Sunday, 21 February 2016

The importance of water quality and water treatment for private water supply Louise Ander and Rebecca Close

Rural Cornwall, where many residents use private water supplies
Joint research from the British Geological Survey (BGS) and Public Health England (PHE) has provided new information on the incidence rate of private water supply users using drinking water with high concentrations of some naturally occurring chemicals in Cornwall, UK.

Louise Ander (BGS) and Rebecca Close (PHE) briefly describe this joint study between the two organisations which was designed to fill a gap in knowledge spanning this area of public health and environmental sciences.

Our study has re-emphasised the importance of householders being aware of their tap water chemistry, and treating to improve it where necessary.

Why did we sample in Cornwall?

There are many people in rural Cornwall who use private water supplies, rather than the mains public water supply. When a private water supply is used only for a single domestic household, it is the choice of the householder(s) as to whether they test the quality of water and treat it. This means that, unlike public supplies, there is little systematic understanding of what the chemical quality of drinking/cooking water may be at the tap of householders using private water supplies.

Natural geological properties of the various rocks which are found in Cornwall means there is the potential for high groundwater concentrations of potentially harmful elements, which may be exacerbated in some areas by the impacts of historical ore extraction and smelting.  Thus, this environmental legacy, combined with the large number of single domestic households using private water supplies, meant that  the possible impacts on public health of chemical quality of private water supply in Cornwall were worthy of further investigation.

Where did we sample?

We visited ~500 properties across Cornwall, where householders had volunteered to be part of our study. We collected the small-volume samples required for laboratory analysis and measured properties such as water temperature and acidity (pH) at the tap.  The participants were provided with feedback about their water chemistry, and guidance if concentrations exceeded those in the English water quality standards.

Images from L-R: (a) Measuring pH and conductivity at the tap; (b) householder with an iron-coated old particulate filter from their domestic treatment system; (c) example of part of a domestic treatment system. 
We would like to thank, once again, all the participants in the study. Without their willingness to volunteer for our visit to collect tap water samples and treatment system information, and sometimes groundwater samples as well, we could not have arrived at the new understanding we now have of chemical properties of private water supplies. 

How does this help other private water supply users in Cornwall?

We designed the study with a ‘random’ sampling approach. Use of the word ‘random’ here is in its statistical sense, and means that we can use the results from the participating households to make predictions about outcomes where we didn’t collect and analyse a sample. For instance, if we find that 5% of households exceed a particular chemical water quality standard in our ~500 households, we infer that the overall Cornish exceedance for that chemical at household taps where private water supply from groundwater is used, may be expected to be 5%.

As we specified to the participants, this study only considered 25 chemical parameters for which there are water quality standards. Where UK standards do not exist, we cited World Health Organization, WHO, guideline values. These chemical parameters are not the only quality standards relevant to drinking water, and users should familiarise themselves with their supply’s quality in relation to the wider suite of regulation parameters, including microbiological properties.

What did we find?

We found that 65% of households exceeded one or more chemical drinking water quality standards. Of particular note are those percentage exceedances which relate to health-based chemical quality standards, especially nitrate (11%) and arsenic (5%). The maximum measured arsenic concentration was 440 µg/L, which is considerably above the drinking water quality standard of 10 µg/L. Whilst the national manganese water quality standard is set on aesthetic grounds (e.g. visible particulates in water, unpleasant taste), some of the 12% of tap waters which exceeded that value had a measured concentration which was above the WHO health-based guideline value.

Why is it important for householders to have their water tested?

Arsenic and nitrate (and some other potentially harmful chemicals) are tasteless and colourless in water. This means that you will only find out you have higher concentrations than is desirable if you commission analysis of your tap water.

This is in contrast to chemicals such as iron and manganese, which will typically cause visible sediment to form, or impart a discoloration, odour or taste to water when at high concentrations.

Treatment of domestic tap water

Treatment options suitable for installation in domestic contexts are available, and these will need to be tailored to the specific chemical (or other) quality parameter(s) that require treatment. We do not endorse any specific products, suppliers or fitters – but you may be able to access a list of useful contacts from your local authority (the regulator for private water supplies) if you have a private water supply in the UK.

