Translational toxicology in setting occupational exposure limits for dusts and hazard classification – a critical evaluation of a recent approach to translate dust overload findings from rats to humans

Table 3 First volumetric approach to derive a NOAEC in rats (3rd paragraph of the section on lung overload on page 181 in Pauluhn [14]), all data are relative to a rat mass of 1 kg

Ventilation volume per day	Dead space fraction	Alveolar ventilation volume per day	Critical particle alveolar volume per day	Critical particle volume concentration in the alveolar space	Dust deposition fraction in the head and in the tracheo-bronchial region	Critical particle volume concentration in the inhaled air: NOAEC
0.29 m³	1/3	0.19 m³	0.069 μl	0.36 μl/m³	1/3	0.54 μl/m³
		=		=		=
		2(0.29)/3 m³		0.069 μl/0.19 m³		3(0.36)/2 μl/m³
		Dead space correction	Output Fortran program		Setting the “inhalability adjustment” off in MPPD 2.0*	Correction for the dust deposition in head and tracheo-bronchial region

*Input data to MPPD V2.0: MMAD = 1.8 μm, GSD = 2, density = 1 g/cm³; particle characteristics according to Pauluhn [14], all other MPPD input parameters as listed in the MAK document ([11], p. 57,58 and Appendix).

ISSN: 1743-8977