Using Thlaspi plants to clean zinc-contaminated soil
The amount of zinc removed from soil by the Thlaspi plant will not be significant.
Phytoremediation is the process of using plants to remove contaminants from soil. It is a simple method of treating soil without having to excavate the land and dispose of the soil somewhere else. This method can be applied to both soil and stagnant water in lakes and ponds.
The advantage of using phytoremediation is the lower cost of implementation, compared to excavating the land or pumping out the contaminated water. The plants can also be monitored, and the retrieved metal stored and processed for future use. This method is a natural process and is hence environmentally friendly. The disadvantages are that the process is time-consuming and the effectiveness is limited to the surface area or the length of the roots. Care must also be taken to prevent the plants from entering the food chain.
An example of phytoremediation is the use of the Thlaspi plant to remove zinc from soil. The Thlaspi plant can accumulate up to 1500ppm of cadmium and 30000ppm of zinc in its leaves and shoots, compared to other plants that can tolerate only 50ppm cadmium and 1000ppm zinc.
The Thlaspi plants are a genus of herbs ofwhich grow in temperate regions. There are 5 common varieties, namely:-