Gå til hovedinnhold

Monitoring program for pharmaceuticals, illegal substances and contaminants in farmed fish

— Annual report for 2020

Forfatter(e): Annette Bernhard og Rita Hannisdal (HI)

Sammendrag

This report summarises the monitoring data collected in 2020 on the status of illegal substances, pharmaceuticals and contaminants in Norwegian farmed fish. In 2020, a total of 13 845 fish were sampled. Samples examined for illegal compounds were collected at all stages of farming and are representative of farmed fish under production. The samples were analysed for substances with anabolic effects or unauthorized substances. No residues of illegal compounds were detected. Samples tested for approved veterinary drugs and contaminants were collected at processing plants and are representative of Norwegian farmed fish ready for human consumption. Residues of the anti-sea-lice agent emamectin were found in one sample, with a concentration below the Maximum Residue Limit (MRL). Other veterinary drugs, like antibiotics or drugs used against internal parasites were not found. No environmental contaminants were found above the EU maximum level.

1 - Introduction

1.1 - Background

According to EU legislation (EU 2017/625, replacing Directive 96/23/EC), all food producing animals should be monitored for certain substances and residues thereof. The following residues or substance groups are monitored in Norwegian farmed fish:

Group A- Substances with anabolic effects and unauthorized substances:

A1: Stilbenes, derivatives and their salts and esters

A3: Steroids

A6: Prohibited substances

Group B- Veterinary drugs and contaminants:

B1: Antibacterial agents

B2a: Anthelmintics

B2d: Sedatives

B3a: Organochlorine compounds

B3b: Organophosphorus compounds

B3c: Chemical elements

B3d: Mycotoxins

B3e: Dyes

B3f: Others

1.2 - Group A, Substances with anabolic effects and unauthorized substances

Fish tested for illegal compounds were collected at the farm by official inspectors from the Norwegian Food Safety Authority, without prior notification to the farmers. Samples were taken at all stages of farming in order to represent farmed fish during production. Substances monitored in Group A include growth promoters like steroids and stilbenes, and unauthorized drugs. Unauthorized drugs considered most relevant for aquaculture are chloramphenicol, nitrofurans, metronidazole and dyes. Since the use of the dyes malachite green, crystal violet and brilliant green is not allowed for food producing species (EU 37/2010), they are considered Group A substances and hence monitored in samples throughout the production chain. However, according to Regulation (EU) 2017/625, these dyes belong to the group B3e. Thus, in order to fulfill criteria for group B sampling, some of the samples assigned to analysis of dyes were also collected at the slaughterhouse.

To ensure harmonized levels for the control of unauthorized substances, the analytical methods should meet a minimum required performance limits (MRPLs) set by the European Union (EU 2003/1881, EU 2004/25, CRL 2007), and European reference laboratories (EU-RLs), (EU 2003/1881, EU 2004/25, CRL 2007). Table 5.3 gives an overview of MRPLs of relevant compounds.


1.3 - Group B, Veterinary drugs

In order to protect public health, current EU legislation (EU 37/2010) provisions the assignment of Maximum Residue Limits (MRLs) for all legally applied pharmacologically active substances in products intended for human consumption. An MRL denotes the highest permitted residual concentration of a legally applied veterinary drug and is evaluated for each substance and each food product individually. Consumption of food with drug residues below the MRL should not pose a health risk to the consumer. For fish, the MRLs are set for muscle and skin in natural proportions. Samples examined for veterinary drugs were collected from fish at processing plants and the samples are representative of fish ready to be placed on the market for human consumption.

1.4 - Group B, Contaminants

Samples examined for contaminants were collected from fish at processing plants and are representative of fish ready for human consumption. The EU (EU 1881/2006) has set a Maximum limit (ML) for some of the contaminants in fish, while for others, like the pesticides, PAH, PFC and BFR, maximum limits have not yet been established.

2 - Material and methods

2.1 - Sampling

Samples were taken on fish farms or slaughterhouses, by official inspectors from the NFSA, in all fish-producing regions in Norway. The sampling plan was randomised according to season and region. In 2020, the monitoring program included Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), turbot (Scophthalmus maximus), Atlantic halibut (Hippoglossus hippoglossus), Arctic char (Salvelinus alpinus), Atlantic cod (Gadus morhua) and spotted wolffish (Anarhichas minor) .

Samples were transported to IMR in a frozen state. For most analyses, the Norwegian quality cut (NQC) was used (Johnsen, Hagen et al. 2011). However, both NQC and individual liver samples were collected for analysis of antibiotics. Samples to be used for analyses of substances with anabolic effects or unauthorized substances also included small fish from early life stages, and in these cases, the whole fish except head, tail and gut were homogenised. The samples were analysed as pooled samples comprising five fish from the same cage/farm.

2.2 - Pre-treatment

Upon arrival at IMR the sample identification was anonymised for the analysts. A back-up sample was stored for all samples. Pooled samples of muscle from five fish from the same cage/farm were homogenised before analyses. Samples of liver were excised from the fish to be screened for residues of antimicrobial agents by the microbiological inhibition zone assay. Liver samples were examined individually, if residues were detected, the back-up sample of muscle was analysed by chemical methods. The maximum residue limits for veterinary drugs are set for muscle and skin in natural proportions (EU 37/2010). Therefore, according to the analytical protocol, any detection of drug residues in the muscle or liver was followed by a re-analysis of the back-up sample, consisting of muscle and skin in natural proportions, in duplicate.

2.3 - Analytical methods

The laboratory routines and most of the analytical methods are accredited in accordance with the standard ISO 17025. A summary of the analytical methods and their limit of detection (LOD) or limit of quantification (LOQ) is shown in Table 5.4. The LOD is the lowest level at which the method is able to detect the substance, while the LOQ is the lowest level for a reliable quantitative measurement. For all methods, a sample blank and a quality control sample (QC) with a known composition and concentration of target analyte are included in each series. The methods are regularly verified by participation in inter-laboratory proficiency tests, or by analysing certified reference material (CRM), where such exist.

2.3.1 - Group A substances

A1, Stilbenes

Stilbenes were extracted by water and acetonitrile. Liquid-liquid extraction was used for sample clean-up. The stilbenes were and analysed by LC-MS/MS.

A3, Steroids

Steroids were extracted by water and acetonitrile. Liquid-liquid extraction followed by solid phase extraction was used for sample clean-up, before the samples were analysed by LC-MS/MS.


A6, Illegal veterinary drugs

Chloramphenicol

Chloramphenicol was extracted with ethyl acetate. Liquid-liquid extraction was used to purify the extract. The samples were analysed by LC-MS/MS.

Nitrofurans

The nitrofuran metabolites were extracted with aqueous hydrochloric acid and derivatized with nitrobenzaldehyde. Solid phase extraction was used for sample clean-up. The analytes were determined by LC-MS/MS.

Metronidazole

Metronidazole and its metabolite hydroxymetronidazole were extracted by ethyl acetate. Solid phase extraction was used for sample clean-up. The analytes were determined by LC-MS/MS

Malachite green (MG), crystal violet (CV), brilliant green (BG)

The analytes were extracted with acetonitrile. Sample clean-ups were performed by solid phase extraction. MG, CV, BG and the metabolites leuco malachite green (LMG) and leuco crystal violet (LCV), were determined by LC-MS/MS.

