Lead in the Japanese living environment

Table 4 Estimated daily intake of lead in Japanese

Medium	Environment Agency 2000 [33] (adult)		Aung et al. 2004 [41] (children)		Nakanishi et al. 2006 [9] (children 6 years)
Medium	Lead concentration	Inhalation/ingestion rate	Lead concentration	Inhalation/ingestion rate	Lead concentration	Inhalation/ingestion rate^a
Atmosphere	0.073 μg/m³	15 m³/day	0.045 μg/m³	8.75 m³/day	0.0253 μg/m³	7.2 m³/day
Inhalation^b	1.1 μg/day		0.4 μg/day		0.2 μg/day
Diet	44 μg/day		4.79 μg/day		NA (28.3)^d
Drinking water	0.01 μg/L	2 L/day			3.8 μg/L	0.28 L/day
Drinking water	0.01 μg/L	2 L/day			2.3 μg/L	0.28 L/day
Soil	13 μg/g	0.2 g/day (child)	46.4 μg/g	0.1 g/day	13.2 μg/g	0.087 g/day
Soil	13 μg/g	0.1 g/day (adult)	46.4 μg/g	0.1 g/day
House dust	–	–	117 μg/g	0.1 g/day
Oral^c	45.3 μg/day		21.1 μg/day		31.2 μg/day^e

^aEstimated ingestion rate for a 6-year-old child is given in the literature. Median or geometric mean is shown in this table
^bInhalation = atmospheric lead concentration × inhalation rate
^cSum of total oral exposure
^dNot specified in the literature. Dietary intake was calculated by subtracting lead intake from water and soil/dust from total oral intake [originally given as 1.3 μg/kg body weight/day (median value) which was multiplied average body weight of 6 years child as 24 kg] and indicated in parenthesis
^eThe value was calculated by the present author by using 50 percentile values reported in Nakanishi et al. [9] in which intake or ingestion rate was expressed as distribution; therefore, this value may involve uncertainty

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