More Testing Issues - Using the Wrong Research

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Yesterday we at last received a reply from the Department of Health (DoH) regarding not-so-recent inquiries we had made into the estimates for tolerable daily intake (TDI) of antimony reported on the Community Information website; the ‘safe’ daily amount. 

We sent this information and our questions to a DoH Officer familiar with Costerfield in August. We waited three weeks for a reply. The message that we eventually received advised us that the officer was going on holidays for two weeks and would get back to us then (!)… That’s more than two weeks ago.

Yesterday we eventually received the patronising reply transcribed below.

Just in time, too! Testing starts Monday, 6 October 2014.

We are far from satisfied by this wholly inadequate response and so will take up the issue again here.

So to clarify, while this reply is ostensibly from the Department of Health, it is in fact a reply from Golder Associates, but we’ve become used to speaking to people other than the Department of Health about Health Issues by now.

We can only assume that the Department’s officer isn’t familiar with the TDI calculation himself, so he called in the all-purpose consultants for advice...

From, ahem, the DoH, then:

Please forgive the delay in getting back to you
I have been in contact with John Frangos from Golders and please find below his response

1.        Intake Calculation

Intake can be expressed in two ways; as a unit body weight dose or as a mass per person.  
The WHO (page 9) description is of a drinking water concentration.  
The intake is different.  
Below you will find a step by step explanation of the difference.
Calculation of a Drinking Water Guideline

Where:

Item	Units	Description
DWG	micrograms per litre (µg/L)	Drinking water guideline expressed as a concentration in water.  This is not an intake however the calculation is based on an intake.
Safe intake or tolerable daily intake	micrograms per kilogram bodyweight	This is a lifetime average daily dose that should not cause adverse health effects within the general population.
Body weight	kilograms	Mass of an individual.  For standard setting purposes the WHO use 60 kilograms as they are interested in global average bodyweight of adults.  In Australia we use 70 kilograms given that the average body weight of an Australian is closer to 80 kg than 60 kg.
Proportion TDI to DWG	Proportion	This is the proportion of the TDI allocated to drinking water.  The TDI is for all sources of exposure.  For this reason only a proportion is allocated to Drinking Water.

For antimony the WHO Drinking Water Guideline is calculated as follows:
                                                     

 

= 18 µg/L (rounded to 20)

 

Calculation of a daily intake per unit body weight:
Intake = mass of compound (milligram or microgram per day) ÷ bodyweight (kg)
Example:  The antimony TDI is 6 micrograms per kilogram (µg/kg).  

Calculation of a daily intake per person:
Intake (person) = mass of compound (milligram or microgram per day) x body weight of person.
Example:  If we assume the bodyweight of an adult is 70 kilograms then the TDI can be expressed as
6 µg/kg x 70 = 420 µg per 70 kilogram adult per day  

***

Now our questions actually relate to the applicability of the WHO’s Antimony in Drinking Water guidelines that we became familiar with earlier. We know that Golder Associates, DSDBI and now DoH, are employing this document to inform the “next phase of testing”. The above reply, and the rapid response we received from DSDBI this morning confirm this. And it underlies the information given to the Costerfield Community on the DoH website.

According to the recent Community Antimony Fact Sheet on the Department of Health website:

The World Health Organization has calculated a safe level of antimony that a person can take into the body every day over a lifetime. This value has been determined from studies in animals with conservative safety factors applied to protect human health. This acceptable daily intake is 6 micrograms/kg body weight/day.

An adult weighing 70kg can take into their body 420 micrograms of antimony per day without effect. A one year old child weighing 10kg can take into their body 60 micrograms of antimony per day without effect.

The World Health Organization’s Antimony in Drinking Water has this to say about the estimation of a total daily intake of 6 micrograms per kilogram per day. We are familiar with this document from other discussions. You’ll recognise the paragraph at the end…

The most common source of antimony in drinking-water appears to be dissolution from metal plumbing and fittings. The form of antimony in drinking-water is a key determinant of its toxicity, and it would appear that antimony leached from antimony-containing materials would be in the form of the antimony(V) oxo-anion, which is the less toxic form. It is therefore critical that the study selected for guideline derivation be a drinking-water study.

