Environmental Science Leader, Liping Pang and her research team have been awarded a 2016 Smart Ideas Fund from MBIE’s Endeavour Investment round totalling $900,000 over three years. ESR’s successful fund application proposes to develop 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.

Traditionally dye and salts have been used for water tracing purposes but they are mostly used one site at a time, which is time consuming, and, at high concentration, they can be toxic to aquatic organisms. The novel idea proposed by the team at ESR is to use multiple synthetic double-stranded DNA tracers, each with a unique identifier, to concurrently track different contamination sources and pathways.

Synthetic DNA is environmentally safe as it is not derived from the genome of any organism and doesn’t have genetic functionality. As DNA is extremely sensitive for detection, only a trace amount is needed. A preliminary study carried out by ESR has shown that for the same water tracing effect, the quantity needed for a DNA tracer is 6-8 orders of magnitude less than those required for dye and salt tracers (figure below). DNA tracers can be repetitively amplified using the polymerase chain reaction (PCR) and the analysis of DNA samples using PCR or quantitative PC is rapid. 

The research will develop two classes of new double-stranded DNA tracers for pollution tracking: encapsulated DNA within food-grade gels for use in wastewater and surface waters, and naked DNA for use in soils and groundwater. The hypotheses are: (1) encapsulated DNA tracers are better protected from environmental stresses (e.g., microbial activity, UV radiation, temperature and chemicals), which exist in wastewater and polluted surface-water; and (2) naked DNA tracers will be transported better into the porous media of aquifers and soils due to their smaller size.

The research project partners ESR with the University of Canterbury and the University of Calgary. Field experiments will be conducted in collaboration with Environment Canterbury (ECan), the CAREX group and Waikato Regional Council. This project will recruit a PhD student who will be based at ESR Christchurch Science Centre.

The first phase is to develop the tracers while the second phase intends to conduct rigorous laboratory and field testing to ensure the developed tracers and applied methods provide a robust system for tracking water contamination.

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.

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