In a previous post I outlined the human health risks of exposure to lead, mercury, and cadmium. At the end of each description I provided a threshold or guidance value set out by the Canadian government, which essentially is the exposure value deemed to be "safe" based on past research. In my literature review I came across a number of studies looking at these particularly toxic heavy metals, and describing the exposure levels among residents of communities where e-waste disassembly is occurring. I found the results of these studies astounding! And you will eventually come to understand why, after reading this post. Given the extensive amount of research that already describes the human health impacts of exposure to these metals, a lot of the studies did not measure health outcomes (i.e. cancer, behavioural changes, kidney damage, etc.). The studies I chose to look at were those that measured internal exposure (human hair, blood, umbilical cord blood and meconium samples).
I have created and included a table outlining the blood lead levels in the three studies that measured it. As you look at the levels reported, recall what was mentioned in my previously posting about lead: no lead exposure levels are deemed safe in children, and the current Canadian threshold for treatment is 10 micrograms per decilitre in blood.