Quebec researchers have developed an approach to more easily and quickly identify a potential source of faecal contamination in water using genetic indicators.
Posted at 2:27 p.m.
Professor at the Armand-Frappier Health Biotechnology Center of the National Institute for Scientific Research (INRS), Richard Villemur has been working for twenty years on strategies for detecting animal contamination in water by faecal waste. It uses mitochondrial DNA, a circular DNA molecule found in all living things.
Mr. Villemur recently published the results of his latest research work in collaboration with doctoral student Rose Ragot in the scientific journal Environmental Monitoring and Assessment.
With the help of databases, they designed genetic primers to recognize the majority of mammals and birds, as well as many amphibians and fish. These primers are small DNA sequences, which at the time of analysis stop on a DNA of its own in a sample, explains Mr. Villemur.
By using PCR technology, the same technology used for COVID-19 screening tests, this portion of the DNA is amplified in “astronomical” numbers in order to determine the species possibly present.
The method developed by the professor considers several animals at the same time, avoiding multiple PCR analyses.
Mme Ragot, a biology student, was able to demonstrate the effectiveness of the approach with water samples from four rivers flowing in particular near agricultural areas.
Mr. Villemur mentions that the bacterial indicators (such as coliforms) currently used to detect the presence of fecal contamination do not make it possible to determine the source of the problem, unlike mitochondrial DNA.
“With the tool that I developed, it would make it possible to identify or potentially give which animal would be the cause of the faecal contamination. Watershed managers could knock on the right doors […] and take remedial actions to prevent the contamination from returning on a regular basis, ”he said in an interview with The Canadian Press.
According to him, the approach could be useful in regions where human and agricultural activities intersect while the possible sources of pollution are multiple: overflows, problematic septic tanks or a defective water treatment plant, for example.
He mentions that the presence of bovine material in a river can come from the consumption of meat by humans and thus signal a problem in the treatment of wastewater.
Mr. Villemur would like his method to be deployed in the field using an instrument that would give results almost in real time.
“It would require having partners who would be interested in developing and moving forward with the application of the technology,” he says.
Other utility
The professor believes that the method can also be used to follow the evolution of the animal profile in the rivers.
This observation could take place at the same time as the taking of samples to measure the level of coliforms, evokes Mr. Villemur.
Watershed managers could then establish a correlation between the detection of faecal contamination and the presence of certain species, in particular invasive species, in greater numbers compared to others, he explains.
It is a management and monitoring tool that could lead us to better control of the environment.
Richard Villemur, professor at the Armand-Frappier Health Biotechnology Center of INRS
He points out that new research addressing this avenue is forthcoming. He and doctoral student Rose Ragot examined nearly a hundred samples from around thirty river points.
This article was produced with the financial support of the Facebook and The Canadian Press News Fellowships.