[Emphasis added.]

The suggested NOAEL (Lynch et al., 1999) in the subchronic drinking-water study in rats conducted by Poon et al. (1998) was 6.0 mg/kg of body weight per day based on decreased body weight gain and reduced food and water intake. A TDI of 6 μg/kg of body weight can be determined by applying an uncertainty factor of 1000 (100 for intra- and interspecies variation and 10 for the use of a subchronic study). A guideline value of 20 μg/litre (rounded figure) can be derived from this TDI by assuming a 60-kg adult drinking 2 litres of water per day and allocating 10% of the TDI to drinking-water. It should be noted that this value could be highly conservative because of the nature of the end-points and the large uncertainty factor; further data could result in a lower uncertainty factor.

[Emphasis added to indicate the “conservative safety factors applied to protect human health” noted by the DoH.]

There are adequate analytical methods for antimony in drinking-water with detection limits below the guideline value. As the most common source of antimony in drinking-water appears to be dissolution from metal plumbing and fittings, control of antimony from such sources would be by product control. At one time, antimony was suggested as a possible replacement for lead in solders, but there is no evidence that this has occurred. Antimony is not removed from water by conventional treatment processes (EUREAU, 1994). Control would therefore be by source selection or dilution.

The possibility of co-exposure of consumers to arsenic and antimony in drinking-water would necessitate an assessment of the local geological conditions on a case-by-case basis. If both elements were found to be present, case-specific risk evaluations for possible additivity and synergistic effects would need to be performed.

The WHO then, bases its TDI on the assumption of exposure to antimony(V) oxo-anion, which is most commonly sourced “from metal plumbing and fittings”. Earlier in the WHO document (p. 8) it is stated that:

In general antimony(III) is more toxic than antimony(V), and the inorganic compounds are more toxic than the organic compounds (Stemmer, 1976) with stibin (SbH3), a lipophilic gas, being most toxic (by inhalation).

Now one would assume that, given that antimony(III) is more toxic than antimony(V) as per page 1 of Antimony in Drinking Water:

Soluble pentavalent antimony (antimony(V)) compounds (sodium stibogluconate, stibosamine) are used as specific therapeutics against different forms of leishmaniasis and are physiologically tolerated more than trivalent antimony (antimony(III)) compounds (Winship, 1987).

and since we are not dealing with the leaching of antimony(V) from plumbing and fittings, then the Department’s estimate of 6 micrograms per kg of body weight per day would very much appear to be an over-estimate of the TDI for antimony(III).

The critical antimony species involved at Costerfield are cationic (positive) ions of inorganic compounds derived from the ore body components. They are definitely not the anionic (negative) antimony oxo species the WHO used to determine its guidelines. Our expert advice tells us that these antimony cations are not only more soluble (in water), they are more mobile through the soil profile, [this runs counter to the nebulous Sim/Priestly report on this point] and as a consequence are far more toxic to mammalian species.

The WHO data related to organic forms of antimony (and any derived data based on organic antimony forms of "lesser" toxicity), has absolutely no applicability to the Costerfield scenario. A very pertinent fact that it seems DoH, DSDBI and Golder are simply choosing to ignore .

(There is also absolutely no doubt whatsoever that arsenic (As) species do occur along with antimony at Costerfield [and there are a number of other cationic inorganic species present at concern levels, too]. Given these major pathways of toxicity, cumulative exposures MUST be considered for all toxic species present. It is an absolutely essential requirement that ALL of the major toxic cationic species be so determined, collectively. )    

It is our understanding that the only directly applicable antimony toxicity data is that published by

US ATSDR and US EPA which is clearly far more pertinent to Costerfield, and, it should be noted, far more damning of the actual situation in light of the actual concentrations of metals in the soil and water in Costerfield.

You see, the Community has already undertaken testing of its own. Long before the Regulators or their hired consultants arrived on the scene. We had to. It took from March until May for the DoH and DSDBI to even front the Costerfield Community to announce a “rapid assessment” was beginning. We still laugh at the irony.

