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What We Did
Wātakirihi (watercress) is harvested from rural waterways. Unfortunately, rural waterways can have unsafe concentrations of bacteria. Exposure to these bacteria could put the gatherer or consumer of wātakirihi at risk of infection. Additional concern is for bacteria that are also resistant to antibiotics because it becomes more difficult to treat an infection. We are monitoring the levels of Escherichia coli because this is a standard indicator bacterium to assess microbiological safety of water. We also measure the frequency of E. coli resistant to antibiotics. Measurements are taken at six places in North Canterbury where wātakirihi is harvested, with the goal of establishing a new site where wātakirihi can be harvested safely.
Who Was Involved
Irai Weepu, Tangata Whenua Facilitator, Environment Canterbury; Te Ngāi Tūāhuriri Rūnanga. With prior knowledge of the potentially dangerous bacteria present at existing wātakirihi sites, Environment Canterbury’s Tangata Whenua Facilitator, Irai Weepu, has begun overseeing the creation of a new wātakirihi harvesting site. This site will have improved access, yield of wātakirihi and water quality. We are providing ongoing support through long term microbial monitoring to complement historical water quality data.
Why It Matters
Wātakirihi is a mahinga kai. Mahinga kai are traditional Māori sources of food and the places where they are grown or harvested. Access to these foods has been eroded over time, and lack of knowledge surrounding the microbial safety of mahinga kai is one barrier to their consumption. We hope to support local communities to source safe wātakirihi grown using traditional methods. This research is a small part of a bigger project to revitalise mahinga kai practices in Canterbury.
Learn More
This work is part of a larger body of work on water quality in Canterbury.
- https://brianmasontrust.org/portfolio-item/herbicide-induced-antibiotic-response-in-bacteria/
- van Hamelsveld, S. et al. Prevalence of antibiotic resistant Escherichia coli isolated from urban and agricultural streams in Canterbury, New Zealand. FEMS Microbiol Lett 366, fnz104. doi: 110.1093/femsle/fnz1104 (2019).
