Contamination levels of lead, cadmium and mercury in imported and domestic lobsters and large crab species consumed in France: Differences between white and brown meat

Journal of Food Composition and Analysis 24 (2011) 368–375

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Original Article

Contamination levels of lead, cadmium and mercury in imported and domestic lobsters and large crab species consumed in France: Differences between white and brown meat Laurent Noe¨l a,*, Claude Chafey a, Christian Testu a, Je´re´my Pinte b, Pierre Velge b, Thierry Gue´rin a a

Unite´ des Contaminants Inorganiques et Mine´raux de l’Environnement, Laboratoire d’Etudes et de Recherches sur la Qualite´ des Aliments et des Proce´de´s Agroalimentaires, Agence Franc¸aise de Se´curite´ Sanitaire des Aliments, 23 Avenue du Ge´ne´ral de Gaulle, F-94706 Maisons-Alfort Cedex, France Bureau de la le´gislation alimentaire et Bureau des produits de la mer et d’eau douce, Direction ge´ne´rale de l’alimentation, Ministe`re de l’Alimentation, de l’Agriculture et de la Peˆche, 251 rue de Vaugirard, 75732 Paris Cedex 15, France

b

A R T I C L E I N F O

A B S T R A C T

Article history: Received 11 March 2010 Received in revised form 30 July 2010 Accepted 14 August 2010 Available online 8 December 2010

Lead, cadmium and total mercury contents have been determined by atomic absorption spectrometry in white and brown meat of 108 batches of crustaceans (lobsters, spider crabs, common crabs, swimming crabs and king crabs) collected in France between April and December 2009. With mean levels of 0.041, 0.132 and 0.128 mg kg1 for Pb, Cd and Hg, respectively, concentrations in white meat were systematically below the European legislation maximum level of 0.50 mg kg1. Cd concentration in the brown meat of common crabs (mean concentration: 11.8 mg kg1 and maximum of 14.3 mg kg1) was well above the observed levels for white meat. The consumption of one whole common crab of 1 kg (about 120 g of white and brown meat) would not contribute significantly to the Pb and Hg provisional tolerable weekly intake (PTWI) for adults, but the ingested Cd would greatly exceed the TWI of 2.5 mg kg1 body weight, which may be a health issue for consumers of brown meat. Therefore, we recommend moderate brown meat consumption. ß 2010 Elsevier Inc. All rights reserved.

Keywords: Crustaceans Toxic trace elements Cadmium Mercury Lead Homarus gammarus Maia squinado Cancer pagurus Portunus puber Paralithodes spp. Food analysis Food composition

1. Introduction Crustaceans such as lobsters or common crabs are highly prized and appreciated food commodities worldwide. In southern Europe, especially in countries such as Italy, France, Spain, Greece and Portugal, these crustaceans are widely consumed. For example, the European lobster (Homarus gammarus) production in 2007 was 3633 tonnes in all EU countries (EUROSTAT, 2009). Usually, only white meat from the appendages/claws and abdomen of large crustaceans (opposed to smaller crustaceans which include species that are either microscopic or range up to a few inches (about 5 cm) in size), is consumed. In some cases, such as spider crab for instance (Maia squinado), the white meat from the cephalothorax is also eaten. Up to now, the only regulatory limits have been set for white meat ‘excluding the brown meat of crab and excluding the

* Corresponding author. Tel.: +33 1 49 77 26 90; fax: +33 1 49 77 26 50. E-mail addresses: [email protected], [email protected] (L. Noe¨l). 0889-1575/$ – see front matter ß 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jfca.2010.08.011

head and thorax meat of lobster and similar large crustaceans (Nephropidae and Palinuridae)’ (EC, 2006, 2008) according to the ALARA principle (‘‘as low as reasonably achievable’’) based on the data gathered during the EC SCOOP task (SCOOP, 2004). The typical concentrations found in the muscle of crustaceans was 0.02– 0.2 mg kg1 for both Cd and Hg, and 0.02–0.1 mg kg1 for Pb (Francesconi, 2007; SCOOP, 2004). Consequently, the same maximum concentration level (0.50 mg kg1 fresh weight) was defined for these three toxic trace elements (EC, 2006, 2008). However, due to local consumer habits, some groups of European coastal populations also eat the so-called brown meat of these large crustaceans, namely the soft meat from the body of the crab that adheres to the inside of the hard upper shell, hepatopancreas and in some cases, gonads and roe. No maximum limit has been set for brown meat, although it is known that these parts of crustaceans can contain high levels of toxic trace elements (Davies et al., 1981). As shown by different studies such as total diet studies, seafood contributes to human exposure to toxic trace elements due to the

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contamination of the food chain by anthropogenic sources or natural deposits (Leblanc et al., 2005; Sioen et al., 2008). Toxicity due to trace elements has been regularly assessed by food safety authorities (Francesconi, 2007; EFSA, 2004; WHO, 2000). The Joint FAO/WHO Expert Committee on Food Additives (JECFA) established provisional tolerable weekly intakes (PTWIs) for these elements; the limits being 25 mg kg1 for Pb (JECFA, 2000), 5 mg kg1 for total mercury and 1.6 mg kg1 for MeHg and 7 mg kg1 body weight for Cd (JECFA, 2004). Cadmium toxicity was recently reassessed by EFSA and the JECFA’s PTWI was changed to a TWI of 2.5 mg kg1 b.w. (EFSA, 2009). In this context, a particular problem with regard to cadmium in crabs was raised in 2007, when large crustaceans were rejected by Italian food authorities following Cd analysis of the whole body compared to the maximum limit for white meat. Italy was concerned about coastal consumers who were used to eating both the white and brown meat of crustaceans. Since then, more than 60 notifications have been recorded in the European Commission’s Rapid Alert System for Food and Feed (RASFF) (RASFF, 2009). In order to increase our knowledge about the distribution of toxic trace elements in large crustaceans, the French General Directorate for Food (DGAL) of the Ministry of Food, Agriculture, and Fisheries decided to launch in 2009 a specific monitoring plan which stipulated separate analysis of white and brown meat. This survey aimed to provide French authorities with up-todate contamination data for crustaceans fished or imported by French operators. Taking into account the particular problem with regard to Cd in crabs, not only Cd level but also Pb and Hg levels were determined after separate dissection of both white and brown meat. 2. Materials and methods 2.1. Sample selection Samples of crustaceans were collected between April and December 2009. The sample selection only concerned species of the Brachyura and Lithodidae families (lobster (H. gammarus), spider crab (M. squinado), common crab (Cancer pagurus), swimming crab (Portunus puber) and king crab (Paralithodes spp.)). Four administrative regions were asked to provide a random sampling of 150 batches of large crustaceans. With the exception of the Ile-de-France region, each region (BasseNormandie, Brittany and Pays de la Loire) had to (i) identify the most representative species landed in its coastal de´partements, (ii) collect samples for two categories of product: products of national origin (landed in France) covering the majority of species landed and consumed in France and the France’s overseas de´partements vs. products of non-national origin, each origin sampled with respect to its ratio to the total imported quantity. The samples were representative of major categories of fishery products, listed by species and country of origin. Sampling was performed by DGAL local inspectors at the final consumer level, without particular consideration for the type of facility (supermarkets, fishmongers, outdoor markets, etc.). Samples were randomly taken and one sample corresponded to a homogeneous batch of individuals of a given species (same fishing area, similar size, caught if possible on the same day by a given fisherman, and landed the same day on a given site). 2.2. Sample preparation A total of 108 batches of crabs were finally obtained. Depending on the species, each batch consisted of one to four individuals for spider crab or lobster and up to more than ten for swimming crab.

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It should be noted that only legs and claws were collected for king crab and only the white meat was considered for swimming crab. Sample was prepared while taking care to avoid metal contamination and loss as much as possible. After washing with distilled water to remove foreign matter and dirt, the crab and lobster samples were dissected using stainless steel dissection instruments which were cleaned or replaced for each batch, while wearing rubber latex gloves, then divided into three parts for weighing: (i) white meat from the body, legs and claws, (ii) brown meat with thorax and (iii) the abdomen including all the contents of the digestive system without separation, and eggs when found. It should be noted that this third item was not considered for this study and that only white and brown meat were analyzed. The working surface was also cleaned after each operation. The samples were handled in such a way to avoid any contact with external surfaces. The material of each batch was mixed thoroughly using a modern domestic food processor with stainless steel blade (cleaned for each batch). After homogenisation, all the material obtained was transferred to polyethylene containers (Fisher Scientific, Illkirch, France), which had previously been washed, soaked in 10% (v/v) nitric acid, rinsed with de-ionized water, dried and stored at 20 8C before analysis. 2.3. Analytical methods 2.3.1. Apparatus A Varian SpectrAA 220FS (Varian S.A., Courtaboeuf, France) FAAS with a SPS 5 Varian auto sampler and a standard configuration was used for Hg determination. A Varian 220Z (Varian S.A., Courtaboeuf, France) ET-AAS, with Zeeman-effect background correction, equipped with a GTA 110 graphite tube atomizer, a PSD auto-sampler and Varian hollow cathode lamps, was used for the Cd and Pb measurements. The total digestion of the samples was carried out using a DigiPREP digestion system (SCP-Science, Courtaboeuf, France). 2.3.2. Reagents All solutions were prepared with analytical reagent grade chemicals and ultrapure water (18 MV cm) obtained by purifying distilled water with the Milli-QTM PLUS system associated with an Elix 5 pre-system (Millipore S.A., St Quentin-en-Yvelines, France). Suprapur nitric acid (HNO3, 67%, v/v), hydrochloric acid (HCl, 37%, v/v) and sulphuric acid (H2SO4, 96%, v/v) were purchased from VWR (Fontenay-sous-Bois, France). Standard stock solutions containing 1000 mg L1 of each element were purchased from Analytika (Prague, Czech Republic) and were used to prepare calibration standards. Working standards were prepared daily in 10% of HNO3 and were used without further purification. Tin(II) chloride (SnCl2) used as a reducing agent, and ammonium dihydrogen phosphate ((NH4)H2PO4) and magnesium nitrate (Mg(NO3)2), used as matrix modifiers, were purchased from Merck (Fontenay-sous-Bois, France). A mixed solution was prepared by dissolving 2 g (NH4)H2PO4 and 0.10 g Mg(NO3)2 in 200 mL of ultra pure water. Certified reference materials (CRMs) CRM 463R (Tuna fish) and ERM CE278 (Mussel tissue) were purchased from Promochem (Molsheim, France). These CRMs were used as provided without further grinding. 2.3.3. Digestion and quantitation of elements Pb, Cd and Hg concentrations were determined using the official methods of the French National Reference Laboratory (Maisons-Alfort, France), which has full accreditation for the ISO/ IEC 17025:2005 Standard. These methods include Hg determination by wet digestion and Cold Vapor Atomic Absorption Spectrometry (CVAAS) in foodstuffs of animal origin and Pb and

