Bioremediation is not just a scientific endeavour; it's a call to action to reclaim Nepal's rivers, restore its soil and safeguard its air. By embracing this green technology, we can build a sustainable future for generations to come
The Bagmati River, once a symbol of purity and spirituality, now symbolises severe ecosystem degradation. Once pristine and potable, the holy river is now heavily polluted due to accumulated waste, reflecting significant ecological degradation and ecocide. The ongoing pollution crisis, driven by improper waste management and unchecked industrial discharge, extends beyond the river, affecting the surrounding soil, air and food chains. To address these interconnected issues, bioremediation-a promising, eco-friendly solution-has the potential to restore ecological balance and mitigate contamination.
Nepal is facing escalating environmental damage due to rapid urbanisation and industrialisation, exacerbated by improper and irrational waste management practices. The country's primary landfills, including Sisdol, Banchare Danda and Karaute Danda, are reaching their limits, posing critical public health risks to the surrounding communities. Parallelly, many urban water bodies and rivers are experiencing severe contamination, further reflecting a deepening environmental health crisis. Conventional physical and chemical pollution treatments, though effective, are expensive and pose secondary pollution risks. Bioremediation, by contrast, offers a cost-effective and eco-friendly solution, utilising natural processes to neutralise pollutants.
Bioremediation leverages organisms-bacteria, fungi, microalgae and plants-to degrade, detoxify or transform pollutants into harmless byproducts. It's effective in managing diverse contaminants, including agrochemicals, greenhouse gases, heavy metals, plastics and sewage, across varied ecosystems. While composting, a common bioremediation technique for breaking down organic waste has limitations in handling all pollutants. Advanced techniques like phytoremediation, cyanoremediation and bioaugmentation manage a broader spectrum of pollutants, restoring natural resources without additional harm.
Microorganisms are integral to bioremediation due to their remarkable adaptability to metabolise a diverse array of pollutants. Notable examples include Fusarium, Streptomyces, Bradyrhizobium, Pseudomonas putida, Deinococcus radiodurans, Bacillus, Alteromonas, Aspergillus and Rhizopus, which have been employed to remediate contamination from heavy metals, pesticides and hydrocarbons. Plants like Helianthus populous, Azolla, Salvinia, Hydrilla are utilised to bioaccumulate certain metals and recover post-remediation through phytomining. Sunflower plants remediate toxic metals – arsenic, chromium and lead in soil sediment sludge via phytostabilisation. Bioremediation offers multiple benefits by reducing ecosystem disruption and enhancing ecological balance. It's also more cost-effective than conventional treatments, positioning it as a particularly viable solution for resource-limited countries like Nepal.
Bioremediation has proven effective globally, such as in Japan post-2011 Tsunami disaster, where collective microorganisms were employed to reduce soil salinity and heavy metals, and in Iraq, where local petroleum-degrading microbes were used to tackle the environmental damage from oil spills. In India, the National Mission for Clean Ganga launched a bacterial bioremediation initiative to restore the Ganga River in 2017. In Pakistan, researchers assessed metal contamination along the Lahore-Okara-Faisalabad busy road and explored the phytoremediation potential of roadside plants to absorb pollutants.
Nepal thus needs bioremediation to manage its increasing waste generation. In 2006, Shrestha & team explored in-situ bioremediation feasibility of atrazine-contaminated aquifers using Pseudomonas, while Kathmandu University Biotechnology team in its 2012 study isolated arsenic-resistant microbes from Nawalparasi groundwater. Research on phytoremediation using local plants to remove heavy metals and isolating plastic-degrading soil bacteria Pseudomonas has shown promise, although limited to a laboratory setting.
Nepal's path to achieving SDG6-ensuring clean water, sanitation and hygiene, hinges on scaling up bioremediation efforts. This requires urgent resource allocation, improved governance and enhanced technical capabilities to translate research into practical solutions.
Bioremediation presents significant economic opportunities for Nepal. Bioremediation could benefit hospitals and waste-generating facilities, create new economic prospects and retain skilled workers by boosting the local economy. Nepal's energy, water, health and environmental sectors, alongside private entities – Nepal Bioscience Research, Biocomp Nepal and other start-ups – must lead in promoting bioremediation adoption as a sustainable green solution for pollution/healthcare waste.
Nepal is at a crucial juncture in addressing its pollution crisis, with bioremediation presenting a promising green solution that safeguards biodiversity. Successful implementation necessitates strong commitment from the government, private sector and research institutions, along with increased funding, skill development and resource allocation. Effective bioremediation will require multistakeholder collaboration among biologists, environmental scientists and engineers to tackle this environmental challenges.
Bioremediation is not just a scientific endeavour; it's a call to action to reclaim Nepal's rivers, restore its soil and safeguard its air. By embracing this green technology, we can build a sustainable future for generations to come-one where its ecosystems thrive, and its natural resources are preserved. The time to act is now, before Nepal's rich biodiversity and cultural heritage are irreversibly damaged.
The authors are Nepal-based researchers in the field
