If you want an example of structural racism, lead poisoning is basically as literal an interpretation of it as you can get. The coronavirus is shining light on some of the racial inequality and socioeconomic determinants of health, with Black people dying at over twice the rate of white people. The coronavirus is acting as a flashlight, but the problems have been there the whole time. And they reach further than “just” a lack of access to quality affordable healthcare and a scarcity of fresh food options. They reach further than the fact that people of color are more likely to work in the jobs so essential that we need them to put their health at risk go to work during a pandemic, yet not considered valuable enough to pay them a living wage. Racial inequities when it comes to health in America can be found in the very buildings and pipes in predominantly minority neighborhoods. 

As I will get into, lead can mimic other molecules to literally get into your brain and play around, causing learning difficulty and developmental delay that can lead to lifelong problems. Children are especially at risk for lead’s toxic effects – and for being exposed to it. And Black children are especially likely to be exposed to it. The CDC guidelines say that NO amount of lead in the blood is safe for children, yet a study looking at data from 2011-2014 found that 15.2% of non-hispanic black children had blood levels at or above 2μg/dL, nearly twice as high a rate as white children. https://bit.ly/32uBuil 

How’d we get here? In part, it’s due to years and years of racial segregation through practices such as redlining, whereby Black people were unable to get mortgages for houses in nice neighborhoods, and racial covenants whereby housing deeds literally forbid the transfer of the house to Black people. These practices led to Black people being limited to living in the places white people didn’t want to live in. Even after those blatant discriminatory practices are outlawed, housing segregation still exists, because our society was set up that way. Black people have made communities in those less-desirable places. And, even if they wanted to leave, the black-white wealth gap makes moving or upgrading out of reach.  

Speaking of upgrading, there has been a gross inattention by the government and landowners to the upkeep and renovation of the buildings in these predominantly-minority areas (from houses to schools) and the plumbing that supplies those buildings, allowing lead levels to build up in the air, soil, water, and ultimately the blood of Black children. This has had the effect of setting Black children up to fail. Before they even enter the underfunded schools they’re able to attend. Before they even enter the job markets that are less likely to hire them. Before they even have a “chance” to get pulled over by a cop for nothing. Our society is setting up Black people to fail. And this is not okay. 

More about sources of contamination at the end, but first I want to tell you about *why* lead is so dangerous – from the biochemical level to the person level to the humanity level. 

Our bodies actually use metals a lot. Atoms link together by sharing subatomic particles called electrons and the atoms of metals are really useful because they have these big electron clouds that can “easily” give and take electrons (referred to as oxidation & reduction, respectively) allowing reactions to happen. And they can bind multiple things at the same time, allowing them to hold things in place. They can also act as signaling molecules. A few of the main metals used by our bodies are Zinc (Zn), Magnesium (Mg), Calcium (Ca), & Iron (Fe). Those metals “belong” in our bodies, where they do important things. Take iron, for instance. It gets held by protoporphyrin to make the heme in the hemoglobin protein in our blood cells. And, since metals can bind multiple things, it can also grab onto an oxygen, allowing the hemoglobin to transport oxygen throughout the body. And that iron gets stuck into protoporphyrin by a protein (ferrochelatase) that depends on Zinc. 

So, some metals are good (all in moderation of course). But there are other metals, the so-called “heavy metals” that do not belong in our bodies – and one of the main ones is Lead (Pb).

Lead is a trickster – when it comes to metals, it’s less picky than some others about where it likes to hang out. So it can take their place physically. But it can’t take their place when it comes to carrying out the displaced metals’ functions. So, for example, if lead kicks the zinc out of your iron-adder, that iron-adder (ferrochelatase) can’t add the iron. And without the iron the hemoglobin can’t hold oxygen. And if hemoglobin can’t hold oxygen it can’t deliver oxygen throughout your body, a type of anemia (anemia is a sort of catchall term for a condition where blood is unable to carry oxygen sufficiently – usually either because there are too few red blood cells and/or not enough functioning hemoglobin). 

As if that weren’t bad enough, since you don’t have functional heme being made, the body keeps trying to make more, and this can lead to the toxic buildup of precursor products including the neurotoxin ALA. As the term “neurotoxic” suggests, this molecule is able to cause problems to the nervous system, including the brain. And that’s not the only way lead causes nervous system problems. Because, in addition to displacing Zn²⁺, lead can displace calcium,  Ca²⁺. A lot of the complex signaling that occurs in our brains relies on calcium. Lead can “pretend” to be calcium, sneaking past the blood-brain-barrier & confusing brain cells and making them less sensitive to legit calcium. This can cause severe neurological and psychological problems – especially in children, whose brains are rapidly developing and are more vulnerable. And kids aren’t just building their brains – they’re also building bones – and bones store calcium – and if bones think lead’s calcium, they can store lead instead – so lead can build up in their bodies and get released over time, leading to long-term consequences even years after initial exposure. 

