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A report for the Canadian government has called living by the Great
Lakes a ‘hazard to human health’. Å®ÉúСÊÓƵs have found increasing evidence
that pollutants in the water are causing insidious neurological damage,
particularly in children, and infertility among adults.

The findings are presented in a report by the International Joint Commission,
a team appointed by the United States and Canada to monitor shared waters.
The Great Lakes form the world’s largest body of fresh water, and the area
around them is home to about 37 million people.

Concern about toxic chemicals has grown over the past 20 years. Industry
and farmers on the surrounding land have used the lakes to dispose of waste
chemicals such as polychlorinated biphenyls (PCBs) produced in the manufacture
of electrical equipment, and organochlorine insecticides such as dieldrin
and DDT.

Jack Vallentyne, Canadian co-chair of the Science Advisory Board and
coeditor of the report, says that these persistent toxins remain a serious
risk to human health, even though their concentrations in the water have
stabilised.

In children, he says, PCBs in blood are associated with impaired learning
abilities. Children with high levels have a shorter attention span and deficits
in short-term memory.

Vallentyne is particularly concerned about future effects. He says that
in children the damage ‘represents neurobehavioural rather than anatomical
defects. The defects are not clinical. Neither parents nor physicians would
be likely to recognise them. They are of concern in terms of public health’.

Fears about human fertility are also raised by the report. Quoting a
study by the Canadian Department of National Health and Welfare, which found
traces of the toxic chemicals in the human reproductive tract, it concludes:
‘This could be a factor contributing to the otherwise unexplained declines
in North American fertility rates.’

The author of the fertility study was Andy Gilman of The Great Lakes
Health Effects Program within the health and welfare department. He recognises
that there is little evidence on the effects of these chemicals specifically
on the human reproductive system.

Nevertheless, Gilman insists that the dangers are clear to see. ‘If
you have those kinds of effects occurring consistently across five orders
of animals, and one is mam mals, there’s enough information to know these
contaminants pose a risk to health,’ he says.