Promising new groundwater pollution sensor – New UPGro paper published

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Field test set-up and data output from the MFC biosensor monitoring. A) The diagram shows an aerial view of the system configuration and distance between sensing system and data collection system. B) MFC1 and MFC2 were biosensors placed on the well; MFC3 and MFC4 were control biosensors placed in a vessel simulating the groundwater well. MFC3 and MFC4 were located in a room close to the well and the arrow indicates when they were intentionally contaminated. Monitoring of the sensors contained in the well lasted for 60 days obtaining the same trend as for the period shown.

Shallow groundwater wells, are the main source of drinking water in many rural and peri-urban communities.

The quantity and variety of shallow wells located in such communities make them more readily accessible than private or government operated deep boreholes, but shallow wells are more susceptible to faecal contamination, which is often due to leaching pit latrines.

For this reason, online monitoring of water quality in shallow wells, in terms of faecal pollution, could dramatically improve understanding of acute health risks in unplanned peri-urban settlements.

More broadly, inexpensive online faecal pollution risk monitoring is also highly relevant in the context of managed aquifer recharge via the infiltration of either stormwater or treated wastewater into the subsurface for aquifer storage and recovery.

 To tackle this challenge, IN-GROUND – an UPGro Catalyst Project – trialled four different types of Microbial Fuel Cell (MFC) water quality biosensor in the lab (Newcastle University, UK) and in the field (Dar Es Salaam, Tanzania).  

While further work is needed, the results provided proof-of-concept that these biosensors can provide continuous groundwater quality monitoring at low cost and without need for additional chemicals or external power input.

 Full details of the work can be founded in this open access paper: Velasquez-Orta SB, Werner D, Varia J, Mgana S. Microbial fuel cells for inexpensive continuous in-situ monitoring of groundwater quality. Water Research 2017, 117, 9-17. 

 For more details contact Dr Sharon Velasquez-Orta 

Fossil groundwater vulnerable to modern contamination

Study shows that over half of global groundwater is over 12,000 years old

Most of the groundwater in the world that is accessible by deep wells is fossil groundwater, stored beneath the earth’s surface for more than 12,000 years, and that ancient water is not immune to modern contamination, as has been widely assumed.

This study, led by Dr. Scott Jasechko (University of Calgary) and co-authored by an international team of researchers including Professor Richard Taylor (UCL Geography & UPGro GroFutures), is published online today (April 25) in Nature Geoscience.

Groundwater is the water stored beneath the earth’s surface in soil pore spaces and within the fractures of rock formations. It provides drinking and irrigation water for billions of people around the world.

Jasechko, Taylor and his co-researchers dated groundwater from over 6,000 wells around the globe. By measuring the amount of radioactive carbon in the water, the team was able to determine the age of the groundwater. They discovered that the majority of the earth’s groundwater is likely fossil groundwater, derived from rain and snow that fell more than 12,000 years ago. The team determined that this fossil groundwater accounts for between 42 to 85 per cent of total fresh, unfrozen water in the upper kilometre of the earth’s crust.

Until now, the scientific community has generally believed that fossil groundwater is safe from modern contamination but this study has proved otherwise.

“Deep wells mostly pump fossil groundwater but many still contain some recent rain and snow melt, which is vulnerable to modern contamination,” says Jasechko.

Rain and snow that fell after the 1950s contains tritium, a radioactive isotope that was spread around the globe as a result of thermonuclear bomb testing. Disturbingly, traces of tritium were found in deep well waters, which indicates that contemporary rain and snow melt can mix with deep fossil groundwater and, in turn, potentially contaminate this ancient water.

According to Taylor, this discovery has important ramifications that should influence the way humans use groundwater in the future,

“Our results reveal not only current use of fossil groundwater but also the potential risks to water quality associated with the use of deep wells. Indeed, we need to better understand how the construction and pumping of deep wells themselves may connect fossil groundwater to the present-day water cycle.”

With no access to piped water, residents of Accra meet their own water needs. Here’s how.

re-blogged from SIWI: http://www.siwi.org/news/siwi-explores-complexities-of-groundwater-governance-in-peri-urban-accra-ghana/

Low accountability and complex governance landscape complicate understanding of reliance on groundwater in peri-urban Accra, Ghana, finds article by SIWI’s Dr. Jenny Grönwall.

Poor urban dwellers tend to be disadvantaged in terms of public service delivery, often relying instead on groundwater through self-supply, but their specific needs and opportunities—and own level of responsibility—are seldom on the agenda. The Greater Accra Region of Ghana and the country as a whole serve to illustrate many interconnected aspects of urbanization, inadequate service provision, peri-urban dwellers’ conditions, private actors’ involvement and user preferences for packaged water.

Based on interviews and a household survey covering 300 respondents, this case study aims to provide insights into the water-related practices and preferences of residents in the peri-urban, largely unplanned township of Dodowa on the Accra Plains in Ghana and to discuss implications of low accountability and a complex governance landscape on the understanding of reliance on groundwater.

Self-sufficient from wells and boreholes until a distribution network expansion, Dodowa residents today take a “combinator approach” to access water from different sources. The findings suggest that piped water supplies just over half the population, while the District Assembly and individuals add ever-more groundwater abstraction points. Sachet water completes the picture of a low-income area that is comparatively well off in terms of water access. However, with parallel bodies tasked with water provisioning and governance, the reliance on wells and boreholes among poor (peri-) urban users has for long been lost in aggregate statistics, making those accountable unresponsive to strategic planning requirements for groundwater as a resource, and to those using it.

Dr. Jenny Grönwall, Programme Manager, SIWI, forms part of the T-GroUP consortium led by UNESCO-IHE and funded by the research programme Unlocking the potential of groundwater for the poor in Sub-Saharan Africa (UPGro). The project focuses on parts of Kampala (Uganda), Arusha (Tanzania), and Accra (Ghana) as examples of growing mixed urban areas in Sub-Saharan Africa, including poor people in slums, who depend on groundwater.

Self-supply and accountability: to govern or not to govern groundwater for the (peri-) urban poor in Accra, Ghana. Available with Open Access from Environmental Earth Sciences, 75(16), 1-10.