One of the two research projects that splintered off this original research was looking at remediation methods to reducing the amount of lead that is absorbed by plants. There are certain plants are able to absorb lead, which can then be absorbed into the bloodstream. I actually want to rephrase/clarify, there is a grouping of plants that are considered hyperaccumulators, some of these plants are better at absorbing lead vs another element like mercury or arsenic, it varies from element to element and plant to plant. Some of these plants are commonly consumed by people, for instance mustard greens.
In the first part of this post, I mentioned some the sources of lead in soil/compost. While lead paint chips do break into smaller pieces when they chip off, a less obvious method of entry is airborne, but how does lead from paint become airborne? Fire. When whites started moving from the city to suburbs/African Americans started moving into the city for jobs; whites burned down their homes to prevent African Americans from having places to live. The fires “released” the lead into the air and soil.
Another point of entry was through former landfills/brownfields becoming suitable housing properties. Lead acid batteries have been around for a while, just as long as people’s failure to properly dispose of them. Fast-forward to the resurgence/necessity of home gardening or the emergence of urban agriculture, however you want to phrase it (although the former is more accurate). Add this into the urbanization, density, and racist housing policies/practices of America and you might start to see a few connections. The communities where African Americans moved into tended to stay African American (and some became home to other communities, mostly POC/immigrant), and many started to become food deserts (i.e. areas were fresh, healthy, affordable food are unavailable). In some communities, people wanted to grow foods that were foreign to mainstream/white grocery stores that are in the area. The most obvious approach to this issue/system failure— gardens. One of the foods that is frequently grown (because of other historical reasons and its ease to grow) is mustard greens. A plant that also happens to be a hyperaccumulator for lead, which I’ve previously mentioned in prolific in some soils and compost.
The upside is mustard seeds are easy to come by and grow, and therefore figuring their absorption rates is more accessible than potential other methods and creates a more realistic experiment. This experiment was actually pretty involved, because the mustards had to be grown (and multiples of the plant in variations of mixtures of soil, compost, and a manganese oxide component) and the leaves tested, which also involved mimicking human digestion; in order to assess lead’s absorption and movement throughout this whole process. The starting and ending concentrations of the soil mixtures were measured and recorded, too. The results produced a ton of new questions and inquires.
Honestly, I was super excited to work on this project and it led me to think about other methods of remediation, which is an entirely different project that I will discuss in my next post. It also connected back to a ton of other interests and passions (gardening, food, history, and spaces).
Just to clarify some of the information presented here has been simplified for condensing/privacy purposes, but I’m happy to answer most questions (especially if things were unclear). However, I request that you try googling before asking me questions that are easily googleable.