|MadSci Network: Environment & Ecology|
There is not one standard for biodegradability - it all depends on the chemistry of the compound you are using. Some compounds will degrade rather quickly (hours to days or weeks) and some will not degrade at all. Also, just because a compound doesn't readily decay doesn't mean this is bad. Take for example lignin. This material comes from plants and is found in organic matter. It takes a pretty long time to get rid of it because the rest of the carbon in decaying plant matter is easier for bacteria to use than the carbon in lignin. Getting back to the point, lignin is everywhere and isn't really toxic so even though it takes a while to break down it doesn't really matter all that much. The opposite scenario is also true. Short term compounds such as MTBE (gasoline additive used in the winter) reputedly causes all kinds of problems (there is a lot out there about this so I won't go into detail). So now you have two factors: time and toxicity. The third issue is concentration. A little bit of fertilizer run-off, say from one lawn, is no big deal to a neighboring pond. However, if you dump a whole lot of it into the pond, it will quickly be taken up by algae resulting in the death of the pond by eutrophication. A fourth thing to consider is the locality and mode of transport. Locality plays a role with respect to population density, climate, topography, soil type etc. Mode of transport can sometimes determine the environmental effect of the compound - ammonia volatilization results somewhat different problems than ammonium run-off. So, the short answer to you question is - it depends on SEVERAL factors. What you should first determine is the ingredients of the product. Second, go on-line and look for Material Safety Data Sheets. I've included the address for a page full of links to pertinent sites. Then depending on what you are using and how you are using it (in what concentrations, where, etc.) apply that information. http://www.phys.ksu.edu/~tipping/msds.html
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