MORE than 90 per cent of Manx rivers were of good or better quality this summer, results released by the Department of Environment, Food and Agriculture show.
This trend is encouraging compared to recent years, when a gradual decline had been noted in the island’s better rivers, based on measures of organic chemical water quality, which reflect pollution such as sewage, farm waste and slurry.
The majority of Manx rivers are not polluted and are capable of supporting diverse and sensitive wildlife, such as caddis flies, shrimps, snails and brown trout.
This improvement indicates that some rivers which were only of moderate or poor quality and could only support tolerant animals such as worms, hog-lice and midge larvae, have gradually increased in quality to the point that they are now capable of supporting more sensitive insects and, in some cases, fish.
Despite these largely positive results, problems do, however, remain.
In the 10 years up until 2008, summer monitoring indicated that 70 per cent of the island’s rivers fell into the highest water quality class of ‘very good’, which meant they were unspoilt, pollution-free and capable of supporting animals such as sensitive mayfly and salmon and trout.
However, there was a sharp decline in this water quality class in 2009 and since then the number of pristine rivers has hovered around the present 61 per cent.
In addition, a few rivers persistently show very poor quality, indicating signs of pollution and stress.
Rivers are good reflectors of the state of the natural environment. Although the Manx government’s freshwater biologist monitors many rivers regularly and the environmental protection unit seeks to regulate discharges and resolve pollution problems, it is ultimately the responsibility of the public, industry and the farming community to minimise any impacts on the island’s rivers.
Brenda Cannell, MHK, member for the Environment Directorate, said: ‘This is an encouraging report but we must not be too complacent.
‘I would urge businesses and individuals to think long and hard about the type of material finding its way into our drainage systems and ultimately our rivers and the impact that material may have on our environment.’
A copy of the report is available on the Government Laboratory website {http://www.gov.im/daff/enviro/govlabs/riverwater.xml|gov.im/daff/enviro/govlabs/riverwater.xml}
