| #P001 | unknown | health | guideline | Significant contribution threshold (volatile organic chemical exposure routes) | drinking water | requirement | >= 10 % | Both the dermal and inhalation routes of exposure for a volatile organic chemical are considered significant if they contribute to at least 10% of the drinking water consumption level | Applies to dermal and inhalation routes of exposure for a volatile organic chemical in multi-route exposure assessments. | high |
| #P002 | unknown | health | unknown | Skin permeability coefficient (Kp) tier 1 goal threshold | drinking water | requirement | > 0.028 cm/h | For a tier 1 goal of 0.15 L-eq, the skin permeability coefficient (Kp) for benzene should be higher than 0.028 cm/h. | Tier 1 of the multi-route exposure assessment to determine if dermal exposure contributes a minimum of 10% of the drinking water consumption level. | medium |
| #P003 | unknown | health | unknown | Air to water concentration (Fair:water) tier 1 goal threshold | drinking water | requirement | > 0.000 89 ratio | For a tier 1 goal of 0.15 L-eq, the air to water benzene concentration (Fair:water) value should be greater than 0.000 89. | Tier 1 of the multi-route exposure assessment to determine if inhalation of benzene during bathing or showering is likely to contribute at least 10% of the drinking water consumption level. | medium |
| #P004 | design | health | unknown | Standard Canadian drinking water consumption rate | drinking water | unknown | 1.5 L/day | Adding these values to the standard Canadian drinking water consumption rate of 1.5 L/day results in a total litre-equivalent daily exposure of 3.5 L-eq. | | high |
| #P005 | operational | health | guideline | Tier 1 goal (multi-route exposure assessment) | drinking water | requirement | 0.15 L-eq | For a tier 1 goal of 0.15 L-eq, the skin permeability coefficient (Kp) for benzene should be higher than 0.028 cm/h. | Represents 10% of the standard 1.5 L/day drinking water consumption level. | high |
| #P006 | operational | health | guideline | Exposure duration (showering/bathing) | drinking water | requirement | 0.5 h | duration of the shower or bath, assumed to be 0.5 h | Used as the standard duration for calculating dermal and inhalation exposure in the multi-route assessment. | high |
| #P007 | operational | health | guideline | Adult skin area (exposed) | drinking water | requirement | 18000 cm2 | area of skin exposed, assumed to be 18 000 cm2 for adults | Standard value used for adult dermal absorption calculations. | high |
| #P008 | operational | health | guideline | Adult alveolar ventilation rate (Qalv) | drinking water | requirement | 675 L/h | adult alveolar ventilation rate, assumed to be 675 L/h | Standard value used for adult inhalation absorption calculations. | high |
| #P009 | operational | health | guideline | Transfer efficiency (inhalation model) | drinking water | requirement | 61 % | 0.61 is 61% transfer efficiency | Parameter used in the air to water concentration equation for benzene. | high |
| #P010 | operational | health | guideline | Average bathroom air volume | drinking water | requirement | 6420 L | volume of air in an average bathroom (6420 L) | Used to calculate the ratio of air volume to water volume for inhalation modeling. | high |
| #P011 | operational | health | guideline | Average showering/bathing water volume | drinking water | requirement | 80 L | average volume of water (80 L) used during the showering/bathing event | Used to calculate the ratio of air volume to water volume for inhalation modeling. | high |
| #P012 | chemical | health | guideline | Benzene skin permeability coefficient (Kp) | drinking water | requirement | 0.14 cm/h | Kp is the skin permeability coefficient of 0.14 cm/h (Nakai et al., 1997) | Used for benzene dermal absorption calculations in tier 2 assessment. | high |
| #P013 | operational | health | guideline | Dermal fraction of dose absorbed (Fabs) | drinking water | requirement | 0.6 fraction | Fabs is the fraction of dose absorbed, assumed to be 0.6 (Lindstrom et al., 1994) | Assumed value for dermal absorption during 0.5 h shower. | high |
| #P014 | chemical | health | guideline | Benzene unitless Henry's law constant (Kaw) | drinking water | requirement | 0.22 unitless | Kaw is the unitless Henry's law constant of 0.22 at 25°C (U.S. EPA, 2000) | At 25°C | high |
| #P015 | operational | health | guideline | Inhalation fraction absorbed (Fabs) | drinking water | requirement | 0.5 fraction | Fabs is the fraction absorbed, assumed to be 0.5 (Perbellini et al., 1988; Pekari et al., 1992; ATSDR, 2007) | Assumed value for inhalation absorption in multi-route assessment. | high |