Table 3 Characteristics of crystalline silica and exposure
Characteristics | N (%) | |
|---|---|---|
Animal model | Mice | Rats |
Type | ||
 Min-U-Sil-5 (1.5–2 µm, > 99% purity) | 12 (29.3%) | 10 (24.4%) |
 Sigma Aldrich (1.5–2 µm, > 99% purity) | 3 (7.3%) | 10 (24.4%) |
 Forsman Scientific (1.6 µm, > 99% purity) | 3 (7.3%) | – |
 DQ12 (2.2 µm, 87% purity) | – | 1 (2.4%) |
 Not mentioned | – | 2 (4.9%) |
Exposure method | ||
 Intratracheal instillation | 6 (14.6%) | 9 (22%) |
 Inhalation chamber | – | 14 (34.1%) |
 Intranasal instillation | 8 (19.5%) | – |
 Oropharyngeal aspiration | 4 (9.8%) | – |
Dosage, frequency and duration of exposure | ||
Acute exposure | 14 (32.6%) | 9 (20.9%) |
 1 dose | 14 (32.6%) | 8 (18.6%) |
  ≤ 5 mg/exposure | 9 (20.9%) | 1 (2.3%) |
  6–20 mg/exposure | 5 (11.6%) | – |
  ≥ 21 mg/exposure | – | 7 (16.3%) |
 1 dose during 6 h | – | 1 (2.3%) |
  248 mg/m3 | – | 1 (2.3%) |
Chronic exposure | 6 (14%) | 14 (32.6%) |
 2 doses | 2 (4.7%) | – |
  2.5 mg at 3 days apart | 1 (2.3%) | – |
  1 mg at 2 weeks apart | 1 (2.3%) | – |
 3 doses | – | 1 (2.3%) |
  45 mg at days 0, 7 and 14 | – | 1 (2.3%) |
 4 doses | 4 (9.3%) | – |
  1 mg once weekly during 4 weeks | 4 (9.3%) | – |
 3 h/day | – | 4 (9.3%) |
  50 µg/m3 during 24 weeks | – | 3 (7%) |
  50 µg/m3 during 4, 12, 16 or 24 weeks | – | 1 (2.3%) |
 6 h/day | – | 9 (20.9%) |
  ≤ 2 mg/m3 during 5 days | – | 1 (2.3%) |
  3–15 mg/m3 during 5 days or 3, 6, 12 weeks | – | 8 (18.6%) |
 19 h/day | – | 1 (2.3%) |
  1 mg/m3 during 2 weeks | – | 1 (2.3%) |
Timing of outcome measurement | ||
  ≤ 1 week | 9 (14.1%) | 8 (12.5%) |
2–11 weeks | 16 (25%) | 11 (17.2%) |
  ≥ 12 weeks | 6 (9.4%) | 14 (21.9%) |