Our study did show that successful treatment to decrease high concentrations of chemicals such as arsenic, iron and manganese is being achieved in some of the participant households. There were also examples of successful treatment of low pH values, which is beneficial in decreasing corrosion of metal pipes and tanks in domestic plumbing systems.

We would like to take this opportunity to reiterate the importance of treatment system maintenance, in order for the systems to work as they are intended and have the benefit to water quality that is expected. For instance, we found that 31% of the properties which self-reported the use of treatment to correct low pH water, had pH values below the lower water quality threshold value of 6.5 when we sampled them. Very few households reported treatment to decrease nitrate concentrations in tap water, but of those that did 40% were demonstrably not working effectively, and thus were presumably not achieving the outcome expected or assumed by the householders.

What next?

The project outputs will continue as we continue to learn and publish more from the collected data. These activities will include predictions of the numbers of private water supply users in Cornwall using tap water with key chemicals above drinking water quality standards, and spatial variation in groundwater chemistry.

This study was the precursor to the ongoing arsenic biomonitoring study (BGS, PHE and the University of Manchester) which is also in the process of publication – you can read more on the project website.

Further information

The scientific paper has been published open-access, so it is free of charge for anyone to read or download. The reference is:

Ander, E L, Watts, M J, Smedley, P L, Hamilton, E M, Close, R, Crabbe, H, Fletcher, T, Rimell, A, Studden, M, and Leonardi, G. 2016. Variability in the chemistry of private drinking water supplies and the impact of domestic treatment systems on water quality. Environmental Geochemistry and Health, 1-20. DOI: 10.1007/s10653-016-9798-0.

You can learn more about activities and outputs from this survey of private water supplies by looking at our website. This website includes the guidance provided to householders with chemical concentrations above the English private drinking water quality standards. The webpage will be updated as future outputs become available. We also provide external links to some of the governmental private water supply drinking water quality guidance and information which is available for the UK. If you are a Cornish resident, you will find local information on the Cornwall Council webpage.

Friday, 19 February 2016

Fossil Hunters: Unearthing the Mystery of Life on Dave Millward and Tim Kearsey

Today sees the opening of the ‘Fossil Hunters: Unearthing the Mystery of Life on Land’ exhibition at the National Museums Scotland in Edinburgh. This event tells the story of how animals stepped out on to land for the first time about 360 million years ago. It also relates how a team of scientists discovered the evidence from rocks exposed in Scotland!

“One is accustomed these days to hear of sensational new fossil finds being made in other parts of the world. But to learn of a site in this country ..., in geological terms is wonderful and exciting.” Sir David Attenborough

Image by Mark Witton of the environment around 360 million years ago when animals stepped on to land for the first time.  
The free exhibition will be open to the public until 14th August 2016, and is the culmination of four years of scientific investigation into how and why tetrapods – vertebrates with four limbs – made the transition from water to land in early Carboniferous times. Previously, in the Devonian, 370 million years ago, tetrapods were fish-like and lived mostly in water. The next time we see them in the fossil record some 25 million years later, they were adapted fully to live on land. That hiatus in time during which no tetrapod fossils had been found became known as Romer’s Gap, after the celebrated American vertebrate palaeontologist, Alfred Romer. Many people at that time thought the gap was real and there were no fossils to be found.

The search for fossils that might occur during Romer’s Gap was begun by the late Stan Wood, a Scottish fossil hunter and owner of Edinburgh’s Mr Wood’s Fossil Shop, and Dr Tim Smithson of Cambridge University. After more than 20 years, they began to find specimens at two localities in the Scottish Borders. This confirms that Romer’s Gap was simply a gap in fossil collecting and key fossils were waiting to be found right here in Scotland. These finds were the catalyst for the start of the TW:eed Project (Tetrapod World: early evolution and diversification) funded by the Natural Environment Research Council. The team is led by Professor Jenny Clack and includes scientists from the Universities of Cambridge, Leicester, Southampton, the National Museums Scotland and the British Geological Survey.
A reconstruction of 'Ribbo' by Karen Carr.
'Ribbo' is a small tetrapod found within Romer's Gap.

