Emamectin benzoate (EMBZ) - environmental quality standard implementation timescales: consultation analysis

Background

EQSs set limits on the concentration of pollutants in water. They set the maximum allowable concentration of a substance in water and are key to the protection of the water environment and the achievement of our River Basin Management Plan objectives. They underpin assessments of whether waters are at risk of deterioration and what improvements would be needed to improve the status of waters that are not at good status.

In 1999, SEPA undertook a risk assessment of emamectin benzoate in the marine environment following its use for control of sea lice infestations on farmed salmonids in the marine environment. As part of this risk assessment, the Scottish Environmental Protection Agency (SEPA) derived an EQS for emamectin benzoate in sea water and sediment. The standard was 763 ng/kg of sediment (wet weight). ^[1]

In 2016, on the basis of accumulated scientific evidence, SEPA requested the UK Technical Advisory Group (UKTAG) to determine if the EQS derived in 1999 remained scientifically valid and, if required, to develop recommendations on a new EQS for emamectin benzoate.

UKTAG is a partnership of technical experts from the UK's environment and conservation agencies. It was set up jointly by the devolved administrations to provide scientific advice on EQSs and other matters relating to the protection of the water environment.

EQSs are developed by UKTAG to be protective of all species that may be at risk. For example, aquatic animals and plants, sediment-dwelling organisms, or predators that feed on aquatic organisms. In developing the new EQS, UKTAG used the best available scientific information and followed the latest EU protocols for deriving an EQS. As well as UKTAG undertaking its own consultation, an expert independent peer review was also carried out to ensure that proposals were scientifically valid, and that the data used to derive them were sound and complete.

Whilst the new EQS was being developed by UKTAG, SEPA applied the precautionary principle by adopting an interim EQS. This interim EQS only applied to new fish farm applications, or applications to increase discharges at existing fish farms.

UKTAG published its recommendations following independent scientific peer review in July 2022, recommending a new EQS for marine sediments of 131 ng/kg sediment (dry weight). Ministers agreed to adopt the new EQS for emamectin benzoate whilst acknowledging the possible risk to farmed fish health resulting from reducing the allowable amount of emamectin benzoate. Ministers also agreed to run a public consultation to gather views on an appropriate implementation period for the new EQS on fish farms with an existing license in order to reduce these additional risks whilst also considering business impact.

In January 2023, UKTAG notified the Scottish Government of a possible error in the calculation of the derived EQS. Subsequently the Scottish Government paused the launch of the consultation. This allowed UKTAG to investigate further and in March 2023 they published a corrected value for the EQS. This changes the EQS from 131 ng/kg dry weight to 272 ng/kg dry weight. UKTAG published an updated report in March 2023.

Upon publication of the new EQS SEPA began applying it to all licence variations and new applications to protect the water environment from deterioration.

Our consultation sought views on the implementation timescales of the new EQS. Specifically we asked for:

Views on what timescales people and organisations consider to be most appropriate for the implementation of the new EmBz EQS and why, for example, 0, 24 or 48 months.

Evidence on how long it might take to implement any adjustment to sea lice management which may be required as a result of these changes.

Any available information about the socio economic impacts of implementing the new EQS