|LEAD Action News vol 11 Number 2, December
2010, ISSN 1324-6011
Incorporating Lead Aware Times (ISSN 1440-4966) & Lead Advisory Service News (ISSN 1440-0561)
The journal of The LEAD (Lead Education and Abatement Design) Group Inc.
Guest Editor, Dr Chrissie Pickin. Editor-in-Chief: Anne Roberts
The role of toxicologists in the Rosebery investigation
By Chrissie Pickin, Deputy Director of Public Health, Tasmania, in collaboration with clinical toxicologists, Professor Frank Daly and Professor George Braitberg
Toxicologists have played a major role in investigating allegations of heavy metal poisoning in Rosebery, since they were first raised in 2008.
But just what is a toxicologist and how do they arrive at their conclusions?
In simple terms, a toxicologist is a scientist or physician who studies the adverse effects of chemicals on living organisms. This includes the symptoms, mechanisms, detection, and treatment of adverse effects in people.
But, in their day-to-day research, nothing is simple, as toxicologists face the complex and challenging task of determining the relationship between the dose of a chemical and its effects on the exposed organism.
In the case of the Rosebery investigations, three independent toxicologists were brought in to analyse all of the data, to determine whether poisoning has actually occurred or whether other factors are to blame for some residents’ health problems.
The allegations were initially investigated by an experienced environmental toxicologist from Monash University School of Public Health and Preventive Medicine, Professor Brian Priestly. Professor Priestly is also Director of the Australian Centre for Human Health Risk Assessment.
In his report released in March last year, Professor Priestly found soil, dust, water and air samples did not show dangerous levels of heavy metals and nor did blood samples taken from residents (Priestly 2010).
Unhappy with those findings, several people sought further medical advice from Dr Andreas Ernst, an Occupational Health and Musculoskeletal specialist.
Based on his assessment of ten patients, Dr Ernst made a diagnosis of heavy metal poisoning, and provided a report to the Director of Public Health, Dr Roscoe Taylor.
In December last year, the Health Department re-opened an investigation into the allegations, appointing two independent clinical toxicologists from Western Australia and Victoria, Professors Frank Daly and George Braitberg.
Professor Daly is Consultant Clinical Toxicologist at Royal Perth Hospital and the West Australian and NSW Poisons Information Centres, as well as Professor of Emergency Medicine and Clinical Toxicology at the WA Institute of Medical Research.
Professor Braitberg is a Consultant Toxicologist and Director of Emergency Medicine at Southern Health – including Monash Medical Centre – in Victoria, as well as Professor of Emergency Medicine at Monash University.
Both have extensive experience in clinical medicine and research, both in Australia and overseas. Professor Daly's overseas experience includes travelling to China, to assist in research looking at the effects of chronic arsenic poisoning in people following environmental exposure. While there, he saw firsthand the effects that substantiated and significant chronic environmental arsenic exposures can have.
Both experts separately reviewed all available data in detail, and concluded that there was no evidence of heavy metal poisoning in the ten cases (Braitberg 2010, Daly 2010).
In his final report, Professor Braitberg described the complex nature of his work.
“A clinical toxicologist is a specialist in drugs, poisons and envenoming, trained to look at the health aspects of any exposure and to use evidence-based principles to determine cause and effect (Braitberg 2010).
“The symptoms must be consistent with the expected signs and symptoms caused by the poison; any signs must fit the expected course of the poisoning and the investigations must correlate with known toxicity levels” (Braitberg 2010).
In the course of their investigations, the experts examined numerous documents, including:
Files containing doctors’ correspondence, examination and investigation results for ten patients – all current or former residents of Rosebery;
Reports and a presentation by Dr Ernst;
Previous investigations into heavy metals exposure in the Rosebery environment, including blood lead testing of residents; and
The previous toxicology advice from Professor Brian Priestly.
The toxicologists’ review of all the available clinical reports and investigations took into account the known effects of the heavy metals investigated.
They placed particular emphasis on the appropriateness of any test performed and how the test was interpreted.
Their evaluations also incorporated a huge body of international science, research and peer reviewed literature.
