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

At 72 mg dichlorvos/m 3 (1800g a.i./ha):D = 0.5 x 5000 x 0.3 x 0.5 x 1.8 x 0.05 / 70 = 33.75 / 70 = 0.482 μg a.s./kg b.w./dayWhere:D = Dermal Exposure [μg a.s./person*d]DFR = Dislodgeable Foliar Residue per kg a.s./ha = 0.5 μg a.s./cm² per kg a.s./ha[Note: a DFR based on the Casida et al. (1962) data is used, showing only 5% ofapplied active available for skin contamination 20 minutes after application; seeSections 5.9 & 5.10]TC = Transfer Coefficient [cm²/person/h] [e.g. Ornamentals - Cut / Sort / Bundle /Carry - 5000 (UK CRD)]DA = percentage dermal absorption [30%], expressed as a fractionWR = Work Rate [0.5 hours/day]AR = Application Rate [1.3 or 1.8 kg a.s./ha]P = Penetration Factor for Clothing [= 0.05] German BBA Model for re-entrytasks that assumes a Penetration Factor (P) for PPE of 0.05 (i.e. 95% protection)hood/visor + overalls over long-sleeved shirt and long-legged trousers + boots +glovesBW = bodyweight [70 kg]5.44 Predicted total exposures and risk assessments indicate that re-entry to treatedglasshouses for the purpose of venting (taking 30 minutes or less) may beacceptable 4 hours after application if PPE (hood/visor + overalls over longsleevedshirt and long-legged trousers + boots + gloves) and RPE (full-face or airhose)are used. See Tables XVI and XVII:Table XVI: Re-entry into glasshouses treated at 52 mg dichlorvos/m 3 – total exposure and risksat venting: 30 minutes exposure (240 minutes after application)Dose (mg/kg b.w.) aRespiratory protection bNone Half-face Full-face Air-hoseInhalation 0.014 0.001 0.0003 NilDermal (with PPE above) 0.0003 0.0003 0.0003 0.0003Total 0.0143 0.0013 0.0006 0.0003Risk Quotient (RQ) c 10 d 0.9 0.4 0.2abBody weight, 70kg;Protection factors from APVMA, 2008b: factor of 0.1 for a half face mask and a factor of 0.02 for afull face mask respectively, and no exposure for air-hose (supplied air system) [results rounded];cdRQ = Total Estimated Occupational Exposure / AOEL where AOEL = 0.0014 mg/kg b.w./day;RQ > 1 indicates the likelihood of an unacceptable risk to those exposed.Dichlorvos reassessment – application Page 320 of 436