2.3.2 - Group B substances

B1, Antibacterial agents (antibiotics)

The presence of antibacterial agents was determined by a three-plate microbiological assay or by chemical analysis.

Microbiological assay

For the three-plate microbiological inhibition method, a specific bacterial strain was added to a plate containing growth agar. Small pieces of liver were placed on the plates before incubation. If the samples contained residues of antibacterial agents, the bacterial growth would be inhibited in a zone around each piece of liver tissue. Thus, a transparent zone with no bacterial growth surrounding the liver sample would indicate a positive sample. Any positive detection was verified by chemical analysis of muscle and skin.

Oxolinic acid, flumequine, florfenicol, enrofloxacin, ciprofloxacin and trimethoprim

The analytes were extracted with acetonitrile and water. The analysis was performed by LC-MS/MS.

Tetracyclin

Oxytetracycline, doxycycline, chlortetracycline, and tetracycline were extracted with acetonitrile. Liquid-liquid extraction was used to purify the extract. The analytes were analysed by LC-MS/MS.

B2a, Anthelmintics

Flubenzurons

Diflubenzuron, teflubenzuron, lufenuron, hexaflumuron and fluazuron were extracted with acetone. Solid phase extraction was used for sample clean-up. The samples were analysed by LC-MS/MS (Samuelsen, Lunestad et al. 2014).

Emamectin

Emamectin was extracted with acetonitrile, and analysed by LC-MS/MS.


Ivermectin

Ivermectin was extracted with organic solvent, and the extract were purified by solid phase extraction. The samples were analysed by LC-MS/MS.

Cypermethrin and deltamethrin

Cypermethrin and deltamethrin were extracted by soxhlet extraction. The extracts were purified by gel permeation chromatography. The samples were analysed by GC-MS/MS.

Fenbendazole and praziquantel

Fenbendazole and praziquantel were extracted using acetone. The samples were analysed by LC-MS/MS.

B2d, Sedatives

Isoeugenol and eugenol

Isoeugenol and eugenol were analysed by GC coupled to a flame ionization detector (FID).

B3a, Organochlorine compounds

Dioxins, dl-PCBs, PCB-6 and PBDEs.

This is an adaptation to modern clean-up equipment of the US-EPAs (Environmental Protection Agency) methods No. 1613 and 1668. Separation and quantification were performed by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). The method measures all of the 29 compounds on the WHO list: 17 PCDD / PCDF congeners, four non-ortho substituted PCBs: PCB -77, 81, 126 and 169 and eight mono-ortho substituted PCBs: PCB-105, 114, 118, 123, 156, 157, 167 and 189 (Berntssen, Julshamn et al. 2010). The PCBs included in PCB-6, PCBs no. 28, 52, 101, 138, 153 and 180, were analysed by GC-MS/MS. The PBDEs were analysed by GC/MS in a relevant solvent fraction from the EPA clean-up procedure (Pirard, De Pauw et al. 2003). Tri-hepta PBDEs (no. 28, 35, 47, 49, 66, 71, 75, 77, 85, 99, 100, 119, 138, 153, 154, 183) were analysed by GC-MS/MS. Okta-deca PBDEs (no. 196, 197, 206, 207, 209) were analysed by GC-MS in negative chemical ionization mode (NCI).

Chlorinated pesticides

Pesticides were extracted by organic solvent, and the extract were cleaned up by column chromatography, before the pesticides were analysed by HRGC-HRMS.

B3b, Organophosphorus compounds

Azamethiphos and dichlorvos

The analytes were extracted with acetonitrile, and analysed by LC-MS/MS.

B3c, Elements

Lead, mercury, cadmium, arsenic, cobalt, chromium, copper, iron, manganese, molybdenum, nickel, selenium, silver, vanadium, and zinc

The sample was decomposed by acid treatment, assisted by heat and high pressure. The metals were analysed by inductively coupled plasma mass spectrometer (ICP-MS) (Julshamn, Maage et al. 2007).

Inorganic arsenic

Inorganic arsenic was extracted by hydrochloric acid in hydrogen peroxide at 90 °C. Inorganic arsenic includes As (III) and As (V). As (III) was oxidised to As (V) during the extraction. Inorganic arsenic was separated from other arsenic compounds by anionic exchange HPLC, and detected by ICP-MS.

Methylmercury

Methylmercury was extracted by tetramethylammonium hydroxide. The pH was adjusted before derivatization and extraction by hexane. The samples were analysed by GC-ICP-MS.

Tributyltin

Tributyltin was extracted by acetic acid/methanol. The pH was adjusted before derivatization and extraction by hexane. The samples were analysed by GC-ICP-MS.

B3d, Mycotoxins

Enniatin and beauvericin

Beauvericin, enniatin A, enniatin A1, enniatin B and enniatin B1 were extracted with acetonitrile and water. Solid phase extraction was used for sample clean up. The mycotoxins were analysed by LC-MS/MS.

B3f, Others

HBCD

HBCD was extracted by a soxhlet apparatus, using a mixture of acetone and hexane. Sulfuric acid was used for purification. The extract was further cleaned up by an alumina column. The HBCD isomers were analysed by LC-MS/MS.

TBBPA

TBBPA was extracted by a soxhlet apparatus using a mixture of acetone and hexane. Sulfuric acid was used for purification. O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) was used for derivatization. The extract was purified using column chromatography. TBBPA was analyzed by GC-MS using Electron Ionization (EI).

PFC

PFCs were extracted by methanol, the extract was purified by solid phase extraction. PFCs were analysed by LC-MS/MS.

PAH

PAHs were extracted by dichloromethane and cyclohexane using an Accelerated Solvent Extractor (ASE). The extract was purified by solid phase extraction and analysed by GC-MS/MS.

Ethoxyquin

EQ and EQDM were extracted by hexane, after saponification in a mixture of ethanol, NaCl and NaOH. EQ and EQDM were quantified by reversed-phase high-performance liquid chromatography with fluorescence detection, using an external standard curve (Bohne, Hove et al. 2007, Ørnsrud, Arukwe et al. 2011).


