Computation of Average Daily Dose
The Average Daily Dose from all exposures to reclaimed water (ADDRW) can be estimated using the following equation (modified from Hutcheson et al., 1990):
ADDRW = ADDR + ADDD + ADDI
The Average Daily Dose from ingestion of the reclaimed water (ADDR) can be estimated using the following equation (modified from Hutcheson and Martin, 1992):
where
ContaminantR | = Concentration of chemical in reclaimed water (mass/volume), | |
VI | = Daily volume of reclaimed water ingestion (mass/volume), | |
BAF | = Bioavailability adjustment factor, | |
D2 | = Duration of the exposure period (time), | |
BW | = Average body weight (e.g., 70 kg), | |
AP | = Averaging period (time), | |
C | = Appropriate units conversion factor. |
The Average Daily Dose from dermal contact with reclaimed water (ADDD) can be estimated using the following equation:
where
ContaminantR | = Concentration of chemical in reclaimed water (mass/volume), | |
SA | = Skin surface area in contact with the surface water during the period of exposure (area), | |
PC | = Permeability constant (volume/time × area), | |
D1 | = Average duration of each exposure event (time/event), | |
D2 | = Duration of the exposure period (time), | |
BAF | = Bioavailability adjustment factor, | |
F | = Number of exposure events during the exposure period divided by the number of days in the exposure period (events/time), | |
D1 | = Average duration of each exposure event (time/event), | |
D2 | = Duration of the exposure period (time), | |
BW | = Average body weight (e.g., 70 kg), | |
AP | = Averaging period (time), | |
C | = Appropriate units conversion factor. |
The Average Daily Dose from inhalation of contaminants in reclaimed water (ADDI) can be estimated using the following equation:
where
ContaminantR | = Concentration of chemical in reclaimed water (mass/volume), | |
VR | = Daily respiratory volume during the period of exposure (volume/time), | |
BAF | = Bioavailability adjustment factor, | |
F | = Number of exposure events during the exposure period divided by the number of days in the exposure period (events/time), | |
D1 | = Average duration of each exposure event (time/event), | |
D2 | = Duration of the exposure period (time), | |
BW | = Average body weight (e.g., 70 kg), | |
AP | = Averaging period (time), | |
C | = Appropriate units conversion factor. |