normally occurs as salts which are very soluble in water.
Nickel is ubiquitous; typical soils contain between 10-100mg/Kg. The chief ores are arsenides and
sulphides. It is used for alloys, plating, making stainless steel, and other corrosion resistant alloys. Also used in ceramics, batteries and space applications. Nickel normally occurs as salts which are very soluble in water.
The only potential way of removing Nickel from water is by ion exchange.
Health implications
It is poorly absorbed from the gut and is relatively non toxic.
POTASSIUM mg/l
The seventh most abundant element on earth. It is never found free in nature. Chemically many potassium salts are very important: hydroxide, nitrate, carbonate, chloride, chlorate, bromide, iodide, cyanide, sulphate and chromate.
Extensively used in fertilisers, glass and in the chemical industry. It is an essential nutritional element for life.
Potassium is abundant in food.
Health implications
Negligible health effect in water.
SELENIUM mg/l
It is a grey or red (crystalline or monoclinic) element of similar character to
sulphur. Several salts are used for electronic and photocopying applications. Also used in the glass manufacture, pigments, chemicals, pharmaceuticals, fungicides, electrical industry and rubber industry.
Several salts are used for electronic and photocopying applications. Also used in the glass manufacture, pigments, chemicals, pharmaceuticals, fungicides, electrical industry and rubber industry.
Found in trace quantaties in public sewers due to industrial pollution.
Removal tests conducted in the US by jar test show;
a. Ferric sulphate >50% removal possible
b. Excess lime 30-60% removal possible
c. Alum, lime, activated carbon <30% removal possible
Health implications
It is an essential trace element, but at high levels exhibits similar symptoms to that of arsenic.
The guidelevel for WHO is 10ug/l as is the PCV.
SILVER ug/l
Silver is used in jewellery, alloys, photography, batteries, mirrors, electronic components, electroplating and as a disinfectant (in water filtration units). Because silver is a precious metal, it is removed industrially and commercially in most processes, leaving a negligible problem to the environment.
Silver is used in jewellery, alloys, photography, batteries, mirrors, electronic components, electroplating and as a disinfectant (in water filtration units). Because silver is a precious metal, it is removed industrially and commercially in most processes, leaving a negligible problem to the environment.
Silver removal can be affected by
a. Ferric sulphate coagulation at pH 7-9
b. Alum coagulation
c. Lime softening and excess lime softening
Health implications
It is a non essential element for man. In drinking water continuous exposure to high levels (40-400ug/l) over a life time will causes argyria - a non reversible bluish grey tinge to the skin.
SODIUM mg/l
Sodium is a natural constituent of most raw waters. The levels are elevated as water is softened.
Health implications
There is some evidence to link sodium to heart conditions such as hypertension, however at the normal levels in which it occurs in drinking water this is unlikely to be a contributory factor as most sodium is taken in with food.
Strong saline solutions will induce vomiting. Also baby foods reconstituted with softened water can adversely effect their physiology.
ZINC (total) ug/l
Zinc is used as an alloy with brass, nickel, bronze, soft solder and aluminium solder. It is used in galvanisation of iron. It is also used in the preparation of paints, rubber products, cosmetics, pharmaceuticals, floor coverings, plastics, printing inks, soap, storage batteries, textiles, electrical equipment and lots of other products.
Health implications
Zinc rarely has any adverse health effects as it is easily regulated by the body. It is an essential element for human metabolism. At concentrations higher than 20 mg/l an astringent taste is detectable along with a milky appearance and greasy film on boiling.
The WHO set a guidelevel of 5mg/l - this is also the PCV value. This is based on aesthetic criteria.
If the zinc is found at the alert level in a customer's house the internal plumbing configuration should be suspected. The customer is likely to notice "sandy" deposits, which are zinc carbonate.
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