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Table 1 Results (mean  SD) of analyte content in CRMs obtained by AAS (mg kg1; n = 10) with RSD (%) in parentheses. Element d

Pb Cdd Hge

Certified valuea

Confidence intervalb

Observed valuec

2.00  0.04 0.348  0.007 2.85  0.16

1.40–2.60 0.244–0.452 2.34–3.36

2.05  0.13 (10) 0.360  0.023 (10) 2.93  0.11 (1)

a

Uncertainty given as 95% confidence interval. Calculated from the theoretical value (M) of the CRMs as: CI = M  [k  ((CVR  M)/100)] with k = 3 (P = 99%); M the certified value and CVR, the intermediate precision coefficient of variation, set at 10% for Pb, Cd, and 6% for Hg. pffiffiffi c XX Uncertainty ¼ ð2  X f  CV R Þ=ð100  nÞ with k = 2 (P = 95%); Xf = the mean result; CVR, the intermediate precision coefficient of variation, set at 10% for Pb, Cd, and 6% for Hg and n = the number of results. d ERM CE278 (Mussel tissue). e CRM 463R (Tuna fish). b

Cd determination by AAS (Flame and Electro-thermal AAS) in meat, fish and fishery products. For both methods, the manufacturer’s recommendations for wavelength, spectral band width and lamp current parameters were followed. For Cd and Pb determination, between 1 and 2.5 g fresh weight (fw) of each batch (or CRM) was predigested at room temperature for 5 h to facilitate the digestion process with 5 mL nitric acid at 1:2 dilution (v/v with ultrapure water). One randomly selected vessel

was filled with reagents only and taken through the entire procedure as a blank. The samples were then digested using the DigiPREP system (SCP-Science, Courtaboeuf, France) first at 65 8C for 1 h followed by a step at 95 8C for 2 h. For Hg determination, a sample of about 1 g fw with 3.5 mL of a HNO3/H2SO4 (4:3) mixture was digested using DigiPREP system (SCP-Science, Courtaboeuf, France) at 80 8C for 2 h. All the digested solutions were diluted in 25 mL of ultra pure water. To calibrate the instrument a set of at least five different concentrations were used: Hg: 0, 5, 10, 20, 30 and 40 mg L1; Pb: 0, 10, 20, 40 and 80 mg L1 and Cd: 0, 2.5, 5, 10 and 20 mg L1. Standards and digested samples were injected into the detector with a reducing agent (25% SnCl2 in 20% HCl) for mercury and with a matrix modifier (0.05% Mg(NO3)2 + 1% (NH4)H2PO4) for lead and cadmium. 2.4. Calculations and statistical methods Concentrations are expressed in milligrams of elements per kg (mg kg1) of fresh material. Data were subjected to linear regression and ordinary statistical methods were used to calculate the mean, median, percentage and 90th percentile. An independent-samples t-test was used to examine the differences according to white and brown meat or fishing areas. P < 0.05 was regarded as

Table 2 Levels of Pb, Cd and Hg in white and brown meat of common crabs from open sea areas (mg kg1 fresh weight). Fishing areas

Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl

NE NE NE NE NE NE NE NE NE-4B NE-4B7 NE-4C NE-6A NE-6A NE-6A NE-7A NE-7A NE-7D2 NE-7E1 NE-7E1 NE-7E1 NE-7E2 NE-7F1 NE-7H1 NE-7H1 NE-7H1 NE-7H3 NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A1 NE-8E1

