Intelligence vs. Lead Quotient

“Polluted Children, Toxic Nation” is the title of a 2006 study, carried out by Environmental Defence, an organization committed to protecting the environment and human health. It tested families across Canada for 68 chemicals, such as pesticides, PCBs, stain repellants, flame-retardants, mercury and lead. Results showed that there were some children who had higher levels of pollutants, including lead, than their parents.
The report lists the many reasons why children, babies and fetuses are more vulnerable to pollutants than adults. In utero, the embryo and fetus are defenceless against chemicals that cross the placenta. The blood-brain barrier and renal extraction are not fully developed until six months. Up until one year, the digestive tract, skin and lungs are extremely permeable and readily absorb substances. Children and pregnant women can absorb up to 50 percent of ingested lead compared to only 10 to 15 percent by adults.

The World Health Organization and Health Canada have set guidelines for acceptable levels of lead at 10 micrograms of lead per decilitre of blood.  Yet, according to Health Canada, “ Exposure to even small amounts of lead can be harmful, especially to infants, young children and pregnant women. Lead exposure is most serious for young children because they absorb lead more easily than adults and are more susceptible to its harmful effects. Even low-level exposure may harm the intellectual development, behaviour, size and hearing of infants. During pregnancy, especially in the last trimester, lead can cross the placenta and affect the unborn child.”

After the Province of Ontario ordered 36 municipalities to undergo testing for lead levels in their water, Gideon Forman, executive director of the Canadian Association of Physicians for the Environment (CAPE) said “…  there’s no such thing as a safe level of lead, because any amount can make you sick. It’s dangerous to anyone. But our major concern is around the developing brain and nervous system for children. Children who are exposed to lead can suffer from learning disabilities, behavioural problems, and IQ can be affected.”

This opinion is reinforced by a feature produced by the CBC in 2003 based on a report that was published in the New England Journal of Medicine. A team led by Richard Canfield of Cornell University conducted a study of 172 children in New York City to measure the effect of lead exposure on IQ level.  Previous studies that had been conducted only measured effects on children who had 10 to 30 micrograms lead per declitre of blood, much higher than the levels considered safe. The 2003 research found that as blood levels increased from such low levels of 1 to 10, a child’s IQ fell by an average of 7.4 points. This decrease was much steeper than had been found at higher concentrations of lead.

Reduced IQ is just one result of lead exposure according to Barbara McElgunn of the Learning Disabilities Association of Canada. She says “The effects of lead that scientists and pediatricians are most concerned with now go beyond reduced IQ. There are concerns arising from research into the effect of lead on emotional reactivity, aggression, social confidence and social functioning.”

Health Canada is currently cautioning against all unnecessary lead exposure in children.  This stance as well as the frequent media reports on the unsafe lead levels found in the drinking water in schools nationally is creating growing concern among Canadian families.  Where we once thought that small amounts of lead in our drinking water could be processed through our bodies safely, when it comes to children there seems to be no safety margin.  The best way to safeguard our children against exposure to lead is to eliminate it from our drinking supply.