The toxicological database for bispyribac sodium, which consists primarily of toxicity tests conducted in rats,
mice, rabbits and dogs, is considered sufficient to determine the toxicology profile of bispyribac sodium and
characterise the risk to humans. In interpreting the data, it should be noted that toxicity tests generally use
doses that are high compared with likely human exposures. The use of high doses increases the likelihood
that potentially significant toxic effects will be identified. Findings of adverse effects in any one species do
not necessarily indicate such effects might be generated in humans. From a conservative risk assessment
perspective however, adverse findings in animal species are assumed to represent potential effects in
humans, unless convincing evidence of species specificity is available. Where possible, considerations of
the species specific mechanisms of adverse reactions weigh heavily in the extrapolation of animal data to
likely human hazard. Equally, consideration of the risks to human health must take into account the likely
human exposure levels compared with those, usually many times higher, which produce effects in animal
studies. Toxicity tests should also indicate dose levels at which the specific toxic effects are unlikely to
occur. Such dose levels as the No-Observable-Effect-Level (NOEL) are used to develop acceptable health
limits at which no adverse health effects in humans would be expected.
The Office of Chemical Safety and Environmental Health (OCSEH) within the Department of Health and
Ageing, Australia conducted the toxicology assessment of bispyribac sodium.
Bispyribac sodium is to be included in Schedule 5 of the SUSMP at greater than 10% on 1 September 2011