Both toxicologists found no evidence of heavy metal poisoning in any of the ten patients.
The Toxic Heavy Metals Taskforce has refused to accept those findings, claiming that the toxicologists’ reports contained numerous errors of fact and incorrect assumptions (The Lead Group 2010).
The Taskforce criticisms claimed that:
Conclusions drawn were made from incomplete, flawed and deficient DHHS and EPA Investigations;
Assumptions on possible diagnosis were made without patient consultations or examinations;
Assumptions on possible diagnosis were made without up-to-date medications lists, accurate medical reports, documentation, correct data and specialist/diagnostic test results;
Incorrect attribution and analysis of data; and
Conflicting findings between Professor Daly’s and Professor Braitberg’s reports.
However, the DHHS has defended the toxicologists’ investigations and reports.
The Department says Professors Daly and Braitberg had the objective of assessing the diagnosis of Dr Ernst and determining whether that diagnosis could be supported by objective data or evidence. DHHS says the toxicologists did not try to make definitive diagnoses of the causes of the ten patients’ health problems, but rather assessed what alternative diagnoses could be made and whether the diagnosis of heavy metal poisoning could be substantiated based on the evidence. Each toxicologist was commissioned separately and individually to write their reports and did so without consulting the other. As such naturally their comments and discussion was different but not conflicting as suggested.
The Department says it provided all clinical information it held to Professors Daly and Braitberg, including all clinical information held by Dr Ernst as at January 1, 2010. The Department says neither it nor Professors Daly and Braitberg had access to the full medical records of each of the residents, and nor were they able to directly examine the residents. But every effort was made to obtain the available clinical information relevant to heavy metal poisoning, for each alleged case. It says the toxicologists did have access to the files of Dr Ernst and relevant materials from a number of GPs and hospital specialists, and were able to comment on whether there was sufficient evidence to support any diagnosis of heavy metal poisoning of any kind and whether there were alternative possible diagnoses or further testing required for the residents. The doctors also indicated where they thought there was insufficient clinical information provided to comment and were able to request further information or tests be sought.
And, the Department says according to Dr Ernst's own notes, he too did not undertake a physical examination of many of the ten patients.
It says both experts made themselves available to discuss the reports with the GPs of each resident, but that this offer has not been taken up.
In their final reports, Professors Daly and Braitberg emphasised the importance of correct diagnosis, and expressed concerns for the welfare of the patients, urging follow-up tests and medical care to properly identify the causes of their various symptoms and the need for clinical management of a number of possible alternate diseases (Braitberg 2010, Daly 2010).
“As a clinical toxicologist practicing evidence-based medicine, the first priority I have to my patients is to provide evidence of cause and effect”, Professor Braitberg said (Braitberg 2010).
“Ascribing cause where none is found has the potential to prevent or delay the detection of the true illness”, he said (Braitberg 2010).
“I believe it is in the best interests of these patients to continue to seek medical assistance to determine the cause of their symptoms”, Professor Braitberg said (Braitberg 2010).
In his final report, Professor Daly said none of the patients met diagnostic criteria for poisoning or adverse health effects by any of the heavy metals, in isolation or in combination (Daly 2010).
They also reviewed the evidence on synergism – an issue Dr Ernst had raised in his reports. Dr Daly concluded that “there is no epidemiological evidence in the peer review literature to support the general hypothesis of synergistic effects in humans exposed to arsenic, cadmium, chromium or lead in an occupational or environmental setting at what would normally be regarded as sub-toxic levels.” (Daly 2010)
The Deputy Director of Public Health, Dr Chrissie Pickin, says three independent national toxicological experts have now confirmed that none of the concerned residents has any clinical evidence to confirm poisoning.
“In addition the toxicologists all concur that there is no evidence of the residents having absorbed metals from the environment at any level likely to cause harm - alone or in combination”, Dr Pickin said.
These findings have been further supported by more widespread blood and urine testing of many other Rosebery residents, including a number of children, for exposure to metals. None of these results have provided cause for public health concern about excessive exposure to metals in the residential environment of the town.
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Updated 24 January 2012