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

Domestic Indoor Surface ApplicationsScenarios (26 & 27): applications at 2.5 kg a.i./ha (A 600mL can contains 1.86g a.i.that covers 7.44m 2 at the recommended rate, 0.25g a.i./m 2 )1) Children‘s dermal exposureSystemic exposures via the dermal route were calculated using a 100% drift falloutvalue (assumes spray stays to the surface where it is applied and there is no dissipationbefore or during exposure) and the following equation:Where:SE(d) = AR x DF x TTR x TC x H x DABWSE(d) = 25 x 1 x 0.05 x 6000 x 8 x 0.30 = 1200 μg/kg b.w.15SE(d) = systemic exposure via the dermal route;AR = field application rate, 2.5 kg/ha = 25 μg/cm 2 ;DF = drift fallout value, i.e. assumed at 100%;TTR = transferable residues – the EPA default value of 5% was used in theestimate (US EPA, CARES Manual, 2002);TC = transfer coefficient – the standard EPA value of 6000 cm 2 /h was used for theestimate;H = exposure duration for a typical day (hours) – this has been assumed to be 8hours which matches the average time in any one indoor space;DA = percent dermal absorption (30%);BW = body weight - 15kg which is the average of UK 1995-7 Health Surveys forEngland values for males and females of 2 and 3 yrs.2) Children‘s hand-to-mouth exposureHand-to-mouth exposures were calculated using transferable residue levels using thefollowing equation:Where:SE(h) = AR x DF x TTR x SE x SA x Freq x HBWSE(h) = 25 x 1 x 0.05 x 0.50 x 20 x 20 x 2 = 33.33 μg/kg b.w.15SE(h) = systemic exposure via the hand-to-mouth route;AR = field application rate, 2.5 kg/ha = 25 μg/cm 2 ;DF = drift fallout value, i.e. assumed 100%;Dichlorvos reassessment – application Page 372 of 436