Plants fix soil health
By Samuel Kwort, Year 12, Trinity Anglican School
FREEDOM, in many aspects, is regarded with an indescribable uncertainty.
Over a 10-week period I was given the freedom to scientifically investigate any topic of my choosing.
It had to relate to biology and be feasible in the school environment. But how did I choose? In senior biology, one of the three criteria is evaluating biological issues (EBI).
My research led to the use of plants in the treatment of pollution, a field termed phytoremediation.
It is undeniable that humans are exacting massive damage on the environment.
We humans produce vast amounts of waste which pools at landfill sites (colloquially “the dump”).
At these sites, pollutants and harmful chemicals accumulate and seriously debilitate, often destroying, the ecosystem.
One specific group of pollutants, heavy metals, are important micronutrients for plants, but in excessive concentrations adversely affect plant health.
Soils contaminated by heavy metals are dangerous and often remediated through costly, invasive methods.
Phytoremediation is an ecologically sustainable method for combating pollutions.
There are many fields of phytoremediation, but one often used for the treatment of soil contamination is phytoextraction.
This is the use of plants for the extraction of heavy metals from soils.
These specific plants, or hyperaccumulators, can uptake and store large amounts of metal from soils.
My experiment was designed to investigate the phytoextraction capabilities of Indian mustard (Brassica juncea) in the uptake of zinc, for the reclamation and revegetation of closed waste dumps.
It was hypothesised that if Brassica juncea is planted in soil contaminated with phytotoxic levels of zinc (more than 1000mg/kg), then it will absorb zinc until concentration in soil reaches non-toxic levels, that is to less than 100mg/kg.
This was investigated by growing two plants, Indian mustard and pea plant (Piscum sativum) separately and together in zinc contaminated soils.
Plant height was measured and correlated with externally measured zinc soil concentrations, both final and initial.
Numerous difficulties were encountered along the way, such as the time constraints, anomalous growth and synthesis of zinc contamination.
However, these were all overcome to yield the following conclusion: Indian mustard (Brassica juncea) may be used for revegetation of reclaimed waste dumps, but considerations regarding plant competition and environment suitability must be made prior to its use. My hypothesis was partially supported and my aim achieved.
I consider my experiment to have been successful and appreciated the opportunity to investigate and solve major world issues in an empirical fashion.
If I was to repeat the investigation, I would likely conduct field trials, testing different heavy metals, different contaminant concentrations and enhanced metal uptake through inoculation and metal chelating agents. These reports are no small task, taking hours of time and dedication to complete.
But truly, they are freedom, a chance to, metaphorically, straighten a biologically bent world, a chance to do something meaningful.