Scottish Marine and Freshwater Science Volume 1 No 5

Halogenated persistent organic pollutants [chlorobiphenyls (CBs), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD)], along with total lipid, were measured in the liver and muscle of two species of deep water fish (black scabbard and roundnose grenadier) collected from the Rockall Trough, to the west of Scotland, during 2007. The data was compared with that obtained from a similar survey conducted in 2006, and which has recently been published. CB concentrations (SICES7 CBs) greater than 500 µg kg-1 lipid weight were found in 5 of the 30 deep water fish liver samples and 8 of 30 fish muscle samples collected in 2007. Non-ortho CBs (CB81, 77, 126 and 169) were measured in samples with the highest ortho CB concentrations but were not detected in any of the fish muscle or liver samples collected in 2007. Data was assessed using the assessment criteria adopted by OSPAR for use in the 2008 Coordinated Environmental Monitoring Programme (CEMP) assessment and Quality Status Report 2010 and incorporated into a traffic light system. Concentrations were compared to Background Assessment Concentrations (BACs; blue/green transition) and Environmental Assessment Criteriapassive (EACpassive; green/red transition). Concentrations for the individual ICES7 CBs in fish liver were above OSPAR BACs in both species sampled in 2007. The EACpassive was exceeded for CB118 only. As all other CBs were below the EACpassive, CB concentrations in deep water fish were classed as ‘green’. Measured (calculated for the five mono-ortho CBs) and estimated (calculated using published models) Toxic Equivalent (TEQ) concentrations in the fish muscle indicated that consumption of deep water fish muscle is unlikely to represent a risk to human health. PBDEs were detected in both the liver and muscle of the deep water fish collected in 2007. However, concentrations were low with many congeners being below detection limits. HBCD was not detected in any of the Scottish deep water fish collected in 2007. Halogenated persistent organic pollutants were detected in Scottish deep water fish, confirming that these contaminants are transported to the Scottish deep water environment. However, the CB concentrations found are unlikely to give rise to pollution effects and are not of concern from the perspective of human health. PBDE concentrations could not be assessed, due to the lack of assessment criteria. Furthermore there is only very limited data on PBDEs in deep water fish. However, the concentrations observed in this study were similar to the concentrations recently reported in Mediterranean deep water fish.