New technology at Cawthron traces contamination.

New technology at Cawthron now makes it possible to identify sources of faecal contamination in aquatic environments.

The technology, microbial source tracking, allows scientists to determine whether faecal bacteria in the water is from humans, cows, birds or other species – something that hasn’t been possible with the traditional technique for testing for faecal bacteria.

Cawthron senior scientist, Paul Gillespie, says "the potential for use of this technique is just enormous". It will enable contamination problems to be tackled more effectively, and will be a valuable tool in the monitoring and management of river catchments and coastal environments. Local authorities and users of water resources will be among those to benefit. Development of microbial source tracking at Cawthron was prompted by requests from Golden Bay aquaculture farmers, concerned about harvesting restrictions due to faecal contamination in coastal waters.

Cawthron molecular biologist, Andrew Fidler, says until now the standard technique for testing for faecal contamination in water has been to measure the amount of indicator organisms, such as E.coli, that are present. However, with this technique it is not possible to distinguish which species the E.coli come from.

Microbial source tracking instead focuses on identifying the DNA of source-specific bacteria in the water. "It’s more specific and more sensitive" Dr Fidler says. "It’s a qualitative jump forward".

The technology will be used in conjunction with other water quality analysis tools and is a useful addition to Cawthron’s capabilities.

Use of microbial source tracking is growing worldwide and its establishment at Cawthron was assisted by an American specialist in the field, Dr Jody Harwood, Associate Professor of Biology at the University of South Florida. Dr Harwood, whose travel is funded by a Royal Society of New Zealand grant, visited Cawthron earlier this year and is due to return later this year.

For further information please contact: