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Previously, high concentrations of cadmium have been found in the hepatopancreas of the edible or brown crab (Cancer pagurus) sampled from positions north of about 67° N, compared to regions further south along the Norwegian coast, with no clear understanding why. In order to study a similar organism in the same ecosystem, the present study analyze...
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Brown crab Cancer pagurus is appreciated as seafood in several European countries. However, cadmium levels in crabs can be elevated and their consumption may pose a hazard for human health. To assess if cadmium poses a threat to food safety in Norway, crabs were sampled at two different locations along the Norwegian coast: one in the South of Norwa...
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... Various factors affect cadmium accumulation in crab species. In Carcinus maenas (shore crab), factors such as ovarian maturation, moulting stage, condition (e.g., water content of the crab), tissue hydration, sex, and size all affect cadmium bioaccumulation [62,63,[72][73][74]. In brown crabs specifically, there is evidence that cadmium levels differ due to location and cooking (which increases cadmium in claw meat while reducing the concentration in the inner meat), and there is a correlation between crab size and levels of cadmium in the hepatopancreas [30,75], which implies that cadmium accumulates as the crab ages. ...
... This may indicate biases when assessing cadmium levels in crabs that have been processed [30]. Studies have also linked cadmium levels to seasons, where lower levels have been detected in the summer months [63,72], potentially due to the shorter biological half-life of cadmium as the temperature increases during summer [63]. However, the effect of season was inconclusive in another study [31]. ...
Cadmium is a major health risk globally and is usually associated with pollution and an-thropogenic activity. The presence of cadmium in food is monitored to ensure that the health and safety of consumers are maintained. Cadmium is ubiquitous in the Asian and Western diets, with the highest levels present in grains, leafy greens, and shellfish. As part of their natural lifecycle of moulting and shell renewal, all crustaceans-including the brown crab (Cancer pagurus)-bioaccu-mulate cadmium from their environment in their hepatopancreas. The brown crab is an important species to the crab-fishing industries of many European countries, including Ireland. However, the industry has come under scrutiny in Europe due to the presence of cadmium in the brown crab meat intended for live export to Asia. This review explores evidence regarding the effects of cadmium consumption on human health, with a focus on the brown crab. Differences in cadmium surveillance have given rise to issues in the crab industry, with economic consequences for multiple countries. Currently, evidence suggests that brown crab consumption is safe for humans in moderation, but individuals who consume diets characterised by high levels of cadmium from multiple food groups should be mindful of their dietary choices.
... Crayfish close to a source of pollution were found to have cadmium concentrations as high as 5.53 mg/kg in the abdominal muscle and 5.44 mg/kg in the hepatopancreas (Kouba et al., 2010). Cadmium has also been noted to accumulate in soft tissues, such as the hepatopancreas, and the exoskeleton of model organisms, such as the shrimp, Palaemon elegans, and the shore crab, Carcinus maenas (White and Rainbow, 1986;Knutsen et al., 2018). Cadmium exposure is known to cause respiratory disruption, molt inhibition, and decreases in growth in crustaceans. ...
Despite the fact that cadmium has been reported to be present in crustacean exoskeletons, no study has previously been done to determine when cadmium is deposited to the exoskeleton and what effects cadmium has on the shell-hardening process. This project sought to address these scientific questions using the blue crab, Callinectes sapidus, as the model crustacean. It was hypothesized that cadmium would be incorporated into the exoskeleton during post-ecdysial mineralization through ionic mimicry because of the resemblance between cadmium and calcium ions. To test this, soft shell blue crabs were injected with cadmium chloride, and cadmium content in the exoskeleton was subsequently quantified using ICP-OES. Carbonic anhydrase catalyzes the carbon dioxide hydration reaction, which generates bicarbonate ions essential for calcium carbonate formation in the shell. The effect of cadmium injection on epidermal carbonic anhydrase activity as well as exoskeletal calcification was also investigated. It was found that cadmium injection into post-ecdysial Callinectes sapidus significantly increased cadmium content in the exoskeleton, suggesting that cadmium is deposited to the new exoskeleton during post-ecdysial mineralization. Cadmium administration had no effect on epidermal carbonic anhydrase activity or exoskeletal calcification. Interestingly, magnesium content in the exoskeleton was significantly elevated following cadmium treatment. This is most likely a “pseudo” effect stemming from the cadmium-induced reduction in exoskeleton weight. The fact that cadmium had no effect on exoskeletal calcium and that cadmium decreased the weight of the exoskeleton suggests that cadmium has a detrimental effect on the formation of the organic matrix of the exoskeleton. The presence of cadmium in control crabs and exuviae and the amplification of cadmium content in cadmium-treated crabs clearly show that crab shell is a cadmium repository and can be used as a biomarker for aquatic cadmium pollution.
