❓ A parliamentary question regarding lead levels in drinking water at Perth Children's Hospital and King Edward Memorial Hospital, focusing on testing methodologies and compliance with safety standards. The Minister's response clarifies testing procedures and results, disputing some of the questioner's assertions.
AnsweredQoN 4371Legislative Assembly
Asked
6 November 2018
Member
Portfolio
Deputy Premier; Minister for Health; Mental Health
QuestionView source ↗
(1) Can the Minister confirm that the Australian Drinking Water Guideline (ADWG) for the safe content of lead in drinking water is based upon weekly tests on infants and is derived to be an average of no more than 0.010 milligrams/litre consumed per day and is identical to the World Health Organisation (WHO) standard? (2) Can the Minister confirm that because of unavoidable fluctuations in lead concentration in water due to many factors, including; diameter of plumbing fittings, volume of initial test sample taken, time sample was taken, variation in scheme water quality, cathodic action due to bi-metal conditions, microbiological activity and temperature, that the WHO adopted a safe average level for lead concentration instead of a maximum level? (3) Is the Minister aware that the United States Environmental Protection Authority (EPA) utilise a different method to the WHO in order to account for statistical scatter and instead of a daily average have adopted a 90 percentile approach whereby "not more than 10% of samples can exceed the US value of 0.015 mg/L": (a) is the Minister aware that the US EPA also addresses the method of taking samples and the regulations specify that all tap samples shall be first draw samples and all first draw samples shall be 1 litre in volume and have stood motionless in the plumbing system of each sample site for at least 6 hours? (4) Can the Minister confirm that the WA Health Department took 606 water samples from the Perth Children's Hospital in June and July 2017 and that the average lead content of these samples was 0.0072 mg/L with a standard deviation of 0.0066: (a) can the Minister also confirm that each sample size taken was 125 millilitres and that 6% of samples exceeded 0.015 mg/L? (5) If the Minister cannot confirm the information in (4), what are the correct values arising from the analysis of the 606 samples taken? (6) In relation to answers to (4) and (5), can the Minister confirm that using either the ADWG safe average daily lead intake per volume of water consumed methodology or the US EPA testing methodology, the Perth Children's Hospital met both safe water quality standards based on the 606 samples taken, despite sample size being 125mls rather than 1 litre? (7) In relation to the final lead testing undertaken in 2018, following replacement of a substantial number of the brass fittings, involving 304 test samples, can the Minister confirm that from these test results the average lead content in the Perth Children's Hospital is now 0.0034 mg/L with a standard deviation of 0.0027 and with only 2 samples of the 304 exceeding 0.015 mg/L (<1%)? (8) If the Minister cannot confirm the information in (7) what are the correct figures arising from the analysis of the 304 samples taken? (9) Can the Minister advise if testing of water for lead has been undertaken for the King Edward Memorial Hospital in my electorate over the past 3 years and if so: (a) When was this testing undertaken; (b) What was the result of this testing; and (c) What lead testing methodology was adopted for the KEMH for each of these tests? (10) If testing for lead in the water has not been undertaken for KEMH over the past 3 years is the Health department planning to do any testing in the next 12 months?
AnswerView source ↗
Answered
12 February 2019
Response time
9 days
I am advised that:
(1) No. While it is true that the health-related guideline value in the “Australian Drinking Water Guidelines” (ADWG) for lead in drinking water is 0.01 milligrams per litre, and this guideline value is identical to the World Health Organization (WHO) standard, the ADWG recommends that, for health-related criteria (such as lead levels in drinking water), the 95 th percentile statistic of water sample data should be used to determine performance against the guideline value, not an average.
The researchers for ADWG and WHO did not perform weekly blood tests on infants. ADWG health-related guideline values and WHO standards are not derived by averaging research findings or by averaging lead concentrations in the environment. They are derived with appropriate risk equations. Further, the WHO recommends (as does the Department of Health) exclusive breastfeeding for first 6 months.
(2) No. WHO have adopted a provisional guideline level for lead in drinking water on the basis of treatment performance and analytical achievability. The WHO does not prescribe a health based guideline value, as concentrations should be maintained as low as reasonably practical, particularly as infants and children are considered to be the most sensitive subgroups of the population. Non-biological factors, such as those listed in the question, are not relevant in such an assessment.
