1. In response to a question "Does Tordon have Chlorine in it?"

Yes, Tordon does have chlorine in it, and here are some details that may be of interest. There may be material useful to anyone preparing a submission in response to the EIS but the paucity of real data limits its usefulness in this sense.

Synopsis: Both Tordon 101 and Tordon DSH contain chlorinated organic compounds, a family of substances with the potential to form dioxins and furans on combustion at temperatures below 1200oC. Dioxins present in timber entering the retorts may not be broken down and could be emitted. Temperatures in the retorts will reach 400-500oC and in the afterburners 900oC.

The Canberra Times letter by Ed Hazell (referred to in my email of 10 Dec) refers to both Tordon 101 and Tordon DSH (=Double Strength Herbicide). I have not yet been able to find anyone in Forestry to confirm that Tordon DSH and not Tordon 101 has been used, nor for that matter if there is any standing dead timber that has been killed with Tordon DSH.

Tordon 101 contains picloram and 2-4-D as active ingredients as well as a number of surfactants and solvents. The active ingredients are both chlorinated organic compounds. 2-4-D contains virtually no dioxin as a by product of its manufacture.

Tordon DSH is a mixture of picloram and tricoplyr as well as other non-hazardous ingredients (presumed to be surfactants and solvents) (Dow Agrosciences MSDS).

From the website www.vvaa.org.au/white.htm the following is of interest: "An interesting finding has been that the active components of the formulation (2,4-D and picloram) showed little or no toxicity compared with the toxicity of the surfactant present in the mixture. Surfactants are added to herbicides to aid penetration and spreading of the active components. It is unknown what relevance this has to human exposure since the behaviour of the surfactant in humans has not been studied. It is possible that ingested surfactants are not absorbed or are inactivated before they reach important structures."

The following two paragraphs are based on a discussion I had with Dr John Pollack of Sydney University, one of the authors of the report at the above website.

Dealing with an individual ingredient independently of the others in the mixture may overlook the possibility of synergies between two or more compounds under certain conditions, ie the activity (which includes toxicity) of a substance may be increased by being in a mixture with another compound. This could mean that a normally harmless substance could be rendered toxic in the presence of another. Bioassay (ie testing the effect of the mixture on living organisms) is the only way to ascertain if the mix itself is toxic. The individual compounds may meet all the legal requirements but the mix may not. The research discussed at the above website involves bioassay.

All chlorinated hydrocarbons, when combusted at temperatures below about 1200oC, will likely produce dioxins, although the quantities produced are difficult to predict. Whether Tordon 101 or Tordon DSH enters the retorts with the timber, there is potential for dioxin formation. Blown sea salt has a similar potential although most will be removed in any debarking process and further blown sea salt might accumulate on the drying stacks awaiting combustion. This is unlikely to be a significant source of dioxin.

This leads to two questions: (i) what temperatures will be achieved in the retorts? and (i) will the proposed plant's safety measures remove from its emissions any dioxins in either timber fed into it or produced during inefficient combustion?

Possible answers:
(i). The EIS (pp3.16-3.17) sets a target of 85% fixed carbon in the product, achieved at 450oC. At higher temperatures the fixed carbon content rises but the product is more friable resulting in greater handling and transport costs. The expected maximum temperature in the retorts is 400-500oC, something short of the temperature required to break down dioxins. "The chemicals produced are numerous but the quantities are so small that recovery is uneconomical." (EIS p3.17)

(ii). There is an afterburner in each retort which will reduce the residual hydrocarbon (remaining in the emission gases after breakdown in the carbonisation zone) by 99.9%. These gases will be subjected to a temperature of 900oC for 2 seconds which "conditions will minimise the formation of dioxins and furans." This is still short of the temperature required for complete breakdown. There are no absolute quantities quoted in the EIS for either of these gases whether entering or emerging from the afterburner.

I have no information on the breakdown products of the surfactants or the solvents in the retorts or the afterburner.

Some useful websites:
www.vvaa.org.au/chemical.htm lists herbicides used in Vietnam.
www.vvaa.org.au/white.htm discussed above, describes research under way at University of Sydney.
www.dowagro.com/au/ leads to the MSDS [click on Products, scroll down to Tordon Double Strength Herbicide and click on Go, click on Material Safety Data Sheet, Download Now] Warning: this file is 287 Kb.
www.greenpeace.org/~usa/reports/asciiver is a Greenpeace document on Dow chemicals with much on dioxins.

2. Information on Tordon DSH (Double Strength Herbicide)
'Tordon' here is Tordon DSH (Double Strength Herbicide), a mixture of picloram and tricoplyr as well as other non-hazardous ingredients (presumed to be surfactants and solvents) (Dow Agrosciences MSDS). While classed as non-hazardous, their reactions in a mixture may be different from that of each alone.

The following is an excerpt from the MSDS available from the internet.

ENVIRONMENTAL FATE OF PICLORAM AND TRICLOPYR
Notes made by Steve Pickering NSW State Forests, Batemens Bay [SteveP@sf.nsw.gov.au].
The breakdown of picloram in soil is variable and is influenced by soil moisture, temperature and organic content. Under spill conditions or very high use rates, residues could remain in the soil up to four years, particularly in arid soils. At low application rates, under warm, moist conditions, residues decline sufficiently to allow growth of susceptible plants within twelve months.

In soil, picloram is degraded by photodegradation and microbial action. In water, it is degraded by ultra-violet light with a half-life of one to forty days depending on sunlight intensity. Picloram typically remains in the top thirty centimetres of a soil profile depending on soil adsorption properties.

Triclopyr triethylamine salt (triclopyr) is rapidly hydrolysed to triclopyr acid in soil and water. Triclopyr acid is degraded by microbial action and photodecomposition. Triclopyr acid, in soil, has a half-life of approximately forty days, depending on soil and climatic conditions.

In water, triclopyr acid will decompose rapidly with a half-life of one to two days. Minimal leaching of triclopyr acid may occur in light soils under high rainfall conditions.

Contamination of ground water by picloram and triclopyr is highly unlikely. If used according to the label this product will not be harmful to the environment.
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Chris Love of Dow Agrisciences in Brisbane advises that there might be about 0.02 gm picloram and 0.04 gm triclopyr in a 30 cm dia tree into which 10 ml of Tordon DSH had been injected using 7 cuts.

Another Dow Agrisciences source said that 18 months after Tordon DSH injection, firewood is deemed safe to burn provided that it is dry and used in a slow combustiuon stove not an open fire. My comment: After 18 months there should be little of the Tordon DSH remaining; if wood is too moist, combustion temperatures will be lower and more dioxins and furans are likely to be formed.
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Information supplied by Steve Pickering:

Q: How much Tordon is likely to be left in a sawlog or residue poisoned for thinning?
A: Concentrations are very small in the timber (see above). The half life might be as short as 6 months (unconfirmed). The concentrations are highest in the growing tips which are not removed as a forest product.

Q: What can you tell me about poisoned timber used for firewood?
A: Trees are poisoned by injecting the herbicide into the sap stream - ie the band of slippery stuff just beneath the bark. Sapwood is the first piece of material to decay when a piece of wood begins to decompose. The majority of wood which will be used for firewood production will be heartwood.

The areas within State Forests from which firewood collectors can collect are stipulated on their permits and no permits are issued to collect from areas where tree have been poisoned. State Forests cannot police all firewood collection and there is no guarantee that the conditions of the permit are strictly adhered to at all times.

Q: Has Tordon 101 (Agent White) ever been used in NSW Sate Forests?
A: No.