Sure – it’s a good point about striking a balance between being willing to take action even with imperfect information, while also not wanting to overclaim. In that vein: We think that it may often be coming from lead chromate (high-lead plastics often also read high in chromium), which is a bright yellow-orange pigment, so most likely to be found in yellow/orange/green plastics; we saw it most in orange and bright green, which are both very popular colors in Malawi. We also saw high lead levels in at least one white plastic, which we suspect is coming from a different compound.
We have some testing underway at a lab to try to assess what drives leaching – heat, acid, fat/oil, and time are the variables we hypothesize might drive it. So juice could be worse than plain water, fatty stew worse than something leaner, etc—hopefully we’ll know more soon about which of these factors are most important though. It’s also still possible that despite the high lead levels in some of these plastics, not much of the lead is actually getting into food/drink, which would be great news.
And to speculate a bit more—it makes sense to me that a plastic that is flaking/fragmenting would pose a greater risk than one that is intact, though I don’t have much of a guess of the order of magnitude. On the other hand, we also think it’s possible that plastics may leach more on the first use than on subsequent uses, if that first use sheds a lot of the most ‘available’ lead...
Something I suspect may not be a good proxy is price. Again, we haven’t done any research in Uganda, but in Malawi we saw that branded and unbranded pots/pans were similarly likely to be contaminated, whereas we’d initially suspected that informally produced pots and pans would be much riskier. But other countries may vary.
And thanks for the thoughts on geophagia! We’re designing a study right now that will take BLLs of pregnant women who are geophagic, and those who aren’t, and compare BLLs across those two groups.
Sure – it’s a good point about striking a balance between being willing to take action even with imperfect information, while also not wanting to overclaim. In that vein: We think that it may often be coming from lead chromate (high-lead plastics often also read high in chromium), which is a bright yellow-orange pigment, so most likely to be found in yellow/orange/green plastics; we saw it most in orange and bright green, which are both very popular colors in Malawi. We also saw high lead levels in at least one white plastic, which we suspect is coming from a different compound.
We have some testing underway at a lab to try to assess what drives leaching – heat, acid, fat/oil, and time are the variables we hypothesize might drive it. So juice could be worse than plain water, fatty stew worse than something leaner, etc—hopefully we’ll know more soon about which of these factors are most important though. It’s also still possible that despite the high lead levels in some of these plastics, not much of the lead is actually getting into food/drink, which would be great news.
And to speculate a bit more—it makes sense to me that a plastic that is flaking/fragmenting would pose a greater risk than one that is intact, though I don’t have much of a guess of the order of magnitude. On the other hand, we also think it’s possible that plastics may leach more on the first use than on subsequent uses, if that first use sheds a lot of the most ‘available’ lead...
Something I suspect may not be a good proxy is price. Again, we haven’t done any research in Uganda, but in Malawi we saw that branded and unbranded pots/pans were similarly likely to be contaminated, whereas we’d initially suspected that informally produced pots and pans would be much riskier. But other countries may vary.
And thanks for the thoughts on geophagia! We’re designing a study right now that will take BLLs of pregnant women who are geophagic, and those who aren’t, and compare BLLs across those two groups.
- Isabel