ESR Water Management Group
Dr Wendy Williamson, Dr Brent Gilpin and Dr Chris Nokes are senior scientists with the Water Management Group at Environmental Science and Research (ESR). Their role is in understanding water quality where it affects people. This includes research into the adverse impacts on the quality of drinking water, recreational water and wastewater, and the measures taken to manage them.
Dr Wendy Williamson
Wendy is a microbial ecologist who is conducting research into the detection and identification of viruses in our drinking and recreational water.
What is Environmental Science and Research?
ESR scientists Wendy Williamson, Chris Nokes and Brent Gilpin are part of the Water Management Group. Here they describe what ESR is and what research the Water Management Group is involved with.
Because viruses may be present in water in very low numbers, they are very hard to detect so are not routinely tested for at present. Unlike bacteria, many of which can be detected by growing in laboratory conditions, viruses will not grow outside a host body.
Detecting viruses in the environment
ESR scientist Dr Wendy Williamson describes how modern molecular polymerase chain reaction (PCR) tools have made it possible to detect viruses in the environment. Previously used methods of detection, such as culture, work well in a medical situation but are unable to detect viruses in the environment. PCR also makes it possible to distinguish between even closely related viruses.
Wendy is working on ways to improve the methods for virus detection and to be able to identify which viruses are present. Her goal is to be able to develop a picture of the present in our waterways and whether these viruses represent a risk to human health. In addition to virus studies, Wendy’s work includes understanding the presence of cyanobacteria and the impacts of their toxins on the health of people and animals through water consumption or contact.
Developing an assay
ESR scientist Dr Wendy Williamson describes the process of developing an assay to detect viruses in the environment. She highlights the importance of checks to make sure that the method is accurate and that it is able to work even with complex samples. Only then can the scientist be confident that it will work on the environmental river samples.
Dr Brent Gilpin
Brent is a water molecular biologist who is developing ways to identify the source of faecal matter in water.
Chemical approaches to detecting poo
ESR scientist Dr Brent Gilpin describes how the presence of chemicals from washing detergents indicate that the water has come from the sewage system and therefore may contain faecal matter. Brent is also able to detect the presence of sterols – these are chemicals that are broken down in our digestive system – to indicate that the water may contain poo.
Traces of faecal matter are occasionally detected in our drinking water, and identifying the source of that pollution is important to ensure appropriate management steps are taken. For example, if the source of faecal pollution is actually from ducks or other wildfowl, replacing sewerage pipes or upgrading sewage treatment systems is unlikely to improve local water quality.
Poo indicators
ESR scientist Dr Brent Gilpin describes how they look for a variety of chemicals and bacteria that indicate the presence of poo in the water rather than the disease-causing organisms themselves. Microorganisms that cause disease are called pathogens and can be present in poo from people who have the disease.
Brent hopes to develop a system by which it is possible to identify the source of contamination by looking at specific bacteria present in the sample. Birds, mammals and humans carry different bacteria as part of their digestive system, so the presence of Rhodococcus coprophilus indicates a herbivore source and Bifidobacterium adolescentis indicates a human origin for the faecal pollution.
Sources of poo
ESR scientist Dr Brent Gilpin discusses the need to identify the origins of any faecal matter in our drinking water, as bacteria and viruses in human poo can make us ill. Brent’s research involves determining a method of identifying species-specific markers in poo so that he can tell if the poo contaminating our water came from ducks, cows or humans.
Brent is using chemical indicators, such as fluorescent whitening agents, which show that the sample may be from humans. Brent is also developing rapid molecular assays for strain typing Campylobacter – a bacterium that is one of the main causes of foodborne disease in many countries.
Whose poo is it?
ESR scientist Dr Brent Gilpin gives an example where he identified the source of pollution and the local council was able to use this information to address the problem. Distinguishing the source of faecal contamination is important in deciding what action to take to prevent further contamination.
Dr Chris Nokes
Chris is a water chemistry scientist presently researching how microorganisms, such as bacteria and viruses, survive in sediments.
Sediment research project
ESR scientist Dr Chris Nokes describes the research he is doing to look at how microorganisms are able to survive in sediment. He inoculated tanks containing different type of sediment with raw sewage and then followed the number of microorganisms present in each tank over the course of eight weeks.
Rain increases the amount of sediment and microorganisms carried by rivers. Under these conditions, the treatment of river water to produce safe drinking water is the most difficult. Chris hopes to be able to determine how risks to the safety of water supplies during rain can be reduced by understanding the factors affecting the number of microorganisms living in the sediment. He is also investigating the impact septic tanks have on ground water quality.
The effect of sediment on water quality
ESR scientist Dr Chris Nokes discusses the effect sediment can have on microorganisms in the water. It is possible that microorganisms survive longer in sediment than they do in water, and when it rains, this sediment is stirred up and the water becomes difficult to treat.
The Water Management Group at ESR have been involved in establishing PulseNet Aotearoa New Zealand, which joins the PulseNet networks in other countries. PulseNet is a real-time monitoring system using pulsed field gel electrophoresis to fingerprint strains of bacteria. This enables rapid identification, tracing and prevention of food and waterborne disease outbreaks. ESR’s work in establishing PulseNet Aotearoa New Zealand was recently recognised by the US Centers for Disease Control (CDC) with an International Recognition Award.
What is PulseNet?
ESR scientist Dr Brent Gilpin is involved with PulseNet – a system of monitoring disease outbreaks in the world. PulseNet uses pulsed field gel electrophoresis to identify individual strains of bacteria, which can help identify the source of the outbreak and can be used to limit the spread of the disease.
Pulsed field gel electrophoresis
ESR Scientist Dr Brent Gilpin explains how pulsed field gel electrophoresis is used to separate very large fragments of DNA. DNA from an organism is digested with an enzyme and run on a gel, which gives a barcode that is unique to that organism. This system is used by the PulseNet organisation to identify common sources of disease outbreaks.
Related content
The article Water quality highlights the importance of the catchment area and how this water is treated.
Activity idea
In the Water issues activity, students investigate the issues surrounding water in their local area and relate this knowledge to water issues in other countries.
Water issues and effects explores water issues in the Waikato region, their effects and alternative possibilities. It includes the image map interactive Land use – impacts on waterways.
Useful links
Information about Pulsenet.
Information about about the Water quality and sanitation services provided by ESR.
