Contaminants in fish and seafood
Recent surveys of contaminant concentrations in fish and shellfish from fishing grounds in the Celtic Seas and the Greater North Sea confirm the results from the UK Initial Assessment in 2012, showing that there has been a high level of compliance with the standards set in European food legislation, and that the UK target has been achieved.
Background
UK target on contaminants in seafood
This indicator is used to assess progress against the target set out in the Marine Strategy Part One (HM Government, 2012), which requires that, for contaminants where regulatory levels have been set, there should be a high rate of compliance based on relevant surveys and including samples originating from commercial fishing grounds in the Greater North Sea and the Celtic Seas.
Key pressures and impacts
In the 2012 UK Initial Assessment (HM Government, 2012), the key pressures and impacts identified were the introduction of discharges, emissions and losses of persistent, toxic and bio-accumulating synthetic and non-synthetic chemicals such as pesticides, antifoulants, pharmaceuticals, heavy metals and hydrocarbons from various sources which impact the marine environment. These chemicals can reach the marine environment from various land-based and marine sources and can accumulate in marine sediments and rise through the food chain into seafood harvested for human consumption. These all remain relevant, and emerging contaminants of concern are kept under review, for example, through amendments to the EU legislation.
Measures taken to address the impacts
The main measures to protect consumers from exposure to harmful levels of contaminants in fish and seafood are set out in the UK Marine Strategy Part Three (HM Government, 2015) and include Commission Regulation 1881/2006 as amended, which sets out limits for chemical contaminants in food. Under Regulation 178/2002, establishing the general principles of food law, action to protect public health can also be taken for unregulated contaminants on the basis of a risk assessment. Consumer protection is enhanced through precautionary advice to restrict the consumption of certain species at higher risk of contamination, such as oily fish (dioxins, polychlorinated biphenyls) and large predators (mercury).
Assessment method
Areas that have been assessed
The assessment scales used were the Greater North Sea and the Celtic Seas areas.
Monitoring and assessment methods
Samples of seafood known to be at greatest risk of accumulating contaminants were collected through surveys of representative commercial fishing grounds in the Celtic Seas and the Greater North Sea. Samples were also collected from Billingsgate fish market in London (Figure 1), where the locations of the catch were known. The target species in recent investigations included: sardines/pilchards, sea bass, dogfish, mackerel, herring, sprats, halibut, turbot, and grey mullet.
Figure 1. Mackerel on sale in Billingsgate Market, London.
The chemicals selected for monitoring were those already set out in the contaminants regulations, Commission Regulation 1881/2006 as amended, together with those identified by the Food Standards Agency as emerging risks and certain candidates for listing under the Stockholm Convention.
The samples were analysed for the regulated contaminants according to the methods and criteria set out in Commission Regulation 333/2007 as amended (metals) and 589/2014 (dioxins and polychlorinated biphenyls). Other contaminants were measured using validated and published methods meeting equivalent performance criteria.
Assessment thresholds
The Maximum Levels set out in Regulation 1881/2006 were used, where available. These represent legal limits above which food may not be placed on the market.
Co-operation with other countries
The UK raised the possibility of collaborating with other countries in the OSPAR Hazardous Substances and Eutrophication Committee on the assessment of this indicator, but so far this has not been taken forward.
Results
Findings from the 2012 UK Initial Assessment
Previous surveys for contaminants in fish and shellfish have indicated that contaminant levels in fish and seafood on the UK market rarely exceed maximum levels set out in legislation, although the samples tested were largely retail and were not generally associated with specific geographical areas in UK waters.
Latest findings
The latest investigation was designed to target samples from known locations in UK waters within the Greater North Sea and the Celtic Seas, although a small number of samples from adjacent waters but destined for the UK market were also included.
Polychlorinated dibenzodioxins, polychlorinated dibenzofurans and polychlorinated biphenyl
Of 191 samples tested, only 2 non-compliant samples were identified. Both were landed at Boulogne in Northern France but were destined for the UK market. Based on their contaminant profiles, they are likely to have come from the Seine Bay area.
Lead
Of the 192 samples tested, only 2 exceeded the limit, both mullet from the Pembrokeshire coast.
Cadmium
Cadmium has tiered limits depending on species. Of the 192 samples tested only one sample of Cornish mackerel, exceeded the applicable limit.
Mercury
Mercury has tiered limits at 0.5 and 1.0 mg/kg with fish species placed in the higher category when supported by sufficient data. Of the 192 samples tested, there were 7 exceedances of the general limit of 0.5mg/kg, all for sea bass (n=25). There was no distinction in the sampling locations to suggest localised contamination, so this is expected to be an issue in sea bass in general. It is likely that the data will be used to support a proposal to the European Commission to re-categorise sea bass to a higher tier limit within the regulations.
