Bioremediation / phytoremediation of soil

Collecting hyperaccumulator samples in Panguna in Papua New Guinea as part of a phytoremediation project. Photo by Pacific Agriculture Alliance.

Across Te Moananui Oceania, the health and biodiversity of soil are increasingly at risk from pollution, agriculture, mining, heavy metal, and chemical contamination (Diarra et al., 2022), as well as coastal erosion. Modern human activities release contaminants and heavy metals into the air, water, and soil. These chemicals adversely affect not only humans but also non-human species that rely on healthy soil. Soil health and biodiversity are critical for food production, nutrition, water quality maintenance, and overall human health. There is an urgent need to find solutions to remediate damaged soil across Te Moananui Oceania for the well-being of both people and the land.

Bioremediation and phytoremediation can be used to address degradation of soil in a long-term, sustainable way. They are regenerative strategies that harness the natural processes of plants to treat soil. Both can act as an alternate method to modern soil treatment and remediation methods (Rhodes, 2013).

Bioremediation uses microorganisms to degrade, detoxify, and/or transform hazardous pollutants into less harmful substances. Naturally occurring, native, or imported soil microbes can break down hazardous substances into less toxic, or non-toxic substances. The process relies on the choice of microbes and organisms, because some are more effective than others. There are several different types of bioremediation (see video).

Phytoremediation of soil is an approach that uses plants to absorb and stabilise nutrients, through the natural absorption processes of the plants. Hyperaccumulator plants are used to extract, accumulate or stabilise heavy metals and pollutants. The process relies on the robust nature of the plants, with strong root systems. There are also several different types of phytoremediation (see image below).

Both bioremediation and phytoremediation are in-situ methods with no need for harmful chemicals or the removal of the soil substrate. Natural chemical and biological processes do take place during bioremediation and phytoremediation, which vary depending on the types of plants and their reaction to the soil and pollutants in it, and to the complex interactions of microbes. 

See also Bioremediation/phytoremediation of water, and Living Machines.

Read More

Name of NbS

 Bioremediation / phytoremediation of soil

Type of NbS

Hybrid living/engineered interventions

Location

  • Urban
  • Peri-ruban
  • Rural
Discussing phytoremediation with Mekamui community. Photo from Pacific Agriculute Alliance

Relationship to Indigenous knowledge

The connection between the peoples of Te Moananui Oceania and the earth and soil is the basis of reciprocal, circular relationships that are the foundation of Indigenous culture and identity in many places. Indigenous communities in Oceania have long understood the importance of healthy soils for maintaining biodiversity, ensuring food security, and supporting overall ecosystem health. Traditional practices often include techniques that contribute to soil remediation, such as agroforestry, crop rotation, and the use of organic compost and natural fertilisers. Soil health is of vital importance.

As it becomes increasingly clear that we are reaching a critical juncture with climate change, valuable lessons can be learnt from Indigenous worldviews. Re-establishing a reciprocal relationship with earth and soil is essential for human survival. This makes caring for it, and repairing it important.

Read More
Climate change benefits
  • Coastal erosion
  • Flooding
  • Increased pests/weeds
  • Loss of food production
  • Reduced soil quality
  • Soil erosion and landslides

Climate change impacts, such as the increased frequency of coastal erosion, landslides, extreme rainfall, and floods, significantly affect soil quality. Bioremediation and phytoremediation are relatively simple, cost-effective, and in-situ strategies for improving soil health. These methods can be integrated with other project goals in revegetation projects, such as biodiversity increase, erosion prevention, and storm surge control.

Bioremediation and phytoremediation enhance soil fertility and structure. This can help mitigate the adverse effects of climate change by restoring contaminated sites and reducing the spread of pollutants during extreme weather events. Phytoremediation contributes to stabilising soil and preventing erosion. 