(3) It is true that the United States EPA utilise a different method to the WHO, but WHO does not advocate a “daily average”. A “daily average” is not sufficiently protective for determining water safety in the context of public health, particularly in a setting to be primarily occupied by children, and is not relevant.
(a) Yes.
(4) Yes.
(a) No. 58 of the 606 sample pairs in total had lead levels that exceeded 0.015 milligrams per litre, which equates to 9.6%. Each sample pair was made up of two 125 millilitre samples.
(5) The correct number of sample pairs and the calculated averages and standard deviation figures of this data set are as set out above and are those adopted in the CHO’s investigation of the situation.
(6) No.
To determine whether the water supply at the Perth Children’s Hospital was safe to drink, the CHO followed a testing procedure that was best suited to the unique conditions of an empty hospital, complex plumbing layout and a persistent problem.
The samples that were taken in June and July 2017 clearly indicated that the lead levels in the water at the Perth Children’s Hospital did not comply with the requirements set out in the ADWG. The ADWG recommends that, for health-related criteria (such as lead levels in drinking water), the 95 th percentile statistic of water sample data should be used to determine performance against the guideline value, not an average.
(7) An average across the data set is not relevant in determining whether water at the hospital was or was not safe to drink. The approach taken by the CHO was the correct methodology to use for the Perth Children’s Hospital and I recommend the CHO’s Report to the Member for Nedlands.
(8) See Answer (7).
(9) Yes.
(10) Not applicable.
(1) No. While it is true that the health-related guideline value in the “Australian Drinking Water Guidelines” (ADWG) for lead in drinking water is 0.01 milligrams per litre, and this guideline value is identical to the World Health Organization (WHO) standard, the ADWG recommends that, for health-related criteria (such as lead levels in drinking water), the 95 th percentile statistic of water sample data should be used to determine performance against the guideline value, not an average.
The researchers for ADWG and WHO did not perform weekly blood tests on infants. ADWG health-related guideline values and WHO standards are not derived by averaging research findings or by averaging lead concentrations in the environment. They are derived with appropriate risk equations. Further, the WHO recommends (as does the Department of Health) exclusive breastfeeding for first 6 months.
(2) No. WHO have adopted a provisional guideline level for lead in drinking water on the basis of treatment performance and analytical achievability. The WHO does not prescribe a health based guideline value, as concentrations should be maintained as low as reasonably practical, particularly as infants and children are considered to be the most sensitive subgroups of the population. Non-biological factors, such as those listed in the question, are not relevant in such an assessment.
(3) It is true that the United States EPA utilise a different method to the WHO, but WHO does not advocate a “daily average”. A “daily average” is not sufficiently protective for determining water safety in the context of public health, particularly in a setting to be primarily occupied by children, and is not relevant.
(a) Yes.
(4) Yes.
(a) No. 58 of the 606 sample pairs in total had lead levels that exceeded 0.015 milligrams per litre, which equates to 9.6%. Each sample pair was made up of two 125 millilitre samples.
(5) The correct number of sample pairs and the calculated averages and standard deviation figures of this data set are as set out above and are those adopted in the CHO’s investigation of the situation.
(6) No.
To determine whether the water supply at the Perth Children’s Hospital was safe to drink, the CHO followed a testing procedure that was best suited to the unique conditions of an empty hospital, complex plumbing layout and a persistent problem.
The samples that were taken in June and July 2017 clearly indicated that the lead levels in the water at the Perth Children’s Hospital did not comply with the requirements set out in the ADWG. The ADWG recommends that, for health-related criteria (such as lead levels in drinking water), the 95 th percentile statistic of water sample data should be used to determine performance against the guideline value, not an average.
(7) An average across the data set is not relevant in determining whether water at the hospital was or was not safe to drink. The approach taken by the CHO was the correct methodology to use for the Perth Children’s Hospital and I recommend the CHO’s Report to the Member for Nedlands.
(8) See Answer (7).
(9) Yes.
(10) Not applicable.
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