Research Article
Sequential Extractions and Toxicity Potential of Trace Metals Absorbed into Airborne Particles in an Urban Atmosphere of Southwestern Nigeria
Table 2
Definitions and values of variables used in the estimation of human exposure.
| | Symbols | Definition | Values |
| | Concentrations of metals in dust (mg/kg) | | | ABS | Absorption factor (unitless) | 0.001 (inorganic) | | AT | Average time (Non carcinogenic ingestion only) yr & day/yr | ED × 365 (noncarcinogenic) | | × 365 (noncarcinogenic) | | BW | Adult body weight (kg) | 70 (adults) | | 15 (children) | | SL | Skin adherence factor (mgcm−2) | 0.2 (children) | | 0.07 (adults) | | CF | Unit conversion factor (kg/mg) | 10−6 | | Unit conversion factor dermal (kgcm2)/mgm2 | 0.01 | | ED | Exposure duration of noncarcinogenic ingestion only (yr) | 24 (adults), | | 6 (children) | | EF | Exposure frequency (day/yr) | 350 | | SA | Adult surface area (cm3) | 5700 (adults) | | 2800 (children) | | Ingesting rate for adults (mg/day) | 100 (adults) | | 200 (children) | | Inhalation rate (m3/day) | 7.6 (children) | | 20 (adults) | | PEF | Particulate emission rate (m3/kg) | 4.28 × 109 | | Absorbed chronic reference dose (mg/kg-day) | Metal specific | | Inhalation chronic reference dose (mg/kg-day) | Metal specific | | Oral chronic reference dose (mg/kg-day) | Metal specific | | Absorbed dose slope factor (mg/kg-day)−1 | Metal specific | | Inhalation slope factor (mg/kg-day)−1 | Metal specific | | Oral slope factor (mg/kg-day)−1 | Metal specific |
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