# 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) <a href="#table-8-2" id="table-8-2"></a>

<table><thead><tr><th width="200">Treatment chemical</th><th width="150">Formula</th><th width="173">Original date of approval by NHMRC</th><th>Uses</th></tr></thead><tbody><tr><td>Aluminium chlorohydrates</td><td>AlCl(OH)₅ </td><td>2005</td><td>Coagulation</td></tr><tr><td>Aluminium sulfate (alum)</td><td>Al₂(SO₄)₃</td><td>1983</td><td>Coagulation</td></tr><tr><td>Ammonia</td><td>NH₃ aq.</td><td>1983</td><td>Generation of chloramines for disinfection</td></tr><tr><td>Ammonium sulfate</td><td>(NH₄)₂SO₄</td><td>1983</td><td>Generation of chloramines for disinfection</td></tr><tr><td>Calcium hydroxide (hydrated lime)</td><td>Ca(OH)₂</td><td>1983</td><td><p>pH correction</p><p>Softening</p><p>Corrosion control</p></td></tr><tr><td>Calcium hypochlorite</td><td>Ca(OCl)₂</td><td>1983</td><td>Disinfection/oxidation</td></tr><tr><td>Calcium oxide (quick lime)</td><td>CaO</td><td>1983</td><td><p>Coagulation aid</p><p>pH correction</p><p>Softening</p><p>Corrosion control</p></td></tr><tr><td>Carbon, powdered activated/granulated activated (PAC/GAC)</td><td>C</td><td>1983</td><td>Adsorption</td></tr><tr><td>Chlorine</td><td>Cl₂</td><td>1983</td><td>Disinfection/oxidation</td></tr><tr><td>Chlorine dioxide</td><td>ClO₂</td><td>2005</td><td>Disinfection/oxidation</td></tr><tr><td>Copper sulfate</td><td>CuSO₄</td><td>1983</td><td>Algicide</td></tr><tr><td>Ferric chloride</td><td>FeCl₃</td><td>1983</td><td>Coagulation</td></tr><tr><td>Ferric sulfates</td><td>Fe₂(SO₄)₃</td><td>1983</td><td>Coagulation</td></tr><tr><td>Hydrochloric acid</td><td>HCl</td><td>2005</td><td>pH correction</td></tr><tr><td><p>Hydrofluorosilicic acid</p><p>(fluorosilicic acid)</p></td><td>H₂SiF₆</td><td>1983</td><td>Fluoridation</td></tr><tr><td>Hydrogen peroxide</td><td>H₂O₂</td><td>1983</td><td><p>Disinfection</p><p>Oxidation</p></td></tr><tr><td>Hydroxylated ferric sulfate</td><td></td><td>2005</td><td>Coagulation</td></tr><tr><td>Ozone</td><td>O₃</td><td>2005</td><td>Disinfection/oxidation</td></tr><tr><td>Polyacrylamides</td><td>(C₃H₅NO)ₙ</td><td>1977</td><td><p>Coagulation aid</p><p>Flocculation aid</p><p>Filter aid</p></td></tr><tr><td>Polyaluminium chlorides</td><td>Alₙ(OH)ₘCl₍ ₃ₙ₋ₘ₎</td><td>1979</td><td>Coagulation</td></tr><tr><td>Poly aluminium silica sulfates</td><td>Na₁₂(AlO₂)<br>(SiO₂)₁₂.xH₂O</td><td>2005</td><td>Coagulation</td></tr><tr><td>Polydiallyldimethylammonium chlorides (polyDADMACs)</td><td></td><td>1982</td><td>Coagulation and coagulation aid</td></tr><tr><td>Potassium permanganate</td><td>KMnO₄</td><td>1983</td><td>Disinfection/oxidation</td></tr><tr><td>Sodium aluminates</td><td>NaAlO₂</td><td>1983</td><td>Coagulation</td></tr><tr><td>Sodium bicarbonate</td><td>NaHCO₃</td><td>1983</td><td><p>pH correction</p><p>Softening</p><p>Corrosion control</p></td></tr><tr><td>Sodium carbonate (soda ash)</td><td>Na₂CO₃</td><td>1983</td><td><p>pH correction</p><p>Softening</p><p>Corrosion control</p></td></tr><tr><td>Sodium fluoride</td><td>NaF</td><td>1983</td><td>Fluoridation</td></tr><tr><td>Sodium fluorosilicate</td><td>Na₂SiF₆</td><td>1983</td><td>Fluoridation</td></tr><tr><td>Sodium hexametaphosphate</td><td>(NaPO₃)ₓ</td><td>1983</td><td>Corrosion control</td></tr><tr><td>Sodium hydroxide (caustic soda)</td><td>NaOH</td><td>1983</td><td><p>pH correction</p><p>Softening</p><p>Corrosion control</p></td></tr><tr><td>Sodium hypochlorite</td><td>NaClO</td><td>1983</td><td>Disinfection/oxidation</td></tr><tr><td>Sodium silicate</td><td>Na₂SiO₃</td><td>1983</td><td><p>Coagulation aid</p><p>Flocculation aid</p><p>pH correction</p><p>Corrosion control</p></td></tr><tr><td>Sodium tripolyphosphate</td><td>Na₅P₃O₁₀</td><td>2005</td><td><p>Corrosion control</p><p>Softening</p></td></tr><tr><td>Sulfuric acid</td><td>H₂SO₄</td><td>1983</td><td>pH correction</td></tr><tr><td>Zinc orthophosphate</td><td>Zn₃(PO₄)₂</td><td>1987</td><td>Corrosion control</td></tr></tbody></table>


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