The quality of Manx river water is improving, the government says.

A report has given 95% of water courses the best chemical rating.

Environmental protection officers from the Department of Environment, Food and Agriculture (DEFA) use a classification to produce a rating for each site, based on biological, chemical and nutrient data.

Readings are taken at various points on streams and rivers and do not cover an entire watercourse.

The chemical status analyses for dissolved oxygen, ammonia and biochemical oxygen demand whereas nutrients is split into nitrate and phosphate.

Biological grading assesses the invertebrates that inhabit the riverbed.

All 26 monitored sites achieved a biological rating of very good or good over the past three years.

The ratings demonstrate that the percentage of river length achieving ’very good’ chemical status improved from 88% in 2015 to 95% in 2018 - the highest ever improvement.

Geoffrey Boot, MHK the Minister for Environment Food and Agriculture, said: ’Water quality is of huge importance. Looking after our water quality in rivers and beaches is crucial to our international reputation and our UNESCO biosphere status.’

’The report shows an encouraging and positive trend in the right direction.’

Monitoring nutrients in the form of phosphate and nitrate is important as high concentrations can cause increased organic enrichment with excessive plant and algal growths.

The main sources of these substances are land run off from agricultural fertiliser, animal excrement and detergent from sewage effluent.

The report shows phosphate levels have decreased over the past 20 years, with 95% of watercourses classified as very low and just less than half of the rivers achieved a very low status for nitrate.

Further investigations are required to identify the source of the nitrate and then steps will be taken to reduce the concentrations entering our watercourses.

Other studies into the effects of historic mining activity and redundant landfills are also required to further improve the health of our rivers and protect the environment.

To report any incidents of potential water pollution, ring the government’s environmental protection unit on 685885.