Over the past 4 years hundreds of fossil-bearing rocks have been collected and processed, a 500m-deep borehole drilled and thousands of samples analysed in detail. A river has also been partially dammed to excavate fossil-bearing strata in the bed. During this project the team has found many more new tetrapods species within Romer’s Gap in Scotland to demonstrate that a remarkable diversity of species existed at that time. Most striking of the finds was a tetrapod found by Ben Otto and Ket Smithson, a masters and PhD student respectively at the University of Cambridge. They discovered a very small tetrapod skull and other bones completely encased in the rock using CAT scans.

Along with colleagues from Leicester and Southampton universities, the BGS team has sought to understand the environment in which these tetrapods lived, and how it changed through time. This may help to explain why they came on to land, rather than just how. The tetrapods were living in a world very different from the cold, windswept conditions experienced in northern Britain today. In the early Carboniferous, the UK was 4° south of the equator with a landscape that would have superficially looked like the Florida everglades. However, if you were on a boat trip through the lakes and creeks of the vast coastal plain the landscape would have appeared very alien. There were no grasses and no flowering plants at that time, but instead the ground was covered with bizarre plants like Oxroadia, affectionately called the ‘creeping toilet brush’. We also know that the climate was very seasonal, with contrasting wet and dry periods. Flooding of the coastal landscape was commonplace. It is possible that the wide range of habitats present and the climate pattern may have been factors that allowed tetrapods to adapt to the terrestrial environment and thrive.

The TW:eed project team at the launch of "Fossil Hunters" at the National Museums Scotland. 
The exhibit now at the National Museums Scotland gives everyone the chance to experience a world very different from our own. These earliest terrestrial tetrapods shed light on a crucial event in the evolution of life on Earth. If this had not occurred, we would not be here today.

Wednesday, 10 February 2016

First direct evidence of a deep-water cold-seep ecosystem within UK Heather Stewart

The 'Scotia Seep' Pirates offshore on board the Marine Scotland Science
Vessel M/V Scotia in July 2015 
In 2012 Marine Scotland Science discovered two new species of chemosynthetic bivalve (those that don't rely on sunlight as a source of energy but oxidation of molecules such as methane) and a polychaete (a type of segmented worm) during a biological survey of Rockall Bank located 500km west of Scotland. The discovery of these species suggested for the first time the presence of a deep-sea cold-seep (an area of the sea floor where the seepage of fluids such as hydrogen sulphide and methane occurs) within UK waters. However, the precise location and size of the seep remained unknown as these new species (amounting to a handful of shells) were collected in 1200m of water during a 3 mile long trawl. After two failed attempts to secure funding from Europe to go out and find the seep (“it can’t be done, you’ll never find it”), the BGS along with researchers from Marine Scotland Science, Oceanlab (University of Aberdeen), National Museum of Wales and the Scottish Association for Marine Science went out to Rockall last July with the aim of finding this ‘needle in a haystack’.

Frozen core packed in dry ice
waiting for transport to BGS
The search and discover expedition was a resounding success and the ‘Scotia Seep’ was located within a deep-sea furrow that forms an enclosed depression approximately 10km long and 3km wide in water depths between 1100m and 1200m. The first observational evidence revealed bacterial mats and extensive areas of remobilised sediment that form positive topographic features on the seafloor. Excitingly, evidence of active fluid expulsion at the seabed was also observed, recorded in all its glory in HD.

The surrounding seabed habitats include areas of burrowing animals and anemones in churned-up soft sediment, sponge aggregations on soft sediment and cold-water corals. Several chemosynthetic bivalves (those that feed on chemicals from the sea water) were also recovered and are being identified by collaborators at the National Museum of Wales.

Six megacore samples were recovered from the seep and were frozen offshore to preserve unusual layering observed within the sediment and overlying water. One of those cores was packed in dry ice and transported to BGS for analysis including scanning electron microscopy (SEM) and geochemical analyses.  Some of these analyses have already yielded some interesting results including a marked increase in concentration of base and heavy metals in particular copper, nickel, cobalt, arsenic and perhaps most interestingly uranium within sediments immediately below the sediment/water interface.

These analyses thus far indicate that upwelling, sulphurous and methane-rich fluids are being expelled at seabed on the western flank of Rockall Bank which supports a chemosynthetic community. This cold-seep is the first documented within the UK deep sea and the combination of unusual geochemistry and species suggests that it is quite different from the other cold-seep ecosystems in the north-east Atlantic such as those offshore Norway and Spain.

