Accumulation of gliotoxin, a cytotoxic mycotoxin from Aspergillus fumigatus, in blue mussel (Mytilus edulis).

A strain of Aspergillus fumigatus has been isolated from sediments of a mussel bed. When cultured in hyper saline conditions (with sea-water), it produces a cytotoxic and immunosuppressive toxin, gliotoxin, which is excreted in an exudate. In order to know if this toxin could represent a risk for shellfish consumers, an experiment of bioaccumulation of gliotoxin in mussel has been carried out. After 6 days of contamination, toxin was accumulated in the meat of the mussels, at a level up to 2.9 microg/mg of extract weight, with a mode of contamination different to the classical digestive process described for a majority of marine toxins, but similar to the contamination mode of domoic acid.     

Dietary selenium's protective effects against methylmercury toxicity

Dietary selenium (Se) status is inversely related to vulnerability to methylmercury (MeHg) toxicity. Mercury exposures that are uniformly neurotoxic and lethal among animals fed low dietary Se are far less serious among those with normal Se intakes and are without observable consequences in those fed Se-enriched diets. Although these effects have been known since 1967, they have only lately become well understood. Recent studies have shown that Se-enriched diets not only prevent MeHg toxicity, but can also rapidly reverse some of its most severe symptoms. It is now understood that MeHg is a highly specific, irreversible inhibitor of Se-dependent enzymes (selenoenzymes). Selenoenzymes are required to prevent and reverse oxidative damage throughout the body, particularly in the brain and neuroendocrine tissues. Inhibition of selenoenzyme activities in these vulnerable tissues appears to be the proximal cause of the pathological effects known to accompany MeHg toxicity. Because Hg's binding affinities for Se are up to a million times higher than for sulfur, its second-best binding partner, MeHg inexorably sequesters Se, directly impairing selenoenzyme activities and their synthesis. This may explain why studies of maternal populations exposed to foods that contain Hg in molar excess of Se, such as shark or pilot whale meats, have found adverse child outcomes, but studies of populations exposed to MeHg by eating Se-rich ocean fish observe improved child IQs instead of harm. However, since the Se contents of freshwater fish are dependent on local soil Se status, fish with high MeHg from regions with poor Se availability may be cause for concern. Further studies of these relationships are needed to assist regulatory agencies in protecting and improving child health.     

Fish consumption by children in Canada: Review of evidence,challenges and future goals

Fish consumption is of great importance to children’s health and is essential for neurodevelopment, which begins in pregnancy and continues throughout early childhood and into adolescence. However, fish consumption presents conflicting health outcomes associated with its nutritional benefits and its adverse contaminant risks, because both avoiding fish as well as the consumption of contaminated fish can potentially harm children. This may be challenging to communicate. The present review was performed to assess the current knowledge and recommendations around ‘smart’ fish-consumption decisions. Health Canada advises, as well as other advisories and guides, that fish should be consumed for its health benefits, while also informing consumers, especially women and children, to limit certain fish consumption. The current literature must attempt to handle the challenges inherent in communicating the dilemmas of children’s fish consumption. Incorporation of new knowledge translation strategies are proposed as a means to raise the level of knowledge about optimal fish consumption practices.     

Human exposure in Italy to lead,cadmium and mercury through fish and seafood product consumption from Eastern Central Atlantic Fishing Area

The presence of cadmium (Cd), lead (Pb) and mercury (Hg) was investigated in fish and seafood products collected from the FAO Major Fishing Area 34, Eastern Central Atlantic. Samples were purchased from different retail outlets in Italy. Samples were selected so as to assess human exposure through diet. Metals were detected by Q-ICP-MS and Hg-AAS. All the metal concentrations detected were largely below the maximum levels (MLs) established by the European Union. The exposure assessment was undertaken by matching the concentration of Cd, Pb and total Hg in fish and other seafood products selected purposed according to Italian consumption data. The estimated weekly intakes (EWIs) for the evaluated elements related to the consumption of fish and other seafood products by the median of the Italian total population accounted for 14%, 2% and 14% of the standard tolerable weekly intake (TWI) for Cd and Hg as well as the provisional tolerable weekly intake (PTWI) for Pb, respectively.     

Role of fruits,grains, and seafood consumption in blood cadmium concentrations of Jamaican children with and without Autism Spectrum Disorder

Human exposure to cadmium has adverse effects on the nervous system. Utilizing data from 110 age- and sex-matched case–control pairs (220 children) ages 2–8 years in Kingston, Jamaica, we compared the 75th percentile of blood cadmium concentrations in children with and without Autism Spectrum Disorder (ASD). In both univariable and multivariable Quantile Regression Models that controlled for potential confounding factors, we did not find any significant differences between ASD cases and typically developing (TD) controls with respect to the 75th percentile of blood cadmium concentrations (P > 0.22). However, we found a significantly higher 75th percentile of blood cadmium concentrations in TD Jamaican children who consumed shellfish (lobsters, crabs) (P < 0.05), fried plantain (P < 0.01), and boiled dumpling (P < 0.01). We also observed that children living in Jamaica have an arithmetic mean blood cadmium concentration of 0.16 μg/L which is similar to that of the children in developed countries and much lower than that of children in developing countries. Although our results do not support an association between blood cadmium concentrations and ASD, to our knowledge, this study is the first to report levels of blood cadmium in TD children as well as those with ASD in Jamaica.     