Trace metals and non dioxin like polychlorinated biphenyls
A survey on haddock, monkfish and herring in the North Sea and the West Coast of Scotland concluded that regulatory levels had been generally achieved for trace metals and non dioxin-like polychlorinated biphenyls. A survey of shellfish in Scottish waters showed that concentrations of non dioxin-like polychlorinated biphenyls and trace metals are below regulatory levels in nearly all samples. Dioxins and dioxin-like polychlorinated biphenyls were not measured.
Pesticides
A subset of samples was screened for pesticides. Default maximum residue levels for pesticides set under Regulation 396/2005 do not currently apply to fish. Some legacy pesticides such as Dieldrin, Dichlorodiphenyltrichloroethane (DDT) and its metabolites and hexachlorobenzene were regularly detected but only in the very low parts per billion range and these would not give rise to a health concern.
Table 1. Summary of results from the surveys of regulated contaminants in fish sampled at known locations in UK waters. Concentrations are given in milligram of metal per kilogram of seawater, and nanogram of metal per kilogram of seawater, as well as picogram total toxic equivalency (TEQ, defined by the World Health Organization – WHO) per gram of seawater. * indicates use of 90th percentile value.
|
Contaminant |
Mean |
95th Percentile |
Maximum |
Limit |
Species |
|
Lead |
0.02 |
0.07 |
0.90 |
0.30mg/kg |
All |
|
Cadmium |
0.01 |
0.02 |
0.06 |
0.05mg/kg |
All excluding: |
|
0.03 |
0.10 |
0.16 |
0.10mg/kg |
mackerel |
|
|
0.03 |
0.06* |
0.06 |
0.25mg/kg |
sardines |
|
|
Mercury |
0.07 |
0.19 |
0.43 |
0.50mg/kg |
All excluding: |
|
0.18 |
0.82 |
1.0 |
1.00mg/kg |
halibut, mullet, dogfish |
|
|
Dioxins |
0.41 |
1.36 |
2.55 |
3.5pg WHO-TEQ/g |
All |
|
Total Toxic Equivalent |
1.36 |
3.86 |
12.5 |
6.5pg WHO-TEQ/g |
All |
|
Non dioxin-like polychlorinated biphenyls |
11.6 |
32.7 |
145 |
75ng/g |
All |
All results show that, for the fish tested, there was a high level of compliance with regulatory thresholds that have been set. There is a high level of confidence in the conclusions of this investigation because the species targeted were generally those considered of highest risk of contamination by organic contaminants, since these tend to bioaccumulate in oily fish such as mackerel and herring.
Further information
Contaminants in shellfish in Scottish Waters.
Available data for trace metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls and dioxins in shellfish obtained by Marine Scotland Science from the Food Standards Agency for Scotland and the UK Marine Environment Monitoring and Assessment Database in 2013-2014 indicate that concentrations are below the applicable maximum levels in nearly all samples examined. Further details can be found in Webster and others (2015).
Contaminants in fish in Scottish waters.
A fish sampling programme for this descriptor was designed in 2013/14 (Webster and others, 2014). Haddock, monkfish and herring were selected based on their importance to the human diet based on landings data, and their ability to accumulate contaminants. Fish were obtained during existing stock assessment research surveys, with the proportion of samples from each haul reflecting the haul location with respect to landings of the Scottish fishing fleet.
European Commission maximum limits were not exceeded in any individual sample for trace metals or polybrominated biphenyls. The 95th percentiles of the distributions of trace metal and non-dioxin like (known as ICES-6) polychlorinated biphenyls concentrations were estimated for each species and area. These were significantly below the regulatory levels, apart from mercury in monkfish on the West Coast, where the point estimate of the 95th percentile was about half the regulatory level, but the upper likelihood limit was above it. However, only 16 monkfish were sampled and analysed on the West Coast, rather than the target of 20, so the estimate of the 95th percentile was not as precise as intended. In the North Sea, the 95th percentile of the mercury distribution in monkfish was significantly below the regulatory level but was based on only 4 fish which did not adequately represent the target sampling population. Further details can be found in Webster and others (2015).