Mean Median P90 Min Max

Origin

UK FR FR UK FR FR FR FR UK NL NL IE IE IE UK UK FR UK UK FR FR FR FR FR FR FR FR FR FR FR FR FR FR FR FR FR IE

Number of crabs

2 2 2 1 4 3 4 3 2 3 3 4 3 3 3 3 3 2 2 2 4 2 3 2 3 4 2 2 2 2 2 6 4 3 2 3 4

% white meat

73 79 74 65 72 76 74 67 70 77 73 60 67 82 n.a. 67 84 72 72 70 71 78 72 86 81 67 67 78 63 76 69 66 77 83 77 72 68 71 72 81 60 86

Pb

Cd

Hg

White meat

Brown meat

White meat

Brown meat

White meat

Brown meat

<0.040 <0.040 <0.040 <0.040 <0.040 <0.040 0.048 <0.040 0.089 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 0.041 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040

0.095 0.097 0.072 0.118 0.077 0.090 0.126 0.095 0.044 0.136 0.078 <0.040 <0.040 0.061 <0.040 0.083 0.138 0.054 <0.040 0.116 0.110 <0.040 <0.040 0.053 0.044 0.055 0.063 0.079 0.044 0.050 0.060 0.048 0.081 0.097 0.061 0.081 0.158

0.300 0.034 0.111 0.332 0.242 0.096 0.408 0.243 <0.020 <0.020 0.508 0.414 0.348 0.055 0.318 0.056 0.210 0.107 0.035 0.172 0.203 0.088 0.261 0.118 0.557 0.081 0.041 0.138 0.037 <0.020 0.115 0.081 0.504 0.192 0.162 0.274 0.260

2.79 16.6 6.10 27.6 11.5 41.7 23.3 31.0 0.782 2.17 14.6 8.74 11.2 7.58 21.3 8.46 4.36 9.01 16.7 17.3 10.2 13.3 15.8 9.91 25.5 9.62 5.18 38.6 7.25 20.9 26.6 8.12 51.7 6.55 11.8 16.7 26.8

0.094 0.066 0.117 0.089 0.077 0.142 0.050 0.078 0.153 0.175 0.108 0.167 0.121 0.120 0.096 0.057 0.086 0.061 0.243 0.277 0.084 0.062 0.220 0.100 0.135 0.104 0.105 0.192 0.084 0.132 0.261 0.131 0.308 0.074 0.162 0.405 0.112

0.043 0.162 0.079 0.082 0.074 0.104 <0.040 0.072 0.061 0.108 0.061 0.117 0.060 0.068 0.077 0.085 0.071 0.067 0.133 0.320 0.058 0.116 0.108 0.083 0.120 0.211 0.105 0.041 0.149 0.109 0.307 0.144 0.288 0.068 0.119 0.240 0.128

0.042 0.040 0.040 0.040 0.089

0.076 0.072 0.121 0.040 0.158

0.194 0.162 0.410 0.020 0.557

15.9 11.8 28.9 0.782 51.7

0.136 0.112 0.250 0.050 0.405

0.116 0.104 0.223 0.040 0.320

Abbreviations: Atlantic North East (Atl NE), France (FR), The United Kingdom (UK), The Netherlands (NL) and Ireland (IE). n.a. = not available.

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the statistically significant level. All statistics were performed using the Data Analysis function in Microsoft Office Excel 2007. For several samples, concentrations of metals were below the limits of quantitation (LOQ). To calculate mean concentrations, it was assumed that the values below the LOQ were equal to the LOQ (upper bound values). 2.5. Quality assurance The methods complied with the Commission Regulation (EC) No 333/2007 (EC, 2007), concerning sampling and analysis for official control of levels of Pb, Cd and Hg in foodstuffs. The LOQs met the Regulation requirements and were found to be 0.040, 0.020 and 0.040 mg kg1 for Hg, Pb and Cd, respectively for a typical sample weight of 1 g and a final dilution of 25 mL. For each experiment, an analytical sequence included a reagent blank, a certified reference material (CRM) and several digested samples (one sample per batch of crustaceans). The calibration curves showed determination coefficients of r2  0.995 (five points) for all elements and no outliers were found for blank controls. Control charts were built up by following CRM sample results for each

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element throughout the study. The trueness obtained in CRM 463R (Tuna fish) and ERM CE278 (Mussel tissue) was well within the confidence interval (CI) (n = 1; k = 3; P = 99%) around the reference value (Table 1). 3. Results and discussion The concentrations of Pb, Cd and Hg obtained in the 108 selected batches of crustaceans (more than 300 individuals) were reported for white and brown meat of the crabs separately (Tables 2–4). The number of animals for each batch is also given. Furthermore, the origin, the fishing area (in the open sea or along coastlines) and, when available, the fishing areas were specified as defined by the International Council for the Exploration of the Sea (ICES, 2009). Sufficient data about the fishing area were acquired only for the common crab and the spider crab. The total edible portion (both white and brown meats) accounts for approximately 12% of the whole crab for common crabs and spider crabs and 25% for lobsters. These 12% consist of about 61%, 73%, and 91% of white meat, respectively for spider crabs, common crabs and lobsters (only legs and claws were collected for king

