Chemistry Reference
In-Depth Information
medical surveillance, and reduction of exposure when
the workers B-Pbs are >400
in the reproductive age, and 150
g/L in men > 45 years,
while there were an increased risk of adverse effects at
150 and 250
µ
g/L, the
worker should be removed from exposure. There are
no additional restrictions for women. It may be men-
tioned, that in the U.S., the current goal of the Depart-
ment of Health and Human Services is to eliminate all
occupational exposures resulting in B-Pb >250
µ
g/L; at >600
µ
g/L, respectively (Ewers
et al
., 1999).
In the United States, the
ambient air
quality stand-
ard is 1.5
µ
g/m
3
(quarterly average; U.S. EPA, 2003).
The EU (1999) ambient air quality guideline for Pb is
0.5
µ
µ
g/L
g/m
3
on an annual basis (2005). In the immediate
vicinity of specifi c industrial sources, the value is 1
µ
(1.2
mol/L).
Also in the United States, ACGIH (2001; 2003) has a
threshold limit value (TLV) in air for lead and its inor-
ganic compounds of 0.05 mg/m
3
and consider them to
be confi rmed animal carcinogens with unknown rel-
evance to humans. Lead chromate has the same TLV,
but is listed as a suspected human carcinogen. Lead
arsenate has a TLV of 0.15 mg/m
3
as the total compound
to also protect from the toxic effects of arsenic. The rec-
ommended biological exposure index (BEI) for elemen-
tal and inorganic lead is 300
µ
µ
g/m
3
until 2010.
A provisional tolerable weekly intake (PTWI) of
25
g/kg body weight through
food and drinking water
has been established for all age groups by the Joint
FAO/WHO Expert Committee on Food Additives
(JEFCA; WHO, 2000b).
The tolerable concentration of lead in drinking
water in the EU is 10
µ
g/L (EU, 1998a). This is based
on a health-based guideline value for bottle-fed infants
(provisional tolerated weekly intake 25
µ
g/L blood, with a special
warning that women with a B-Pb >100
µ
µ
g/kg body
g/L are at risk
of delivering a child with a B-Pb over the U.S. CDC
guideline of 100
µ
weight = 3.5
g/kg body weight/day; body weight
5 kg; 50% allocation to water; 0.75 L/day; rounded
fi gure; WHO, 2003). In the United States, the EPA
action level is 15
µ
g/L, which should not be exceeded.
The OEL in the European Union is 150
µ
g/m
3
(EU,
1998b). Medical surveys shall be made if the air-Pb
is >75
µ
g/L.
The maximal permissible level in foods within the
European Union ranges from 0.02 mg/kg wet weight
for milk and milk supplements for infants, over
0.1 mg/kg for most meat and vegetables up to 1 mg/kg
for mussels, for example (EU, 2001).
µ
g/m
3
(TWA during a 40-hour week) or if the
B-Pb is >400
µ
g/L in an individual worker. However,
the Scientifi c Committee on Occupational Exposure
Limits (EU SCOEL, 2002) has recommended an OEL
of 100
µ
g/m
3
(fumes and dust) and a biological limit
value (BLV) for B-Pb of 300
µ
2.13.2.2 Cancer and Reproduction
The International Agency for Research on Cancer
(IARC, 2006) stated that there is limited evidence for
carcinogenicity to humans of exposure to inorganic
lead, but suffi cient evidence in animals. Hence, IARC
classifi ed inorganic lead as probably carcinogenic to
humans (Group 2A).
g/L (for both males and
females). It is noted that it is not easy to set an OEL
for airborne Pb, because a considerable fraction of
the Pb is ingested orally. Furthermore, the B-Pb is not
seen as entirely protective for the offspring of working
women; no threshold for potential CNS effects in new-
born and infants could be identifi ed. Several within the
EU apply lower OELs of 50 or 100
µ
g/m
3
.
In Japan, the OEL is 0.1 mg/m
3
and the occupational
exposure limit on the basis of biological monitoring is
400
µ
2.14 Diagnosis, Treatment, and Prognosis of
Poisoning and Medical Surveillance
2.14.1 Diagnosis
µ
g/L (Japan Society for Occupational Health, 2002).
2.13.2 Other Assessments
The diagnosis of lead poisoning depends on a his-
tory of lead exposure, symptoms and signs compatible
with lead toxicity, laboratory tests supporting the diag-
nosis, and exclusion of other, more reasonable expla-
nations (differential diagnoses). The toxic effects have
been discussed previously under the respective organ.
The clinical picture depends on the age of the sub-
ject and the duration and intensity of the exposure. In
infants, encephalopathia with confusion and seizures
is the most common presenting syndrome; lead poi-
soning is a differential diagnosis of infectious encepha-
lopathia and brain tumor (Erickson and Thompson,
2005).
2.13.2.1 Environmental Exposure
In the United States, the Centers for Disease Control
and Prevention in 1991 identifi ed a goal to reduce chil-
dren's B-Pb below 100
g/L (U.S. CDC, 2005). Inter-
ventions for individual children were recommended
at levels of 150
µ
g/L and above.
The WHO B-Pb level of concern is 200
µ
g/L (WHO/
ICPS, 1995). However, later a critical B-Pb of 100
µ
µ
g/L
was given (WHO, 2000a).
In Germany, as to “human biological monitoring
values” for B-Pb for the general population, no risk was
assumed at 100
µ
g/L in children < 12 years and women
