Chemical analysis by X-ray fluorescence in induced sputum particles retrieved from exposed workers and from raw material dust
| Nonexposed controls | Exposed workers | p-value | Natural stone | Artificial stone | |
| Zinc | <LOD | 160.2±97.8 | <0.01 | <LOD | 1233.7±24.78 |
| Copper | 178.4±16.6 | 216.8±58.1 | 0.217 | <LOD | 57.8±13.92 |
| Iron | 293.4±59.6 | 1479.2±760.1 | 0.012 | 507.260.34 | 3574.0±80.8 |
| Titanium | <LOD | 603.6±268 | 0.064 | <LOD | 41 412.2±255.7 |
| Calcium | 4522±811.2 | 19 321.2±10 151 | 0.016 | 546 368.6±309 | 9058.2±245.9 |
| Aluminium | <LOD | 3192.7±2052 | <0.01 | 899.1±170.3 | 20 146.9±430.2 |
| Silica | <LOD | 5739.6±1577 | <0.01 | 4041.9±102 | 647 603.4±1198 |
| Chloride | 517 548.7±136 374 | 18 634.9±7005 | <0.01 | <LOD | 13 167.5±96.7 |
| Sulfur | 153 316.3±57 024 | 434 674.1±213 233 | 0.022 | 794.8±41.7 | 3350.4±89.7 |
Data are presented as the mean±sd of two measurements in three subjects for each group. LOD: limit of detection. p<0.05 (independent t-test).