Biodegradation in Soil

Page No. Source Quotes from Decision Documents
349 11 Agency App. C “Data gaps..biodegradation in aquatic systems and in soils at varying pH, soil type and temperature”
350 3 Agency App. C “The Agency sought an independent expert review of the degradation of 1080 in water and soil” (review was of 17 papers provided by ERMA, none on degradation in soil or water under field conditions)
360 2 Agency App. C “the Agency was not able to locate, any data on the..toxicity of the metabolite fluorocitrate in water or soil”
367 1 Agency App. C “under sterile [soil] conditions, 1080 is stable”
367 2 Agency App. C “in most of these studies [on soil] the micro-organisms have been..[cultured]..on 1080-rich media in the laboratory..rather than using soil as in standard soil biodegradation studies”
367 3 Agency App. C “Soil organisms identified as being able to degrade 1080..isolated from Australia. In NZ, there are reports of similar organisms being isolated from soil..and vegetation”
367 4 Agency App. C “In 1994 the Auckland Regional Council commissioned analyses of 8 soil samples for micro-organisms capable of degrading 1080..the source was not identified..3 of the 8 samples had the capacity to defluorinate was seen over..4 weeks in the remaining samples using enrichment techniques, indicating ..a microbial population capable of defluorination was absent from those samples”
368 1 Agency App. C “The authors noted..due to the highly heterogeneous nature of the soil environment a more comprehensive sampling would be required to adequately characterise the microbial population [regarding its ability to defluorinate 1080]”
368 4 Agency App. C “[1080 degradation rate in silt loam from a native forest] approx. DT 50 10 days at 23°C, 30 days at 10°C, 80 days at 5°C”
368 5 Agency App. C “No determination of degradation products [in soil biodegradation test]”
368 6 Agency App. C “[1080 degradation rate in a sandy loam from Central Otago, incubated at 21°C] approx. DT50 >40 days at 9% soil moisture, 35 days at 20% soil moisture, 15 days at 36% soil moisture”
369 1 Agency App. C “At 5°C [a] ‘low level’ [of 1080] was reached at day 32 [in leaf litter]. DT50 8 is not clear..what effects the additional simulated rain [5mm/day] may have had (i.e. potential leaching..]”
373 1 Agency App. C “many vertebrate pest control operations are conducted in NZ during winter or early spring when ground temperatures are well below 20°C, microbial activity is slower and soils wet. Under dry conditions, microbial activity is also less than optimum, resulting in slower degradation..even when soil temperatures are higher’
373 2 Agency App. C “No studies have been conducted using standard international guidelines to assess the route and rate of degradation of 1080 in soil..while [lab] studies have indicated the ability of some soil organisms to biodegrade 1080, the rate of such degradation under New Zealand conditions is uncertain. Likewise, no robust studies on the adsorption/leaching of 1080 were available to the Agency”
373 3 Agency App. C “The Agency sought an independent review of the available information on the degradation of 1080 [in] soil” (reviewer stated there were more references but didn’t try to access them)
373 4 Agency App. C “The [independent] reviewer concluded that 1080 has representative half-lives in soil of 10 days at 23°C and 30 days at 10°C” (no mention of 80 days at 5°C)
384 5 Agency App. C “there were significant issues with the analysis of the test concentrations in the the test with garden snails..attributed to degradation of 1080 in the samples in storage”
455 1 Agency App. C “There are some references within the sources provided which could be obtained and reviewed, although it is unlikely they will change the overall conclusions”
434 1 Agency App. C: Fisk “[Peter Fisk Associates was asked to] provide a review of a number of sources [17 papers] describing the behaviour of the monofluoroacetate ion in the environment” (16 papers were lab studies)
435 1 Agency App. C: Fisk “The pathway and rate [of uptake by organisms] would need to be considered in order to determine whether such a process is important in determining the assessment of overall persistence”
436 1 Agency App. C: Fisk “the half life in soil [DT 50] which is the time required to reduce the original concentration of the substance in the soil by 50% and would usually be assessed using a standard test guideline”
440 2 Agency App. C: Fisk “a..bacterium..from garden soil in SE England, was capable of growing on fluoroacetate”
440 4 Agency App. C: Fisk “it is not possible to say how important this is to the rate of degradation [of 1080] in soil [that a species of bacteria was able to grow on 1080 in a laboratory]”
440 5 Agency App. C: Fisk “this paper examines..soil microbes from five sites in western Australia..[they] might be expected to show increased ability to metabolise [1080]”
441 1 Agency App. C: Fisk “[this study on 1080 degradation by soil microbes from Australia] is clearly a summary and a few more details would be useful”
