8.5.1 Chemicals assessed prior to 2004

The addition of drinking water treatment chemicals to the Guidelines as listed in Table 8.2 occurred in 2004. This list was based on the NHMRC Drinking Water Treatment Chemicals Committee’s consideration of NHMRC’s Chemicals used for treatment of drinking water supplies (1989). The acceptability of the chemical was dependent upon: the practical application of the chemical (e.g., to clarify dirty water, or destroy or inactivate harmful microorganisms); whether it achieved its purpose; and it being non-toxic when ingested at concentrations present in treated water.

As a result, the Guidelines consider the chemicals in Table 8.2 suitable for use in water supplies where:

• standard operating procedures are applied;

• risk control measures to ensure effectiveness of a particular chemical are applied (e.g., controls to revent over- or under-dosing);

• it is ensured that residuals and contaminants from the addition of multiple treatment chemicals will not exceed recommended health-based guideline values at the consumer’s tap, taking into account combined contributions from all treatment chemicals added and source water; and

• the potential for a chemical to interact with any other added chemical or other compounds present in the water has been considered.

The fact sheets in Part V provide detailed information on chemicals listed in Table 8.2.

Table 8.2 Chemicals recommended for use in the treatment of drinking water (2004)

Treatment chemical	Formula	Original date of approval by NHMRC	Uses
Aluminium chlorohydrates	AlCl(OH)₅	2005	Coagulation
Aluminium sulfate (alum)	Al₂(SO₄)₃	1983	Coagulation
Ammonia	NH₃ aq.	1983	Generation of chloramines for disinfection
Ammonium sulfate	(NH₄)₂SO₄	1983	Generation of chloramines for disinfection
Calcium hydroxide (hydrated lime)	Ca(OH)₂	1983	pH correction Softening Corrosion control
Calcium hypochlorite	Ca(OCl)₂	1983	Disinfection/oxidation
Calcium oxide (quick lime)	CaO	1983	Coagulation aid pH correction Softening Corrosion control
Carbon, powdered activated/granulated activated (PAC/GAC)	C	1983	Adsorption
Chlorine	Cl₂	1983	Disinfection/oxidation
Chlorine dioxide	ClO₂	2005	Disinfection/oxidation
Copper sulfate	CuSO₄	1983	Algicide
Ferric chloride	FeCl₃	1983	Coagulation
Ferric sulfates	Fe₂(SO₄)₃	1983	Coagulation
Hydrochloric acid	HCl	2005	pH correction
Hydrofluorosilicic acid (fluorosilicic acid)	H₂SiF₆	1983	Fluoridation
Hydrogen peroxide	H₂O₂	1983	Disinfection Oxidation
Hydroxylated ferric sulfate		2005	Coagulation
Ozone	O₃	2005	Disinfection/oxidation
Polyacrylamides	(C₃H₅NO)ₙ	1977	Coagulation aid Flocculation aid Filter aid
Polyaluminium chlorides	Alₙ(OH)ₘCl₍ ₃ₙ₋ₘ₎	1979	Coagulation
Poly aluminium silica sulfates	Na₁₂(AlO₂) (SiO₂)₁₂.xH₂O	2005	Coagulation
Polydiallyldimethylammonium chlorides (polyDADMACs)		1982	Coagulation and coagulation aid
Potassium permanganate	KMnO₄	1983	Disinfection/oxidation
Sodium aluminates	NaAlO₂	1983	Coagulation
Sodium bicarbonate	NaHCO₃	1983	pH correction Softening Corrosion control
Sodium carbonate (soda ash)	Na₂CO₃	1983	pH correction Softening Corrosion control
Sodium fluoride	NaF	1983	Fluoridation
Sodium fluorosilicate	Na₂SiF₆	1983	Fluoridation
Sodium hexametaphosphate	(NaPO₃)ₓ	1983	Corrosion control
Sodium hydroxide (caustic soda)	NaOH	1983	pH correction Softening Corrosion control
Sodium hypochlorite	NaClO	1983	Disinfection/oxidation
Sodium silicate	Na₂SiO₃	1983	Coagulation aid Flocculation aid pH correction Corrosion control
Sodium tripolyphosphate	Na₅P₃O₁₀	2005	Corrosion control Softening
Sulfuric acid	H₂SO₄	1983	pH correction
Zinc orthophosphate	Zn₃(PO₄)₂	1987	Corrosion control