By integrating these remediation techniques into broader environmental management strategies, we can create multifunctional landscapes that support carbon sequestration, enhance water retention, and promote diverse ecosystems. These practices help build resilience against the impacts of climate change, ensuring that soils remain productive and ecosystems remain robust. Consequently, bioremediation and phytoremediation not only address immediate soil health issues but also contribute to long-term climate change mitigation and adaptation strategies (Diarra et al., 2022).

Read More
Societal / socio-cultural benefits
  • Food security
  • Empowerment/equality
  • Waste management and hygiene

The health and biodiversity of soil are critical for the well-being of communities, particularly those reliant on locally grown food. In parts of Te Moananui Oceania, soil pollution from industrial activities like mining and chemical storage has caused health issues and compromised food production for local people (Rungwa et al., 2013). Bioremediation and phytoremediation offer significant societal benefits by addressing these environmental concerns.

Remediating soil through these nature-based methods allows communities to restore their natural environments, removing harmful chemicals that infiltrate food sources. This directly improves the health of both humans and non-human species. Additionally, these techniques can be implemented on varying scales, providing opportunities for community involvement and education. This fosters a sense of empowerment, enabling local people to actively participate in healing their land. Such engagement not only aids environmental restoration but also strengthens community bonds and promotes sustainable practices, ensuring healthier, more resilient communities. 

Read More
Ecological and biodiversity benefits
  • Disturbance prevention
  • Purification

Bio-remediation involving microorganisms can degrade pollutants like oil or pesticides, contributing to the restoration of habitats and supporting the regeneration of native flora and fauna. Ultimately, these methods foster ecological health and biodiversity by remediating the impacts of pollution and nurturing healthier ecosystems. Phytoremediation may offer a way to clean soil while also increasing biomass cover and habitat provision.

Read More

Technical requirements

Expertise in plant biology, microbiology, and environmental science is necessary for designing, implementing, and overseeing bioremediation and phytoremediation projects, ensuring their efficacy and environmental safety. 

Phytoremediation and bioremediation require constant assessment, monitoring, and understanding of the history, hydrology, biology, and soil composition on-site to design the system correctly. Detailed site studies and testing are necessary to establish the best species and combination of species or microorganism strains to employ. This may often require experimentation.

In bioremediation, how microorganisms react to each other and the pollutants must be considered. For successful phytoremediation, plant species must be carefully selected based on their biomass, growth properties, and capacity for absorbing pollutants without being irrevocably damaged. Some forms of phytoremediation, such as using plants to uptake of radiation, may necessitate the removal of the plant itself to eliminate the pollutant (Dushenkov et al., 1999).

Read More
Polluted soil is connected to all human and non-human lives. Image: UN
Non-contaminated soil and polluted soil. Image from UN
Different ways that plants can process pollutants. Image from Environmental Risk Assessment of Soil Contamination

Issues and Barriers

One significant challenge with bioremediation and phytoremediation is the variability in results, as the success of these methods depends on factors like soil composition, climate, hydrology, terrain, and contaminant type. Limited understanding of the interactions between plants, microorganisms, and pollutants can lead to unpredictable outcomes, necessitating time to develop effective systems.

Education, training, and implementation may present barriers to establishing bioremediation and phytoremediation systems for soil in Te Moananui Oceania. The region has few bioremediation and phytoremediation experts or research projects, hindering progress.

The slow pace of remediation compared to traditional methods, albeit potentially more costly and less effective in the long term, and the need for long-term monitoring and maintenance can pose logistical and financial burdens.

Inadequate public awareness and acceptance, alongside regulatory constraints, may impede the widespread adoption of bioremediation and phytoremediation.

The availability of suitable plant species and microbial strains for different contaminants and environmental conditions in more remote parts of Te Moananui Oceania can also be a limiting factor.

Read More

Opportunities

There is an opportunity to employ bioremediation and phytoremediation of soil on the islands of Te Moananui Oceania, where soil quality affects the lives of local communities.  There is a particular opportunity to use these strategies to reclaim land that has been damaged due to mining in the region. They are an ecologically sound alternative to physical and chemical methods. (Sales Da Silva et al., 2020) and can be integrated with other remediation techniques (Diarra et al., 2022).

