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❓ Mr. Marmion questions the Treasurer regarding lead contamination in the potable water supply, specifically concerning the dezincification of brass fittings and the role of chlorine. The Treasurer's response confirms the potential for lead loss and the influence of chloride levels.

AnsweredQoN 1978Legislative Assembly

Asked

5 September 2017

Member

Mr W.R. Marmion

Portfolio

Treasurer

QuestionView source ↗

(1) I refer to the Treasurer's answer to Question on Notice No. 39, part (c), in which you advised on 16 May 2017, that 'lead was detected in the potable water testing with both particulate and dissolved lead levels traceable in all testing to date. Particulate lead is now being detected in very low levels in the potable water system with the remaining lead levels being detected as dissolved lead' and I ask: (a) in the dezincification process of brass, is lead loss both particulate and dissolved; (b) is there a direct or indirect correlation between the amount of lead and amount of zinc lost through the dezincification process; and (c) if most of the lead loss from brass fittings, through dezincification, is by dissolving, how do you account for the presence of lead particulates in the potable water supply? (2) Does the flushing of chlorine enriched water increase the likelihood of dezincification of brass fittings, and if so, why? (3) Does the flushing of chlorine enriched water increase the possible leaching of lead from brass fittings in either particulate or dissolved form, and if so, why?

AnswerView source ↗

Answered

10 October 2017

Response time

9 days

The Department of Finance advises:
(1)(a) Yes, there is potential for both.
(b) Testing at Perth Children’s Hospital has typically indicated a correlation in lead and zinc concentrations.
(c) Not applicable – see (a).
(2) Research has confirmed that chloride level is a factor in dezincification.
(3) Potentially yes, for the reasons outlined in (2).

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