The exciting and unique results from this cruise are currently being written up for publication.

Photos a-i: a. remobilised sediment, b. bacterial mats, c. active fluid expulsion and soft-sediment remobilisation at seabed, d. burrowing animals and anemones in bioturbated soft sediment, e. sponge aggregations on soft sediment, f. cold water corals, g. gypsum/anhydrite crystals that crystallised following thawing of the core indicating sulphate-rich pore-waters near the sediment/water interface, h. vase-shaped coccosphere (a microscopic marine organism) with more typical round coccosphere on the right, and i. authigenic, magnesium-rich calcium carbonate precipitated on the surface of a foraminifera shell (photos g. to i. seen using a SEM). 
Scientific Team and Acknowledgements

The Offshore Science Party
Francis Neat (Marine Scotland Science (MSS)) led the offshore expedition to find the elusive seep with Alan Jamieson (Oceanlab), Heather Stewart (BGS), Jim Drewery (MSS), Neil Collie (MSS), Mike Stewart (MSS), Mike Robertson (MSS), Graham Oliver (National Museum of Wales), Dave Hughes (Scottish Association for Marine Science (SAMS)), Amy Scott-Murray (Oceanlab), Thom Linley (Oceanlab) and Chris Welch (SAMS).

Post-Cruise Work
Geological interpretation has been undertaken by Thomas Barlow, Aurelie Devez, Lorraine Field, Andrew Marriott, Antony Milodowski and Heather Stewart at the British Geological Survey.

Biological interpretation has been undertaken by Jim Drewery (MSS), Brodie Fischbacher (Oceanlab), Martin Foley (SAMS), Dave Hughes (SAMS), Alan Jamieson (Oceanlab), Bhavani Narayanaswamy (SAMS), Francis Neat (MSS), Graham Oliver (National Museum of Wales), and Matthew Snape (SAMS).

Thanks to the officers and crew of the MRV Scotia. Offshore data acquisition was supported by the Marine Alliance for Technology Scotland Deep-Sea Forum.

Monday, 8 February 2016

Chile: big mines, big data and big Mark Patton

Mark at Rio Blanco 
Following the trip to Alaska in August, the final residential for the 2015 Camborne School of Mines Mining Professional Programme began in Santiago, Chile, only 12 weeks after getting back from the previous one. Thankfully it was to the southern hemisphere, because as I touched down to 25° in Chile it was -25° in Fairbanks.

We spent the first 5 days in Santiago, visiting the Consejo Minero to discuss the current state of mining in Chile, the Sandvik factory to check out some of the machinery workshops and one of the local universities (so the Professor could make a few contacts). All of this interspersed with teaching sessions, presentations and the receipt of details of more presentations to be made during the course of the visit.

Early starts had been a feature of the Alaska trip but the 3am departure to the airport for an internal flight north trumped all of them. Santiago had been dry, but our new location Calama, located in the Atacama region, was more so. It was our base for some incredible mine visits.

First up was the Centinela Mine run by Antofagasta, an open pit copper operation about 40km south of Calama. You couldn’t quite call the equipment shiny, but it was relatively new and the operation was clearly streamlined. Everything was observed from a distance so we had a chance to get a good overview of the full mining process, from the pit, through to the processing mill.

Prepared for the plant at Chuquicamata
The second visit was to the biggest open pit copper mine in the world – Chuquicamata, operated by the Chilean national copper company CODELCO. It’s huge, as are the waste rock mountains that form much of the scenery on the drive in. Where Centinela was new and shiny, Chuquicamata has been on the go for a considerable time and the operation is sprawling. Here we got to see the pit and the processing plant in all its glory and the highlight was watching smelted copper get poured into moulds. It’s surprisingly runny. When cooled these lumps of copper are then used as the anode in the electrical process where the copper is purified to 99.99%.

Our mid residential day out was to the Atacama Desert itself. It was a long drive, mostly up on the way there. Previous experience of high altitude has always involved rugged Alpine style peaks so it was bizarre to find out we were at over 4700m and pretty much surrounded by flat desert. The scenery was spectacular though. Too much running about taking group photographs resulted in a spot of altitude sickness, but thankfully the pounding head and nausea eased on the drive back down to Calama.