Table 3 Levels of Pb, Cd and Hg in white and brown meat of common crabs from coastal areas (mg kg1 fresh weight). Fishing areas

Origin

Number of crabs

% white meat

White meat

Brown meat

White meat

Brown meat

White meat

Brown meat

Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl Atl

FR FR FR FR FR FR FR FR FR FR FR UK UK FR UK UK UK FR NL IE NL UK UK IE UK FR FR UK FR FR FR FR FR FR FR FR FR FR FR FR

3 2 2 2 3 3 3 3 2 2 2 – 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 3 2 2 1 1 1 1 3 1 1

65 81 79 77 77 75 77 66 64 71 83 – 75 65 69 65 70 69 74 73 70 70 59 76 72 77 72 65 82 79 82 69 67 76 77 66 79 70 79 79

<0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040

0.059 0.072 <0.040 0.068 0.120 0.221 0.142 0.054 0.170 0.055 0.070 – <0.040 <0.040 0.048 0.062 0.050 0.054 0.041 0.073 0.120 0.055 <0.040 <0.040 0.072 0.091 <0.040 0.083 <0.040 0.079 0.164 0.099 0.070 0.055 0.079 0.095 0.072 0.046 0.050 0.080

0.047 0.181 0.163 0.270 0.027 <0.020 0.047 0.192 0.066 0.034 0.090 0.061 0.080 0.073 0.139 0.052 0.107 0.475 0.050 0.587 0.036 0.463 0.129 0.227 0.347 0.341 0.068 0.060 0.025 0.096 0.070 0.025 0.026 0.061 0.384 0.225 0.196 0.070 0.021 <0.020

3.65 10.3 9.46 53.1 2.50 2.29 2.73 12.2 10.5 3.61 11.0 – 10.9 7.09 10.4 6.83 9.04 27.3 2.56 60.6 2.42 61.8 16.6 7.84 12.7 26.7 6.86 10.0 1.73 4.79 2.30 2.67 3.90 4.53 23.6 26.4 18.0 4.21 2.24 2.28

0.129 0.169 0.115 0.407 0.076 0.166 0.123 0.052 0.150 0.078 0.049 0.246 0.105 0.064 0.105 0.127 0.294 0.088 0.135 0.134 0.116 0.084 0.224 0.096 0.145 0.159 0.068 0.102 0.062 0.061 0.097 0.199 0.070 0.087 0.214 0.465 0.327 0.121 0.082 0.082

0.100 0.245 0.121 0.272 0.054 0.133 0.125 0.084 0.212 0.061 0.060 – 0.123 0.086 0.087 0.073 0.171 0.082 0.067 0.134 0.089 0.123 0.150 0.116 0.087 0.184 0.081 0.101 <0.040 0.066 0.076 0.141 0.089 0.126 0.169 0.331 0.220 0.126 0.062 0.095

73 73 80 59 83

0.040 0.040 0.040 0.040 0.040

0.076 0.068 0.124 0.040 0.221

0.141 0.072 0.351 0.020 0.587

12.8 7.84 26.8 1.73 61.8

0.142 0.116 0.251 0.049 0.465

0.122 0.101 0.214 0.040 0.331

NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE-6A NE-6A NE-7E1 NE-7E1 NE-7E2 NE-7F1 NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A NE-8A1 NE-8C1 NE-8C1

Mean Median P90 Min Max

Pb

Cd

Hg

Abbreviations: Atlantic North East (Atl NE), France (FR), The United Kingdom (UK), The Netherlands (NL) and Ireland (IE).

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Table 4 Levels of Pb, Cd and Hg in white and brown meat of some crustaceans (mg kg1 fresh weight). Species

Fishing areas

Origin

Spider crab

a

Atl NE a Atl NE-6A a Atl NE-8A a Atl NE-6A a Atl NE-8A b Atl NE-7E2 b Atl NE b Atl NE b Atl NE-7E2 b Atl NE-7E2 b Atl NE b Atl NE-8A b Atl NE-7E1 b Atl NE b Atl NE b Atl NE