Compounds Fish Atlantic salmon Rainbow trout Atlantic halibut Arctic char Turbot Atlantic cod Spotted wolffish
A1 Stilbenes

Zeranol

17alpha-Estradiol

17alpha-Ethinyl-estradiol

17beta-Estradiol

beta-Zearalanol

Dienestrol

Diethylstilbestrol

Estriol

Estrone

Hexestrol

825 785 35   5      

16-Hydroxystanozolol

17alpha-Boldenone

17alpha-Trenbolone

alpha-Nandrolone

Boldenone

Chlor-Testosterone

Epitestosterone

Methyl-Boldenone

Methyltestosterone

Nortestosterone

Stanozolol

Testosterone

Testosterone propionate

Trenbolone

Trenbolone-acetate

830 785 45          
A6 Illegal substances
Chloramphenicol 830 785 40   5      
Metronidazole 835 790 35 5 5      
Nitrofuran metabolites (AOZ, AMOZ, AHD, SEM) 825 780 35 5 5      

Malachite green*

Crystal violet

Brilliant green

825 785 30   5   5  
B1 Antibiotics

Oxytetracycline

Doxycycline

Chlortetracycline

Tetracycline

105 95 10          

Florfenicol

Flumequine

Oxolinic acid

Enrofloxacin

Ciprofloxacin

Trimethoprim

460 420 35     5    

Quinolones (liver)

Tetracyclines (liver)

Amphenicols (liver)

Sulphonamides (liver)

1470 1325 125   15     5
B2 Other veterinary drugs
Emamectin 590 550 35 5        

Cypermethrin

Deltamethrin

605 550 50   5      

Diflubenzuron

Teflubenzuron

Hexaflumeron

Lufenuron

Fluazuron

545 515 30          

Ivermectin

Abamectin

Doramectin

Eprinomectin

Moxidectin

80 70 10          

Praziquantel

Fenbendazole

495 465 30          

Isoeugenol

Eugenol

195 165 30          
B3a Organochlorine compounds
Pesticides 505 440 60   5      

Dioxin and dl-PCBs

PCB-6

425 375 45   5      
B3b Organophosphorous compounds

Azamethiphos

Dichlorvos

250 230 15 5        
B3c Chemical elements

Lead

Cadmium

Mercury

Arsenic

Cobalt

Chromium

Copper

Iron

Manganese

Molybdenum

Nickel

Selenium

Silver

Vanadium

Zinc

300 260 35     5    

Inorganic arsenic

Methylmercury

105 95 10          
Tributyltin 250 220 30          
B3d Mycotoxins

Beauvericin

Enniatin

500 455 40     5    
B3e Dyes

Malachite green*

Crystal violet

Brilliant green

465 420 45          
B3f Others
PBDE 425 375 45   5      
HBCD and TBBPA 355 345 10          
PAH 360 335 20   5      
PFC 360 310 45   5      
Ethoxyquin 400 380 15 5        
Table 2.1. Number of fish analysed for each substance.

Some of the samples collected have been analysed by more than one method. Therefore, the total of fish in this table will be higher than the number of fish collected.

* Malachite green, crystal violet and brilliant green belongs to the group B3e. However, these dyes are not allowed to be used for food producing animals, therefore samples analysed for dyes have been collected as both group A samples (illegal drugs) and group B samples (dyes) (EU 2017/625).

3 - Results

3.1 - Substances with anabolic effects and unauthorized substances

3.1.1 - Stilbenes

In 2020, a total of 165 pooled samples from Atlantic salmon, rainbow trout and Arctic char were examined for presence of stilbenes. None of the included stilbenes were detected in the samples analysed.

3.1.2 - Steroids

The presence of steroids was examined in 166 pooled fillet samples of Atlantic salmon and rainbow trout. None of the substances were detected in the samples analysed.

3.1.3 - Unauthorized veterinary drugs

A total of 663 pooled samples from Atlantic salmon, rainbow trout, Atlantic halibut, Arctic char and Atlantic cod were analyzed for unauthorized veterinary drugs, including chloramphenicol, nitrofurans, metronidazole and dyes (malachite green, crystal violet, brilliant green). No residues of the included substances were detected in any of the samples.

3.2 - Veterinary drugs

Samples analysed for veterinary drugs were collected from fish at processing plants, representing fish ready for human consumption. The maximum residue limit (MRL) for veterinary drugs is defined for muscle and skin in natural proportions (EU 37/2010). Therefore, according to the analytical protocol, any detection of drug residues in a sample of muscle or liver would be followed by a re-analysis of the backup sample, consisting of muscle and skin in natural proportions, in duplicate.

3.2.1 - Group B1, Antibacterial agents

The antibacterial agents were determined by a combination of the three-plate bioassay and chemical methods. The broad groups a) quinolones, b) amphenicols and tetracyclines and c) sulphonamides were measured in liver samples from 1470 fish. Oxytetracyclin (21 pooled samples) and florfenicol, flumequin, oxolinic acid, enrofloxacin, ciprofloxacin and trimethoprim (92 pooled samples) were also analysed using chemical methods. No residues were detected in any of the analysed samples. The LOQs of the respective compounds are listed in Table 5.4.

3.2.2 - Group B2a, Anthelmintics

The levels of the anthelmintics; teflubenzuron, diflubenzuron, hexaflumenuron, lufenuron, fluazuron, cypermethrin, deltamethrin, emamectin, ivermectin, abamectin, doramectin, eprinomectin, moxidectin, praziquantel and fenbendazole were determined in 463 pooled muscle samples representing 2315 fish. Emamectin was detected in one out of 118 pooled samples of Atlantic salmon, at a concentration of 7.1 µg/kg ww. This concentration is below the MRL of 100 µg/kg (EU 37/2010). No residues were detected for the other anthelmintics. LOQs for the substances are given in Table 5.4.

3.2.3 - Group B2b, Organophosphorous compounds

The levels of the B2b substances azamethiphos and dichlorvos were determined in 46, three and one pooled fillet samples of Atlantic salmon, rainbow trout and Atlantic halibut, respectively. No residues of these agents were detected in any of the examined samples.

3.2.4 - Group B2d, Sedatives

No residues of isoeugenol were detected in any of the 39 samples analysed.


3.3 - Contaminants

Samples analysed for contaminants were collected from fish at processing plants and are representative of fish ready for human consumption.

3.3.1 - Group B3a, Organochlorine compounds

The levels of organochlorine compounds were determined in 186 pooled samples. The results are summarised in Table 3.1 to 3.3.

3.3.1.1 - Organochlorine pesticides

For several of the pesticides, the MRL residue definitions include not only the parent compound, but also its metabolites or other transformation products (EU GD SANTE 2017). To calculate the sum of the components, conversion factors (Table 5.5) are used to adjust for different molecular weights (EU GD SANTE 2017). The results for this group of pesticides are presented in Table 3.1. The sums in Table 3.1 were calculated according to the upper bound (UB) formula. When using UB calculations, the numerical value of LOQ is substituted for analytes with levels below LOQ. UB represents a “worst case scenario”. As an example, all measurements of endosulfan were below LOQ, however, a sum was generated based on the LOQ-values. There are currently no MRLs established in fish fillet for any of the listed pesticides.

Pesticide Atlantic salmon Rainbow trout Arctic char
Sum n 88 12 1
DDT Median (UB) 4.7 4.3 -
Max (UB) 21 9.0 5.5
Endosulfan Median (UB) 1.3 1.3 -
Max (UB) 3.4 3.1 1.3
Aldrin and dieldrin Median (UB) 1.0 1.0 -
Max (UB) 3.3 1.8 0.86
Chlordane Median (UB) 0.90 0.90 -
Max (UB) 2.0 1.8 0.79
Heptachlor Median (UB) 0.53 0.53 -
Max (UB) 1.3 1.3 0.53
Toxaphene Median (UB) 2.3 2.0 -
Max (UB) 7.6 4.8 2.0
Table 3.1. Sums of pesticides (µg/kg w.w.) in fillets of farmed fish.

