I have done some direct research on the impacts of exposure to lead in the community of Belledune, where the province did do blood sampling. Bio-monitoring testing is done, but if you can't correlate it to any symptoms that you might see in these children, it really isn't going to tell you very much.
We went into the population and did a survey of children's health. We actually looked at children living at various radiuses from the smelter. We knew what their blood lead levels were, and we then had the parents tell us what symptoms they had. What we found astonishing was that children living closer to the smelter had on the order of three to four more health problems per child than children living further out of a three-kilometre radius. We have done that kind of work, and there is a correlation.
They also had higher lead levels in their soil. So now you have a direct link between contaminants in the soil, contaminants in their blood, and health problems.