The one thing I don't see is the lead levels of the water supply. Doesn't the EPA have limits on that and isn't it an easy thing to test?
It is true that different water supplies will have different levels of contaminants (lead, arsenic, etc) but can all be within EPA limits. Switching to a water supply with a higher level of contamination will increase exposure. The medical study seems to look at the percentage of children below 5g/dL before and after the switch. It goes from 2% to 4%. So with the old water supply, a certain percentage of children were already being exposed to elevated levels of lead. Switching to a water source with higher lead levels will push more children who are being exposed to lead through other sources to above the 5g/dL mark. However, this would seem to indicate that the primary source of lead for these children above 5g/dL is something other than the water.
It is true that different water supplies will have different levels of contaminants (lead, arsenic, etc) but can all be within EPA limits. Switching to a water supply with a higher level of contamination will increase exposure. The medical study seems to look at the percentage of children below 5g/dL before and after the switch. It goes from 2% to 4%. So with the old water supply, a certain percentage of children were already being exposed to elevated levels of lead. Switching to a water source with higher lead levels will push more children who are being exposed to lead through other sources to above the 5g/dL mark. However, this would seem to indicate that the primary source of lead for these children above 5g/dL is something other than the water.