... For Cr, the levels detected in the present study were comparable to those found in muscle of Rapana venosa (0.47 ± 0.01 μg g -1 ) from the Black Sea (Topcuoğlu et al. 2002) and in muscles of the blue crabs (0.68 ± 0.50 mg kg -1 ) collected from the northern Bay of Bengal (Karar et al. 2019), while the Cr levels resulted higher than those found in muscle of Rapana venosa (0.1 to 0.2 μg g -1 ) from the Black Sea analysed by Mülayim and Balkıs (2015) and in muscle of warty crab from Adriatic Sea (Zotti et al. 2016). Moreover, it has been reported by many authors that the bioaccumulation of toxic metals in crabs, and in general in all marine animals, depends on several physiological and biometric factors among which the body size is recognized as an important parameter (Pinheiro et al. 2012;Knutsen et al. 2018;Wiech et al. 2020). In the current study, the statistical analysis showed that the heavy metal levels were not statistically correlated to the size of the crabs (p > 0.05), suggesting that these parameters have a minor effect on metals accumulation in subjects inside the size range considered in this study. ...
This study assesses the PAH and heavy metal levels in muscle of warty crabs (Eriphia verrucosa), from the northern coast of the Campania region improving the data on toxic contaminants in this crustacean. The results showed a minimal PAH contamination; the mean concentrations were as follows: 0.2, 1.6 and 1.7 μg kg-1 wet weight (ww) for BaP, PAH4 and PAH6, respectively. Regarding the levels of the two PAHs not included in the European regulations, the BkF mean concentration was 0.1 μg kg-1 ww, while DahA was detected only in 10.7% of samples. Pb and Cr were also detected at low levels with mean values of 0.068 and 0.468 mg kg-1 ww, respectively; instead, high As levels, with a mean value of 5.021 mg kg-1 ww, were found. Considering the EWIs and the ILCRs calculated in this study, the PAH, Pb and Cr contamination levels found in the edible part of the crabs resulted safe for human consumption. Contrariwise, the ILCR calculated for the As exceeded the acceptable level of cancer risk, although the calculation did not refer to the inorganic form which is the only one recognized as carcinogenic. Hence, this study shows that warty crabs can accumulate environmental contaminants in their muscle tissue representing an important route of exposure to these toxics for the local population that regularly consumes them. This finding highlights the importance of monitoring the presence of these pollutants in crabs and in general in all fish and seafood in order to ensure food safety for consumers.
... w.), which were consequently not influenced by the water content. When necessary (for comparison purposes), concentrations from brown crab and fish biological media were converted from d.w. to wet weight (w.w.) dividing by a factor of 3.2 and 5, respectively (Cresson et al., 2017;Knutsen et al., 2018). The water content in brown crab and fish biological media was estimated at 69 and 80%, respectively (Cresson et al., 2017;Knutsen et al., 2018). ...
... When necessary (for comparison purposes), concentrations from brown crab and fish biological media were converted from d.w. to wet weight (w.w.) dividing by a factor of 3.2 and 5, respectively (Cresson et al., 2017;Knutsen et al., 2018). The water content in brown crab and fish biological media was estimated at 69 and 80%, respectively (Cresson et al., 2017;Knutsen et al., 2018). A portion of 100-400 mg of the dried environmental or biological sample was transferred to a polytetrafluoroethylene (PTFE) vessel and 9 mL of aqueous nitric acid (50% v/v) was added. ...
