|
The Test
|
&
What It Means
|
Standard
|
Units
|
|
Microbiological
Parameters
|
|
|
|
|
E. Coli
|
Groups of bacteria indicating
possible faecal contamination of water supplies. Occurrence of these organisms is always immediately
investigated.
|
0
|
per 100
ml
|
|
Enterococci
|
Groups of bacteria indicating
possible faecal contamination of water supplies. Occurrence of these organisms is always immediately
investigated.
|
0
|
per 100
ml
|
|
Chemical
Parameters
|
|
|
|
|
Antimony
|
Antimony is toxic and is not
present in water sources. Trace concentrations in drinking, water, which are
not of any significance to health, can be derived from brass fittings and
joint solders.
|
5
|
µgSb/l
|
|
Arsenic
|
Very low levels appear naturally.
|
10
|
µgAs/l
|
|
Benzene
|
Can be introduced into water by industrial effluents and
industrial pollution.
|
1
|
µg/l
|
|
Benzo (a)
pyrene (Benzo 3,4 pyrene)
|
This is a PAH, as it is recognised as being of a greater
health significance it has an additional specific standard.
|
1
|
µg/l
|
|
Boron
|
Occurs naturally.
|
1
|
mgB/l
|
|
Bromate
|
Can be formed in the disinfection process of water.
|
10
|
µgBrO3/l
|
|
Cadmium
|
Very low levels appear naturally.
|
5
|
µgCd/l
|
|
Chromium
|
Very low levels appear naturally.
|
50
|
µgCr/l
|
|
Copper
|
Presence is largely due to influence of domestic plumbing
systems.
|
2
|
mgCu/l
|
|
Cyanide
|
Very low levels appear naturally.
|
50
|
µgCN/l
|
|
1,2
Dichloroethane
|
Can enter surface water from industrial
effluents related to chemical industries.
|
3
|
µg/l
|
|
Epichlorohydrin
|
Used in industry in the
manufacture of glycerol, unmodified epoxy resins and water treatment resins.
|
0.1
|
µg/l
|
|
Fluoride
|
Occurs naturally.
|
1.5
|
mg/l
|
|
Lead
|
Presence is largely due to influence
of domestic plumbing systems. Mains water contain little or no lead.
|
10
|
µgPb/l
|
|
Mercury
|
Very low levels appear naturally.
|
1
|
µgHg/l
|
|
Nickel
|
Presence is largely derived from protective coatings on
taps and fittings.
|
20
|
µgNi/l
|
|
Nitrate
|
Occurs naturally from both
mineral or soil processes and from agricultural activity.
|
50
|
mgNO3
/l
|
|
Nitrite
|
May be associated with ammonia
or nitrate in river water.
|
0.5
|
MgNO2/l
|
|
Pesticides
|
Many water sources contain
traces of pesticide residues as a result of agricultural and non agricultural
use of pesticides on crops.
|
0.1
|
µg/l
|
|
Pesticides
Total
|
This is the sum of all the
individual pesticides detected in any one sampling occasion.
|
0.5
|
µg/l
|
|
Polycyclic
Aromatic Hydrocarbons (PAH)
|
PAHs are associated with fossil
fuels, if found in mains water they often originate from coal tar linings in
old mains.
|
0.1
|
µg/l
|
|
Selenium
|
This is an essential trace
element. Foodstuffs such as cereal, meat and fish are the principle source in
the general population.
|
10
|
µg/l
|
|
Tetrachloroethene
and Trichloroethene
|
Chlorinated solvents, which are
used in industry and in dry cleaning processes. They are widespread in the environment and are found in trace
amounts in water.
|
Combined
Standard of 10
|
µg/l
|
|
Trihalomethanes
Total (THMs)
|
Formed when chlorine is added to
water as a disinfectant and reacts with organic substances.
|
100
|
µg/l
|
|
Vinyl
Chloride
|
May occur in migration from UPVC
pipes. Controlled by product formulation.
|
0.5
|
µg/l
|
|
Indicator
Parameters
|
|
|
|
|
Aluminium
|
Is naturally present in most
water sources.
|
200
|
µg/l
|
|
Ammonium
|
Is naturally present in most
water sources.
|
0.5
|
mg/l as NH4
|
|
Chloride
|
In association with sodium it
occurs naturally in water resources. Very high levels are present in seawater
and are removed by treatment through desalination.
|
250
|
mg/l
|
|
Colour
|
Occurs naturally in water.
|
Acceptable
to consumers and no abnormal change.
|
|
|
Conductivity
|
A measure of the dissolved
mineral content of the water
|
2500
|
µS cm-1
|
|
Hydrogen
ion concentration (pH)
|
Is controlled at treatment works
to prevent corrosion of pipes and fittings.
|
≥
6.5, and ≤ 9.5
|
pH units
|
|
Iron
|
Occurs naturally. Some mains are
made from cast iron and may corrode with time to give the water a rust
coloured appearance, which while undesirable is not a health hazard.
|
200
|
µg/l
|
|
Manganese
|
Naturally occurring as a result
of passage of water through ground.
|
50
|
µg/l
|
|
Odour
|
As well as chemical tests we
compare the sample with one, which is free of smell.
|
Acceptable
to consumers and no abnormal change.
|
|
|
Oxidisability
|
Provides a measure of the
organic content. This is an alternative measure to TOC
|
5
|
mg/l
|
|
Sulphate
|
Naturally occurring as a result
of passage of water through ground.
|
250
|
mg/l
|
|
Sodium
|
Naturally occurring as a result
of passage of water through ground.
|
200
|
mg/l
|
|
Taste
|
As well as chemical tests we
compare the sample with one, which is free of smell.
|
Acceptable
to consumers and no abnormal change.
|
|
|
Coliform
|
This bacteria indicates that the
water may be contaminated. In most cases this is from the tap itself and may
be present due to normal domestic use.
We recommend that taps including the inside of the spout be regularly
cleaned. Occurrence of the organism is always immediately investigated.
|
0
|
Per 100
ml
|
|
Total
Organic Carbon
|
Provides a measure of the
organic content. The concentrations present in water do not present any risk
to health.
|
No
abnormal change
|
|
|
Turbidity
|
This is the clarity of the
water, which can be affected by minute air bubbles or finely suspended
particles. If you allow a glass of water to stand for a few minutes it will
normally clear.
|
Acceptable
to consumers and no abnormal change.
|
|