UK IE FR IE FR FR FR FR FR FR FR FR FR FR FR FR

b

Atl NE Baltic Baltic Baltic Atl NE Atl NE

RU RU RU RU NO RU

b

Atl Atl Atl Atl Atl Atl

Lobster

b

King crab

Swimming crab

NE NE NE NE NE NE

Atl NE Atl NE a Atl NE b

Crabs Nb

% white meat

Pb White meat

Brown meat

White meat

Brown meat

White meat

Brown meat

77 67 43 53 69 59 62 52 68 54 42 63 64 66 67 73

<0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 <0.040 0.053 0.046 <0.040

0.089 0.060 0.047 0.048 0.048 <0.040 <0.040 0.110 <0.040 <0.040 0.070 <0.040 0.068 0.161 0.154 0.185

0.039 0.070 0.021 0.039 0.095 0.038 0.051 0.096 <0.020 0.120 0.060 0.047 0.114 0.035 0.047 0.087

0.801 1.89 0.317 0.498 5.34 0.533 5.21 2.72 0.308 0.91 2.08 1.32 3.64 0.628 0.610 1.00

0.070 0.048 <0.040 <0.040 0.074 0.060 0.053 0.156 <0.040 0.043 0.175 0.049 0.075 0.100 0.170 0.126

0.076 <0.040 <0.040 0.042 0.070 0.055 0.048 0.129 <0.040 <0.040 0.119 0.046 0.062 0.128 0.242 0.115

c – – – – – –

– – – – – –

<0.040 <0.040 <0.040 <0.040 <0.040 <0.040

– – – – – –

0.055 0.028 0.021 0.042 0.069 0.058

– – – – – –

0.078 0.083 0.041 0.048 0.116 0.091

– – – – – –

FR FR FR FR FR FR

12 10 12 11 13 11

– – – – – –

<0.040 <0.040 <0.040 <0.040 <0.040 <0.040

– – – – – –

0.027 0.025 0.030 0.024 0.025 0.028

– – – – – –

0.175 0.174 0.176 0.144 0.102 0.133

– – – – – –

FR FR FR

3 4 3

90 87 97

<0.040 <0.040 <0.040

0.030 0.022 0.034

2.74 1.47 2.74

0.148 0.122 0.115

1 4 3 4 4 2 1 2 2 3 2 2 3 2 2 2

Cd

0.080 0.042 0.044

Hg

0.065 0.050 0.043

Abbreviations: Atlantic North East (Atl NE), France (FR), The United Kingdom (UK), Norway (NO) and Russia (RU). a Open sea area. b Coastal area. c Only legs and claws were collected.

crabs and only the white meat was considered for swimming crabs). 3.1. Mercury Total mercury was quantified in 97% of samples (Table 5). The mean Hg concentrations in white meat ranged between 0.076 mg kg1 for king crabs and 0.151 mg kg1 for swimming crabs. The concentration obtained was within the range of typical concentrations found in crustacean muscle (0.02–0.2 mg kg1) (Francesconi, 2007). The highest levels were found in common crabs in both white meat (0.465 mg kg1) and brown meat (0.331 mg kg1) but all values were below 0.50 mg kg1. The mean level of Hg in the white meat was found to be slightly higher (P < 0.05) than in brown meat (Table 5) and no significant difference (P = 0.39 and 0.34 for white meat and brown meat, respectively) was observed in Hg levels in common crab from different fishing areas and places (open sea or coastal area) (Tables 2 and 3). The levels estimated in common crab (C. pagurus) are similar to those observed by Barrento et al. (2009a) (0.16– 0.61 mg kg1 fm in white meat and 0.15–0.51 mg kg1 fm in hepatopancreas), with more concentrated Hg levels in winter than in summer. The levels estimated in lobster (H. gammarus) are also similar as previously observed (0.15  0.04 mg kg1 fm in white meat and 0.09  0.02 mg kg1 fm in hepatopancreas) (Barrento et al., 2008). The PTWI was set to 5 and 1.6 mg kg1 body weight for total mercury and MeHg, respectively (JECFA, 2004). Taking into

account the mean contamination levels in white and brown meat of common crabs (0.139 and 0.119 mg kg1, respectively) and considering that the total edible portion represents 120 g for a 1 kg crab (73% of white meat and 27% of brown meat), the consumption of one whole crab represents a mercury intake of 16 mg. In other words, a single crab consumed per week contributes to 4.6% of the total mercury PTWI for an adult of 70 kg or 14% of the MeHg PTWI assuming that almost all of this is methyl mercury. 3.2. Lead Among the samples of white meat, 95% were found to be below the LOQ compared to only 19% for brown meat (Table 6). Pb is a contaminant usually detected at low concentrations in crustaceans (Sivaperumal et al., 2007), and the concentrations obtained fell within the range of typical concentrations found in crustacean muscle (0.02–0.1 mg kg1) (Francesconi, 2007). Brown meat appeared to accumulate more Pb than white meat (P < 0.05), with a total mean concentration of 0.075 mg kg1 for brown meat (range 0.055–0.078 mg kg1). The highest levels of Pb were found in the brown meat of common crab, either taken from the open sea (0.158 mg kg1) or from coastal areas (0.221 mg kg1), and in the spider crab (0.185 mg kg1) (Tables 2 and 3). All values were largely below the maximum concentration level of 0.50 mg kg1 (EC, 2006, 2008). No difference was observed in Pb levels in common crab collected from different areas and places (open sea or coastal area, P = 0.46 for brown meat) (Tables 2 and 3). The mean levels estimated in common crab (C. pagurus) are similar to those