The brown crab (Cancer pagurus; the edible crab) is consumed worldwide and greatly appreciated for the essential elements (e.g., Zn, Se) that it contains. However, alongside these, it contains toxic elements that can pose serious risks for human health. For the brown meat parts of the brown crab, which contain considerable Cd concentrations, official legal limits of exposure are still lacking by regulatory bodies, rendering its consumption a potential food safety threat. In this study, a survey was conducted during 2016-2018 in a major Mid-Norway commercial crab fishing area of Mausund in Frøya municipality, Norway, where brown crab media samples were collected to assess the occurrence and profile of select elements, including toxic elements (Cd, Pb, Hg, Sr, As). A yearly median concentration ranging from 6.75 (2016) to 14.0 (2017) mg Cd/kg dry weight (est.: 2.11 (2016) to 4.37 (2017) mg Cd/kg wet weight) indicated high Cd concentrations, which were alarming when compared to the maximum allowed concentration of 0.5 mg/kg wet weight set by the E.U. for raw white crab meat. Human exposures were assessed by estimating intakes of elements per 100 g serving portion of dry edible media (white/brown meat), and the tolerable upper intake levels (ULs) (as specified by the United States National Academy of Sciences) were exceeded for Fe, Cu, Ni, Se, Ca, Mg and P. The median Se and Cd estimated human dietary intakes (EDIs) (from brown crab) were 8.21-8.59 and 9.64-20.0 μg/kg body weight, respectively. The human intake dose (ID) of Cd (from brown crab) reached the order of a few tens of milligrams (mg). In addition, 33% of brown crab samples were found to be suitable for human consumption when the Se:Cd concentration ratio was applied and a stoichiometric excess of Se over Cd was indicated.
... In shore crab Carcinus maenas different physiological factors including moulting stage Bondgaard et al., 2000;Nissen et al., 2005;Nørum et al., 2005), ovarian maturation (Bondgaard et al., 2000) and condition (water content) of the crab (Bjerregaard, 1991) were found to influence the accumulation of Cd and so did tissue hydration, crab size (Bjerregaard and Depledge, 2002) and sex (Knutsen et al., 2018). ...
... Bjerregaard et al (2002) compared small (body wet weight: 34 ± 7 g) and large (body wet weight: 108 ± 11 g) crabs, and found differences in HP for dry weight based Cd concentrations but not for wet weight based concentrations. In shore crab from Norwegian waters, the correlation with size was, as in brown crab, strongest for the total amount of cadmium (Knutsen et al., 2018). ...
... However, also earlier studies found no difference between males and females in HP Cd levels in brown crab (Barrento et al., 2009a) and burrowing crab Neohelice granulate (Beltrame et al., 2010). Only in the shore crab Carcinus maenas, sex differences have been observed earlier (Knutsen et al., 2018. In brown crab, for muscle meat and gills, higher concentrations were found in females (Barrento et al., 2009a). ...
Brown crab Cancer pagurus is appreciated as seafood in several European countries. However, cadmium levels in crabs can be elevated and their consumption may pose a hazard for human health. To assess if cadmium poses a threat to food safety in Norway, crabs were sampled at two different locations along the Norwegian coast: one in the South of Norway and one in the North of Norway. Cadmium levels were determined in different tissues (claw meat, hepatopancreas and inner meat). To highlight specific risk factors for cadmium, the concentration of cadmium was related to different exogenous (location, cooking and season) and physiological (size, sex, moulting stage, gonad maturation stage, condition) factors. The results confirmed previous findings of much higher cadmium levels in brown crab sampled in the North of Norway compared to the South. Cooking of crabs further led to higher concentrations in claw meat. The effect of season on cadmium levels was different in the North and South and no clear patterns could be identified, probably due to a high inter-individual variation in cadmium levels. Size showed a correlation with the total amount of cadmium for crabs in the North indicating an accumulation of cadmium over time; together with a slower growth, this may lead to the higher cadmium levels, observed in the crabs from Northern Norway. The risk connected to cadmium exposure when consuming brown crab mainly depends on the consumption pattern, the parts of the crab consumed and the origin of the crab. Regardless of origin, the consumption of claw meat does not display a consumer health risk. However, the consumption of meals consisting of inner meat only and inner meat of brown crab from Northern Norway may pose a health risk.
