A representative sampling of tuna muscle for mercury control.

The mechanisms of mercury accumulation and distribution in fish tissues are related to its high affinity for sulfhydryl groups in proteins. There is evidence that mercury is distributed unevenly based on the different reactivity of these groups in the various muscle proteins. Tuna fish also shows numerous specialized anatomical features including the structure of the swimming muscles and some form of endothermy, which generates variations in the mercury content between dark and white muscle and between muscle tissues with different lipid content. The aim of the study is to verify, through a suitable sub lot of Thunnus thynnus caught by a static trap in south-western Sardinia, the effective uneven distribution of mercury in the various muscles and also identify the sites representative of the entire carcass. In agreement with other authors, the results show that even in the Bluefin tuna of the Mediterranean, the site "anterior extremity of upper loin (schienale in Italian)" is representative of the mercury average content of muscle tissues as a whole.

Occurrence of hexabromocyclododecanes and tetrabromobisphenol A in fish and seafood from the sea of Sardinia - FAO 37.1.3 area: Their impact on human health within the European Union marine framework strategy directive.

Levels of hexabromocyclododecane isomers α, ß, γ, (HBCDDs) and tetrabromobisphenol A (TBBP-A) were determined in 24 representative samples of different wild fish and seafood species (benthic: N = 16; pelagic: N = 8) and 16 samples of farmed bivalve molluscs from the West Mediterranean Sea (FAO 37, 1.3 sub-area). An LC-MS/MS-based method with limits of quantification (LOQS) in the range of 0.01-0.05 ng g-1 fresh weight (fw) was utilized. While α HBCDD was found in 80% of the 24 wild species samples, ß and γ congeners were found in 33% and 25%, respectively. ΣHBCDD content ranged from 0.03 (Aristeus antennatus) to 0.68 (Sardina pilchardus) ng g-1 fw as Upper Bound values across 2.00-4.46 trophic levels. In farmed molluscs, HBCDD congeners were always present and ranged from 0.22-0.52 ng g-1 fw, with the exception of one farm (1.23-2.06 ng g-1 fw), whose values suggest the presence of a regular emission source. TBBP-A levels always fell below the LOQ of 0.05 ng g-1 fw in all samples. The results are in good agreement with results of previous studies from the Mediterranean Sea. The Environmental Quality Standard for human health from fish and seafood local consumption was set at 165 µg g-1 fw. The Margin of Exposure of 490,020 as the ratio between the considered Health Based Guidance Level of 0.79 mg kg-1 body weight and the geo-referenced HBCDD intake (P95 fish and seafood intake; mean ΣHBCDD contamination) indicates no threat to food safety.

A case study on the development of representative sampling procedure to determine mercury levels in a lot of tuna caught by static trap.

Mercury contamination in fish products, and in large pelagic predatory fish in particular, is a remarkable food safety issue that affects fish industry. A lot made up by Bluefin tunas caught at Porto Paglia - in the south-western coast of Sardinia - was subject to several sessions of fish meat official sampling, as disputable results of mercury level determination suggested a potential non-compliance to maximum allowable limit. Local competent Veterinary Service reviewed the sampling procedure introducing more rigorous details including the identification of a specific muscular portion as sampling site, after having taken into account both statutory provisions laid down by Regulation (EC) No 333/2007 and available scientific evidence on variables affecting uneven distribution of mercury across tuna carcasses. This case-study aims to provide an initial contribution in order to ensure an appropriate and representative field sampling protocol of tuna lots that are to be analysed for mercury content.

[Monitoring plan of environmental contaminants in sheep milk from areas next to an Italian contaminated site named «Aree industriali di Porto Torres e discarica di Calancoi¼ (Industrial areas of Porto Torres and landfill of Calancoi) in Sardinia Region (Southern Italy)]. / Piano di monitoraggio per la ricerca di contaminanti ambientali in latte ovino prodotto in aree prossime al sito di interesse nazionale denominato «Aree industriali di Porto Torres e discarica di Calancoi¼ in Sardegna.

OBJECTIVES: to assess concentration levels of dioxins, PCBs, and chemical elements in sheep milk produced in areas close to the Italian contaminated site (CS) located in the North-West of Sardinia (Southern Italy), named «Aree industriali di Porto Torres e discarica di Calancoi¼ (i.e., industrial areas of Porto Torres and landfill of Calancoi). DESIGN: monitoring plan of environmental contaminants on zootechnical productions based on analysis of dioxins, PCBs, heavy metals (Cd, Hg, Pb), and other elements (As, Be, Cr, Ni, Tl , Zn) in sheep bulk milk. SETTING AND PARTICIPANTS: 60 samples of sheep bulk milk were collected in rural farms where animals were fed mainly with forage and feed produced in the CS: 30 samples from farms located near the industrial area of Porto Torres and 30 taken from farms spread out the landfill area of Calancoi, a former waste dump in the East of Sassari city. MAIN OUTCOME MEASURES: the concentration levels of target substances were determined and compared to legal thresholds fixed on EU regulations. RESULTS: concentrations of target substances in all samples were below the maximum limits set by EU regulations. Dioxins and DL-PCBs (expressed as the sum) were in the range 0.20-1.30 pg WHO-TEQ/g fat, NDL-PCB (sum of the six marker congeners) were in the range 0.50-7.50 ng/g, while concentrations of all heavy metals were not detectable or were near the limit of quantitation of the method. Undetectable concentrations were also observed for the toxic elements beryllium and thallium. CONCLUSIONS: concentration levels of micro-pollutants in milk samples were significantly lower than the legal thresholds. Concentrations and congener profiles showed no relevant differences compared to milk samples from areas with low environmental impact, therefore consumption of milk from the studied area do not produce a higher intake of contaminants respect to the regional milk. The results of this study do not make the resident population safe from health risks caused by critical issue of the CS, but provide information limited to the safety of the milk from these areas, without showing peculiar contamination and hazard for food from local sheep farms.