 

The levels of pesticides calculated from a sum of several components were comparable to the previous years. The highest values measured in Atlantic salmon fillet were 21 µg/kg w.w. of DDT, and 7.6 µg/kg w.w. Toxaphene. DDT and Toxaphene were also the highest measured concentrations in rainbow trout, with 9.0 and 4.8 µg/kg w.w, respectively.

The results for the other pesticides are summarised in Table 3.2. Hexachlorbenzene and trans-nonachlor were present in concentrations above LOQ in most of the samples. In 2020, the highest levels measured were 3.0 µg/kg w.w. of hexachlorobenzene and 2.1 µg/kg w.w. of trans-nonachlor in Atlantic salmon samples.


Pesticide Atlantic salmon Rainbow trout Arctic char LOQ
  n 88 12 1  
α-Hexachlorocyclo-hexane #Values 1 0 0  
Median LOQ - -  
Max 0.27 LOQ LOQ 0.13-0.60
β-Hexachlorocyclo-hexane #Values 3 0 0  
Median LOQ - -  
Max 0.66 LOQ LOQ 0.13-0.60
γ-Hexachlorocyclo-hexane #Values 1 0 0  
Median LOQ - -  
Max 0.25 LOQ LOQ 0.13-0.60
δ -Hexachlorocyclo-hexane #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.13-0.60
Hexachlorobenzene #Values 83 10 1  
Median 0.80 0.75 -  
Max 3.0 1.4 0.80 0.06-1.0
Pentachlorobenzene #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.30-1.2
Trans-nonachlor #Values 86 10 1  
Median 0.50 0.56 -  
Max 2.1 1.0 0.50 0.13-0.60
Endrin #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.15-0.71
Mirex #Values 2 0 0  
Median LOQ - -  
Max 0.14 LOQ LOQ 0.05-0.24
Octachlorstyrene #Values 5 1 0  
Median LOQ LOQ -  
Max 0.25 0.14 LOQ 0.03-0.12
Table 3.2. Pesticides (µg/kg w.w.) in fillets of farmed fish.
3.3.1.2 - Dioxin, dl-PCBs and PCB-6

The levels of dioxin (PCDD+PCDF), dl-PCBs and PCB-6 in farmed fish are shown in Table 3.3. The data is mainly represented by Atlantic salmon, but also samples from rainbow trout and Arctic char were examined. The sums of dioxins, dioxins+dl-PCBs and PCB-6 are calculated as upper bound (EU 1259/2011). Accordingly, the numerical LOQ values were used for congeners with levels below LOQ.

The levels of dioxins and dl-PCBs are reported as ng toxic equivalents 2005 (TEQ05)/kg and represent the sum of 17 different PCDD/F and 12 dl-PCBs where each congener was multiplied by a Toxic Equivalency Factor (TEF). TEF values are determined by WHO, and the toxicity of each congener is expressed relative to the most toxic form of dioxin, which has a TEF value of 1 (EU 1259/2011, Van den Berg, Birnbaum et al. 2006).

For salmon, the median of the sum of dioxins was 0.24 ng TEQ/kg w.w. The maximum value found in salmon (0.61 ng TEQ/kg w.w.) was below the EU maximum limit of 3.5 ng TEQ/kg w.w.

Corresponding to the concentrations found in 2019, in 2020, the median of the sum of all 29 PCDD/F and dl-PCBs was 0.46 ng TEQ/kg w.w for salmon and 0.41 ng TEQ/kg w.w for rainbow trout. The highest result for sum dioxin and dl-like PCBs in salmon was 1.81 ng TEQ/kg w.w. All measured values were below the EU maximum limit of 6.5 ng TEQ/kg w.w.

The median of PCB-6 for salmon was 3.4 μ g/kg w.w and 3.7 in rainbow trout, with maximum concentrations of 12.3 and 5.8 μ g/kg w.w, respectively. The concentration of PCB-6 in Arctic char was 7.7 μ g/kg w.w. For PCB-6, a maximum limit is set at 75 μ g/kg w.w. in the EU.

  Atlantic salmon Rainbow trout Arctic char Maximum limit
  Samples 75 9 1  
Sum dioxins (ng TEQ/kg w.w.) Median 0.24 0.21 -  
Max 0.61 0.33 0.30 3.5

Sum dioxin + dl-PCBs (ng TEQ/kg w.w.)

Median 0.46 0.41 -  
Max 1.81 0.64 0.82 6.5
PCB-6 (µg/kg w.w.) Median 3.4 3.7 -  
Max 12 5.8 7.7 75
Table 3.3. Dioxins, dl-PCBs and PCB-6 in fillets of farmed fish.

 

3.3.2 - Group B3c, Chemical elements

In 2020, monitoring of the levels of chemical elements, such as arsenic (and inorganic arsenic), total mercury in addition to methylmercury, cadmium, lead included 52 samples of Atlantic salmon, 7 samples of rainbow trout, and one sample of turbot. Mono-, di- and tributyltin were analysed in 44 samples of Atlantic salmon and 6 samples of rainbow trout.

The concentrations of total mercury were found below the EU maximum limit, which is set at 0.50 mg/kg w.w. for these species. The highest concentrations of total mercury were 0.05 mg/kg w.w. in salmon and turbot, and 0.03 mg/kg w.w. in rainbow trout (Table 3.4), mainly present as methylmercury (Table 5.1).

Cadmium was at concentrations above the LOQ was found in two out of a total of 60 samples. With a level of 0.004 mg/kg w.w. in the fillet salmon, and 0.003 mg/kg w.w. in rainbow trout, the measured concentration was well below EUs maximum limit of 0.05 mg/kg w.w. (EU 1881/2006).

Arsenic is determined as “total arsenic”, comprising the sum of all arsenic species. In addition, inorganic arsenic was determined in 21 of the samples. The median level of total arsenic in Atlantic salmon was 0.63 mg/kg w.w., and, same as in the previous year, the highest concentration measured was 2.1 mg/kg w.w. (Table 3.4). The concentrations of inorganic arsenic were below the LOQ in all samples measured (Table 5.1), indicating that arsenic in fish is present mainly as organo-arsenic compounds of low toxicity (Shiomi 1994). There is currently no EU upper limit for neither total arsenic nor inorganic arsenic in fish fillets.

Of the 60 samples analyzed, a lead concentration above LOQ was found in one sample of salmon. With a fillet concentration of 0.02 mg/kg w.w., the lead concentration was well below the EU maximum level, which is currently set at 0.30 mg/kg w.w. in muscle meat of fish (EU 1881/2006).

Eleven additional chemical elements were included into the surveillance from 2019. There is currently no EU-limit established for any of the newly included elements.

