Levels of Chemicals Low in Scottish Marine Sediment, Says Watchdog

Levels of certain chemicals used in forestry, agriculture and fish farming are low in marine sediment off Scotland, research published recently by Scotland’s environment watchdog shows.

The Scottish Environment Protection Agency’s (SEPA) has published two reports on the presence of chemicals in marine sediments, resulting from its surveillance monitoring programmes in 2008 and 2009. Occurrence of Chemical Residues in Sediments looks at nine Scottish sea lochs over the two documents and can be found on SEPA’s website at www.sepa.org.uk

Andy Rosie, SEPA Head of Operations for North Scotland, said:

 “I’m please to say that, for the majority of sites in the surveys, the levels of compounds in the sediments are low indicating there is likely to be limited environmental impact. The majority of samples showed residue levels below the reporting limits for the substances concerned and where positive results arose, the majority were within safe environmental standards. In the small number of cases where safe environmental standards were exceeded, levels were within limits set for the seabed close to fish farm premises.

 “This is important research and will be used to inform our work in this area in the coming years. Effective regulation is about assessing risk to the environment, and looking at how it is managed through regulations and authorisations. Directing inspection and enforcement activity at the highest risk and poorest performing operations, while providing better environmental advice and guidance, will enable us to better protect Scotland’s marine environment. By carrying out this important research, SEPA’ s experts can identify any areas of concern, and enable us to target work and resources to improve them.

 “However, the results also show that we need to focus further monitoring efforts to learn more about the likely sources of some of these chemicals. The dynamics of the marine environment are complex, making it difficult to interpret the source of the detected residues with certainty. They may have arisen from activities such as those connected with agriculture, forestry or aquaculture within the water catchments.”

The lochs surveyed were:

2008 – Loch Kanaird, Summer Isles, Loch Fyne, Portree Bay, Loch Slapin, Loch na Keal.

2009 – Loch Linnhe, Loch Ewe, Loch Nevis.

The chemicals found can be used legally, and in a variety of areas.

Teflubenzuron is used in a sea louse medicine, Calicide. It is also used as a crop protection insecticide, for example the product Nomolt © used to treat whiteflies in tomato crops.

Diflubenzuron is the active ingredient in a sea louse medicine known as Lepsidon ©. It is also present in a range of pesticides such as forestry/crop protection products used to deal with insect pests, for example the product Dimilin ©.

Ivermectin is present in medicines commonly used to treat agricultural livestock for a wide range of pests – helminth worms, insects and other arthropod parasites. It is also used in certain treatments for companion animals for example in Xeno © used for the treatment of lice in pet rabbits.

Emamectin benzoate is the active ingredient in the sea louse medicine Slice. It is also used to deal with cockroach and other insect infestations and is available in products to treat certain infestations in trees and food crops such as lettuce and broccoli.

Andy Rosie also explained:

 “The majority of farmers, land managers and fish farm operators understand their environmental obligations and work with us to ensure that they remain within the strict limits set out in their licences and authorisations. Where there are problems SEPA will work with the individuals or companies involved to resolve them, but we will ensure that tough action is taken against those who continually fail to meet acceptable standards.”

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Source: sepa, October 26, 2011