I have no knowledge in this area but I am deeply concerned with practices that could have potential impacts on current river ecology. Some obvious questions: 1. What species currently occur in these shell deposits? 2. One presumes these deposits have an impact on current stream chemistry, is there data on this? 3. What impact will the removal methods have (dredge, access roads)? Do current acquatic inverts use these deposits? Oyster shell reefs have a major impact on marine systems, is there an analogous impact from freshwater shell deposits? How do current deposits impact stream flow, sediment depostion, etc? Are there alternatives like waste shells from seafood processing that could be used with less impact on the river.
Shells have a long history of use for various purposes, both agricultural and other. Uses have ranged from road bed toppings to supplemental feeding of chickens (my wife's family used them on their egg farm in Connecticut). I am surprised that there would be enough shell available in a freshwater system. I would suspect that under NEPA this project would require a full EIS. I would be interested in seeing comments from experts. David Burg President WildMetro On Fri, Feb 4, 2011 at 2:07 PM, David L. McNeely <[email protected]> wrote: > ---- "Chalfant wrote: > > Greetings all - > > > > I'm interested in people's persuasions on the wisdom of crushing up > mollusk shells found in a local river (the Susquehanna near Harrisburg, > Pennsylvania to be specific) and use the crushings as a soil amendment in > food garden/farm. Great natural source of calcium and carbonate for crops > that like less acidic soils and need calcium for strong bones, right? ; ) > I'd particularly like to know if there is any reason to be concerned about > contaminants being incorporated into the shells and thence into the > plants... this seems intuitively unlikely to me, but I'd like to get some > other opinions on this practice since I intend to eat, sell, and share the > food grown in said soil. Thank you kindly. > > Hi Brian, I've just finished reading David R. Montomery's fascinating > history of agriculture and soil degradation, _Dirt, the erosion of > Civilizations_ (University of California Press 2007). From Montgomery, I > learned that the ancient Greeks, Romans, and other agriculturists of their > time used crushed mollusk shells as soil amendments, to correct acidity and > provide nutrients. The practice is longstanding, and if you think about it, > the modern practice of adding limestone, whether processed or not, is simply > drawing from a more ancient time for the material, but it is essentially the > same stuff. > > Now, so far as contaminants -- you might want to be sure of your source, > and to read up on uptake of heavy metals into plant tissues. I know nothing > about it. I do know that mollusk shells serve as an index to the presence > of such metals in the environment where they occur, and that we are > cautioned about lead in soils, for example from paint peeling from barns and > other structures. > > david mcneely >