441 2 Agency App. C: Fisk “Micro-organisms capable of degrading fluoroacetate were only isolatable from temperate [western Australian] soils, but not from semi-arid tropical regions”
441 3 Agency App. C: Fisk “In the degradation experiments [with isolated micro-organisms from western Australian soil] the maximum amount of 1080 degraded was 65-87% and occurred in 5-49 days”
441 4 Agency App. C: Fisk “There was almost no breakdown..[by micro-organisms from Western Australia] where the soil moisture content was only 2.6%”
441 5 Agency App. C: Fisk “Soil pH, moisture and temperature has marked effects on the rate of 1080 decomposition, with high temperature, low moisture and acidic pH all being deleterious”
442 1 Agency App. C: Fisk “[this study] does little to address the question of how quickly fluoroacetate is hydrolysed in the soil”
443 1 Agency App. C: Fisk “Samples of soil and water were taken from 8 localities in (presumably) New Zealand..there are no data in the report on the type or localities..or prior 3 [out of 8 soil samples] and 2 (out of 8) water samples it was possible to culture..bacteria..that could use 1080..1080-utilising bacteria were either absent in the other samples or were not viable under the conditions used for enrichment”
443 3 Agency App. C: Fisk “Sampling soil [for organisms that can degrade 1080]..presents a..problem of heterogeneity”
447 1 Agency App. C: Fisk “The DT 50 of [1080] was 10 days at 23°C, 30 days [at] 10°C and 80 days at 5° experiment using soil of only 9% moisture showed a much lower degradation rate”
447 6 Agency App. C: Fisk “The one criticism is that soils and water used in the degradation studies could have been subject to prior exposure to fluoroacetate”
449 2 Agency App. C: Fisk “This is a summary paper with little experimental detail; however, it does have some very important conclusions..that the ability to detoxify fluoroacetate is a common attribute in soil bacteria and fungi”
450 1 Agency App. C: Fisk “species [micro-organisms from western Australian soils] varied in their ability to defluorinate [1080] and from 2 – 87% was degraded in 57 days”
450 2 Agency App. C: Fisk “Soils from arid tropical areas [of Australia] showed no ability to defluorinate fluoroacetate”
450 3 Agency App. C: Fisk “there might be problems with persistence in very hot dry areas”
451 2 Agency App. C: Fisk “The lowest rate [of degradation of 1080 in soil] occurred at 30% moisture”
454 1 Agency App. C: Fisk “[Fisk conclusion][1080 is] rapidly biodegradable in natural waters and soils, although this is very temperature dependent..degradation is also much slower in soils with lower moisture content” (based on only 1 field study on water and none on soil)
454 2 Agency App. C: Fisk “[Fisk conclusion] in naturally arid soils, the soil microflora have been shown to degrade [1080] quite rapidly”
454 4 Agency App. C: Fisk “[Fisk conclusion] These enzymes [that catalyse defluorination] are present in soil bacteria and fungi”
454 7 Agency App. C: Fisk “In soil there are no reports where degradation studies have been performed using a standard test guideline”
454 9 Agency App. C: Fisk “[soil DT 50 at 5°C was] 80 days”..(highlight left off whereas the faster degradation times at higher temperatures were highlighted)
454 8 Agency App. C: Fisk “DT 50 values [for 1080] are highly dependent on temperature (and also soil moisture)”
457 1 Ag. App. C:
Sample storage
“no further work has been undertaken to more fully investigate factors potentially affecting degradation of 1080 in soil during frozen sample storage [at -20°C] e.g. Soil type, water content, microbial population, and from there identify the most valid procedures for storage and processing the light of the findings by O’Halloran & Jones (2003) [1080] present in some samples..may have been degraded during storage at -20°C to present undetectable concentrations at analysis.”
109 1 Applicants’ references “Looking for microorganisms that degrade 1080 in 8 soil and 8 water samples. Three soils and 2 water samples did contain the required bacteria” (Lloyd & McQueen, 1998)
165 1 Applicants’ references “Due to the inability of natural microorganisms to grow under artificial conditions the obtained collection of isolates is not a good representation of all 1080 degrading bacteria in soil” (Pronk, 2001)
213 1 Applicants’ references “Using..enrichment culture techniques micro-organisms capable of detoxifying [1080] have been found in many and diverse samples of local soils” (Walker, 1994)
222 1 Applicants’ references “The amount of defluorination varied with different species of microorganisms, ranging from 2 to 85% in soil and 2 to 89% in 1080 solutions” (Wong et al., 1992)
58 5 Committee Decision “there is little scientific data on the degradation of 1080 in New Zealand soils at cool temperatures”
158 2 Decision App. A “the documentation provided with 1080 must include..its expected soil or water degradation rate”