Table 5.
Reference concentrations for inhalation of the contaminants of interest
| Contaminant | RfC (μg/m3) | Reference |
|---|---|---|
| Copper (Cu) | 140 | ISS 2015* |
| Lead (Pb) | 0.2 | US-EPA 2017 |
| Chromium (Cr) | 0.1 | US-EPA 2017 |
| Zinc (Zn) | 1050 | ISS 2015* |
| Nickel (Ni) | 0.014 | US-EPA 2017 |
| Aluminum (Al) | 5 | US-EPA 2017 |
| Cobalt (Co) | 0.006 | ISS 2015* |
| Barium (Ba) | 0.5 | US-EPA 2017 |
| Strontium (Sr) | 0.2 | US-EPA 2017 |
| 2,3,7,8-TCDD | 0.00004 | US-EPA 2017 |
*Obtained from the data provided for oral exposure by the US-EPA—Region 9 (2015). Environmental protection agency, toxicity, and chemical/physical properties for regional screening level (RSL) of chemical contaminants at superfund sites (http://www.epa.gov/region9/superfund/prg/)