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373

Table 5 Mercury levels in white and brown meat of some crustaceans (mg kg1 fresh weight). Species Lobster Common Crab Spider crab Swimming crab King crab Total

n

% < LOQ

n > 0.50 mg kg1

Mean

Median

P90

Min

Max

White meat Brown meat White meat Brown meat White meat Brown meat White meat White meat

3 3 77 76 16 16 6 6

0% 0% 0% 3% 3% 4% 0% 0%

0 0 0 0 0 0 0 0

0.128 0.053 0.139 0.119 0.082 0.081 0.151 0.076

0.122 0.050 0.115 0.103 0.065 0.059 0.159 0.081

0.143 0.062 0.252 0.216 0.163 0.129 0.176 0.104

0.115 0.043 0.049 0.040 0.040 0.040 0.102 0.041

0.148 0.065 0.465 0.331 0.175 0.242 0.176 0.116

White meat Brown meat

108 95

3% 6%

0 0

0.128 0.110

0.107 0.089

0.221 0.212

0.040 0.040

0.465 0.331

n = number of batch; P90 = 90th percentile.

Table 6 Lead levels in white and brown meat of some crustaceans (mg kg1 fresh weight). Species Lobster Common crab Spider crab Swimming crab King crab Total

n

% < LOQ

n > 0.50 mg kg1

Mean

Median

P90

Min

Max

White meat Brown meat White meat Brown meat White meat Brown meat White meat White meat

3 3 77 76 16 16 6 6

100% 0% 96% 17% 88% 31% 100% 100%

0 0 0 0 0 0 0 0

0.040 0.055 0.041 0.076 0.041 0.078 0.040 0.040

0.040 0.044 0.040 0.069 0.040 0.054 0.040 0.040

0.040 0.073 0.040 0.123 0.043 0.158 0.040 0.040

0.040 0.042 0.040 0.040 0.040 0.040 0.040 0.040

0.040 0.080 0.089 0.221 0.053 0.185 0.040 0.040

White meat Brown meat

108 95

95% 19%

0 0

0.041 0.075

0.040 0.063

0.040 0.132

0.040 0.040

0.089 0.221

n = number of batch; P90 = 90th percentile.

observed by Barrento et al. (2009a) (0.02–0.03 mg kg1 fm in white meat and 0.02–0.10 mg kg1 fm in hepatopancreas), with a peak in female hepatopancreas during autumn. The levels estimated in lobster (H. gammarus) are also similar as previously observed (0.10  0.00 mg kg1 fm in white meat and 0.10  0.06 mg kg1 fm in hepatopancreas) (Barrento et al., 2008). A PTWI for Pb of 25 mg kg1 body weight has been established for both adults and children, equivalent to 1750 mg per week for an adult of 70 kg (JECFA, 2000). The consumption of all edible parts of a 1 kg crab per week represents a lead intake of 6.0 mg, which would contribute to only 0.34% of the Pb PTWI for an adult. 3.3. Cadmium Cd levels in the two parts of the five species of crustaceans are shown in Table 7. Cd was quantified in 94% of white meat samples and all of them showed values below the maximum concentration level of 0.50 mg kg1, except for 4 samples of common crabs in both coastal (0.587 mg kg1) and open sea areas (0.504, 0.508 and

0.557 mg kg1). However, in compliance with the prescriptions of Commission Regulation No 333/2007 (EC, 2007), these 4 batches were accepted because the samples did not exceed the maximum level when taking into account the expanded uncertainty of the measurement result (e.g. for the highest concentration: 0.587  0.111 mg kg1). Cadmium distribution in crabs is not homogeneous for the different parts of a crustacean. Levels of Cd in white meat represented only an average of 2.2% of the levels of Cd in brown meat (min–max 0.1–13.2%), with 2 values > 10% for one spider and one common crab, the minimum value having also been found in a common crab. Cd in brown meat was quantified in all samples and 97% exceeded 0.50 mg kg1. Taking into account the measurement uncertainty, it should be noted that 95% of the batches would be rejected if brown meat compliance was assessed with regard to the current existing limit for white meat (EC, 2006, 2008). The highest mean concentrations in brown meat were observed in decreasing order in: common crab (14.3 mg kg1), lobster (2.32 mg kg1) and

Table 7 Cadmium levels in white and brown meat of some crustaceans (mg kg1 fresh weight).