Unregulated contaminants
In addition to the investigation of regulated contaminants, a sub-set of samples were tested for a range of halogenated contaminants that are of current concern to the European Commission, are newly listed in the Stockholm Convention and/or have previously been investigated by the Food Standards Agency. These included polybrominated diphenyl ethers, perfluorinated alkyl substances, polychlorinated naphthalenes and brominated and mixed halogenated dioxins and biphenyls. All were found to be quite widespread, with no clear geographical trends except in the case of polychlorinated naphthalenes levels which were higher in samples from the Irish Sea. This may be associated with a high polychlorinated naphthalene loading in the river Mersey. The levels of polybrominated diphenyl ethers and perfluorinated alkyl substances found were consistent with previous results and assessment against health-based guidance values, where available, did not indicate a health concern. The contribution of brominated and mixed halogenated dioxins and biphenyls to the total toxic equivalent were relatively small, in line with other studies, although it should be noted that only a small proportion of the toxicologically relevant mixed congeners were measured due to non-availability of laboratory standards.
Conclusions
The recent investigations show that there has been a high degree of compliance with regulatory levels and confirm the findings of the Initial Assessment in 2012 that the target for this descriptor are already achieved in both the Celtic Seas and the Greater North Sea.
Knowledge gaps
No significant knowledge gaps.
References
HM Government. (2012) Marine Strategy Part One: UK Initial Assessment and Good Environmental Status, December 2012. (viewed on 5 July 2018)
HM Government (2015). Marine Strategy Part Three: UK Programme of Measures. December 2015. (viewed on 5 July 2018)
European Commission (2002) Regulation (EC) No 178/2002 of the European Parliament and of the Council of 28 January 2002 laying down the general principles and requirements of food law, establishing the European Food Safety Authority and laying down procedures in matters of food. Official Journal of the European Union, L 31, 1.2.2002, p. 1–24. (viewed on 24 September 2018)
European Commission (2006) Commission Regulation (EC) No 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs (Text with EEA relevance) Official Journal of the European Union, L 364: 20.12.2006, p. 5-24 (viewed on 24 September 2018)
European Commission (2014) Commission Regulation (EU) No 589/2014 of 2 June 2014 laying down methods of sampling and analysis for the control of levels of dioxins, dioxin-like PCBs and non-dioxin-like PCBs in certain foodstuffs and repealing Regulation (EU) No 252/2012 (Text with EEA relevance) Official Journal of the European Union, L 164, 3.6.2014, p. 18–4. (viewed on 24 September 2018)
European Commission (2016) Commission Regulation (EU) 2016/582 of 15 April 2016 amending Regulation (EC) No 333/2007 as regards the analysis of inorganic arsenic, lead and polycyclic aromatic hydrocarbons and certain performance criteria for analysis (Text with EEA relevance) Official Journal of the European Union, L 101, 16.4.2016, p. 3–6. (viewed on 24 September 2018).
Webster, L., Mackay, Z.L., Robinson, C.D., Smith, A., and Fryer, R.J. (2014) Development of a Sampling Programme and Measurement of Contaminants in Food for Marine Strategy Framework Directive Descriptor 9. Scottish Marine and Freshwater Science Volume 5 Number 15. (viewed on 24 September 2015)
Webster, L., Mackay, Z.L., Robinson, C.D. and Fryer, R.J. (2015) Measurement of contaminants in food for Marine Strategy Framework Directive Descriptor 9. Scottish Marine and Freshwater Science Vol 6 No 11. (viewed on 24 September 2015)
Acknowledgements
Assessment metadata
| Assessment Type | UK MSFD Indicator Assessment |
|---|---|
D9 Contaminants in seafood | |
| Point of contact email | marinestrategy@defra.gov.uk |
| Metadata date | Saturday, May 1, 2021 |
| Title | Contaminants in fish and seafood |
| Resource abstract | Samples of seafood were collected through surveys of representative commercial fishing grounds in the Celtic Seas and the Greater North Sea, and from Billingsgate fish market in London (where the locations of the catch were known). The samples were analysed for the regulated contaminants according to the methods and criteria set out in Commission Regulation 333/2007 as amended (metals) and 589/2014 (dioxins and polychlorinated biphenyls). |
| Linkage | |
| Conditions applying to access and use | © Crown copyright, licenced under the Open Government Licence (OGL). |
| Assessment Lineage | The results from the Food Standard Agency research project ‘Geographical investigation for chemical contaminants in seafood collected from UK marine waters and coastline’ in 2017 provided the baseline and data for this indicator assessment. |
| Dataset metadata | Data sets are available in the published research report ‘Geographical investigation for chemical contaminants in seafood collected from UK marine waters and coastline’ |
| Links to datasets identifiers | Please, see reference above |
| Dataset DOI | Please, see reference above |
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Recommended reference for this indicator assessment
David Mortimer1 2018. High rate of compliance regarding current EU regulation on contaminants in seafood. UK Marine Online Assessment Tool, available at: https://moat.cefas.co.uk/pressures-from-human-activities/contaminants-in-seafood/contaminant-concentrations-in-seafood/
1Food Standards Agency