Phytoregeneration

Over the past week, I have been researching into phytoregeneration as part of my graduation architecture studio. Phytoregeneration is the process of using plants and other flora to repair and heal the landscape, and has been used to varying degrees of success all over the world. 

In particular, I was looking at how it might be used to remove heavy metals, polychlorinated biphenyls, asbestos, and lead-based paints from the soil on an old industrial site. A key method of phytoregeneration is through the use of reed-beds, of varying plant species. Success of these reed beds varies, depending on the type of contamination in the soil. When treating contamination of heavy metals, such as lead, reed beds were highly effective. One study concluded that a large reed bed was capable of filtering out 10mg of lead per litre of water over a 7 day period. In higher concentrations of lead, between 30mg and 50mg, this took longer, up to 14 days. However, this still represents a great success, and an environmentally friendly way of healing the landscape, while also providing a degree of green amenity to the public. In treating PCBs, reed beds were moderately successful, but studies noted that high chlorine concentrations in the soil prevented the PCBs from being absorbed by the reeds. Unfortunately, the reed beds were not very successful in treating asbestos contaminated soils, and failed to remove any significant amount from the soil. However, it should be noted that the reeds would help to seal the soil, and protect top soil to prevent aesbestos from becoming airbourne. Thus, reed beds could be considered as a more sustainable alternative to removing and treating asbestos contaminated top soil. 

In conclusion, phytoregeneration and the success of reed beds in treating soil contamination for industrial sites provides some fascinating possibilities, and could help a great number of old industrial locations be made habitable. Not only do these reed beds help in cleaning the soil and decreasing the risk to inhabitants, but they also create public greenspace, contributing to public parkland and native reserves.