csefh - Kinder-Umwelt-Gesundheit

epresent the direction of movement of those
contaminants within the gastrointestinal tract.
To place these recommendations into context,
it is useful to compare these soil ingestion rates to
common measurements. The bulk densities of surface
soils are often in the range of 1.3 to 1.7 g/cm 3 . U.S.
EPA (1996) recommends using 1.5 g/cm 3 as a default
value for dry soil bulk density. The central tendency
recommendation of 50 mg/day, or 0.050 g/day, dry
weight basis, with a 1.5 g/cm 3 bulk density would be
equivalent to approximately 0.03 cm 3 . A teaspoon is
approximately 5 cm 3 in volume, so the 50 mg/day
quantity would be roughly equivalent to seven
thousandths of a teaspoon per day. The 50 g/day
ingestion rate recommended to represent geophagy
behavior would be roughly equivalent to 5 to 7
teaspoons per day in volume.
Indoor settled dust could be expected to have
a lower dry bulk density than the surface soil bulk
density cited above (for example, bulk densities of five
grain dusts are reported by Parnell et al. (1986) to be
0.15-0.31 g/cm 3 , “specific density” of Danish office
building dust is reported by Mølhave et al. (2000) to be
1.0 gm/cm 3 ). Thus, volumes of indoor settled dust
could be expected to weigh less than comparable
volumes of surface soil. The central tendency “dust”
recommendation for children of 60 mg/day, or 0.060
g/day, dry weight basis, with a 1.0 g/cm 3 bulk density
would be equivalent to approximately 0.06 cm 3 , or
roughly equivalent to twelve thousandths of a teaspoon
per day.
Child-Specific Exposure Factors Handbook
Chapter 5 - Ingestion of Soil and Dust
Page Child-Specific Exposure Factors Handbook
5-4 September 2008