Environmental Science Leader, Liping Pang and her research team have?developed a new environmentally safe tool for simultaneously tracking multiple water contamination source locations and pathways in order to equip end users with faster and more efficient response to water contamination investigations.
The team have been awarded a 2016 Smart Ideas Fund from MBIE’s Endeavour Investment round totalling $900,000 over three years.
With this new tool, tracking the sources of freshwater contamination will soon be a lot quicker and more accurate with the completion of successful field trials of a new DNA-based tracer technology. The most important thing is that the new tracers are biodegradable and non-toxic, so they can be used in ecologically sensitive freshwater environments.
Current contamination tracking uses fluorescent dyes and salts. They are limited to one location at a time and can have an adverse impact on aquatic organisms if applied at high concentrations.
DNA tracer technology offers a rapid and efficient means of tracking multiple potential contamination sources and pathways. The technology enables those in charge of water resources to identify which of multiple potential sites are responsible for the contamination, and mount a quick response to any event that may be having an impact on water quality.
The tiny DNA tracers are chemically synthesised in a laboratory. These synthetic DNA sequences are environmentally safe as they are not derived from the genomes of any organism and have no genetic function.
As a result of the research a suite of 20 different DNA tracer sequences is now available, each with a unique identifier. These are either free DNA molecules or encapsulated within microparticles of naturally occurring biopolymers.
Pang says the tracers will allow scientists to track multiple pollution sources and pathways without posing risk to sensitive environments and can be used to track water contamination by a wide range of contaminants.
The microencapsulated tracers are protected from environmental factors such as UV and chemicals. They are designed to be used in surface water and wastewater. “Free” DNA tracers can be used in porous soils and aquifers.
In a contamination event, the tracers could be applied to suspected contamination source and will be carried along with the water body, eventually reaching a receiving water.
Water samples are collected downstream and analysed for their DNA concentrations using extremely sensitive quantitative polymerase chain reaction technique (qPCR). Since the individual tracers have unique identifiers, like fingerprints, analysis can be linked back to an application site.
Pang says validation trials have taken place in groundwater systems in Canterbury and Waikato, and in a stream and soil lysimeters in Canterbury.
Because DNA is extremely sensitive to detection, the quantities of DNA tracers required were more than a million times less than that dyes and salts traditionally used.
Both the free and microencapsulated DNA tracers were able to be detected and identified in field conditions at distances of at least one kilometre in surface water.
The tech promises much better tools to investigate water contamination events like the one that struck the Havelock North, says Dr Liping Pang of ESR
If proven successful, the tracers could have further application in New Zealand where tracking of materials or ingredients is important e.g. food security, protection of high-value goods, forensic, hospital, ecological and environmental investigations.