Persistent organic pollutants and trace metals in sediments close to Scottish marine fish farms Marie Russell, Craig D. Robinson, Pamela Walsham, Lynda Webster, Colin F. Moffat PII: DOI: Reference:
S0044-8486(11)00510-2 doi: 10.1016/j.aquaculture.2011.06.030 AQUA 629757
To appear in:
Aquaculture
Received date: Revised date: Accepted date:
4 January 2011 17 June 2011 22 June 2011
Please cite this article as: Russell, Marie, Robinson, Craig D., Walsham, Pamela, Webster, Lynda, Moffat, Colin F., Persistent organic pollutants and trace metals in sediments close to Scottish marine fish farms, Aquaculture (2011), doi: 10.1016/j.aquaculture.2011.06.030
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ACCEPTED MANUSCRIPT PERSISTENT ORGANIC POLLUTANTS AND TRACE METALS IN SEDIMENTS CLOSE TO SCOTTISH MARINE FISH FARMS
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Marie Russell*, Craig D. Robinson, Pamela Walsham, Lynda Webster and Colin F. Moffat
Marine Scotland Science, Marine Laboratory, PO Box 101, 375 Victoria Road, Aberdeen,
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Scotland AB11 9DB.
*corresponding author. Tel +44 1224876544; Fax +44 1224 295511;
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e-mail address
[email protected]
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ACCEPTED MANUSCRIPT ABSTRACT The global demand for aquatic food products is increasing and the aquaculture industry is expanding as it strives to meet this increasing demand.
There are concerns about the
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environmental impact of aquaculture to the seabed close to fish farm cages, including potential
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effects from persistent organic pollutants and trace metals, which may come from the feed or anti-foulants on the cages. To determine if this could be a problem in Scotland, three main aquaculture areas were examined; Western Isles, North West Coast of Scotland and the
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Shetland Isles. Samples of sediment were collected from various sea lochs in these areas in 2005 and 2006 and concentrations of persistent organic pollutants (polychlorinated biphenyls
(Zn)) were determined.
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(PCBs) and polybrominated diphenyl ethers (PBDEs)) and trace metals (copper (Cu) and zinc Concentrations of PCBs were below the EAC (environmental
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assessment criteria) for all bar one congener in one sample, and below the BAC (background assessment concentration) for most. PBDE concentrations in the sea lochs are comparable with those found at remote sites around Scotland and comparable with the lower end of
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concentrations found in the more industrialised Firth of Clyde. Although slightly elevated Cu and Zn concentrations were measured in sediments from 750 m from any fish farm cages
Trace metals data were analysed for normality (Ryan-Joiner test) and equal variances
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(Levene’s test). Normally distributed data were examined using t-tests and one-way ANOVA
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with Tukey’s pair-wise comparisons.
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3. Results and Discussion
3.1 Physical Characteristics of the Sea Lochs
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For many of the sea lochs and voes in this study there is restricted exchange between the waters of the sea lochs/voes and coastal waters (Edwards and Sharples, 1986; Gubbins et al., 2006). This may in turn lead to higher sedimentation rates than in the more dispersive coastal
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water bodies (Gubbins et al., 2006). For Sandsound Voe, Loch Duich , Loch Ewe and Loch Greshornish there are multiple sills present and, except for Sandsound Voe, there is at least
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one sill between the fish farm and the open sea. For Sandsound Voe the fish farm is seaward
Kishorn.
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of the sill. There are no sills restricting the circulation in Collafirth and Swinister Voes or Loch
One of the possible impacts of fish farming is the introduction of excess particulate organic material to the sediments close to the fish farm from waste feed and faecal material, which sinks to the seabed below the cages where it can accumulate. The PS (% 0.05). This would indicate that overall there is no significant organic enrichment at or near the cages due to the influx of organic material in the form of faeces or uneaten feed.
3.2 Polychlorinated Biphenyls (PCBs)
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ACCEPTED MANUSCRIPT 3.2.1 Sediment Concentrations
Twenty-eight (Appendix B) of the 209 possible PCB congeners (CB31, 28, 52, 44, 49, 70, 74,
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110, 101, 99, 97, 149, 118, 132, 153, 105, 157, 137, 138, 158, 183, 128, 156, 180, 187, 189,
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170, 194) were measured in the sediments. PCBs 105, 118, 156, 157 and 189 are five of the eight mono-ortho PCBs included in the group of ‘dioxin-like’ CBs. These compounds are more toxic than those PCBs with more than one chlorine in the ortho position and are normally found
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at much lower concentrations compared to the ortho-PCBs. The seven ICES (International Council for the Exploration of the Sea) PCBs (CB28, 52, 101, 118, 153, 138, 180) are the most
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frequently measured PCBs and are often used as indicators in environmental monitoring. ΣPCB28 (sum of 28 congeners) ranged from
