Environmental Engineering Reference
In-Depth Information
Table 2.10
Blood Lead Levels and Associated Health and Physiological Effects in
Children and Adults
Blood lead level
(
µ
g/dL)
Children
Adults
<10
Early signs of hypertension
ALA-D inhibition
10-15
Crosses placenta
Neuro-developmental effects
ALA-D inhibition
Impairment of IQ
Increased erythrocyte
protoporphyrin
Reduced gestational age and
birth weight
15-20
Increased erythrocyte
protoporphyrin
20-30
Altered CNS electrophysical
response
Interference with Vitamin D
metabolism
30-40
Reduced hemoglobin synthesis
Peripheral nerve dysfunction
Systolic hypertension
Altered testicular function
Peripheral nerve dysfunction
40-50
Reduced hemoglobin
synthesis
Overt subencephalopathic
neurologic symptoms
60
Peripheral neuropathy
Reproductive effects in
females
70
Anemia
80
Anemia
Encephalopathy symptoms
80-100
Encephalopathy symptoms
Chronic nephropathy
Colic and other gastrointestinal
symptoms
Chronic nephropathy
Encephalopathy symptoms
Hematological changes (effects on blood chemistry and related physio-
logical changes) are one of the earliest manifestations of chronic lead expo-
sure in both adults and children. Lead interferes with heme synthesis. Heme
is a component of hemoglobin and cytochrome P-450 and other electron-
transferring cytochromes. As such, heme is essential to the proper function-
ing of the brain, kidney, liver, and blood-forming tissues. Interference with
hemoglobin synthesis results in mild to severe anemia. Inhibition of enzymes
involved in heme biosynthesis has been observed at BLLs as low as 10
µ
g/dL,
with an unknown threshold.
