What Research is Needed?
There is already exceptional work identifying the lead pollution problem, its pathways to childhood lead poisoning and public education on its health risks. There is also a large body of scientific literature pertaining to how lead is absorbed in the body and how it affects human health. Therefore, the most pressing research challenge is finding more effective and efficient methods for abating and remediating the existing lead pollution effecting children where they live, play and learn.
Where Should Researchers Focus Their Efforts?
Fortunately, the replacement of older homes and business structures with new construction will eventually eliminate the lead paint problem. However, the pervasive problem of lead contaminated soil is without an effective remediation method. Many research efforts are attending to this problem. These investigations fall into two general categories:
- Invent new ways to make removal, isolation, stabilization, and bioremediation methods more effective and less expensive.
- Invent new soil amendment technologies rendering lead particles biologically inert and thus less capable of effecting human health.
Which Research Avenue is Most Promising?
For several reasons the most attractive solution is soil amendment technologies that will reduce the bioavailability of lead:
- Amendment materials are typically very inexpensive to manufacturer, warehouse and ship.
- As a chemical additive, amendments can be mixed into water for quick and easy application to wide tracks of land.
- As the amendment / water mixture migrates down into the contaminated soil, it takes the remedy down to where the lead particles reside.
What About Improving Existing Methods?
Even improved removal, isolation, stabilization methods will likely be too difficult and expensive to implement on the large scale needed for a true solution to lead contaminated soil. With respect to bioremediation, this method is much less expensive, but it can be impractical for many sites, it is a slow process and it still involves a disposal issues with mature plants full of dangerous lead.
How Does Soil Amendment Work?
Researchers are looking for new materials and combinations of materials that when added to the soil, bind with the hazardous lead particles to form a secondary substance that does not react within a child’s biology. In scientific terms this is called biologically inert.
Soil amendments have distinct advantages. They can be very inexpensive to manufacturer and when dissolved into water, they can be easily and inexpensively spread on the soil surrounding private homes, schools, parks and other public and private lands.
Is Anyone Researching Soil Amendments?
Yes, one promising approach is to mix calcium phosphate into lead polluted soil. Wetting the amended soil with rain or artificial methods causes the calcium phosphate to migrate in the soil where it comes into contact with hazardous lead particles. When contact occurs, the calcium phosphate binds with the lead to form a crystalline mineral that is not harmful to humans even when it is consumed.
Current calcium phosphate products are effective in reducing bioavailability (see Fishbone). However, they are still expensive because considerable labor is needed to roto-till the material into the soil. Therefore further research is needed to find more efficient materials that can be easily and inexpensively added to wide tracts of land.