Stop the spraying

Response to DPIWE Review of the Scammell Report

This response has been prepared to address criticism of the report called "Review of the Scammell Report" prepared by the Department of Primary Industries, Water and Environment (DPIWE).

The authors of the "Scammell Report" believe that a number of the criticisms are unfounded and some of the facts have been misrepresented or misinterpreted. The following lists a number of comments in the review, the available evidence relating to these comments and any conclusions or questions that follow.

Firstly, it should be noted that six people collected the information of which Scammell was one. Ignoring five of them on the basis that they are not scientists and therefore cannot contribute information is not appropriate. The weight of evidence approach used by Scammell, Bleaney and the St Helen's Marine Farmers is a common approach in many disciplines including science and can incorporate input from people with non-scientific backgrounds. Experimental manipulations are used by scientists after they have been able to articulate a clear hypothesis, not before. The weight of evidence is the culmination of a series of observations leading to a hypothesis. It is the conclusion of the authors that this hypothesis should be further developed and tested in the interests of public health and environmental integrity.

Point 1:

DPIWE (page 2, line 3): There is no evidence that either the oysters or the water in which they were growing was contaminated.

Available Evidence: $1.6 million worth of oysters were killed. This is a catastrophic event that cannot be caused by freshwater alone. A six week long rainfall event in the Hawkesbury River (NSW) with low salinity for the entire period resulted in less than 5% mortality (field measurements by Scammell). Up to 95% mortality was observed at the most affected leases in Georges Bay. Empirical data from other oyster growing areas in Tasmania demonstrate oysters have survived flood events lasting for two to three weeks without significant mortality (less than 5%) (personal communication with Colin Dyke). Oysters in Georges Bay also survived flood events prior to 1997.

Conclusion: This constitutes clear evidence that something killed them and pathology undertaken either by DPIWE or at their behest ruled out known pathogens. The question remains unanswered as to what caused the mortality.

Point 2:

DPIWE (page 2, line 6): Cypermethrin is a synthetic pyrethroid made up of eight compounds. Two of these compounds make up alpha-cypermethrin. Alpha-cypermethrin accounts for 90% of the toxic activity of cypermethrin. These chemicals are interchanged within the DPIWE document and while their names are similar they are two different pesticides (with different CAS numbers and different approval numbers).

Available Evidence: Alpha-cypermethrin is substantially more toxic than its parent compound, cypermethrin. Permethrin, cypermethrin, alpha-cypermethrin and deltamethrin are four different pesticides and each has substantially different toxicity despite having similar names. DPIWE and Public Health need to be mindful that information on these chemicals cannot be substituted.

Conclusion: To substitute a lower toxicity compound in order to refute the effects of a more toxic compound is erroneous. It also ignores the manufacturer's own warnings (as provided in the Material Safety Data Sheet) that alpha-cypermethrin is toxic to some species at levels as low as 4 ng/L.

Point 3:

Surprisingly, DPIWE uses the 1992 WHO guidelines (page 2,line 8) instead of the current "Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC 2000)". These are the guidelines that Australian environment agencies are meant to use for the protection of aquatic ecosystems. These guidelines do not allow the substitution of one chemical for another because it is misleading. Instead the guidelines call on the investigating parties to derive Trigger Values via toxicity testing. Trigger Values are the concentrations that should prompt further investigation so that ecosystem health can be protected. Trigger Values are only listed for two of the artificial pyrethroids and this does not include the chemical of interest. Remember, according to the manufacturer's own label, alpha-cypermethrin has been found to be toxic at concentrations of 4 ng/l to some aquatic invertebrates.

Point 4:

DPIWE (page 3, line 38): Asserts that not much alpha-cypermethrin was used (29kg), therefore it is not a problem. It appears that the 29kg was applied at the one time on one plantation (based on Public Health's Report).

Available Evidence: A nano-gram per litre is equivalant to one gram per 1 thousand million litres of water.

Conclusion: Of the 29,000 grams of chemical said to be in use (DPIWE), 4 grams would be enough to contaminate 1 million cubic metres of water at concentrations deemed hazardous by the manufacturer. The manufacturer also provides explicit warnings to keep their product away from aquatic ecosystems.

Point 5:

The calculation by DPIWE (page 3, line 30) of the amount required to have an impact on oysters uses data for the wrong chemical (cypermethrin, not the more toxic alpha-cypermethrin). This is then multiplied by the entire water flow for the entire storm event ie. assumes that it is dissolved and evenly dispersed through the water column, through time. The analysis does not take "first flush" effects into account (larger proportions of contaminants are delivered at the beginning of a flood) and does not take the known properties of the chemical into account (water insoluble).

These are critical oversights because water insoluble chemicals are likely to be concentrated in the surface layer of the initial floodwaters. This is the layer which carries the most food and which is rapidly filtered by intertidal oysters. Intertidal oysters are the animals that were observed to be most affected.

Point 6:

DPIWE (page 4, line 24): In their own investigation they found 218 mg/kg of alpha-cypermethrin in soil at the helicopter crash site.

