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Toxic metals in tuna and swordfish: literature review and meta-analysis
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O pescado é uma das principais fontes de alimentação, nutrição, rendimento e meios de subsistência. O consumo de pescado está associado não só por ser fonte de proteínas, às vitaminas D e A ou aos minerais, mas também de ácidos gordos polinsaturados (poli-unsaturated fatty acids, ou PUFA) ómega-3, que desempenham um papel importante na prevenção da maioria das patologias cardiovasculares. Foi demonstrado que o pescado tem vários benefícios para a saúde, tais como propriedades antioxidantes, anti-inflamatórias, de cicatrização de feridas, neuroprotetoras e cardioprotetoras. A produção de pescado a nível mundial aumentou muito, passando de 19 milhões de toneladas
(peso vivo equivalente) na década de 1950 para um recorde de cerca de 179 milhões de toneladas em 2018 (FAO, 2020). O pescado tem registado uma maior procura (Delgado et al., 2004), e o consumo está a aumentar globalmente 2,5% ao ano (Peterson & Fronc, 2007; Banco Mundial, 2013). Os peixes marinhos mais importantes do ponto de vista comercial são incluem salmão, arenque, bacalhau, cantarilho, a cavala, o atum, a sardinha e o espadarte. Devido ao seu elevado valor comercial, espécies como o espadarte e o atum são comercializadas em quantidades relativamente mais pequenas com um valor de mercado mais elevado, enquanto outras espécies são comercializadas em maiores quantidades, mas com valores mais baixos. Os atuns têm sido um importante produto económico de elevado valor comparativo entre vários recursos aquáticos com uma ampla quota de mercado. Incluem cerca de >10 espécies que ocorrem nos oceanos Atlântico, Índico e Pacífico e no mar Mediterrâneo. Em 2021, foram capturadas cerca de 4,8 milhões de
toneladas das principais populações comerciais de atum, com gaiado (Katsuwonus pelamis) a representar 56 % das capturas, albacora (Thunnus albacares) 31 %, o patudo (Thunnus obesus) 8 % e o atum voador (Thunnus alalunga) 4 %. O espadarte (Xiphias gladius) é um peixe mesopelágico altamente migratório (Fig. 5) e um predador de topo, amplamente distribuído no Oceano Atlântico e no Mar Mediterrâneo. A captura anual total de espadarte registada em 2021 foi de 712 000 t (ISSF, 2023). A nível mundial, estima-se que a biomassa do espadarte tenha diminuído pelo menos 22% nos últimos 20 anos. Apesar dos benefícios comprovados para a saúde, o consumo de pescado pode ocasionalmente
constituir um risco para a saúde devido à contaminação, nomeadamente com determinados metais pesados ou tóxicos no caso de algumas espécies como são o espadarte e o atum. As funções e características químicas do grupo heterogéneo de elementos que se designam metais pesados ou tóxicos são diversas. Manganês (Mn), cobre (Cu), níquel (Ni), ferro (Fe) e zinco (Zn) são metais (pesados) necessários, enquanto cádmio (Cd), arsénio (As), mercúrio (Hg) e chumbo (Pb) são metais (pesados) não-essenciais.
Mercury (Hg), cadmium (Cd), lead (Pb) and Arsenic (As) are toxic metals that continue to attract much attention because they are prone to be accumulated in fish tissues and can harm human health if taken up with food. The aim of the work was to explore the concentration levels of toxic metals and associated risk assessment in commercially, widely available tuna and swordfish thru a literature review and then using meta-analysis. Data was extracted from papers on the bioaccumulation of these metals in the tuna and swordfish from various water bodies Mediterranean, Pacific, Indian and Atlantic Ocean are utilized to identify general tendencies and specifics in the accumulation of toxic metals depending on the moderator (“explanatory”) variables such as species, location, fish size. Literature results show that the mean concentrations in muscle samples of swordfish and tuna were Hg>Pb>Cd and As>Hg>Cd=Pb, respectively. Meta-analysis is a statistical examination of data from several studies that results in a quantitative synthesis of study findings. It has the potential to be an important tool for accelerating development in fishing industry by identifying known and unknown facts (toxic metals). Toxic metal toxicity because of fish consumption with high metal concentrations can result in damage or reduced mental and central nervous system function, lower energy levels, and damage to blood composition, lungs, kidneys, bones, liver, and other vital organs. The mean concentration of As is 7.19 mg/kg in Tuna and 1.13 mg/kg in Hg for swordfish, including muscle, exceeding the permitted levels set by EU regulations, Codex Alimentarius general standards, FDA standards, and WHO. Moreover, noncancer risk using the target hazard quotient (THQ) of each of the four toxic metals was assessed, and cancer risk using the Carcinogenic risk (CR) for Portugal was evaluated. The THQ value of Hg is 2.36 in swordfish and 6.57 for As in tuna, were higher than the limits of safe (THQ <1) and CR showed the high carcinogenic risk for As (1.77) for tuna consumers. The total target hazard quotient (TTHQ) was also high, 10.13 for Hg in swordfish and 6.32 for Hg and 10.96 for As in tuna, which is 6 to 10 folds higher than safe limits (TTHQ <1). The Estimated Daily Intakes (EDI) as well as THQ for Hg, Cd and As indicated that swordfish and tuna consumption pose a high risk to human health in Portugal. (...)
Mercury (Hg), cadmium (Cd), lead (Pb) and Arsenic (As) are toxic metals that continue to attract much attention because they are prone to be accumulated in fish tissues and can harm human health if taken up with food. The aim of the work was to explore the concentration levels of toxic metals and associated risk assessment in commercially, widely available tuna and swordfish thru a literature review and then using meta-analysis. Data was extracted from papers on the bioaccumulation of these metals in the tuna and swordfish from various water bodies Mediterranean, Pacific, Indian and Atlantic Ocean are utilized to identify general tendencies and specifics in the accumulation of toxic metals depending on the moderator (“explanatory”) variables such as species, location, fish size. Literature results show that the mean concentrations in muscle samples of swordfish and tuna were Hg>Pb>Cd and As>Hg>Cd=Pb, respectively. Meta-analysis is a statistical examination of data from several studies that results in a quantitative synthesis of study findings. It has the potential to be an important tool for accelerating development in fishing industry by identifying known and unknown facts (toxic metals). Toxic metal toxicity because of fish consumption with high metal concentrations can result in damage or reduced mental and central nervous system function, lower energy levels, and damage to blood composition, lungs, kidneys, bones, liver, and other vital organs. The mean concentration of As is 7.19 mg/kg in Tuna and 1.13 mg/kg in Hg for swordfish, including muscle, exceeding the permitted levels set by EU regulations, Codex Alimentarius general standards, FDA standards, and WHO. Moreover, noncancer risk using the target hazard quotient (THQ) of each of the four toxic metals was assessed, and cancer risk using the Carcinogenic risk (CR) for Portugal was evaluated. The THQ value of Hg is 2.36 in swordfish and 6.57 for As in tuna, were higher than the limits of safe (THQ <1) and CR showed the high carcinogenic risk for As (1.77) for tuna consumers. The total target hazard quotient (TTHQ) was also high, 10.13 for Hg in swordfish and 6.32 for Hg and 10.96 for As in tuna, which is 6 to 10 folds higher than safe limits (TTHQ <1). The Estimated Daily Intakes (EDI) as well as THQ for Hg, Cd and As indicated that swordfish and tuna consumption pose a high risk to human health in Portugal. (...)
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Keywords
Atum Espadarte Metais tóxicos Riscos para saúde Revisão da literatura Meta-análise