Genetic and molecular basis of organic-arsenic-microbe interactions in arsenic prone aquifers (GOAM)

Lead Research Organisation: University of Manchester
Department Name: Earth Atmospheric and Env Sciences

Abstract

Contamination of groundwater from naturally occurring arsenic (As) in the subsurface poses a global public health crisis in countries including Mexico, China, Hungary, Argentina, Chile, Cambodia, India (West Bengal), and Bangladesh and has been termed "the largest mass poisoning" in human history. The mechanism of arsenic release from these sediments has been a topic of intense international debate. However, microbially-mediated reduction of assemblages comprising arsenic (most likely as arsenate) sorbed to ferric oxyhydroxides has gained consensus as the most likely method of mobilization of arsenic into these groundwaters, although the precise mechanism of release remains to be identified. Critical questions that remain include (i) the identity of the organisms that catalyse the process; (ii) the physiological mechanism that leads to electron transfer to the extracellular Fe/As mineralogical assemblage; (iii) the nature (and delivery route) of the organic material that activates metal reduction and release; and (iv) the interplay between other competing processes such as oxidation, sulfidation and sorption that can attenuate the process in situ. By focusing the combination of cutting edge microbiological, high throughput molecular ecology (meta-omics), geochemical and mineralogical techniques against samples obtained directly from two contrasting field sites with high arsenic groundwaters, GOAM is a hypothesis driven research programme that aims to identify the critical molecular scale factors causing this environmental disaster, while informing strategies to minimise their impact. A mature network of international collaborations will underpin our field related activities, transfer of molecular scale data to inform hydrogeochemical models and subsequent knowledge exchange with key stakeholders in countries including Bangladesh and Cambodia.

Planned Impact

The research outcomes will be of interest to academic beneficiaries (as noted above) and also, groundwater resource stakeholders (Government and non-government organisations who have responsibilities, authority and/or interests in protecting public health in the regions impacted) and the wider general public, including those in regions impacted by groundwater arsenic, whom we have a particular responsibility to reach out to.

We will use a range of activities tailored to best effectively impact the different major target groups. For example academic researchers will benefit from high profile of this work will be maintained by publications in high quality peer-reviewed journals, presentations at (inter)national scientific meetings and publishing our results on the University of Manchester and, as appropriate, our project partners websites. If possible, the samples of drill-core and/or well waters will be made available to other suitable collaborating scientists with access to complementary techniques and/or research questions. We will also archive our data following standards for the storage and retention of data set by the University of Manchester Code of Good Research Conduct and make sure that data can be widely and transparently accessed. As appropriate, we will provide copies of our data to a NERC or other institute site.

We will email/write to groundwater resource stakeholders, particularly in Cambodia, Bangladesh and elsewhere in circum-Himalayan Asia, with lay summaries of our key findings. We will also make further personal contacts with key government and non-government organisation officers to highlight key relevant findings and through a short workshop in Cambodia and/or Bangladesh in the final year of the project. To achieve this, networking links and collaborations established through the recently completed NERC NE/J023833/1 project in Cambodia, as well as the AquaTRAIN MRTN (pan European), EU Asia-Link CALIBRE (South-East Asia) and UKIERI PRAMA (India) networks will be used (all led from Manchester), in addition to the mature networks into Bangladesh developed by our colleagues in Columbia.

A website will also be established with content specifically targeted at non-science readers in arsenic impacted regions & in the UK. The key components will be to give a description of our approach, the methods used and the results obtained in a user-friendly and accessible way. All educational material as a result of other activities, such as the workshop, our UK outreach programme and the video (see below), will be made freely available through this website.
We will also produce press releases describing key research results will be communicated in lay terms through press releases via the University Press Office (after, as appropriate, liaising with the NERC press office) and through other media, including TV and radio. The PDRA/PI/Co-Is will participate in a number of public events, including the Science Showcase week at University of Manchester (one of the most extensive outreach programmes of any UK university), lecturing (through a programme open to all ages) at The Manchester Museum and/or assisting in running workshops on public engagement in Science.

Finally we deliver targeted outreach programmes in Cambodia, in collaboration with our local university partner RUPP and other local partners, building upon knowledge exchange activities already undertaken as part of NE/J023833/1 (including an international workshop in Phnom Penh which drew participants from local, provincial, national and international levels, as well as a short-course on environmental training for local university students) and activities already undertaken as part of the EU Asia-Link CALIBRE Project. We will also participate in parallel activities in Bangladesh organised by our US collaborators.
 
Description An initial study has been published with Colombia University, using next generation sequencing alongside geochemical and mineralogical analyses to identify new organisms associated with arsenic mobilisation in Bangladeshi sediments. A full metagenomic analysis of the microbial communities in these samples has been completed and is being written up. Similar work is also being pursued with collaborators in CUG Beijing on Mongolian, and we have recently published together on the first study implicating ammonium as an electron donor for Fe(III)/As(V) reduction/release. Further metagenomic work is ongoing with the Beijing team also.
This grant has also been key in developing a collaboration with Colombia University studying the potential for the biological release of arsenic into groundwaters using methane as the electron donor; preliminary data support this hypothesis. The manuscript describing these findings is also being prepared.
This grant helped build collaboration with the Royal University of Phnom Penh, Cambodia, which is expected to produce two high impact publications.
One of the main outcomes from this grant is that it enabled, for the first time, the deployment of GasClam units to measure gas release in relation to arsenic release into the groundwater.
Finally we have just published on novel microbial bait techniques, again from this grant, which have been used to recover metal-reducing bacteria from aquifers. These tools are now being applied in Cambodia.
Exploitation Route The projects that were funded by this grant are ongoing and the results are still being collected and analysed, however, both academic researchers and groundwater resource stakeholders are expected to benefit from the outcomes of these projects. These projects utilise cutting edge techniques including high-throughput metagenome sequencing and long-term in situ water and gas analysis that researchers can apply in their respective fields. These findings will also help inform predictions of high arsenic areas and help researchers and stakeholders model appropriate pathways for public health protection.
Sectors Agriculture, Food and Drink,Environment,Healthcare