LC-ICP-MS联用测定海产品中有机锡

目的采用液相色谱与电感耦合等离子体质谱联用分析法(LC-ICP-MS),测定广东沿海海域海产品中三丁基锡、三苯基锡含量,探明广东沿海海产品有机锡的污染状况。方法有代表性地采集广东海域17个海区及部分市售海产品,样品冻干处理制成干粉,加入流动相经超声萃取、离心、过滤等处理后,用LC-ICP-MS法测定三丁基锡、三苯基锡含量。结果所检测的32种共112个海产品样品中,以湿重计算的三丁锡含量最高的为58.7ngSn/g,平均浓度是8.6ngSn/g,以湿重计算的三苯基锡含量最高的为324.1ngSn/g,平均浓度是44.9ngSn/g。结论广东沿海海域海产品已受到一定程度的有机锡污染,而其中三苯基锡的污染情况比三丁基锡严重。     

Assessment of exposure to inorganic arsenic,a human carcinogen,due to the consumption of seafood

 To assess whether regular consumption of seafood, particularly fish and shellfish, by humans may lead to an overexposure to inorganic arsenic, a well-established human carcinogen, the urinary excretion of the relevant As metabolites (As_i, inorganic form; MMA, monomethylarsonic acid; DMA, dimethylarsinic acid) was compared in groups of subjects with different seafood consumption habits and in volunteers after ingestion of a known amount of seafood arsenicals. Studies of Italian cohorts, involving five groups of ±30 subjects with different seafood consumption habits, and balance studies in Belgian volunteers failed to show a biologically significant absorption of inorganic arsenic either present as such in the food or formed from organoarsenicals during cooking or digestion. The results suggest that the digestion of some seafood, especially mussels, may increase the urinary excretion of the dimethylated arsenic metabolite. Therefore, the biological monitoring of exposure to inorganic arsenic in an industrial context should mainly rely upon specific measurement of the unmetabolized form when recent ingestion of seafood cannot be excluded. Received: 29 March 1996 / Accepted: 23 May 1996     

Paralytic shellfish poisoning: Seafood safety and human health perspectives

Paralytic shellfish poisoning (PSP) is the foodborne illness associated with the consumption of seafood products contaminated with the neurotoxins known collectively as saxitoxins (STXs). This family of neurotoxins binds to voltage-gated sodium channels, thereby attenuating action potentials by preventing the passage of sodium ions across the membrane. Symptoms include tingling, numbness, headaches, weakness and difficulty breathing. Medical treatment is to provide respiratory support, without which the prognosis can be fatal. To protect human health, seafood harvesting bans are in effect when toxins exceed a safe action level (typically 80 μg STX eq 100 g⁻¹ tissue). Though worldwide fatalities have occurred, successful management and monitoring programs have minimized PSP cases and associated deaths. Much is known about the toxin sources, primarily certain dinoflagellate species, and there is extensive information on toxin transfer to traditional vectors - filter-feeding molluscan bivalves. Non-traditional vectors, such as puffer fish and lobster, may also pose a risk. Rapid and reliable detection methods are critical for toxin monitoring in a wide range of matrices, and these methods must be appropriately validated for regulatory purposes. This paper highlights PSP seafood safety concerns, documented human cases, applied detection methods as well as monitoring and management strategies for preventing PSP-contaminated seafood products from entering the food supply.     

Levels of selected trace metals in canned tuna fish produced in Turkey

Trace metals (iron, zinc, copper, cadmium, tin, mercury and lead) in canned tuna, obtained from 4 different brands in Turkey, were determined using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The trace metals were found to be in the range of 20.2-38.7 mg/kg for iron, 8.20-12.4 mg/kg for zinc, 0.48-0.58 mg/kg for copper, 0.01-0.02 mg/kg for cadmium, 0.02-0.13 mg/kg for tin, 0.06-0.30 mg/kg for mercury, and 0.09-0.45 mg/kg for lead. These results showed that there is no risk in canned tuna with respect to the concentrations of zinc, copper, cadmium and tin. However, it was determined that some of the samples may contain iron, lead and mercury above the legal limits set by health authorities. It was concluded that trace metals in canned tuna must be monitored comprehensively and periodically with respect to the consumer health.