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Australian Drinking Water Guidelines: Draft amendments to Chapters Six and Eight submission

This submission reflects the views of
Organisation Name: 
Helix Solutions
Personal Details
Specific Questions
1. Is the new text in Chapter 6 (Section 6.5) relevant, accurate and easy to understand?: 
No comment
2. Do you have any comments on the process for determining interim guideline values for chemicals that have been detected in drinking water but do not have a guideline value in the Australian Drinking Water Guidelines?: 
No comment
3. Are the proposed amendments to Chapter 8 relevant, accurate and easy to understand?: 
I have two comments regarding the proposed amendments to Chapter 8: 1. My general concern is that the exclusion of specific water treatment chemicals previously approved by NHMRC, from Table 8.2, implies these chemicals are no longer considered suitable for use by the NHMRC. My specific concern is associated with the exclusion of Silver Hydrogen Peroxide from Table 8.2. I have addressed this issue further, in section 5 below. 2. As a business, we are concerned about the uncertainty, possible lack of consistency, and potential considerable cost and time required to address the use of chemicals not listed in Table 8.2, with each individual state or territory health regulatory agency. Our preference is to have "one port of call", where this can be addressed, assessed and approved (or not). Currently, state level health regulatory agencies direct the assessment of chemicals not approved for use in drinking water to the ADWG, whilst the ADWG direct this to the state level health regulatory agencies. This circular approval mechanism is a significant barrier for businesses seeking to promote innovation in the drinking water sector. Ultimately, we respect the need for a national standard, and we are seeking a clearer mechanism for this standard to be applied.
5. Do you have any suggestions about other sections of the Australian Drinking Water Guidelines that need to be revised as part of NHMRC’s rolling review process?: 
This submission is made by Helix Solutions, the exclusive Australian distributor for the internationally patented, and Swiss manufactured silver hydrogen peroxide disinfectant, Sanosil. The submission proposes the inclusion of silver hydrogen peroxide in Table 8.2, Chapter 8 of the Australian Drinking Water Guidelines. The principal purpose of the submission is to address the following aspects of the utilisation of silver hydrogen peroxide based disinfection of drinking water: 1. NHMRC’s previous assessment of the suitability of silver hydrogen peroxide 2. What Australian Drinking Water Guidelines 2011 (ADWG) says about utilisation of hydrogen peroxide and silver 3. Australian and International approvals for silver hydrogen peroxide 4. Enhanced antimicrobial activity of silver hydrogen peroxide The inclusion of silver hydrogen peroxide in Table 8.2 will remove any doubt regarding its suitability for use as a drinking water disinfectant, confirming NHMRC’s previous assessment of silver hydrogen peroxide. 1. NHMRC Previous Assessment of Silver Hydrogen Peroxide 1.1. Silver hydrogen peroxide is included in the now rescinded list from NHMRC, Chemicals used for treatment of drinking water supplies (1989). Silver hydrogen peroxide is addressed in 107th session, p17. 1.2. In a letter to Sanosil Australia from NHMRC, dated 3 November 1993, the following statements address silver hydrogen peroxide: 1.2.1. It (Council) noted that the effect of these two chemicals (hydrogen peroxide and complexed silver ions), when used in combination, was greater than the added effects of the chemicals used alone. 1.2.2. Council considered that the process would be effective in batch disinfection of water. 1.2.3. Council recommended maximum dosage of 17.5 mg/L (as hydrogen peroxide) and 0.0125 mg/L (as silver ion). Council further established that at the maximum dosage levels employed, there would be no significant adverse health effects. 2. ADWG; hydrogen peroxide and silver 2.1. Hydrogen peroxide is recommended for use for disinfection and oxidation in drinking water in Chapter 8, Table 8.2. 2.2. Silver is not recommended for use as a disinfectant for municipal drinking water supplies in Part IV, Information Sheet 1.8, citing a comprehensive review of the effectiveness of silver as a disinfectant, undertaken by the Australian Pesticides and Veterinary Medicines Authority (APVMA). We note that this guideline addresses the use of silver as the sole disinfection agent, and does not address silver hydrogen peroxide. 2.3. The health guideline for silver is set as 0.1 mg/L in Chapter 10, Table 10.5. The derivation of this guideline is detailed in Part V, Silver Fact Sheet. 2.4. We note that when Sanosil is dosed at recommended rates, to achieve satisfactory disinfection and maintain a residual hydrogen peroxide concentration, the maximum silver concentration in the treated drinking water will be in the order of 0.01 mg/L, around 10% of the health limit for silver. 2.5. Sanosil is a 50% hydrogen peroxide solution, stabilised with 0.05% silver. 3. Australian and International Approvals for silver hydrogen peroxide 3.1. Sanosil is registered under EU Biocidal Products Regulation, Article 95, including Product Type 5; Drinking Water, for the disinfection of drinking water for humans and animals. Active substances registered include hydrogen peroxide (p71), silver nitrate (p74) and silver (p52). 3.2. Huwa-San, another silver hydrogen peroxide product, is registered in USA and Canada under National Sanitation Foundation (NSF) Standard 60 for Drinking Water Treatment Chemicals (C0038609). 3.3. Sanosil and other silver hydrogen peroxide products are registered under the APVMA as swimming pool and spa sanitisers (Product No: 40742, 69472, 70221, 70448). 4. Enhanced antimicrobial activity of silver hydrogen peroxide 4.1. In a recently published open access journal article, “Antibacterial Properties and Mechanism of Activity of a Novel Silver Stabilized Hydrogen Peroxide”, the outcomes of a study undertaken by the Department of Biomedical and Molecular Sciences at Queen’s University in Ontario Canada are presented. The study assessed the synergistic biocidal properties of a proprietary silver stabilised hydrogen peroxide product, with the following key findings: 4.1.1. Contact/kill time (CT) comparisons between silver stabilised hydrogen peroxide, hydrogen peroxide and sodium hypochlorite demonstrated that silver stabilised hydrogen peroxide was found to be more or equally effective as sodium hypochlorite or hydrogen peroxide. 4.1.2. When compared to hydrogen peroxide, silver stabilised hydrogen peroxide showed improved resistance to neutralisation of the hydrogen peroxide by microorganism produced enzymes which are naturally produced to protect the cells by breaking down hydrogen peroxide to water and oxygen. This demonstrates that the action of the silver serves to improve the efficacy and residual of the silver stabilised hydrogen peroxide, compared to hydrogen peroxide. 4.1.3. The microbiocidal activity of silver stabilised hydrogen peroxide was demonstrated to be due to hydrogen peroxide, rather than silver. 4.1.4. Overall, the study concludes that the antimicrobial activity of silver stabilised hydrogen peroxide is enhanced over that of hydrogen peroxide. It also found the presence of silver enhances the interactions of the silver stabilised hydrogen peroxide with the bacterial cell surface, rather than acting directly as a biocide. Reference Nancy L. Martin, Paul Bass, Steven N. Liss (2015), Antibacterial Properties and Mechanism of Activity of a Novel Silver-Stabilized Hydrogen Peroxide, PLoS ONE 10(7): e0131345. Doi:10.1371/journal.pone.0131345

Page reviewed: 10 February, 2016