Chemistry Reference
In-Depth Information
70
N = 3,715
= Landskrona
= Trelleborg
60
50
40
30
20
10
No petrol lead
1995
1975
1985
2000
2005
1980
1990
Year
FIGURE 2
Blood lead levels (B-Pb; geometric means) in Swedish chil-
dren in the towns of Landskrona and Trelleborg, 1978-2005. Strömberg
et al
.
(2003), and to be published.
adults living in the United States dropped 78% (from
128 to 28
Lead paint for anticorrosion purposes often contains
much more lead than house paint, up to 70-80% lead.
Flame cutting in metal painted with such paint (e.g.,
in scrapping of ships) causes a considerable risk. Other
occupational environments well known for being lead
exposing are lead smelters and storage battery manu-
facturing. In the work environment, exposure occurs
both through inhalation (air and contaminated tobacco
smoking) and through ingestion of contaminated foods,
drink, and snuff. As examples of air-lead levels, average
concentrations in the ranges 0.05-0.2 mg/m
3
(Richter
et al
., 1979) and 0.01-0.03 mg/m
3
(Hodgkins
et al
., 1992)
were found in different parts of a U.S. storage battery
plant. This issue is further discussed in Section 2.5.1.
g/L) between 1976 and 1991, and a similar
decline was seen among children (Pirkle
et al
., 1994).
In Turin, Italy, the mean B-Pb in adults dropped
58% (from 153-64
µ
g/L) between 1985/1986 and
1993/1994 (Bono
et al
., 1995), and in Swedish chil-
dren a similar decline has been observed between
1978 and 2005 (Figure 2). Erythrocyte samples from
adults indicated that there was still a decline in Swe-
den throughout the 1990s; approximately 4% annual
decrease (Wennberg
et al
., 2006). In all these cases,
the decrease or removal of lead from gasoline is cer-
tainly the main reason for the decline, although the
removal of lead from soldered cans probably also
plays a role. There is less lead contamination of foods
(Larsen
et al
., 2002).
The phaseout of leaded gasoline has been success-
ful in several parts of the world, including recently the
nations in Sub-Saharan Africa. As of January 1, 2006,
leaded gasoline was still being used in parts of the
former Soviet Union (though not Russia), some coun-
tries in Southeast Asia, a few countries in eastern Eur-
poe and Northwest Africa and a few other countries
(UNEP, 2006).
µ
2.5 Toxicokinetics
A simple model of the toxicokinetics of lead is
shown in Figure 3.
2.5.1 Absorption
2.5.1.1 Inhalation
Lead may be inhaled as an aerosol. The pattern
of deposition of inhaled lead in the respiratory tract
depends on the particle size. Particles with an aero-
dynamic diameter > 5
2.4.2 Occupational Environments
m are mainly deposited in
the upper- and middle-sized airways, cleared by the
mucociliary mechanism, and swallowed. Some of this
lead is then absorbed from the gastrointestinal tract
(see later).
µ
In addition to the exposure from the general envi-
ronment, many work environments imply exposure
to lead. Between 100 and 200 different lead-exposing
occupations have been listed (Table 2).
