Below our feet there is a complex web of life constantly at work. Soil hosts all types of life like microorganisms, fungi, and bacteria, all of which work together to make soil, soil. Why do we care about soil? Well food and materials such as cotton, silk, wood, etc are dependent on the nutrients and structure soil provides. The living things inside the soil plays a vital role in producing the nutrients and qualities soils have. For example earthworms are constantly chomping on dead organic material and breaking it down to even simpler molecules that plants can then take up through their roots. The amount of organisms like earthworks can be a gauge to how healthy the soil is in terms of its ability to host plants, fungi, or bacteria. There are also a variety of other factors that can affect soil health which includes pH, salinity, oxygen content, and grain size.
One major concern that can arise is the contamination of soil by pesticides, heavy metals, or toxic man made organic compounds like PCB’s or PAH’s. These toxins can make it into the food chain and bioaccumulate to toxic levels in animals and plants and in soil, contaminants are transported through air (wind) or water to other systems. The negative effects of the ecosystem due to soil contamination are so severe that remediation techniques have been studied extensively and many options are now available. The article from Science Daily “Plants, fungi, and bacteria work together to treat polluted land” posted by bjoyce on the Environmental Chemistry ponder blog provides an example of how scientists are coming up with natural remediation processes, namely bioremediation.
The article summarizes research at McGill University and Universite de Montreal. Scientists found complex relationships that exist within the soils between plant roots, fungi, and bacteria can break down toxic molecules that normally would be resistant to natural decomposition. Symbiotic relationships allow ectomycorrhizal fungi to grow around roots of certain plants which in turn providing nutrients to hydrocarbon degrading bacteria. This bioremediation tool, classified as phytoremediation, can potentially be used to clean up oil spills or certain pesticides that have caused soils to become toxic to plant and animal life. Biologists say that this “secondary metabolism” is a coping mechanism to deal with stressful situations.
Other types of remediation techniques include adding agents in soil like limestone to bind contaminants, covering up contaminated areas with clean soil, and phytoextraction which involves plants essentially sucking out all of the contaminates in soil naturally. The benefits of bioremediation are it’s cheap, natural, and unobstructive. However the type of contaminate and the extent of the contamination can factor into choosing the best remediation technique. For bioremediation, conditions need to be optimal for the microbe or plant that is being implemented. Although phytoremediation is new avenue of soil remediation the pressing issue of environmental damage it is important to continue to explore all alternatives.