Copper, iron, manganese, selenium and zinc were found at levels above LOQ in all samples analysed (Table 3.4), with median values similar to the year before. The maximum concentrations were 0.6 mg copper/kg, 4 mg iron/kg, 0.43 mg manganese/kg, 0.33 mg selenium/kg and 7.9 mg zinc/kg, respectively, and were all found in salmon. Cobalt, silver, molybdenum or nickel were not detected in any of the analysed samples. Chromium and vanadium were detected in 15 and 44 out of 60 samples, respectively. The highest concentrations were 0.14 mg chromium/kg and 0.013 mg vanadium/kg (both salmon) in 2020.

Mono-, di- and tributyltin were monitored in a total of 50 pooled fillet samples of both salmon and rainbow trout. There is currently no EU upper limit for tin in fish fillet. Monobutyltin was found at levels above LOQ in 3 samples, with the maximum concentrations of 0.6 µg/kg w.w. and 0.5 µg/kg w.w. in salmon and rainbow trout, respectively. One sample of salmon contained dibutyltin at a concentration above LOQ (0.2 µg/kg w.w.). A total of 14 samples contained tributyltin above the LOQ, with the highest measured level of 1.7 µg/kg w.w. found in rainbow trout (median 0.15 µg/kg w.w.).

Element   Atlantic salmon Rainbow trout Turbot LOQ EU- Limit
  n 52 7 1    
Mercury (mg/kg w.w.) #Values 52 7 1    
Median 0.016 0.025 -    
Max 0.054 0.032 0.047 0.002 0.50
Arsenic (mg/kg w.w.) #Values 52 7 1    
Median 0.63 0.87 -    
Max 1.8 1.8 2.1 0.003 n.a.
Cadmium (mg/kg w.w.) #Values 1 0 1    
Median LOQ - -    
Max 0.004 LOQ 0.003 0.001-0.002 0.05
Lead (mg/kg w.w.) #Values 1 0 0    
Median LOQ - -    
Max 0.018 LOQ LOQ 0.006-0.01 0.30
Cobalt (mg/kg w.w.) #Values 0 0 0    
Median - - -    
Max LOQ LOQ LOQ 0.006-0.009 n.a.
Chromium (mg/kg w.w.) #Values 12 3 0    
Median LOQ LOQ -    
Max 0.14 0.022 LOQ 0.006-0.01 n.a.
Copper (mg/kg w.w.) #Values 52 7 1    
Median 0.37 0.37 -    
Max 0.58 0.48 0.23 0.1 n.a.
Iron (mg/kg w.w.) #Values 52 7 1    
Median 2.7 2.9 -    
Max 4.0 3.3 0.75 0.1 n.a.
Manganese (mg/kg w.w.) #Values 52 7 1    
Median 0.076 0.073 -    
Max 0.43 0.082 0.24 0.03 n.a.
Molybdenum (mg/kg w.w.) #Values 0 0 0    
Median - - -    
Max LOQ LOQ LOQ 0.01-0.4 n.a.
Nickel (mg/kg w.w.) #Values 0 0 0    
Median - - -    
Max LOQ LOQ LOQ 0.07-0.1 n.a.
Selenium (mg/kg w.w.) #Values 52 7 1    
Median 0.16 0.18 -    
Max 0.32 0.33 0.20 0.01 n.a.
Silver (mg/kg w.w.) #Values 0 0 0    
Median - - -    
Max LOQ LOQ LOQ 0.002-0.004 n.a.
Vanadium (mg/kg w.w.) #Values 41 3 0    
Median 0.004  LOQ -    
Max 0.013 0.003 LOQ 0.001-0.002 n.a.
Zinc (mg/kg w.w.) #Values 52 7 1    
Median 3.9 3.6 -    
Max 6.2 4.0 7.9 0.5 n.a.
  n 44 6      
Monobutyltin (µg Sn/kg w.w.) #Values 2 1      
Median LOQ LOQ      
Max 0.6 0.5   0.4-1 n.a.
Dibutyltin (µg Sn/kg w.w.) #Values 1 0      
Median LOQ -      
Max 0.2 LOQ   0.2-0.5 n.a.
Tributyltin (µg Sn/kg w.w.) #Values 9 5      
Median LOQ 0.15       
Max 0.2 1.7   0.06-0.09 n.a.
Table 3.4. Chemical elements in fillets of farmed fish.

 

 

3.3.3 - Group B3d, Mycotoxins

The mycotoxins enniatin A, enniatin A1, enniatin B, enniatin B1 and beauvericin were measured in 91 pooled samples of Atlantic salmon, 8 pooled samples of rainbow trout and one pooled sample of turbot. No residues of these mycotoxins were detected in any of the samples.

3.3.4 - Group B3e, Dyes

In addition to 164 samples analysed for residues of dyes as group A (illegal drugs) samples, dyes were measured in 93 pooled group B samples (contaminants; Group B3e, dyes). No residues of malachite green, crystal violet and brilliant green were detected in any of the group B samples.

3.3.5 - Group B3f, Others

The group B3f, others is a group not required for finfish products by Regulation (EU) 2017/625, but are deemed relevant for analyses in Norwegian aquaculture by the NFSA (Mattilsynet) and IMR, because these undesirable compounds are present in the environment and may affect food safety. This group currently consist of brominated flame retardants (BFR), perfluorinated compounds (PFC), polyaromatic hydrocarbons (PAHs), and since 2018 also the technological feed additive ethoxyquin (EQ) and its main transformation product ethoxyquin dimer (EQDM).

3.3.5.1 - Brominated flame retardants

In addition to the PBDEs included in PBDE-7 (PBDE 28, 47, 99, 100, 153, 154, 183), 10 other tri-hepta PBDEs (PBDE 35, 49, 66, 71, 75, 77, 85, 118, 119, 138) and five octa-deca PBDEs (PBDE 196, 197, 206, 207 and 209) were measured. Median values of PBDE-7 were 0.31 μ g/kg w.w. and 0.33 μ g/kg w.w for salmon and rainbow trout, respectively (Table 3.5). The results for all individually measured PBDE congeners are summarized in Table 5.2. Of 69 pooled Atlantic salmon samples and two pooled rainbow trout samples, TBBPA concentrations were detected above LOQ in four samples of salmon. The highest measured TBBPA value was 0.2 μ g/kg w.w.. HBCD was analysed in 69 salmon fillet samples and two rainbow trout fillet samples. The median HBCD concentration for salmon was 0.07 μ g/kg w.w., with a maximum concentration of 0.97 μ g/kg w.w.. There is currently no EU maximum limit for BFRs in food.

  Atlantic salmon Rainbow trout Arctic char LOQ
  Samples 75 9 1  
UB-Sum PBDE 7 Median 0.31 0.33 -  
Max 1.4 0.54 0.57  
  Samples 69 2 0  
TBBPA #Values 4 0    
Median LOQ -    
Max 0.20 LOQ   0.03-0.14
  Samples 69 2 0  
UB-Sum HBCD(α,β,γ) Median 0.07 -    
Max 0.97 0.05    
Table 3.5 . BFR (µg/kg w.w.) in fillets of farmed fish.
 
3.3.5.2 - Perfluorinated compounds

In 2020, a total of 72 samples were analysed for the PFCs. All results were below the LOQ (Table 5.3). EU has currently no maximum level for PFC in fish.