The Atacama Desert
As a deviation from looking at big holes (and since we were learning about the whole mining life cycle not just the digging it out bit) we spent a pretty fascinating half day at the Anglo American tailings management facility for the Los Bronces mine. These structures are used to contain the residue left over (the tailings) from the mineral processing. Looking down at the tailings pond with its 80m high dam we were informed that by the time the mine closed, the spot we were standing on would be part of the facility and the dam would be 250m tall. This facility sits approximately 5km across a valley (which is filled with vines) from a similar tailings pond operated by CODELCO. Both of these are just 25km north of Santiago...

We returned to the superlatives theme for the trip with the next visit when we called on the biggest underground copper mine in the world. El Teniente is also operated by CODELCO and also relatively close to Santiago. Despite being close however we managed to be late, and as they thought we weren’t coming, the mine had cancelled the trip. Fortunately no one had gone too far and our guide was re-conjured, a spare bus acquired and we set off underground. But not before we had spent over an hour in the bus getting to the portal.

Underground crusher at El Teniente 
The part of El Teniente we visited is being mined by a process called block caving where underground blocks are undermined and allowed to collapse under its own weight, a method not many of us on the course had been exposed to before. One of the issues that can be encountered with this method, and an occurrence at El Teniente, is hang ups at the draw points. This is where a block of the ore gets stuck at the place where the trucks are supposed to access it for transporting to the crusher. Being underground when they carried out a secondary blast (a smaller explosion used to break up theses stuck blocks) was another first for me. We were just round the corner and I was in the process of rolling the second ear plug when the punch hit my chest at the same time as the boom hit my unprotected ear. Fortunately my vocal reaction was muffled.

The last trip of the residential was to another CODELCO operation, the Andina Copper mine, approximately 70km north east of Santiago. Before the mine itself, we stopped in at the operations control centre at Los Andes to see a cutting edge use of ‘big data’. The deputy director, Herman Aguirre, has set up a system where operations at the Andina mine can be monitored and graphically plotted in real time from any coffee shop in Santiago (or the world for that matter). The data he collects can be used to improve the productivity of the operation and the savings, on a scale that CODELCO operates at, can run to tens of millions of dollars, all using open source software.

Bid data in Andina Mine control room
Herman accompanied us to the mine proper, which was approached from the bottom up for a change (as opposed to arriving at the rim and looking down). We did eventually reach the top and from there, as well as looking down on Andina, we could look over the other side of the mountain to the Los Broncos mine which is also exploiting the Rio Blanco copper deposit. This was the final ‘biggest’ of the trip. The Rio Blanco was described by a CODELCO geologist as a planetary anomaly, it is so big. With two major copper mines working at it at once it would need to be.

The final event of the trip (all part of the assessment for the course) was a debate with the motion: This house believes that Chile will continue to lead global copper production over the next 25 years. Despite an emotional and powerful opening statement by those against, the motion carried, which was hardly surprising given every one in the room believed it to be true.

Chile is a fabulous country with stunning geology, better food that Alaska and airport security that is reminiscent of Europe in the 80s. I fully intend learning Spanish and going back for a more leisurely visit, maybe heading south next time.

Wednesday, 3 February 2016

Mapping Hidden Hunger in Edward Joy and Louise Ander

Edward Joy and Louise Ander describe how recently created maps of Malawi predict spatial variation in the dietary supply of seven essential elements (calcium, copper, iodine, iron, magnesium, selenium and zinc). These maps combine information on soil and crop properties, household dietary choices and socio-economic factors. This information can help to identify key controls on mineral micronutrient dietary deficiencies – also known as “hidden hunger” – and identify research priorities for the development of appropriate and feasible interventions to reduce population-wide hidden hunger.

Life in Malawi
Malawi is a land-locked country in south-east Africa. The majority of households rely on subsistence farming with typical land size ~2 ha. Average Gross National Income is just USD 308 capita-1 compared to USD 42,098 capita-1 in the UK. In this context, the quality of diets is affected by the ability of households to grow sufficient, nutritious food, and to supplement this with purchases. Typically, households devote most of their land to the staple crop maize which is a rational strategy when the primary objective is to satisfy energy requirements. If land and other resources such as labour permit, households may also grow legumes, vegetables, fruits etc. and some grow tobacco as a cash crop.

