Application for the Reassessment of a Hazardous Substance under ...

Fruit (tree) 2052 70759 >50Passionfruit 1026 35379 >50These HQ greatly exceed the critical HQ of 50. HQ values that exceed levels ofconcern may be refined using the results of higher tier testing such as semi-field andfield trials. However, no data from higher tier testing were available to ERMA NewZealand.ERMA New Zealand notes that in APVMA (2008) the results of a foliar residue studyare provided. The LD 50 value was reported to be 0.2 kg ai/ha, which is less than NewZealand application rates, but no other information was available. By contrast, USEPA (2006) reports the results of a study on the toxicity of foliar residues to honey bees(guideline 141-2) using the typical end-use product. The study showed residues ofdichlorvos 4E applied at 0.5 lb ai/A (= 0.56 kg ai/ha) were practically nontoxic to honeybees three hours post treatment.Terrestrial invertebrates (other than bees)No data are available to perform a quantitative risk assessment. However, there are twostudies on non-target invertebrates. The results of those tests show that dichlorvos hadadverse effects on the development of adult predatory mites (Phytoseiulus persimilis)and that 0.08 kg dichlorvos per ha caused 60% mortality of the ladybirds (Cuinuscoeruleus). Based on this information and the mode of action of dichlorvos ERMA NewZealand expects dichlorvos to be toxic to a wide range of terrestrial non-targetinvertebrates coming in contact with the spray, vapours or fresh residue.Conclusions environmental risksERMA New Zealand concludes that the levels of concern are exceeded for aquaticorganisms, birds and terrestrial invertebrates. ERMA New Zealand also identified a riskfor earthworms in the field when dichlorvos is applied by airblast equipment. Highertier modelling could potentially refine these estimates of the risks but it is unlikely toreduce the risk quotients, particularly for the aquatic environment by the orders ofmagnitude required to remove the estimation of risks. Therefore risk mitigationmeasures need to be considered.Buffer zones can be used to mitigate risks to the aquatic environment. However, fordichlorvos a buffer zone of more than 304 meters, the maximum calculated by themodel, is needed to reduce the risk to an acceptable level. Buffer zones are notprotective of birds and terrestrial invertebrates that may move in and out of a crop.Timing of application to avoid times bees are foraging will reduce the risks to bees, butwould not reduce the risk to other non-target invertebrates that live within or adjacent tocrops.Dichlorvos reassessment – application Page 153 of 436