Benchmark says Ectosan spill had ‘minimal’ impact

An accidental release of the new sea lice treatment Ectosan last month had a minimal impact on the marine environment, according to Benchmark Animal Health.

The spill took place on 1 June off the coast of northern Norway, during a course of treatment at a fish farm at Heggvika, Nordland. The release, of 110 cubic metres (corresponding to around 110,000 litres of Ectosan), was reported to the Norwegian Directorate of Fisheries on the same day.

Benchmark developed Ectosan, a sea lice treatment based on the neonicotinoid pesticide imidacloprid, for use with its CleanTreat closed system. The system is designed to treat the waste water and remove the pesticide before discharge into the sea.

Imidacloprid is of low toxicity to vertebrates like fish and marine mammals, in the concentrations used in Ectosan, but could kill a range of insects, crustaceans and other invertebrates. Benchmark stressed, however: “Ectosan® Vet degrades rapidly on exposure to water and sunlight.”

The company said that, following the incident: “We worked closely with a third-party specialist to analyse water and sediment samples as part of our response to the event. Analysis of the initial samples taken within 24 hours of the incident suggested that the potential impact would be minimal. Subsequent sampling confirmed this initial conclusion. We have no evidence of any known impact on the environment. This is consistent with the sample results received and our extensive knowledge of how the product behaves in the marine environment.”

Benchmark is understood to be working with the wellboat company to ensure no similar errors occur in future.

The Directorate of Fisheries told news site Intrafish: “The Directorate… takes the incident seriously and is working on following up the case.”