Friday, August 19, 2011

Oakland's Plan to Remove Lead - Fish Bones?

The health effects of lead poisoning and long term exposure to lead are no secret and children are at the greatest risk. Understanding the severity of the toxicity of lead is part of the reason leaded fuels were phased out and eventually banned in the US in 1996. Lately, however, lead is showing up in lots of unexpected places. Lead contamination keeps making it’s way into the news, from toys and drinks for small children to jewelry and even e-waste (where it eventually makes it’s way into the soil). In fact, there is even still significant lead contamination left in our soils from the (70+) years of leaded gasoline use. Once lead made it’s way out of our exhaust pipes, it eventually settled, contaminating soils in every direction. Soils contaminated with lead are hardly healthy, especially when you consider that we grow our food on it!
Not surprisingly, cleaning up lead from contaminated soils is expensive. Typically, the process consists of digging up contaminated soil and “disposing” of it (moving it elsewhere by truck). This gets very tricky when large areas or many tons of soil are contaminated; you can’t just dump tons of contaminated soil anywhere, not to mention that the transport costs alone are quite high.

As unlikely as it sounds, the Environmental Protection Agency (EPA) is using an old, yet unexpected, method to remove lead contamination from the soil in Oakland, California. What is this amazingly simple solution to this serious problem? --  ground up fish bones. Besides being a considerably less expensive process, it is a great deal safer for the environment for a number of reasons.

Fish Bones?

Since fish bones are full of calcium phosphate (the main component of animal bones, even ours), when they break down, the phosphates make their way into the soil. Lead in the soil chemically binds with this newly available phosphate and forms stable crystals called pyromorphite. Pyromorphite essentially locks the lead away into a form that won’t harm anyone, even in the unlikely even that it is eaten (mud pie anyone?).

In addition to removing the threat from lead, the leftover calcium (remember, bones are primarily calcium phosphate) helps to remineralize the soil, which further enhances the health of the surrounding area. If this technique is used on farm land, the results are even better, for everyone involved.

Where do the fish come from?

Fish bones are typically leftovers from food production, since most people don’t eat fish bones. However, even though fish bones are considered “waste”, it is still important to get them from a source that isn’t wasteful or damaging to the ecosystem of the planet. Fortunately, this particular application uses the bones of Alaskan Pollock, which is increasingly and almost completely fished in a sustainable way.

The Alaskan Pollock fishery in the Bering Sea is the largest single-species fishery in the world, and this fish is also the largest single food fish resource in the world. Pollock is used in a variety of foods including: whitefish fillets, fish and chips (increasingly used to help save rapidly depleting cod fisheries), imitation crab meat, fish sticks/fingers, “popcorn” fish, and even the McDonald's Fillet-O-Fish sandwich. While perhaps not on your list of fine dining, Pollock is used worldwide and highly available. Reusing the waste from this industry as a way to improve the environment is a great way to solve this difficult problem. Reusing the waste from an industry as large as Pollock fisheries is another great benefit to the planet.



For more information on lead (and other heavy metal) removal from soil:

Formation and Stability of Substituted Pyromorphite: A Molecular Modeling Study

A Texas Professor received a grant to try adding phosphate (called Apatite II) to bind with lead in the contaminated soils of New Orleans.

Researched and written by Dr. Rebecca Malamed, M.D. with assistance from Mr. Malcolm Potter.

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