3.3.5.3 - Polycyclic aromatic hydrocarbons

PAHs were analysed in 67 samples of salmon, four samples of rainbow trout and one sample of Arctic char. The results for PAH are summarised in Table 3.6. Compared to the previous years, in 2020 elevated levels of PAHs were noted in four out of 72 analyzed fillet samples. However, there is currently no maximum limit for PAH in fresh fish (EU 835/2011).

PAH Atlantic salmon Rainbow trout Arctic char LOQ
  Samples 67 4 1  
5-methylchrysene #Values 1 0 0 0.09 - 0.13
Max 0.2 LOQ LOQ  
Benz(a)anthracene #Values 7 1 0 0.09 - 0.13
Max 2.9 1.2 LOQ  
Benzo(a)pyrene #Values 0 0 0 0.09 - 0.13
Max LOQ LOQ LOQ  
Benzo(b)fluoranthene #Values 0 0 0 0.09 - 0.13
Max LOQ LOQ LOQ  
Benzo(c)fluorine #Values 4 1 0 0.09 - 0.13
Max 0.8 0.6 LOQ  
Benzo(ghi)perylene #Values 0 0 0 0.09 - 0.13
Max LOQ LOQ LOQ  
Benzo(j)fluoranthene #Values 0 0 0 0.09 - 0.13
Max LOQ LOQ LOQ  
Benzo(k)fluoranthene #Values 0 0 0 0.09 - 0.13
Max LOQ LOQ LOQ  
Chrysene #Values 10 1 0 0.09 - 0.13
Max 5.0 1.9 LOQ  
Cyclopenta(cd)pyrene #Values 4 2 0 0.09 - 0.13
Max 0.3 0.3 LOQ  
Dibenz(ah)anthracene #Values 0 0 0 0.09 - 0.13
Max LOQ LOQ LOQ  
Dibenzo(a,e)pyrene #Values 0 0 0 0.44 – 0.66
Max LOQ LOQ LOQ  
Dibenzo(a,h)pyrene #Values 0 0 0 0.44 – 0.66
Max LOQ LOQ LOQ  
Dibenzo(a,i)pyrene #Values 0 0 0 0.44 – 0.66
Max LOQ LOQ LOQ  
Dibenzo(a,l)pyrene #Values 0 0 0 0.44 – 0.66
Max LOQ LOQ LOQ  
Indeno(1,2,3,-cd)pyrene #Values 0 0 0 0.09 - 0.13
Max LOQ LOQ LOQ  
Table 3.6. PAH (µg/kg w.w.) in fillets of farmed fish.
 
3.3.5.4 - Ethoxyquin

EQ and EQDM levels were measured in a total of 80 samples, mostly taken from Atlantic salmon, but also samples of rainbow trout and a sample of Atlantic halibut were included (Table 3.7). The fillet concentrations of the sum EQ and EQDM were calculated as upper bound (UB), using the numerical LOQ values (0.001 and 0.005 mg/kg ww, respectively) for measurements below LOQ. The number of samples with measurements above LOQ is indicated in Table 3.7 as the number of values.

In 2020, EQDM was found at concentrations above LOQ in 26 out of the 80 samples analyzed (23%), while only one sample (salmon) contained a concentration of EQ above LOQ. The median level of the sum of EQ & EQDM was 0.006 mg/kg ww in salmon. Rainbow trout contained sum EQ & EQDM at a median concentration of 0.01 mg/kg ww. One sample of Atlantic halibut was analysed, which contained 0.03 mg/ kg ww (UB) EQ&EQDM. The maximum values of EQ and EQDM were 0.001 and 0.09 mg/kg ww, respectively, and were found in salmon. There are no MRLs established for EQ or EQDM in fish fillet. The use of EQ as feed additive in animal feed has been phased out since July 2020. Samples taken after the phase out did not contain EQ above LOQ, and the maximum level of EQDM was 0.02 mg/kg ww (salmon). 

  Atlantic salmon Rainbow trout Atlantic halibut LOQ
  n 76 3 1  
EQ (mg/kg ww) #Values 1 0 0  
Median LOQ - -  
Max 0.001 LOQ LOQ 0.001
EQDM (mg/kg ww) #Values 26 2 1  
Median LOQ - -  
Max 0.09 0.02 0.03 0.005
Sum EQ&EQDM (mg/kg ww) UB #Values 76 3 1  
Median 0.006 0.01 -  
Max 0.09 0.02 0.03  
Table 3.7. Ethoxyquin and ethoxyquin dimer in fillets of farmed fish.

4 - Conclusions

No residues of unauthorized substances were detected in any of the samples analysed.

Residues of the anti-sea-lice agent emamectin was detected in one sample of salmon. However, the concentration was well below the MRL for emamectin established for fish.

Consistent with the data gathered in the recent years, no residues of antibiotics, endoparasitic agents were detected in any of the samples.

The contaminant levels in 2020 were comparable to the year before. None of the samples exceeded the EUs maximum levels, where such levels have been established (sum dioxins, sum dioxins and dl-PCBs, PCB-6, mercury, lead and cadmium).

5 - Tables

    Atlantic salmon Rainbow trout LOQ
  n 19 2  
Inorganic arsenic (µg/kg w.w.) #Values 0 0  
Median - -  
Max LOQ LOQ 2-3
Methyl-mercury (mg Hg/kg w.w.) #Values 19 2  
Median 0.020 -  
Max 0.052 0.037 0.001
Table 5.1. Inorganic arsenic and methylmercury in fillets of farmed fish.
  Atlantic salmon Rainbow trout Arctic char LOQ
PBDE congener Samples 75 9 1  
PBDE 28 #Values 75 9 1  
Median 0.011 0.012 -  
Max 0.039 0.022 0.019 0.002-0.003
PBDE 35 #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.003-0.005
PBDE 47 #Values 75 9 1  
Median 0.18 0.20 -  
Max 0.74 0.31 0.34 0.014-0.021
PBDE 49 #Values 75 9 1  
Median 0.049 0.056 -  
Max 0.210 0.091 0.11 0.003-0.005
PBDE 66 #Values 73 7 1  
Median 0.006 0.006 -  
Max 0.030 0.013 0.014 0.002-0.01
PBDE 71 #Values 4 2 0  
Median LOQ LOQ -  
Max 0.005 0.004 LOQ 0.002-0.003
PBDE 75 #Values 75 9 1  
Median 0.010 0.009 -  
Max 0.044 0.019 0.026 0.002-0.003
PBDE 77 #Values 2 0 0  
Median LOQ - -  
Max 0.017 LOQ LOQ 0.007-0.01
PBDE 85 #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.003-0.005
PBDE 99 #Values 75 9 1  
Median 0.026 0.022 -  
Max 0.140 0.080 0.055 0.007-0.01
PBDE 100 #Values 64 7 1  
Median (UB) 0.044 0.049 -  
Max 0.220 0.086 0.089 0.007-0.01
PBDE 118 #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.004-0.01
PBDE 119 #Values 7 1 1  
Median LOQ LOQ -  
Max 0.012 0.008 0.005 0.002-0.01
PBDE 138 #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.003-0.02
PBDE 153 #Values 21 3 1  
Median LOQ LOQ -  
Max 0.043 0.017 0.015 0.007-0.01
PBDE 154 #Values 75 9 1  
Median 0.028 0.027 -  
Max 0.160 0.059 0.052 0.007-0.01
PBDE 183 #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.007-0.01
PBDE 196 #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.017-0.026
PBDE 197 #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.01-0.016
PBDE 206 #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.01-0.016
PBDE 207 #Values 0 0 0  
Median - - -  
Max LOQ LOQ LOQ 0.01-0.016
PBDE 209 #Values 11 0 0  
Median LOQ - -  
Max 0.088 LOQ LOQ 0.014-0.021

 

Table 5.2. PBDEs (µg/kg w.w.) in fillets of farmed fish.