Bioremediation and phytoremediation work best on small scales and with constant monitoring. While this may be a barrier in some senses, it is also an opportunity for local communities to be involved in learning, monitoring and growing their nature-based solution to damaged soil.

As Pacific nations face increasing impacts from climate change, food scarcity, and soil degradation, convincing governments and international funding bodies of the benefits of bioremediation and phytoremediation may become easier. Collaboration and funding opportunities with international sources are promising, particularly as these methods represent a developing field of research. 

Organisations like the Pacific Agriculture Alliance (PAA) are already actively promoting research and development in agriculture and biodiversity preservation in the Pacific region including soil remediation. Te Moananui Oceania has the opportunity to contribute to this research and its outcomes by becoming a leader in bioremediation and phytoremediation of soil. This could not only address environmental challenges but also position the region as a pioneer in sustainable land management practices, potentially attracting further support and investment. 

Read More

Financial case

Both bioremediation and phytoremediation are highly cost-effective over the long term and have lower operating costs once established typically. These techniques can enhance land value by restoring contaminated sites to productive use, thereby generating economic returns. Cost savings may also arise from reduced liability associated with environmental contamination.

References
  • Arpa, G., Harakuwe, A., Rungwa, S., & Sakulas, H. (2013). Assessment of Phragmite karka (pitpit) as Possible Phytoremediation Plant Species for Heavy Metal Removal from Mining Environment in PNG. A Case Study on Closed Namie Mine Wau, Morobe Province.
  • Ayilara, M. S., & Babalola, O. O. (2023). Bioremediation of environmental wastes: the role of microorganisms. Frontiers in Agronomy, 5. https://doi.org/10.3389/fagro.2023.1183691
  • Diarra, I., Kotra, K. K., & Prasad, S. (2022). Application of phytoremediation for heavy metal contaminated sites in the South Pacific: Strategies, current challenges and future prospects. Applied Spectroscopy Reviews, 57(6), 490–512. https://doi.org/10.1080/05704928.2021.1904410
  • Dushenkov, S., Mikheev, A., Prokhnevsky, A., Ruchko, M., & Sorochinsky, B. (1999). Phytoremediation of radiocesium-contaminated soil in the vicinity of Chernobyl, Ukraine. Environmental Science & Technology, 33(3), 469-475.
  • Patel, A. K., Singhania, R. R., Albarico, F. P. J. B., Pandey, A., Chen, C.-W., & Dong, C.-D. (2022). Organic wastes bioremediation and its changing prospects. Science of The Total Environment, 824, 153889. https://doi.org/10.1016/j.scitotenv.2022.153889
  • Rhodes, C. J. (2013). Applications of bioremediation and phytoremediation. Science progress, 96(4), 417-427.
  • Rungwa, S., Arpa, G., Sakulas, H., Harakuwe, A., & Timi, D. (2013). Phytoremediation: An eco-friendly and sustainable method of heavy metal removal from closed mine environments in Papua New Guinea. Procedia Earth and Planetary Science, 6, 269-277.
  • Sales Da Silva, I. G., Gomes De Almeida, F. C., Padilha Da Rocha E Silva, N. M., Casazza, A. A., Converti, A., & Asfora Sarubbo, L. (2020). Soil Bioremediation: Overview of Technologies and Trends. Energies, 13(18), 4664. https://doi.org/10.3390/en13184664
  • Tang, C.-S., Sun, W. H., Toma, M., Robert, F. M., & Jones, R. K. (2004). Evaluation of Agriculture-Based Phytoremediation in Pacific Island Ecosystems Using Trisector Planters. International Journal of Phytoremediation, 6(1), 17–33. https://doi.org/10.1080/16226510490439963

Further resources