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Dr Narottam Saha

Research Fellow

Centre for Mined Land Rehabilitation
Sustainable Minerals Institute
n.saha@uq.edu.au
+61 7 334 64414

Overview

Dr Narottam Saha is specialized in the area of environmental analytical chemistry and geochemistry, with Bachelors and Masters Degrees in Applied Chemistry and Chemical Technology, a second Masters Degree (Distinction) in Environmental Sciences ( University of East Anglia, UEA, UK), and PhD in geochemistry (The University of Queensland). In his Masters study, Saha received a commonwealth scholarship, one of the most prestigious international scholarship schemes, for Master Degree in Environmental Sciences, with special emphasis on Clumped Isotope geochemistry and climate science. In 2014, Saha received Australia’s federal government scholarship (IPRS) for undertaking his PhD degree. Saha’s research achievements were well recognised with awards of Stanley Gray Fellowship from Institute of Marine Engineering, Science & Technology (IMarEST, UK) for coral reef research and National Science and Information & Communication Technology (NSICT) Fellowship (2010) from Government of Bangladesh for heavy metal pollution research.

His multidisciplinary research experiences include biogeochemistry of heavy metals, assessment of carcinogenic and non-carcinogenic risks for the population exposed to heavy metals, clumped isotopes geochemistry in recovering palaeo-climate history and developing trace element proxies in coral carbonate skeleton to trace historical gradients of inshore coastal water quality. His PhD research highlights the potential of self-referencing rare earth elements over traditional trace elemental proxies for reconstructing marine water quality, degradation of which is considered as one of the major threats in declining the Great Barrier Reef (GBR) coral community. He has been the first to have discovered a noble V/Ca proxy, which is decoupled from other commonly used runoff proxies, for monitoring historical catchment clearing and firing in coastal areas. His discovery has direct relevance to environmental protection for reefs in the GBR through promoting better land management with improved water quality.

Research Interests

  • Ecological engineering of tailings
    My research interest is in understanding the biogeochemistry of trace elements and their cycling in the environment, with projects addressing key research questions related to ecological engineering of tailings into functional soil for sustainable rehabilitation of mined land.
  • Development of chemical technologies to prevent secondary pollution from sulphidic waste rock dumps
    This Research aims to develop a cost-effective and field-feasible engineering solution to treat the acid-generating waste rock dumps in situ. This will be achieved by passivating and encapsulating reactive minerals and forming hardpan structures to create a barrier to stop air entry and hydraulic flow to attenuate oxidation reactions.
  • organic-inorganic complexation of metal(loid)s
    Physicochemical speciation and organic-inorganic complexation of metal(loid)s and rare earth elements (REE) to understand their fate and transport in the continuum of contaminated soil/tailings-water-vegetation, which is critical for understanding risks of mine wastes (e.g., tailings, wastewater) and designing effective intervention for alleviating the risks.
  • Metal stable isotope geochemistry
    Investigation of sensitive shifts in the relative abundance of metal stable isotopes tracing sources and elucidating processes of their migration pathways from mine tailing and soil to plants to natural waterways and eventually into the oceans.
  • Bio-imaging of metal(loid)s
    Bio-imaging to understand compartmentalization of metal(loid)s and REEs in plant tissues/organs, their uptake mechanism and translocation pathways.
  • Heavy metal pollution
    Metal(loid) contamination in food chain and aquatic ecosystems, and assessment of associated human and ecological risks.
  • Coral reef research
    Understanding the dynamics of trace metal geochemistry in coral skeleton and proxy based reconstruction to infer long-term anthropogenic forcing on coral reefs.

Research Impacts

  • Research Theme 1: In-situ ecological engineering of mine wastes into the functional substrate

The sustainable rehabilitation of alkaline and saline bauxite residue through the ecological engineering approach has a profound impact on managing a huge amount of accumulated bauxite residue in Australia and around the globe (~ 4.6 billion tons). Our cost-effective technology for bauxite residue to functional soil formation by combining multiple interconnected phases such as weathering and bio-neutralization, hydrogeochemical stabilization, and development of physical structures has already proven a significant way forward in bauxite residue management.

Environmental and social benefits - The mobilization of toxic trace elements through seepage and runoff generated from bauxite residue has significant consequences on terrestrial and aquatic ecosystems and groundwater contamination. The dispersion of the fine tailing particles containing toxic elements to the surrounding environment via wind may also affect the environmental quality and human health. The ecological engineering approach of bauxite residue would significantly reduce the environmental pollution risks and transform the hostile tailing environment to soil-like growth media to ensure sustainable colonization of diverse plant species. Rehabilitation of the tailing dam to a new landform through ecological engineering approach may allow different land uses such as grazing, recreational playing field, etc.

Economic benefits – Using the conventional cover system to cap the tailings is associated with a huge financial cost (c.a. several hundreds of thousands of dollars per hector) and acquiring a large volume of topsoil required for the cover system is not feasible and economically viable for rehabilitation of remote mine sites. Our soil-less eco-engineering technology is cost-effective.

  • Research Theme 2: Development of chemical technologies to prevent secondary pollution from sulphidic waste rock dumps

This ongoing research aims to develop a cost-effective and field-feasible engineering solution to treat the acid-generating waste rock dumps in situ by purposely formulated chemicals. This technology would minimize and prevent the AMD generation potential of sulphidic waste rock by passivation, encapsulation, and by forming a hardpan structure to create a barrier to stop air entry and hydraulic flow to retard oxidation reaction.

Environmental benefits – This Research aids both physical and geochemical stabilization of reactive materials and mitigates the toxic element pollution to the surrounding environment and allows a sustainable ecological/environmental performance in post-mining land use. The outcomes of the research through a detailed understanding of microstructure and mineralogy would pave the way forward for the rehabilitation of mine wastes in a much improved and sustainable way.

Economic benefits – The conventional soil cover and revegetation approach is not cost-effective and remains far from matching the environmental criteria of non-pollution for final closure. The large volumes of waste rock dumps (WRD) make it highly expensive to adopt the strategy of relocation and backfill in a deep pit, which warrants investigating a cost-effective alternative option. The surface passivation and hardpan formation technology will tackle those difficulties in a cost-effective manner.

Qualifications

  • Doctor of Philosophy, Qld

Publications

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Grants

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Supervision

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Publications

Book Chapter

Journal Article

Other Outputs

Grants (Administered at UQ)

PhD and MPhil Supervision

Current Supervision

  • The bioavailability and uptake of aluminium, arsenic and vanadium by halophytes in bauxite residue technosols along the gradient of soil formation

    Doctor Philosophy — Associate Advisor

    Other advisors:

  • Biogeochemical processes modifying surface mineralogical structure and stability of environmental hardpan

    Doctor Philosophy — Associate Advisor

    Other advisors:

Completed Supervision

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ORCID: 0000-0002-5457-438X

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