Compound Atlantic Salmon Rainbow trout Arctic char Max value LOQ
PFBA 62 9 1 <LOQ 1.0
PFBS 1.0
PFDA 0.2
PFDoDA 0.2
PFDS 0.2
PFHpA 0.2
PFHxA 0.5
PFHxS 1.0
PFNA 0.2
PFOA 0.6
PFOS 0.2
PFOSA 0.5
PFTeDA 0.2
PFTrDA 0.2
PFUdA 0.2
N-EtFOSA 1.5
N-EtFOSE 1
N-MeFOSA 1
N-MeFOSE 0.5

 

Table 5.3. PFCs (µg/kg w.w.) in fillets of farmed fish

Group of substances Analyte Method LOD (µg/kg w.w.) LOQ (µg/kg w.w.) Level of action (µg/kg w.w.) Laboratory
A1, Stilbenes Diethylstilbestrol LC-MS/MS 1   Presence Eurofins
Dienestrol 1
Hexestrol 1
β-Estradiol 1
α-Estradiol 1
Estriol 1
Estrone 1
Ethinyl estradiol 1
A3, Steroids α-nandrolon LC-MS/MS 1   Presence Eurofins
β-nandrolon 1
α-trenbolon 1
β-trenbolon 1
Trenbolone-acetate 2
16-Hydroxy stanozolol 1
α -Boldenone 1
Boldenone 1
Chlor-Testosterone (Clostebol) 1
Epitestosterone 1
Methyl-Boldenone (Dianabol) 1
Methyltestosterone 1
Nortestosterone/ Nandrolone 1
Stanozolol 1
Testosterone 1
Testosterone-propionate 2
A6, Annex IV substances Chloramphenicol LC-MS/MS 0.25   Presence (MRPL = 0.3) IMR
Metronidazole LC-MS/MS 0.3   Presence (MRPL = 3.0)
Hydroxy-metronidazole 2.0  
Nitrofuran AOZ LC-MS/MS 0.5   Presence (MRPL =1.0)
Nitrofuran AHD 0.6   Presence (MRPL =1.0)
Nitrofuran AMOZ 0.4   Presence (MRPL =1.0)
Nitrofuran SEM 0.5   Presence (MRPL= 1.0)
B1, Antibacterial Substances Micro-biological method1 Quinolones 3-plate Screening Method 2 200   100-600 IMR
Tetracyclines 200   100
Amphenicols 200   1000
Sulfonamides 400   100
B1,  Antibacterial substances Chemical method Oxolinic acid LC-MS/MS   40 100 IMR
Flumequine 40 600
Enrofloxacin 10 100
Ciprofloxacin 10 100
Trimethoprim 2 50
Oxytetracycline LC-MS/MS   30 100 Eurofins
Florfenicol LC-MS/MS   0.5 1000 IMR
B2a, Anthelmintics Praziquantel LC-MS/MS   1 n.a. IMR/ Eurofins
Fenbendazole LC-MS/MS   1 n.a.
Emamectin LC-MS/MS   2-10 100
Diflubenzuron LC-MS/MS   1-10 10
Teflubenzuron 1-50 500
Hexaflumuron 1-50 500
Lufenuron 1-50 1350
Ivermectin LC-MS/MS 2 n.a. Eurofins
Cypermethrin GC-MS   5 50
Deltamethrin 10 10
Isoeugenol GC-FID   50 6000
B3a, Organo-chlorine compounds Dioxins and dlPCB HRGC-HRMS   0.0001- 0.1 ng TEQ/kg 6.5 ng TEQ/kg IMR
PCB-6 GC-MS GC-MS/MS   0.004 – 0.5 75
Pesticides HRGC-HRMS   0.003-0.8 n.a. Eurofins
B3b, Organo-phosphorus compounds Azametiphos LC-MS/MS   10 n.a. Eurofins
Dichlorvos
B3c,  Chemical elements Lead ICP-MS   0.005- 0.01 mg/kg 0.3 mg/kg IMR
Cadmium   0.001- 0.002 mg/kg 0.05 mg/kg.
Arsenic   0.003 mg/kg n.a.
Mercury   0.002 mg/kg 0.5 mg/kg
Inorganic arsenic LC-ICP-MS   4-6 n.a.
Methylmercury GC-ICP-MS   1 n.a.
Tributyltin GC-ICP-MS   0.3-0.5 n.a.
B3d, Mycotoxins Beauvericin, Enniatin A, A1, B and B1 LC-MS/MS   10 n.a. Eurofins
B3e, Dyes Malachite green LC-MS/MS 0.15   Presence (MRPL=2) IMR
Leuco malachite green 0.15  
Crystal violet 0.30   Presence
Leuco crystal violet 0.15   Presence
Brilliant green 0.15   Presence
B3f, Others PBDE GC-MS   0.002-0.01 n.a. IMR
HBCD LC-MS/MS   0.006-0.01 n.a. Eurofins
TBBPA GC-MS   0.03-0.2 n.a. Eurofins
PAH GC-MS/MS   0.5-1.0 n.a. IMR
PFC LC-MS/MS   0.5-13 n.a. IMR
Ethoxyquin HPLC-FLD   0.001 n.a. IMR
Ethoxyquin dimer 0.005 n.a.
1 All methods used muscle as sample matrix except for microbiological methods for antibacterial substances (B1), where liver was used. 2 Only screening method, positive results must be confirmed by a chemical method.

 

Table 5.4. Summary of analytical methods.

Sum Substances included in the sum Conversion factor
DDT ( sum of p,p-DDT, o,p-DDT, p,p-DDD, o,p-DDD, p,p-DDE,and o,p-DDE expressed as DDT) op-DDT 1
pp-DDT 1
op-DDD 1.108
pp-DDD 1.108
op-DDE 1.115
pp-DDE 1.115
Endosulfan (sum of alpha- and beta-isomers and endosulfan-sulphate expressed as endosulfan) alpha-endosulfan 1
beta-endosulfan 1
endosulfan sulphate 0.962
Aldrin and dieldrin (Aldrin and dieldrin combined expressed as dieldrin) dieldrin 1
aldrin 1.044
Chlordane (Sum of cis- and trans-isomers and oxychlordane expressed as chlordane) trans-chlordane 1
cis-chlordane 1
oxychlordane 0.967
Heptachlor ( sum of heptachlor and heptachlor epoxide expressed as heptachlor) heptachlor 1
trans-heptachlor epoxide 0.959
cis-heptachlor epoxide 0.959
Toxaphene ( sum of toxaphene 26, toxaphene 50 and toxaphene 62) Toxaphene 26 1
Toxaphene 50 1
Toxaphene 62 1

 

Table 5.5. Calculation of sums for certain pesticides.

