River Deveron, Scotland
Following concerns raised about water quality, the River Deveron District Salmon Fishery Board (RDevDSFB) and the Deveron, Bogie and Isla Rivers Charitable Trust (DBIRCT) have developed a routine water monitoring strategy for the Deveron catchment, working with the James Hutton Institute (JHI) in Aberdeen.
Initial samples were collected in June 2017 from three sites on the Deveron mainstem (upper, middle and lower) but the sampling programme has now been expanded to nine sites on the five major tributaries (Bogie, Isla, Forgue, Turriff and King Edward) and an upper mainstem site.
The samples are collected when run-off is high (after heavy rain) and the risk of contaminants entering the river is at its highest. The samples are analysed by the JHI for a range of water quality measures. In most cases these analyses were not of significant concern. However, a range of pesticides, fungicides and insecticides have been detected in many of the samples over four consecutive years and appear to be routinely entering the river during high rainfall events.
These chemicals include Clorpyrifos, Epoxicnazole, Permethrin and Cypermethrin. While the data are from a limited number of samples, it is extremely concerning that these chemicals are being routinely detected, even if in very low concentrations. A longer-term study is required to fully understand seasonal fluctuations and potential sources. Using methods developed from a longer-term study on the River Ugie, the JHI has compared the Deveron data to a system of ecotoxicological thresholds and applied categories of risk (low, medium and high). Despite being banned since 2016, Clorpyrifos has routinely shown up in samples at medium risk levels, Epoxicnazole at low levels, Permethrin at low-to-medium levels and, of most concern, Cypermethrin (toxic to aquatic invertebrates and fish) found at low-to-high levels.
As a result of our studies, the Scottish Environmental Protection Agency (SEPA) has begun its own investigations. We have initiated a campaign to raise awareness of the presence of these chemicals and the damage they can cause to the freshwater environment and the fishery.