Hunger, or fear of hunger, is a common concern for most Malawian households. Yet hidden hunger, meaning inadequate vitamin or mineral intakes, is even more widespread. For example, zinc deficiency contributes to a very high stunting rate of 48% of children in rural areas. Food insecurity is one reason why life expectancy at birth is ~55 years, similar to that in the UK 100 years ago. Better data and an improved understanding of diets and nutrition is important to inform health and agriculture policies. We matched food consumption data recorded in a recent national household survey with crop composition data refined by soil type to quantify and map dietary mineral supplies and deficiencies across Malawi.

Images from L-R: Fieldwork in Malawi; Cultivation and weeding are usually done by small-holder farmers using a
hand-held hoe; Locally grown leafy green vegetables being sold at a market in northern Malawi. 
Not only “hidden” hunger…
Most smallholder farmers rely on manual labour and hence have active lifestyles. As part of this study, we show that energy supplies are likely to be inadequate to support active lifestyles in >50% of households. This observation is supported by the finding that as incomes increase, there is no proportional decrease in spending on food. This suggests that those lowest income households are
short of essential food.

Dietary supply of selenium
in micrograms per adult
 male equivalent (AME)
 per day (d).
Seasonal intakes of vegetables cause fluctuation of dietary mineral supply…
Most of Malawi has one long growing (rainy) season from December to April. Subsistence farming results in a change in availability and consumption of pulses, fruits and vegetables (including the leaves of edible ‘weeds’), which are consumed more frequently at the end of the rainy season. This leads to seasonal variation in the dietary supply of essential trace elements.

River and lake fish improve dietary micronutrient supply…
The most commonly-consumed animal product is fish, mainly sourced from Lake Malawi and Lake Chilwa. Fish consumption is greater in households close to the major lakes and this leads to greater consumption of several micronutrients, particularly calcium, selenium and zinc.

Wealthier households have healthier diets, but soil type has the greatest control over selenium supplies…..
Household wealth was negatively associated with risk of deficiency for all nutrients studied. This is due to greater consumption of foods including micronutrient-rich animal-source foods. Previous research has shown that calcareous soils in Malawi result in higher crop selenium concentrations. Here we show that the effect of soil type is more important than household wealth in providing beneficial increases in dietary selenium supply.

What next?
Ensuring food security in Malawi remains a huge challenge but there are possible interventions to improve dietary mineral supplies. Interventions can be successful, e.g. the national salt iodisation programme which is responsible for the majority of the dietary supply of iodine in Malawi (as with many other countries globally). There are crop breeding programmes to increase micronutrient concentrations, particularly for zinc. Selenium could be increased in crops through enriched fertilisers, as shown in experimental trials in Malawi conducted on soils with low inherent selenium availability. Fertiliser fortification is being successfully used as a national approach to increasing dietary selenium supply in Finland.

Images from L-R: Different types of fish provide a good source of micronutrients, here for sale at a market in Malawi;
The clear colour difference betweel bulk soil samples collected over more acidic (red) soils, and calcareous (dark brown to black) vertisols. 
Further information
You can read our open access paper if you would like find out more, including the full set of maps we have generated for Malawi.

This work was one of the outputs of Edward’s PhD, as well as that of the ongoing PhD project of Diriba Kumssa. Dr Edward Joy was supervised by Prof. Martin Broadley, Dr Scott Young, the late Prof. Colin Black (School of Biosciences, University of Nottingham (UoN)), Dr Louise Ander, Dr Michael Watts (British Geological Survey (BGS)) and Dr Allan Chilimba (Ministry of Agriculture and Irrigation, Malawi), with PhD funding from UoN and BGS.

Edward’s PhD research is part of an ongoing programme of research in the Centre for Environmental Geochemistry (Biosciences, UoN and Inorganic Geochemistry, BGS) alongside our fantastic wider network of research partners in Malawi, and beyond.

Our most recent activity is the initiation of the Royal Society – Department for International Development (RS-DFID) Africa Capacity Building project “Strengthening African capacity in soil geochemistry” in Malawi, Zambia and Zimbabwe. We have recently welcomed 5 new PhD students into this 5 year project, two of whom will directly build upon outputs from Edward’s PhD, with plans for more! Edward is now working at the LSHTM.