It’s all well and good referring to a drinking water study when it’s the drinking water system that’s under examination – note this WHO document comes from a collection of Sanitation documents. And the World Health Organization cautions against making this very mistake by stating: “It is therefore critical that the study selected for guideline derivation be a drinking-water study” …. because its own guidelines are for antimony(V).

But that is simply not the case in Costerfield. This is not a drinking water study. Here we are looking at contamination of the people of Costerfield and their water tanks by environmental antimony, much of which would be the “more toxic” inorganic antimony and antimony(III) compounds.

The report into Costerfield by Professors Priestly and Sims for the DoH notes at page 21:

The soil bioavailability studies of Flynn et al (2003) and Gal et al (2007) although limited to studies of leaching and/or ecotoxicology, but not mammalian toxicity, suggested that Sb mobility and bioavailabilty from contaminated soils is extremely limited, so this is unlikely to be a major contributor to absorption in the Costerfield region. [Emphasis added.]

They are also very careful to avoid giving a TDI for antimony. This from their report’s terms of reference (p. 23):

Is there evidence of modelling or kinetic studies that have used intake to estimate a urinary antimony level? If not, can a urinary Sb threshold be derived from intake (in the order of TDI) calculations?

While some of the published papers have estimated intakes and compared them with putative health-based guidelines, no studies were identified that calculated a urinary excretion profile based on these intakes. In fact, some papers (Gebel, 1998, a, b) noted a poor correlation between soil or airborne antimony concentrations and measured urinary outputs.

Nevertheless the authors of the information being provided to Costerfield residents saw fit to declare a TDI. Except they are using the wrong form of antimony!

We'll say that again: the Department of Health is providing residents of Costerfield with misinformation regarding the safe levels of antimony they may ingest because it is using for its terms of reference the incorrect form of antimony - antimony(V) - and thus the wrong guidelines.

Unfortunately we are coming to expect misinformation by now.

The experts brought in by the Department think that “Sb mobility and bioavailability of contaminated soils is extremely limited, so this is unlikely to be a major contributor to absorption in the Costerfield region”. And unlike the Department of Health and the Golder Associates testers - who have “estimated intakes and compared them with putative health-based guidelines” – they aren’t prepared to put a safe threshold “in the order of a TDI” on the safe levels of antimony ingestion.

Yet the Community Antimony Fact Sheet provides Costerfield residents with what it deems to be a safe amount of antimony for ingestion – 420 micrograms/day.

Why does the government website contain potentially dangerous misinformation for the people of Costerfield? 

Is it because to admit that the antimony that needs to be tested for is of the type found in industrial processes would confirm the mine as a source... and that the regulators haven't done their jobs...?

What is the Department of Health’s

– or the DSDBI's or whoever is looking after Health this week –

response to the above observations?

A little summary:

• ·        The antimony in the water tanks isn’t going to be from the plumbing. Or fittings.
• ·        And it’s “unlikely” to be from the soils according to Profs. Priestly and Sim.
• ·        And particulate monitoring ceased at Costerfield on 13 February, 2006.
• ·        And the 2007 EPA SEPP AQM recommends that attention be paid to the possible entry of    heavy metals “such as antimony” in drinking water tanks near mines.
• ·        In 2013/4 two vents were installed at the mine to deal with its expanded operations into the Cuffley Lode; 3m vents that exhaust at up to 12/ms into the Costerfield atmosphere.
• ·        And high antimony levels were taken from people at a distance from the mine.
• ·        And particulates are not detected in these pieces of junk.
• ·        And particulates can be concentrated further from their source because of uplift.

 What do YOU think caused the high antimony readings in and around Costerfield?

We’ll ask the question we asked the other day again here - we are still to receive a reply:

How much material – antimony, arsenic, respirable silica, blasting detritus “including CO₂, CO, SO₂, NO_X and ammonia gases (NH₄)” - does EPA/DSDBI estimate has been emitted by the mine via its vents over the past eight years?  

***

According to the Commonwealth Government’s Department of Environment’s “National Pollution Inventory” antimony emissions in Australia fell from 16,000 kg in 2008/9 to 7,700 kg in 2012/13.

Do these figure need to be revised?