6 - References

Berntssen, M. H. G., K. Julshamn and A. K. Lundebye (2010). "Chemical contaminants in aquafeeds and Atlantic salmon (Salmo salar) following the use of traditional- versus alternative feed ingredients." Chemosphere 78(6): 637-646.

Bohne, V. J. B., H. Hove and K. Hamre (2007). "Simultaneous quantitative determination of the synthetic antioxidant ethoxyquin and its major metabolite in Atlantic salmon (Salmo salar, L), ethoxyquin dimer, by reversed-phase high-performance liquid chromatography with fluorescence detection." Journal of AOAC International 90(2): 587-597.

CRL (2007). "CRL guidance paper (7 december 2007) CRLs view on state of the art analytical methods for national residue control plans."

EU (37/2010). Commission Regulation (EU) No 37/2010 of 22 December 2009 on pharmacologically active substances and their classification regarding maximum residue limits in foodstuffs of animal origin (Text with EEA relevance). OJ L 15, 20.1.2010, p. 1–72. ELI: http://data.europa.eu/eli/reg/2010/37(1)/oj

EU (835/2011). Commission Regulation (EU) No 835/2011 of 19 August 2011 amending Regulation (EC) No 1881/2006 as regards maximum levels for polycyclic aromatic hydrocarbons in foodstuffs (Text with EEA relevance). OJ L 215, 20.8.2011, p. 4–8. ELI: http://data.europa.eu/eli/reg/2011/835/oj

EU (1259/2011). Commission Regulation (EU) No 1259/2011 of 2 December 2011 amending Regulation (EC) No 1881/2006 as regards maximum levels for dioxins, dioxin-like PCBs and non dioxin-like PCBs in foodstuffs (Text with EEA relevance). OJ L 320, 3.12.2011, p. 18–23. ELI: http://data.europa.eu/eli/reg/2011/1259/oj

EU (1881/2006). Commission Regulation (EC) No 1881/2006 of 19 December 2006 setting maximum levels for certain contaminants in foodstuffs (Text with EEA relevance). OJ L 364, 20.12.2006, p. 5–24. ELI: http://data.europa.eu/eli/reg/2006/1881/oj

EU (2003/1881). 2003/181/EC: Commission Decision of 13 March 2003 amending Decision 2002/657/EC as regards the setting of minimum required performance limits (MRPLs) for certain residues in food of animal origin (Text with EEA relevance). OJ L 71, 15.3.2003, p. 17–18. ELI: http://data.europa.eu/eli/dec/2003/181(1)/oj

EU (2004/25). 2004/25/EC: Commission Decision of 22 December 2003 amending Decision 2002/657/EC as regards the setting of minimum required performance limits (MRPLs) for certain residues in food of animal origin (Text with EEA relevance). OJ L 6, 10.1.2004, p. 38–39. ELI: http://data.europa.eu/eli/dec/2004/25(1)/oj

EU (2017/625). Regulation (EU) 2017/625 of the European Parliament and of the Council of 15 March 2017 on official controls and other official activities performed to ensure the application of food and feed law, rules on animal health and welfare, plant health and plant protection products, amending Regulations (EC) No 999/2001, (EC) No 396/2005, (EC) No 1069/2009, (EC) No 1107/2009, (EU) No 1151/2012, (EU) No 652/2014, (EU) 2016/429 and (EU) 2016/2031 of the European Parliament and of the Council, Council Regulations (EC) No 1/2005 and (EC) No 1099/2009 and Council Directives 98/58/EC, 1999/74/EC, 2007/43/EC, 2008/119/EC and 2008/120/EC, and repealing Regulations (EC) No 854/2004 and (EC) No 882/2004 of the European Parliament and of the Council, Council Directives 89/608/EEC, 89/662/EEC, 90/425/EEC, 91/496/EEC, 96/23/EC, 96/93/EC and 97/78/EC and Council Decision 92/438/EEC (Official Controls Regulation)Text with EEA relevance. OJ L 95, 7.4.2017, p. 1–142. ELI: http://data.europa.eu/eli/reg/2017/625/oj

EU GD SANTE (2017). "SANTE/11813/2017. Guidance document on analytical quality control and method validation procedures for pesticide residues and analysis in food and feed. Implemented by 01/01/2018."

Johnsen, C. A., Ø. Hagen, M. Adler, E. Jönsson, P. Kling, R. Bickerdike, C. Solberg, B. T. Björnsson and E. Å. Bendiksen (2011). "Effects of feed, feeding regime and growth rate on flesh quality, connective tissue and plasma hormones in farmed Atlantic salmon Salmo salar " Aquaculture 318: 343-354.

Julshamn, K., A. Maage, H. S. Norli, K. H. Grobecker, L. Jorhem and P. Fecher (2007). "Determination of arsenic, cadmium, mercury, and lead by inductively coupled plasma/mass spectrometry in foods after pressure digestion: NMKL1 interlaboratory study." Journal of Aoac International 90(3): 844-856.

Pirard, C., E. De Pauw and J.-F. Focant (2003). "New strategy for comprehensive analysis of polybrominated diphenyl ethers, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls by gas chromatography coupled with mass spectrometry." Journal of Chromatography A 998(1–2): 169-181.

Samuelsen, O. B., B. T. Lunestad, E. Farestveit, E. S. Grefsrud, R. Hannisdal, B. Holmelid, T. Tjensvoll and A. L. Agnalt (2014). "Mortality and deformities in European lobster (Homarus gammarus) juveniles exposed to the anti-parasitic drug teflubenzuron." Aquatic Toxicology 149: 8-15.

Shiomi, K. (1994). "Arsenic in marine organisms: chemical forms and toxicological aspects." Advances in environmental science and technology-New York: 261-261.

Van den Berg, M., L. S. Birnbaum, M. Denison, M. De Vito, W. Farland, M. Feeley, H. Fiedler, H. Hakansson, A. Hanberg, L. Haws, M. Rose, S. Safe, D. Schrenk, C. Tohyama, A. Tritscher, J. Tuomisto, M. Tysklind, N. Walker and R. E. Peterson (2006). "The 2005 World Health Organization reevaluation of human and Mammalian toxic equivalency factors for dioxins and dioxin-like compounds." Toxicological sciences : an official journal of the Society of Toxicology 93(2): 223-241.

Ørnsrud, R., A. Arukwe, V. Bohne, N. Pavlikova and A. K. Lundebye (2011). "Investigations on the metabolism and potentially adverse effects of ethoxyquin dimer, a major metabolite of the synthetic antioxidant ethoxyquin in salmon muscle." Journal of Food Protection 74(9): 1574-1580.