Use of polyacrylamides as coagulant aids. Use of polyacrylamide grouts for borehole/well linings.
Use of aluminium compounds as coagulants. Occurs in some surface and ground waters.
Possible from domestic plumbing fittings.
Present in some ground waters.
Contamination of raw waters from petrol/diesel etc. Permeation of plastic distribution and domestic plumbing pipes.
Leaching from internal coal tar lining of some distribution pipes.
Contamination of surface waters with detergents mainly from sewage effluents.
Present in sodium hypochlorite used to disinfect water, including electrolytically generated hypochlorite. Formed if ozone used and water contains bromide.
Leaching from galvanised pipes and some domestic plumbing fittings (e.g. plated taps).
Indicator of saline intrusion so relevant in coastal areas. Also relevant if water softener in situ. May indicate sewage pollution of surface water.
Leaching from some domestic plumbing fittings (e.g. chrome plated plastic taps).
Clostridium perfringens (including spores)
Contamination of raw waters from sewage effluents and animal waste.
Leaching from pipes and plumbing fittings. Low pH and low or high alkalinity increases copper leaching.
Possible contamination of raw waters from industry (e.g. metal finishing, wood preservatives).
Volatile solvent used in manufacture of vinyl chloride and other processes. Can contaminate and persist in ground water.
Contamination of raw waters from sewage, sewage effluents and animal waste.
Use of polyamines as coagulant aids. Use of epoxy resins (e.g. to line pipes and tanks). Use to make some ion exchange resins.
May be present in some ground waters.
Use of iron compounds as coagulants. Occurs in some surface water and ground waters. Corrosion of iron distribution mains.
Leaching from lead pipes in distribution and domestic plumbing or from lead soldered copper pipes. Low pH and low or high alkalinity increases lead leaching. Present naturally in some ground waters
Present in some greensand filtration materials. Occurs in some surface water and ground waters.
Contamination from mercury thermometers and float valves
Leaching from some domestic plumbing fittings (e.g. plated taps).
Contamination of surface and ground waters from fertilisers, animal wastes or sewage effluents.
Contamination of raw waters. Use of chloramination as a residual disinfectant or use of chlorine as disinfectant when ammonium ions present.
Contamination of raw waters from use in agriculture, forestry, roads, railways etc.
Pesticides – total
This means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.
Polycyclic aromatic hydrocarbons (PAH)
Leaching from internal coal tar lining of some distribution pipes. Sum of four individual PAH.
May occur naturally in some raw waters.
Present in raw waters but usually below standard. Can be introduced by water softeners and treatment chemicals (e.g. sodium hypochlorite for disinfection) or through saline intrusion of ground waters in coastal areas.
Occurs in some raw waters, but usual below the standard.
Tetrachloroethene and Trichloroethene
Contamination of some ground waters from use of these volatile solvents in dry cleaning and metal finishing. Standard is sum of two compounds.
Contamination of some ground waters from use of this volatile solvent in metal finishing and other industries.
Total indicative dose (for radioactivity)
Contamination of raw waters from natural or manmade radioactive compounds.
Trihalomethanes – total
Formed by reaction of organic matter in raw water with chlorine compounds used as disinfectants. Standard is sum of four compounds.
Cosmic production in upper atmosphere. By-product of nuclear explosions and nuclear industry.
Used for making PVC. Leaching from unplasticised PVC pipes used in distribution or domestic plumbing.