As you can see, leads to lots of problems – and it’s blood-related problems don’t just come for heme problems. The anemia associated with lead poisoning doesn’t just come from reduced heme synthesis – it also comes from the red blood cells that get made not lasting very long before getting destroyed by “hemolysis.” This occurs in part because lead inhibits an enzyme called pyrimidine 5′-nucleotidase (P5NT), which normally helps catabolize (break down) RNA letters. So those letters build up and cause problems. Additionally, Lead likes to bind to the sulfhydryl (-SH) groups of the amino acid (protein letter) cysteine, which antioxidant proteins usually use to regulate redox levels and protect other molecules from getting damaged by highly-energetic “reactive oxygen species (ROS).” When lead interferes with these proteins, redox is thrown out of wack and all sorts of problems can arise. 

So where does lead come from?

One main source of lead is lead paint. Lead isn’t used in paint anymore but it used to be used a lot. Like a lot a lot. One survey found that 52% of homes built before 1978 contain lead-based paint. https://bit.ly/32uBuil And this probably wasn’t that big a deal when the houses were new and the paint stayed on the walls. But as the houses get older, that paint starts chipping off. Little kids might eat it and, even if they don’t purposefully eat it, lead dust can contaminate the place and get into the soil and the air. Houses are just one area. Children can also be exposed at daycare or school. And schools get funding from local people. So the wealthy schools can afford to make sure all their stuff is fine but the schools in poor neighborhoods struggle to just get by. 

Even when it isn’t coming from paint, lead can get into the environment through the use of leaded fuel and factories and power plants that burn coal, which is often contaminated with lead. Some factories also produce lead through mining or smelting processes and the recycling of lead-containing products (such as a lot of e-waste). And where do all those factories get built? Thanks to the NIMBY-ers these factories are predominantly found in minority neighborhoods. 

And of course, there are the pipes. This issue got a lot of attention with the lead poisoning crisis in Flint, Michigan. The government was building a new pipeline so they switched the water to Flint temporarily to the Flint River. The water in the river was corrosive, leading to the degradation of aging pipes and the leaching of lead into thousands of homes and buildings, exposing over 100,000 residents. The water turned colored and nasty-tasting and residents protested and demanded the government take action. But they didn’t. Instead they insisted the water was safe. So the residents organized together with the help of Virginia Tech, collecting water samples that showed that over 40% of he water in the first test batch (252 homes) had elevated lead (over 5ppb) and almost 17% of thad lead levels that require corrective action. https://bit.ly/32tGCDu 

The government finally took action, but it took a year and a half, a full 18 months during which time almost 9,000 children were supplied lead-contaminated water. Here’s a good site for more info: https://on.nrdc.org/30nQWKz 

This problem goes far beyond Flint. The problem in Flint was that the corrosive water exacerbated the corrosion of the lead pipes. But the lead pipes themselves are the major problem. 15-22 million people in the US get their water from lead service lines. https://bit.ly/3976xCl Replacing those would be a huge help because those service lines are the biggest source of lead in the water, but even if you replace those, old plumbing fixtures can still leach lead. Which gets us back to infrastructure on the local level – and where renovation can and can’t be afforded thanks to our inequitable society. 

Take public schools for instance, where parents send their kids, entrusting the government to take care of them. A 2004 study where they measured lead levels in Philadelphia’s public schools found that 57.4% of the buildings had water lead levels exceeding the Environmental Protection Agencies (EPA) action level of 20 ppb. https://bit.ly/2OE1znc And many schools are rarely even tested. So, the very buildings kids are sent to learn in can be exposing them to a toxin that prevents them from learning…

Speaking of learning, I hope you learned something, and I hope that you will help try to get people to take this problem seriously and act to enact environmental justice. 

A really good source of information is this report by Vanessa Sack & Susan Balding, The United States Can and Should Eliminate Childhood Lead Exposure https://bit.ly/3976xCl 

more on topics mentioned (& others) #365DaysOfScience All (with topics listed) 👉 http://bit.ly/2OllAB0 

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