... A recent study has quantified the Cd concentrations in green crabs along the Norwegian coast and found a different pattern between green and brown crab. For green crab, there was no clear difference in Cd concentrations between crabs from North and South (Knutsen et al., 2018), as seen in brown crab (Julshamn et al., 2012). This indicates that there might be differences in uptake and elimination processes in the two species, as already known for other crab species (Rainbow & Black, 2005a, 2005b. ...
High concentrations of cadmium in brown crab are an issue of food safety, and large variations between different areas have been found. To investigate the relative importance of dietary and aqueous uptake regarding the overall accumulation in brown crab, we used stable isotopes to trace the uptake from both routes simultaneously in the same animals. We demonstrated that the analytical challenges regarding background concentrations of natural isotope distribution and polyatomic interferences in the different matrices can be overcome with an appropriate analytical setup and modern mathematical corrections using a computer software. Cadmium was accumulated via both routes and was found in all measured organs at the end of the exposure phase. The obtained data were used to establish accumulation curves for both uptake routes and estimate accumulation parameters for hepatopancreas, as the most important organ in crab regarding total cadmium body burden. Using the estimated parameters in combination with naturally relevant cadmium concentrations in seawater and diet in a model, allowed us to predict the relative importance of the aqueous and dietary uptake route to the total hepatopancreas burden. According to the prediction, the dietary route is the main route of uptake in brown crab with a minimum of 98% of the accumulated cadmium in hepatopancreas originating from diet. Future studies addressing the source and accumulation of cadmium in crab should therefore focus on the uptake from feed and factors connected to foraging.
Rapporten om strandkrabbe og strandkrabbefiskeri er en grundig gjennomgang av den biologiske kunnskapen som finnes. I tillegg er det tatt inn økologisk vurdering av strandkrabbens plass i økosystemet, og trusler den har fra invasjonsarter som penselkrabber. Denne rapporten presenterer oppdatert kunnskap om strandkrabber, fra livssyklus, biologi og økologi.
Rapporten beskriver dagens fiskeri og gir en rekke råd om hvordan videre ekspansjon av fiskeriet kan foregå og forvaltes. Det gis råd om redskap i sammenheng med å utvikle målrettet fiske med liten risiko for bifangst og det diskuteres hvordan tap av redskap kan unngås. I tillegg er det kort nevnt markedspotensial på ulike områder, samt innspill om dyrevelferd, mattrygghet og kunnskapsmangler som kan gjøre overvåking og god rådgiving vanskelig.
Kapitlene i rapporten dekker alle disse temaene, og rapporten har dessuten en fyldig referanseliste.
Bioaccessibility study is of great significance to the health risk assessment of trace elements in the seafood. In this work, the most consumed crab (Portunus trituberculatus) in coastal area of Shandong, China was analyzed to study the distribution and the bioaccessibility of cadmium (Cd) in the edible tissues of crab, and the dietary risk from consumption of crab was also evaluated. Results showed that the content of Cd in the whole edible tissues of 109 crab specimens ranged from 0.052 to 8.89 mg/kg ww (wet weight) with mean of 2.26 mg/kg ww. The Cd content in 85% of the crab samples was higher than the national food safety limits (0.5 mg/kg ww) of China. The gender study indicated that there was no significant difference in Cd content in total edible tissues between the males and females (p > 0.05). Cadmium was highly concentrated in the brown meat with mean value of 4.13 mg/kg ww, which was about 5 times higher than that in the white meat (0.75 mg/kg ww). The bioaccessibility of Cd ranged from 48.1 to 71.0% in the white and brown meat. The risk assessment based on the bioaccessibility of Cd revealed that the consumption of the edible crab brown and white meat for adults should be limited in 0.13 kg and 1.56 kg per week respectively.
