Variability in Toxicity

Page No. Source Quotes from Decision Documents
299 1 Agency App. B “Rabbit Dermal LD 50 1.5 mg/kg bw; Rabbit Dermal LD 50 324 mg/kg bw”
300 1 Agency App. B “Fagerstone et al (1994) reported the dermal LD 50 of..1080 in rabbits as 277 mg/kg bw based on an unpublished report..other available data indicated a much higher dermal toxicity..(Yashimoto, 1969). The rabbit dermal toxicity value from this study is nearly 2 orders of magnitude higher..Although the dermal toxicity results from this report were cited by another US government source..they were not referenced or taken into account in the US RED so the Agency did not consider them authoritative..While the Agency usually uses the lowest LD 50 to derive classifications..277mg/kg bw was used as the basis for the dermal classification”
306 5 Agency App. B “The data for developmental studies (teratology) are relatively sparse. Detailed studies carried out in recent decades in accordance with appropriate test guidelines have only been carried out on rats. Studies in other species commonly used in regulatory decision-making, particularly rabbits are not available. Further studies..are desirable, as species variability in..developmental toxicity is well recognised”
309 1 Agency App. B “One explanation for the difference [in results of birth defect studies] may be the difference in rat strain”
309 2 Agency App. B “The incompleteness of the toxicology database of 1080 overall is highlighted by the fact that no comparative toxicity values (such as LD 50 values) appear to be available for..common strains of rat”
334 1 Agency App. B “the only species in which [developmental effects of 1080] have been identified is the rat..data for other species would give some indication of..the degree of variation in sensitivity between species”
357 1 Agency App. C “Results obtained from the two repeats of the test were inconsistent, with time to loss of half of the 1080 from water [5  μg/L with aquatic plants] varying markedly..[from 17.9 hours  in one test to 65.6 hours in the other]
362 2 Agency App. C “complete growth inhibition at 50 mg/L [duckweed, Spirodella oligorrhiza]..complete growth inhibition at 100g/L [duckweed, Spirodella polyrrhiza]”
371 1 Agency App. C “concentrations [of 1080 in rabbit carcasses]..were highly variable”
375 1 Agency App. C “more rapid leaching of 1080 from Westmere soil..than Stratford soil”
377 2 Agency App. C “The authors did conclude that most 1080 is leached from carrot bait after 200 mm natural rainfall..and noted that this was not consistent with the findings of Bowen..where there was no decrease in 1080 after 200 mm rain”
383 1 Agency App. C “the responses of plants to 1080 are highly variable. Some synthesise and hyperaccumulate the substance”
385 1 Agency App. C “Plants: The applicants submitted a..study on effects of 1080 on seedling emergence and early growth..in oats..and..lettuce. A standard regulatory assessment would normally include a greater number of species in order to assess variability in responses”
386 4 Agency App. C “reductions in bodyweight and mortalities in all treatments which were not dose-dependent [a British earthworm species tested at 0, 10, 25, 50, 100, 200 mg/kg dw soil]
391 2 Agency App. C “predicting the toxicity of 1080 to an untested species from data even on closely related species is difficult given the variations in response across and within taxonomic groupings”
392 1 Agency App. C “observed variation in sensitivity [to 1080] with temperature may..be a reason for the variations in reported toxicity to various species [possum LD 50 16.8 mg/kg at 10.5°C; 41.2 mg/kg bw at 23.5°C; mice LD 50 2.6 mg/kg bw at 12.2°C, 12.8 mg/kg bw at 24°C, 4.5 mg/kg bw at 33°C; same effects for guinea pigs]
393 1 Agency App. C “LD 50 [for possums, values range from] 0.47 mg/kg bw to >125 mg/kg bw”
415 2 Agency App. C “NZ native frogs are taxonomically [distinct] and there is significant uncertainty as to their sensitivity to 1080”
421 2 Agency App. C “there is considerable uncertainty regarding the toxicity for bees..due to the quality of the study and the lack of information on how the LD 50 was derived, and even the units for the LD 50. The relative toxicity between species is also highly uncertain”
426 1 Agency App. C “[mustard beetle larvae LD 50] newly hatched larvae 100% mortality at 0.05%; none in other treatments [including 0.1% 1080]”
443 3 Agency App. C: Fisk “Sampling soil [for organisms that can degrade 1080]..presents a..problem of heterogeneity”
525 1 Agency App. F “analysis of [carrot] bait indicated mean of 0.095% 1080 with high variability between samples”
560 2 Agency App. H “only 3 [sheep] were used [in a study by Eason, et al., 1994 on 1080 in animal tissues], and there appeared to be considerable variability in the half-life in different animals”
721 1 Agency App. N “Evaluation of literature on the effects of [1080] usage [is] complicated due to the variable reporting of the 1080 formulation used”
799 1 Agency App. Q “leaching from baits may have a greater effect on sub-optimal kill rates than loss of palatability”
799 2 Agency App. Q “The Agency considers that discussion with industry is required to develop a process for ensuring such changes in risk profile [from ageing baits] are appropriately assessed”
84 2 Applicants’ references “Genetic polymorphisms caused some [possums] to be much more susceptible to 1080” (Henderson et al., 1999)
91 1 Applicants’ references “It is recommended that age-susceptibility factors be considered in the development of standardized toxological protocols” (Hudson et al, 1972)
119 1 Applicants’ references “The sensitivity of a species to 1080 poison is difficult to predict from toxicity data from other, closely related species” (McIlroy, 1986)
158 1 Applicants’ references “Circadian rhythms..have major influence on  susceptibility [of possums to 1080]..loss of appetite..[is] induced by sub-lethal doses..smell and taste aversion diminishes bait-eating when the toxic load is high” (Peters & Fredric, 1983)
202 2 Applicants’ references “genetic differences between populations may have important implications for the control of possums, because Tasmanian possums have a greater resistance than mainland southeastern Australian possums to 1080” (Triggs & Green, 1989)