An Australian toxicologist has pointed out that some
of the intellectual development problems in children earlier linked to lead, could also be caused by household pesticides.
Professor Brian Gulson at Macquarie University,
however on one hand agrees that lead is harmful for children's intellectual
development, but at the same time he supports many studies showing that low
level exposure to organophosphate pesticides may be equally detrimental to
He also stated that the confusion in the effects of
lead and pesticides must have resulted because of the similarity in effects and
the overlap in timing of the major use of these pesticides in the community and
lead exposure studies. But other scientists have dismissed his comments as an
"interesting idea" that is "not well supported" by the
Gulson's comments come in line with the review of
guidelines for acceptable levels of lead in the blood by the regulatory bodies
in the US, Canada and Australia. He said that the US is under pressure to halve
the current blood lead level of 10 micrograms per decilitre.
He disagrees to the shift to 5 micrograms per
decilitre saying that they do not have the technology to measure impact on IQ,
or intellectual quotient, at that level. Besides, he even suggested that lead
couldn't be solely blamed for all the neurodevelopmental effects.
"Many of the lead studies have been undertaken in
communities where the subjects may be exposed to rodents and insects [and] the
chemicals used to eradicate them," Live Science quoted him, as saying.
He even linked pesticide exposure in pregnancy to
effects on children's IQ. Pointing to a 2002 study of female ethnic minorities
living in New York City in which 85pct agreed to use pest control measures in
their home while they were pregnant, he said that the organophosphate
insecticide chlorpyrifos was banned for residential use in the US in 2002.
But still, he said that in a 2007 study, it was said
that residue of the insecticide in all participating New York City homes was
detected more than 2 years after the ban.
He said that as researchers investigating lead
exposure have never considered pesticides, one couldn't disregard his concern
about their role in damaging intellectual development.
He stressed on the point that future lead studies
should include questions about pesticide use in the home, but admits the
"horse might have bolted. The current very low blood lead levels compared
with the earlier longitudinal studies will limit the possibility to determine
respective contributors to neurodevelopmental deficits."
Despite of his strong recommendations, many
researchers have opposed his view.
is available online in the journal Science of the Total Environment.