Heavy metals are toxic elements that can have a deleterious impact on human health and the environment. These metals accumulate in soils, sediments, and water bodies, leading to contamination and pollution. The traditional methods of cleaning up contaminated sites, such as acid leaching, excavation, and disposal, can be expensive, time-consuming, and often not very effective. Scientists have been experimenting with alternative methods of dealing with heavy metal pollutants. One of these methods is called bioremediation. Bioremediation is the use of microorganisms or plants to remove or degrade pollutants and has emerged as a promising alternative. This method is less expensive, more environmentally friendly, more effective, and does not leave secondary pollutants which makes it a plausible alternative to current methods of heavy metal extraction.

Previously, harsh chemicals or completely excavating contaminated materials caused vast amounts of waste, soil erosion, silty stormwater runoff, site flooding, and polluted soil. In contrast, bioremediation uses microorganisms to clean up the environment without harming it. Bioremediation is already being used as a substitute for harmful chemicals: crime scene cleaners have recently utilized enzyme cleaners, avoiding bleach and ammonia, to eliminate blood and bodily fluids that can pose health risks like hepatitis, HIV, and MRSA. Additionally, bioremediation being used is in oil spills: in 2010, the Deepwater Horizon spilled 3.2 million barrels of oil off the Gulf of Mexico.

There are 2 primary methods for cleaning up oil spills in the ocean: dispersion and burning. The first method, chemical dispersion, is achieved by applying chemicals designed to remove oil from the water surface by breaking the oil into droplets. The second common method is burning. Since oil is flammable, an oil spill can be cleaned up by setting fire to the water and the oil will all be used up as fuel. The water will extinguish the fire and the mess will clean itself up. These systems, however, can have adverse effects on organisms that inhabit the uppermost layers of the water column. In contrast, bioremediation doesn’t introduce harmful chemicals and will not damage wildlife.

To mediate the Deepwater Horizon oil spill, two bioremediation methods were used: bioaugmentation, the injection of a small amount of oil-degrading microbes into an affected area, and biosimulation, the addition of nutrients to stimulate the growth of innate oil-degrading microbes to increase the rate of remediation. Together, these systems cleaned up the oil spill without producing greater harm to the ecosystem.

Microorganisms and plants have the ability to break down or absorb heavy metals and transform them into less toxic forms. Bioremediation can be targeted to specific contaminants and tailored to the unique conditions of each contaminated site, allowing for more efficient cleanup. Bioremediation requires the use of microorganisms, which are selected for their strengths and the conditions in which they thrive. Systems like CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) can also be used to alter the genomes of these microbes to increase their ability to clean up these contaminants. Bioremediation is also more effective at completely removing heavy metals from contaminated soil or water, whereas traditional methods leave residual contaminants behind that may require ongoing treatment. Furthermore, bioremediation does not produce any secondary pollutants that traditional methods produce.

Despite its many advantages, bioremediation also has a significant amount of limitations. The most concerning of them is time. For microorganisms to be prepared for the extraction of heavy metals and for them to accurately destroy the pollutants, it may take an exorbitant amount of time. The effectiveness of bioremediation depends on a variety of factors such as the type and concentration of pollutants, the microbial or plant species used, and the environmental conditions of the contaminated site. Bioremediation can take months or even years to achieve significant results, and there is no guarantee that it will be successful. The Deepwater Horizon oil spill took over 10 years to clean up and it is still not fully recovered. Another limitation of bioremediation is that it cannot be used in all remediation scenarios. There are certain heavy metals that cannot be easily remediated using microorganisms.

Although there are cases to be made against bioremediation as a feasible alternative, it is vital because it allows for a safer and harmless cleanup. Even if it cannot be used in every scenario, more advancements are being made every day so that it is an option for a variety of outcomes. With these developments, bioremediation becomes more streamlined and effective until it is eventually powerful enough to completely replace more harmful methods. Despite its drawbacks, bioremediation is a necessary and valuable tool for the future of environmental cleanup. As we move towards a more environmentally aware future, bioremediation is a promising technology that can help us alleviate the heavy metal pollutants in the natural world.

By Sidharth Nayar

Works Cited

• “What Is Bioremediation? | 3 Real-World Examples of Bioremediation.” Biotrauma, biotrauma.com/resource/bioremediation-examples/#:~:text=Crime%20scene%20cleanup.