Exposure Through Soil and Dust Ingestion - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 263

In this chapter we therefore use the following definitions:

- Soil: outdoor soil and soil used indoors to support plant growth, including particles
that have settled onto outdoor objects and surfaces;
- Dust or house dust: settled indoor material, consisting of soil-derived and non-
soil-derived materials.

On average, house dust includes 30-70% soil material, indicating that contami-
nated soil can lead to contaminated house dust (Oomen and Lijzen 2004 ).
The fraction of exterior soil in interior dust has been examined by various
researchers. Oomen and Lijzen ( 2004 ) and Cornelis and Swartjes ( 2007 ,see
Table 6.1 ) give a good overview of the fraction of exterior soil in indoor dust derived
from different relevant studies.
From Table 6.1 it can be concluded that estimates of the contribution of soil
to house dust range from 8 to >80%, depending on a wide variety of site-specific
factors and methodological approaches. Cornelis and Swartjes ( 2007 ) recommend
the use of 50% exterior soil in interior dust for a residential land use. For the land
use “living without a garden” they propose a fraction of 25% exterior soil in interior
dust. The default value recommended by US EPA ( 1998 ) is 70% exterior soil in
interior dust.
The distinction between soil and house dust (including tracked-in soil) may be
very important in Risk Assessment. House dust is generally composed of finer
particles than soil. Particles with a diameter exceeding 150 μ m represent 80% of

Table 6.1 Overview of the fraction of exterior soil in indoor dust derived from different studies

Study Percent of exterior soil in house dust

Hawley (1985) in Oomen and Lijzen ( 2004 ) 80
Thornton (1985) in Oomen and Lijzen ( 2004 ) 0
Camann and Harding (1989) in Oomen and
Lijzen ( 2004 )

50

Fergusson and Kim (1991) in Oomen and
Lijzen ( 2004 )

32-50

Calabrese and Stanek ( 1992 ) in Oomen and
Lijzen ( 2004 )

31

Sterling (1998) in Oomen and Lijzen ( 2004 ) 37 (based on particle volume weighting)

8 (based on particle concentration weighting)

Rutz, Valentine, Eckart and Yu ( 1997 ) 20, 30

Trownbridge and Burmaster ( 1997 ) P50: 41

Arithmetic mean: 44.5
SD: 16.8 %

Hager ( 2005 ) P50: 26-27

P25: 16-14
P75: 44-42
Arithmetic mean: 42-37

Cornelis and Swartjes ( 2007 )