7 no 2, 1999
Report of Analysis of Flue Dust and Ceiling Cavity Dust
Sample Description : Ceiling cavity dust x 2 (submitted)
Date Received : 23/1/98
Date of Report : 5/2/98
Request : Multi - element analysis
Results: [NB mg/kg = milligrams per kilogram, which is the same as parts per million (ppm) or micrograms per gram (µg/g)]
COMMENT: The normal ranges listed are taken from "Heavy Metals in Soils", Alloway, 1990.
[The results are listed in order (from highest to lowest concentration) of the elements in ceiling dust.]
Simple Observations about the Results
The total mass of elements in the dust is 300,747 mg/kg for the flue dust sample and 310,269 mg/kg for the ceiling dust sample. Though the bulk of the samples most probably consisted of anion group (carbonates, chlorides, hydroxides etc) and inert carbon which were not quantified, it is interesting to ask what other elements would be found in the remaining 70% and 69% of the flue dust and ceiling dust respectively.
In the absence of any government body in Australia having set an acceptable level for various contaminants in ceiling dust, the next best thing is to compare results to soil contamination standards. Knowing that the upper limit (ie 300 mg/kg) of the soil range that is given as "normal" for lead, is also "the level for further investigation" of the NSW EPA, I will assume that to exceed the "normal" level for other elements also warrants further investigation. The elements in the above analysis report for which a "normal" soil range is given and which exceed "normal" are:
It would seem a reasonable hypothesis that for those elements for which the concentration in the flue dust is greater than the concentration in the ceiling cavity in general, that the flue pipe was probably a major contributor of that element to the dust in the cavity. To test this, a researcher would as a minimum, need to determine whether the particular element could have originated in the flue pipe but then escaped from the ceiling void due to being in a fine particulate or gaseous form etc. isotopic fingerprint research methods could be used on those elements with different isotopes which originate in different ore bodies, for example, lead. Such research as carried out by Prof Brian Gulson, a CSIRO researcher in Sydney, has in the past been used to determine for instance whether the lead in a person's blood stream mainly came from petrol or from ore dust in Broken Hill.
So the elements which are higher in the flue dust than in the cavity dust and therefore may have come mainly from the coal gas burner emissions are: arsenic, chromium, copper, lead, magnesium, nickel, sulphur, tin, thallium and zinc. It is vital to note that in some cases the flue dust sample concentration is vastly greater than the cavity dust sample, eg 1000 times for nickel (which therefore may have come solely from the flue pipe) whereas for others the concentration between the two dust samples varies much less, eg less than 5 times for lead (which we know to have numerous other sources).
Which Contaminants of Ceiling Voids Probably come Mainly from Other Sources?
The elements which are lower in the flue dust than in the cavity dust and therefore may have come mainly from sources other than the coal gas burner emissions are: aluminium, calcium, cadmium, iron, potassium, manganese, sodium, phosphorus, silicon and vanadium.
I tried to get some idea of whether the third and fourth points above might form a reasonable hypothesis by asking WorkCover NSW what the emissions from coal gas burning were likely to contain and I was referred to Pollution Line (NSW EPA) as the issue was more an environmental health issue. Pollution Line said the major work on coal gas would have been for a contaminated sites issue - at the storage depots for coal gas. Pollution Line pointed out that I could refer to a textbook on contaminated sites but this would not necessarily tell me what was in the emissions from burning coal gas: "The best source of information on what is in coal gas burner emissions seems to be the analysis report you already have."
I decided to ask the ACTU for a Material Safety Data Sheet (MSDS) on coal gas but I learned that the MSDS is required to comment on the toxicity of ingredients, not the toxicity of contaminants of a chemical in the workplace. This left me with a worker (the ceiling dust removalist) obviously being exposed to a hazardous dust in the workplace (the roof voids of houses) but with insufficient information to help him know what to protect himself from, and how.
I was not only concerned about his lead levels - I had advised him since 1996 to regularly check his blood lead level and to wear a respirator while on the job. Now it seemed he also needed to check the levels of other heavy metals in his body and there was the issue of his persistent cough which concerned me gravely. I never had a conversation with him without wondering about the effects of his work on his respiratory health.
On behalf of ceiling dust removalists in general, I thought it best to get some decent advice from WorkCover. I was put through to Occupational Medicine and received some useful tips from Dr Cullen (see below). I passed on the advice via the ceiling dust removalist's secretary and have often wondered since how he was going and how feasible it is to wear a respirator when you are coughing so persistently.
Every time I have ever asked one of the ceiling dust contractors that ring up the Lead Advisory Service, what their blood lead level is, I get an answer that is uninterpretable eg "it's okay - I can't remember the figure". The only way anyone will prove to me that ceiling dust contractors are not being affected by their exposure to ceiling dust is for me to be presented with a survey of contractors that finds a clean bill of health for both heavy metals and respiratory function. It's time WorkCover stepped in here - to help out a fledgling industry and prevent these contractors being 'statistics' in a few years time. Good occupational health and safety practice involves controlling a hazard as close as possible to the source, not just putting a respirator on the worker. What about all those workers who are exposed to ceiling dust but don't know enough about it to wear a respirator?
The huge advantage of WorkCover licensing asbestos contractors is that licensing entails workers having insurance and being trained for the work they do. There is no training course available anywhere for ceiling dust removalists and no standard to guide their work protocols.
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