Lobster Common crab Spider crab Swimming crab King crab Total

% < LOQ

n > 0.50 mg kg1

Mean

Median

P90

Min

Max

White meat Brown meat White meat Brown meat White meat Brown meat White meat White meat

3 3 77 76 16 16 6 6

0% 0% 6% 0% 6% 0% 0% 0%

0 3 4 76 0 13 0 0

0.029 2.32 0.166 14.3 0.061 1.74 0.027 0.046

0.030 2.74 0.107 10.1 0.049 0.954 0.026 0.049

0.033 2.74 0.394 27.5 0.105 4.43 0.029 0.064

0.022 1.47 0.020 0.782 0.020 0.308 0.024 0.021

0.034 2.74 0.587 61.8 0.120 5.34 0.030 0.069

White meat Brown meat

108 95

6% 0%

4 92

0.132 11.8

0.070 7.84

0.343 26.8

0.020 0.308

0.587 61.8

Species

n

n = number of batch; P90 = 90th percentile.

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spider crab (1.74 mg kg1). Several studies identified an accumulation of Cd concentrations in crabs’ hepatopancreas in several areas of the northeastern (NE) Atlantic: high Cd values were reported in the hepatopancreas of crabs such as C. pagurus (49 mg kg1) (Davies et al., 1981), 0–61 mg kg1 (Falconer et al., 1986) and 12–30 mg kg1 (Barrento et al., 2009b), and to a lesser extent in the king crab Pseudocarcinus gigas (22 mg kg1 dry weight (Turoczy et al., 2001)), the shore crab Carcinus maenas (3 mg kg1 dry weight (Bjerregaard et al., 2005)), and the blue crab Calinectes sapidus (4 mg kg1 (Karouna-Renier et al., 2007)). The levels estimated in common crab (C. pagurus) are slightly higher in white meat and similar in brown meat to those observed by Barrento et al. (2009a) (0.02–0.03 mg kg1 fm in white meat and 6– 28 mg kg1 fm in hepatopancreas). The levels estimated in lobster (H. gammarus) are similar in white meat and lower in brown meat as previously observed (0.02  0.01 mg kg1 fm in white meat and 11  9 mg kg1 fm in hepatopancreas) (Barrento et al., 2008). The concentrations obtained were in the range of the typical concentrations found in crustaceans muscle (0.02–0.2 mg kg1) (Francesconi, 2007). The highest levels of Cd were found in common crabs from both costal (61.8, 60.6 and 51.3 mg kg1) and open sea areas (51.7 and 41.7 mg kg1) (Tables 2 and 3). No significant difference at 5% was observed (P = 0.06 for white meat and P = 0.15 for brown meat) even though common crabs from coastal areas appeared to be less contaminated than those caught in the open sea whatever the type of meat considered (e.g. mean of 12.8 against 15.9 mg kg1 for brown meat in coastal areas and open sea, respectively) (Tables 2 and 3). Contents in the white and brown meat of common crabs were similar in open sea areas others than Zones 7 and 8, compared to all areas (0.224 against 0.166 mg kg1 for white meat, respectively, P = 0.12; 14.7 as against 14.3 mg kg1 in all combined areas for brown meat, P = 0.45). Compared to all combined areas, the brown meat of common crabs taken from the open sea in Zone 8 of the NE Atlantic area were the most contaminated by Cd (mean of 20.0 mg kg1). Paradoxically, however, the brown meat and the white meat of common crabs taken in coastal areas in Zone 8 were significantly less contaminated by Cd than the mean of all combined areas (white meat: 0.102 against 0.166 mg kg1 (P < 0.05) and brown meat: 8.1 against 14.3 mg kg1(P < 0.05)). It should be noted that there was no significant difference (P = 0.41) in Cd levels in different areas and places (open sea or coastal area) for spider crabs. All results can be related to the notifications recorded in the RASFF by Italian authorities from the end of 2007 up to the present (RASFF, 2009) which report concentrations of Cd between 0.64 and 35.4 mg kg1 in the total edible meat (white and brown meat) of common crabs from France, Ireland and the United-Kingdom. A TWI of 2.5 mg kg1 body weight was defined for Cd, equivalent to 175 mg per week for an adult of 70 kg (EFSA, 2009). With the mean values obtained for common crab in white and brown meat (0.166 and 14.3 mg kg1, respectively), the consumption of one crab per week with a total weight of 1 kg (about 120 g of both white and brown meat) represents a cadmium intake of 470 mg that would contribute about 269% of the TWI for adults. This result combined with the fact that Cd concentration in the brown meat of crabs was well above the maximum levels set by the European Commission (for muscle), could represent a health concern for certain types of high consumers of crustacean brown meat. 4. Conclusions Results from this study show that Pb, Cd and Hg concentrations in white meat of crabs were systematically below the maximum

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