Environmental health experts have confirmed the presence of blue-green algae in freshwater lochs in Northmavine.
SEPA today verified that samples showed the water at Lochend was contaminated with algal growth. The substance poses human health risks and has been known to kill animals.
It can cause skin rashes, vomiting, diarrhoea, fever and pains in muscles and joints if humans come into contact with the scum. The substance, which looks like blue-green paint, either forms on the water or collects on the shoreline.
As a precautionary measure, notices are being posted in local shops and next to the lochs in question warning that contact with the algal scum should be avoided.
SIC environmental health officer Patti Dinsdale said adjacent landowners and the local anglers’ association had been informed, along with NHS Shetland and SEPA. At this stage there is no adverse effect on water supplies.
An algal bloom outbreak around a decade ago resulted in the deaths of thousands of farmed salmon in waters off the west coast of Shetland. Livestock and dogs have died as a result of drinking water contaminated with algae.
“At high levels it can actually kill animals and pets,” Mrs Dinsdale said. “It can cause skin irritation if you swim in the loch. A lot of it is alongside a croft. They’re aware as well and won’t graze their animals in the area.
“These types of things exist in water all over the place, and they bloom if they have the right condition. They will bloom, move to the surface, photosynthesise and use up the nutrients, and end up coming into large numbers that can cause toxic events.”
Its toxicity can fluctuate, appearing one day then being dispersed by the wind, then accumulating again at any time.
Mrs Dinsdale appealed for people to keep a lookout for occurrences of blue-green algae in other lochs.