Available Evidence: Not disclosed by DPIWE in the rebuttal was that DPIWE (Their crash report) also found 254 mg/kg of simazine and 75 mg/kg of atrazine in the soil at the same crash site. They suggest in the original report of the crash and repeated in the Review of the Scammell Report, that this was due to poorly rinsed tanks, ie a residual from a previous spray event.

Conclusion: There was a lot more simazine and atrazine found at the crash site than would reasonably be expected as residual after several refills of the helicopter's tanks and sampled 16 weeks after the crash and sampled 11 weeks after the largest rainfall event in the recorded history of the area.

Explanation of Point 6 Conclusion:

According to Public Health two thirds of a 1,000ha property had been sprayed by the time the helicopter accident occurred. According to DPIWE (page 4, line 9) the helicopter carries 1kg of alpha-cypermethrin per 400L load and according to the manufacturer 25g of alpha-cypermethrin needs to be applied per hectare. From this we can conclude that the helicopter delivers 10 L of solution per hectare. If this helicopter was doing all the aerial spraying then it had reloaded at least 16 times by the time it crashed. The St Helen's Marine Farmers believe that two helicopters were working at the time of the accident. It is believed that the second helicopter may have had a carrying capacity of as much as 700L. If both carried the same concentration and both were refilled the same number of times then the helicopter that crashed had been refilled at least six times prior to the accident.

Thus, the helicopter that crashed had been refilled somewhere between six and sixteen times. It is not credible that large amounts of atrazine and simazine would still remain after the tank had been flushed between six and sixteen times.

Similarly, questions arise regarding chlorothalonil at the crash site, a highly water soluble chemical that should not have persisted in soil at all, particularly given the size of the rain / flood event that flushed the area some 11 weeks before the crash site samples were taken.

Chlorothalonil has never been registered for use by forestry in Tasmania (DPIWE, page 5, line 4). Why was it at the crash site?

Point 7:

DPIWE (page 5, line 29): It is unlikely the herbicides (atrazine, simazine and terbacil) would be mixed with an insecticide and applied to a growing plantation. DPIWE also suggest (page 5, line 15) that there is a remote possibility that low levels of these chemicals remain associated with the soil from the time the plantation was established. In the next two sentences they argue that half-lives of the chemicals and the observations at the crash site (found in a splash pattern consistent with a crash) suggest that these chemicals are not residuals from the establishment of the plantation.

Available Evidence: This information is instructive because DPIWE are saying that atrazine, simazine and terbacil, are used at the establishment stage of plantations. This suggests that atrazine and simazine are used on some plantations, although not used by Forestry Tasmania. DPIWE are also saying that one would not use them near the established plantation where the accident occurred. Nevertheless, atrazine, simazine and terbacil were on the helicopter.

Conclusion: The inconsistencies in this information raise the question; where were the helicopters spraying and what was the area under treatment?

Point 8:

On page 6 of the DPIWE response a list of chemicals is given reportedly being all the chemicals used in 2003/04. The helicopter crash occurred in December 2003. Atrazine, simazine and chlorothalonil are not mentioned raising questions regarding the reliability of this list. Further, metsulfuron-methyl is reported to have been used in February 2004 by Public Health but is not present on the list provided by DPIWE.

Point 9:

Pages 8 and 9 of the DPIWE document discuss river health and the monitoring of pesticides. It must be pointed out that the chemicals being reported are herbicides, not pesticides and then only until 1996. There is also a discussion of River Health using macroinvertebrates. The signal index (the basis of the macroinvertebrate monitoring method) was developed to measure the impacts associated with continuous organic inputs ie. sewage. It can measure catastrophic impacts if the measurement is taken within weeks of the catastrophic event (these communities typically take 8 weeks to recover from major disturbances). Examination of the data reveals that measurements were not taken within this time frame after rainfall events associated with oyster mortality. Examination of the data also reveals that the site downstream of the plantation was ommitted from sampling from 1997 until 2003.

Conclusion: The monitoring conducted has not been sufficiently frequent, or for a large period of time, in the right location, to detect the presence of potential impacts that may result from aerial spraying of biocides in adjacent and upstream timber plantations.

Point 10:

Lastly, while none of the measurements of herbicides in rivers exceed the Human health guideline in 1994 or 1995 all of them exceed the trigger value at which action should be taken. What action was taken to remediate the source of contamination?

Review by Department of Infrastructure, Energy and Resources

The Department of Infrastructure, Energy and Resources then goes on to review the use of Unique Property Identifiers (UPI's) as an indicator of changes in land practices. They adequately demonstrate that growth in plantations has been occurring throughout the period in question.

Overall Conclusion

While there are numerous points that can be raised and argued with respect to aerial spraying of plantations, the main point to remember is that a significant environmental problem is occurring resulting in impacts to aquatic life and potentially other aspects of the catchment and it's inhabitants. No amount of arguing is going to solve the problem. The issue needs to be investigated and action taken as a matter of urgency.

In the interests of public and ecological health cease aerial spraying until a proper investigation can be completed.

Earlier:
The test of credibility

The original report: