The Great Cleanup: Bioremediation Explained

If the goal is to clean an environment using natural processes, then living organisms must be employed. If microbes have enzymes that break down toxins, then bacteria and fungi are the logical choice for this biological repair.

If microbes "eat" pollutants to obtain carbon or energy for growth, then their internal chemical reactions are doing the cleaning. If metabolism drives this breakdown, then the statement is correct.

If "In situ" is Latin for "in its original place," then the cleanup happens directly in the soil or water. If "Ex situ" means "out of place," then the contaminated material must be excavated and moved to a lab or treatment facility.

If indigenous bacteria are present but lack the food to multiply, then adding fertilizers "stimulates" them. If this stimulation leads to a biological cleanup, then it is a form of biostimulation within bioremediation.

If a pollutant is organic or can be chemically transformed by enzymes, then it is a candidate for microbial cleanup. While oil and pesticides are "eaten," metals are usually changed into less toxic forms; however, microbes cannot "eat" large pieces of scrap steel.

If microbes break down hydrocarbons, then they typically produce carbon dioxide and water as waste. If these are still chemical byproducts, then the statement that it produces "zero" waste is technically false, even if the waste is harmless.

If the prefix "phyto-" refers to plants, then the term identifies a cleanup method using vegetation. If plants absorb toxins through their roots, then they are performing phytoremediation.

If the local bacteria cannot handle a specific chemical, then scientists must "augment" the population. If they add specialized laboratory-grown microbes to the site, then they are performing bioaugmentation.

If aerobic microbes require oxygen to break down hydrocarbons efficiently, then a lack of air will slow the cleanup. If pumping air (bioventing) provides that necessary oxygen, then it speeds up the bioremediation process.

If a bulldozer can remove contaminated soil in one day, it is fast. If microbes take months or years to slowly digest the same pollutants, then the biological process is significantly slower than mechanical methods.

If bacteria are "heterotrophs," then they need to consume organic carbon to build their cells. If oil is made of hydrocarbon chains, then it provides the carbon and energy the bacteria need to survive.

If microbes are living things, then they require specific conditions to survive. If the soil is too dry, cold, or acidic, then the enzymes won't work and the microbes will die or become dormant.

If "myco-" refers to fungi, then the use of mushrooms and molds for cleaning is mycoremediation. If these organisms use powerful enzymes to rot the pollutants, they are effective bioremediation agents.

If "anaerobic" literally means "without air," then these microbes thrive where oxygen is absent. If they worked in high-oxygen areas, they would be called aerobes instead.

If the Gulf of Mexico has natural oil seeps, then oil-eating bacteria already live there. If a large spill occurs, then those bacteria populations explode and begin to naturally digest the hydrocarbons.

If bacteria transfer electrons to a heavy metal, then they change its oxidation state. If Chromium-6 is the toxic version and the bacteria change it to Chromium-3, then the metal has been remediated.

If the material is gathered and placed in a container (reactor) or a pile (compost), then it has been removed from its original location. Bioventing and planting trees happen directly on the original land, making them In situ.

If different environments have different native species and climates, then the biological "recipe" for cleanup must change. If the swamp has no oxygen and the desert is too dry, then the same bacteria cannot be used in both.

If natural bacteria cannot break down a very tough synthetic chemical, then scientists can insert new genes into them. If these genes provide the "instructions" for new enzymes, then the engineered bacteria can clean up the new pollutant.

If the entire purpose of using microbes, plants, or fungi is to fix a human mistake in nature, then the process is defined as environmental remediation through biology.