Pesticide that hasn't been seen in 17 years found in Guernsey waters

A pesticide called Triallate that has not been seen for 17 years has been detected in Guernsey.

Islanders are being urged to avoid using the chemicals, as traces of herbicides and insecticides are commonly found in raw water samples.

Drinking water is still safe in the island, due to a rigorous testing process.

However, water bills could rise if pesticide levels in raw water continue to increase, as a significant investment would need to be made into Guernsey's water treatment works.

From January to March 2023, there were 58 pesticide detections in Guernsey's streams, excluding glyphosate.

It is likely that these chemicals were released due to commercial and domestic use in gardens.

Guernsey Water are encouraging islanders to stop using pesticides to control plants and insects on driveways, paved areas and near streams, as these locations pose the biggest threat to water.

Businesses for whom pesticides are necessary are being encouraged to refer to the Health and Safety Executive's code of practice for advice on how to reduce their usage.

Last year, 250 million litres of water from the Vale Pond water catchment could not be collected as pesticide levels were too high.

If Guernsey Water cannot treat enough water to meet demand, the risk of drought increases.

Margaret McGuinness, water quality risk manager at Guernsey Water, says: “Glyphosate has been under the spotlight recently because it is now banned from use in most situations.

"However, that does not mean we should simply use other pesticides, without any thought to their effects.

“With more severe droughts predicted for the future, the fact we are having to divert millions of litres of water to sea to safeguard the island’s water supply is significant and concerning."