Effects of Lead on Human Health

Nov 16, 2017

(Excerpt from: NHMRC Information Paper: Evidence on the Effects of Lead on Human Health
Published: May 2015 by National Health and Medical Research Council)

Evidence on the Effects of Lead on Human Health

Health effects as a result of lead exposure differ substantially between individuals. Factors such as a
person’s age, the amount of lead, whether the exposure is over a short-term or a longer period, and
the presence of other health conditions, will influence what symptoms or health effects are exhibited.
Lead can be harmful to people of all ages, but the risk of health effects is highest for unborn babies,
infants and children.

It is well established that blood lead levels greater than 10 micrograms per decilitre can have harmful
effects on many organs and bodily functions. Effects such as increased blood pressure, abnormally
low haemoglobin, abnormal kidney function, long-term kidney damage and abnormal brain function
have been observed at blood lead levels between 10 micrograms and 60 micrograms per decilitre in
adults and children.

Encephalopathy—which is characterised by irritability, agitation, poor attention span, headache,
confusion, uncoordinated walking or movement, drowsiness, convulsions, seizures or coma—can
occur at blood lead levels of 100–120 micrograms per decilitre in adults and 70–100 micrograms
per decilitre in children.

Death can occur at these blood lead levels in some cases.

The evidence for health effects occurring as a result of blood lead levels less than 10 micrograms per decilitre is less clear. NHMRC’s comprehensive review of the health effects of lead found an association between reductions in Intelligence Quotient (IQ) and academic achievement in children
at blood lead levels less than 10 micrograms per decilitre. There is weaker evidence that blood
lead levels less than 5 micrograms per decilitre are associated with reductions in IQ or academic

For blood lead levels between 5 micrograms and 10 micrograms per decilitre, an association was
observed between higher occurrence of behavioural problems (poor attention, impulsivity and
hyperactivity) in children, increased blood pressure in adults (including pregnant women) and a delay
in sexual maturation or puberty onset in adolescent girls and boys.

The relative contribution of lead to the above health effects is difficult to determine. The effects of
blood lead levels less than 10 micrograms per decilitre on IQ, academic achievement and behavioural
problems is likely to be small, with stronger influences being exerted by other factors such as
socioeconomic status, education, parenting style, diet, or exposure to other substances.

For more information visit the source of this article: