Mineral composition of marine macroalgae from the Bulgarian Black Sea Coast

The present study focuses on the trace metal and mineral composition analysis of various seaweeds such as Chlorophyceae (Ulva rigida and Chaetomorpha linum), Phaeophyceae (Cystoseira barbata and Cystoseira crinita) and Rhodophyceae (Gelidium crinale) collected from the Bulgarian Black Sea Coast. The concentration ranges found for each sample, were as follows: Na, 2.59-5.90; K, 0.28-10.9, Ca, 5.52-21.4; Mg, 2.31-4.22; Sr, 0.05-1.18 (in mg/g dw); Pb, 0.02-0.12; Cr, 0.02-0.33; Co, 0.02-0.15; Fe, 6.1-105; Zn, 1.30-3.80; Mn, 1.60-29.4; Cu, 0.24-0.91; As, 0.18-1.54; Ni, 0.04-0.11; Ba, 0.01-1.95; Se, 0.004-0.12 (in mg/100 g dw); Hg, 0.01-0.03 and Cd, 0.03-0.34 expressed in ìg/g dw. Among species analyzed, green algae Chaetomorpha linum and Ulva rigida showed the maximum contents of mineral elements such as Mg, Na, Cr, Co, Fe, Mn, As, Pb and Hg, red alga Gelidium crinale - Cu, Zn and Se, while brown algae Cystoseira barbata and Cystoseira crinita - Ni, Cd, Ca, K, Sr and Ba. Mineral composition of different Black Sea macroalgae species was found relatively higher as compared to the land vegetables as well as to other edible seaweeds. They could  herefore be used as food supplement or as a spice to improve the nutritive value in animal or human diet

Study on the risk exposure of seafood consumers in Bulgaria to hydrophilic marine toxins

INTRODUCTION: Marine biotoxins can be accumulated in shellfish and in turn can lead to severe illness or chronical consequences in human shellfish consumers. AIM: The aim of this study was to assess the levels of hydrophilic marine biotoxins in both farmed and wild mussels from the Bulgarian coast sampled in 2017 and to estimate the exposure (acute and chronic) of Bulgarian consumers to detected toxins if investigated mussels were consumed. To the group of hydrophilic marine toxins belong amnesic toxins (domoic acid, isodomoic acid) and paralytic toxins (neosaxitoxin, gonyautoxins and their decarbamoyl and N-sulfocambamoyl analogs). MATERIALS AND METHODS: The hydrophilic toxin – domoic acid (DA) was determined by liquid chromatography tandem mass spectrometry (LC-MS/MS). Paralytic toxins (saxitoxin (STX), neosaxitoxin (NEO), gonyautoxin-1 (GTX1), gonyautoxin-2 (GTX2), gonyautoxin-3 (GTX3), gonyautoxin-4 (GTX4), gonyautoxin-5 (B1), decarbamoyl gonyautoxin-2 (dcGTX2), decarbamoyl gonyautoxin-3 (dcGTX3), decarbamoyl saxitoxin (dcSTX), N-sulfocarbamoyl gonyautoxin-1 (C1), N-sulfocarbamoyl gonyautoxin-2 (C2)) were investigated via high performance liquid chromatography with fluorescence detection (HPLC-FD). RESULTS: Among all hydrophilic toxins investigated DA and GTX2 were detected in the studied samples. Mean domoic acid in whole mussel meat was estimated to be 0.139 mg/kg mm which is below the regulatory limit of 20 mg/kg mm. Mean GTX2 level in whole mussel meat was calculated to be 0.151 μg saxitoxin dihydrochloride equivalent (STX.2HCl eq)/kg which is far beneath the legislative limit of 800 μg STX.2HCl eq/kg mm. Estimation of acute exposure for both detected toxins – DA and GTX2, and of chronic exposure to domoic acid showed similar results among male and female, as well as among wild and cultivated mussel consumers. CONCLUSION: This study showed an overall low contamination level of wild and farmed mussels with hydrophilic marine biotoxins compared to the regulatory limits. This leads to the conclusion that there is low acute and chronic exposure via consumption of contaminated mussels

Daily intake of arsenic and mercury by consumption of Bulgarian Black Sea fishes

The consumption of marine fish as popular seafood has increased steadily over the past decades. Toxic effects evidenced in the environment are most often caused by a mixture of pollutants such as heavy metals. The daily intake of arsenic (As) and mercury (Hg) through the consumption of nine edible marine species by the general population of Bulgaria was estimated. Health risks derived from this intake were also assessed. The concentrations of As and Hg in nine edible marine fish species were determined by ETAAS and Milestone Direct Mercury Analyzer. The highest metal intake through fish consumption corresponds to As (7.837 μg/day) for male adults. The daily intake of these elements through fish consumption of these elements was compared with the provisional tolerable weekly intakes (PTWI). The data of this study showed that the metal concentrations in edible tissues of the sampled species were within the permissible safety levels for human consumption set by various health organizations

Polychlorinated biphenyls and organ ochlorine pesticides in turbot (Psetta maxima maeotica ) from Bulgarian Black Sea

Persistent organochlorine pollutants (POPs) like polychlorinated biphenyls (PCBs) and DDT residues (DDTs) were determined in muscle tissue of turbot (Psetta maxima maeotica). The samples were collected from Black Sea, near cape Kaliakra, during 2007 - 2011. The fifteen congeners of PCBs, p,p`-DDT and its metabolites p,p`-DDE and p,p`-DDD were determined by capillary gas chromatography system with mass spectrometry detection. The Indicator PCBs UPAC 180, 153, 138, 118 were found most frequently and abundantly. The sum of the Indicator PCBs ranged from 3.80 to 13.94 ng/g wet weight and did not exceed the European maximum limit. The values of toxic equivalency (TEQs) of the 6 `dioxin-like` PCBs were calculated in the range from 0.02 to 0.09 pg TEQ/g ww and did not exceed the European limit of 6.5 pg TEQ/g ww. Among the DDTs, only p,p`-DDE and p,p`-DDD were found at levels 14.45 and 5.05 ng/g wet weight, respectively. The levels of PCBs and DDTs in turbot were determined comparable to those found in fish species from other aquatic ecosystems

Black Sea Shad and Red Mullet as sources of omega 3 Fatty Acids

Purpose: The purpose of this work was to study the seasonal changes of the quantity of omega-3 polyunsaturated fatty acids (n-3 PUFA) in two commonly consumed Black Sea fish species shad (Alosa pontica) and red mullet (Mullus barbatus ponticus). These fish species appear as one of the best sources of omega- 3 polyunsaturated fatty acids.Materialand methods: The total lipids were extracted by the method of Blight and Dyer.The fatty acid composition was analysed by GC/MS.Results: Very-Long Chain n-3PUFA (VLCPUFA) eicosapentaenoic acid (EPA, C20:5 n-3) and docosahexaenoic acid (DHA, C22:6 n-3) were presented in the highest concentration in shad in both season, whereas red mullet show an increased n-3 VLCPUFA levels in autumn. The spring shad total content of n-3 FA was significantly higher than the total content of omega 6 (n-6) PUFA, whereas red mullet showed opposite trend. The n-6/n-3 FA ratio was within the recommended range for the analyzed Black Sea fish species.Conclusion: Shad and red mullet can be classified as fatty fish species. A 100 g portion of fillet delivers between 350 and 2690 mg of sum of EPA and DHA, depending on the season. This is over than 100% of daily recommended amounts of these FAs. Obtained results for omega-3 PUFA content and n-6/n-3 ratio indicates that these Black Sea fish species are an excellent source of these PUFA and would be recommended as part of a healthy or therapeutic diet for adults in Bulgaria during all year

Study on risk of exposure of seafood consumers in Bulgaria to hydrophilic marine toxins

Marine biotoxins can be accumulated in shellfish and in turn can lead to severe illness or chronical consequences in human shellfish consumers.The aim of this study was to assess the levels of hydrophilic marine biotoxins in both farmed and wild mussels from the Bulgarian coast sampled in 2017 and to estimate the exposure (acute and chronic) of detected toxins to Bulgarian consumers if investigated mussels were consumed.The hydrophilic toxin - domoic acid was determined by liquid chromatography tandem mass spectrometry (LC-MS/MS). Mean domoic acid in whole mussel meat was estimated 0.139 mg/kg which is below the regulatory limit of 20 mg/kg.Among all paralytic shellfish (PSP) toxins evaluated only gonyautoxin-2 (GTX2) was detected via high performance liquid chromatography with fluorescence detection (HPLC-FD). Mean GTX2 level in whole mussel meat was calculated to be 0.151 mg STX.2HCl eq/kg which is far beneath the legislative limit of 800 mg STX.2HCl eq/kg.Estimation of acute exposure for both detected toxins - domoic acid and GTX2 and of chronic exposure to domoic acid showed similar results among male and female, as well as among wild and cultivated mussel consumers.This study showed an overall low contamination level of wild and farmed mussels with hydrophilic marine biotoxins compared to the regulatory limits. This is concluding in low acute and chronic exposure via consumption of contaminated mussels

Effect of frozen storage on fat soluble vitamins content in fish fillets

Fat-soluble vitamins content (all-trans-retinol, alpha-tocopherol and cholecalciferol) in edible tissue of Bluefish (Pomatomus saltatrix), a typical Black sea pelagic fish, and in Rainbow trout (Oncorhynchus mykiss), a typical farmed freshwater fish, were determined and compared on raw state and after frozen storage. The sample preparation procedure includes saponification and consequent extraction of fat-soluble vitamins with n-hexane.The extract was dried under nitrogen flow and redissolved in methanol. HPLC analysis of methanolic samples was performed on ODS2 Hypersil (250x4,6, 5um) column with a mobile phase of methanol:water = 97:3. The quantification of fat-soluble vitamins was by the method of standard addition. Retinol and cholecalciferol were monitored by UV detection and alpha-tocopherol was detected by fluorescence.The retinol and cholecalciferol contents in fresh edible tissue of Black sea Bluefish (38.5±2.4 μg.100g-1ww and 11.2±1.2 μg.100g-1ww, respectively) were close to values in the freshwater fish Rainbow trout (58.9±2.6 μg.100g-1ww and 14.9±1.1 μg.100g-1ww, respectively). Alpha-tocopherol content was several fold higher in Rainbow trout (1648.9±68.8 μg.100g-1ww) than in Black sea Bluefish (427.1±37.1 μg.100g-1ww).Long period of storage affected mostly retinol and alpha-tocopherol contents in two fish species. While cholecalciferol content remained almost unchanged

SELECTED CONTAMINANTS IN FISH AND MUSSELS FROM THE BULGARIAN BLACK SEA

The presence of polychlorinated biphenyl congeners, organochlorine pesticides and marine biotoxins in the marine environment is important for the evaluation of a potential risk to human health. The purpose of the present study was to determine concentrations of polychlorinated biphenyl congeners (PCBs) and organochlorine pesticides (DDT and its metabolites) in three fish species and mussels (Mytilus galloprovincialis) and marine biotoxins in mussels from the Black Sea, Bulgaria. Concentration of six Indicator PCB congeners, DDT and its metabolites were determined by gas chromatography coupled to mass spectrometry. The mean levels of I-PCBs ranged between 6.78 ng/g ww and 16.33 ng/g ww (garfish and bluefish respectively). The sum of I-PCBs in all seafood studied did not exceed the EU maximum level. Hydrophilic marine biotoxins determination was performed by HPLC with postchromatographic oxidation. Lipophilic marine toxins were determined on liquid chromatograph coupled to mass spectrometry. The analyzed marine biotoxins were under the limit of detection.</jats:p

Comparison of seasonal and spatial phycotoxin profiles of mussels from South Bulgarian coast

Phycotoxins (marine algal toxins) are toxic metabolites released by certain phytoplankton species. They can be responsible for seafood poisoning outbreaks because filter-feeding mollusks, such as mussels, can accumulate these toxins throughout the food chain and present a threat for consumers’ health. A wide range of symptoms, from digestive to nervous, are associated to human intoxication by biotoxins, characterizing different and specific syndromes, called shellfish poisoning. The aim of this study is to compare the seasonal and spatial phycotoxin profiles of mussels (wild and farmed) harvested from South Bulgarian coast in the period 2017-2018. Analyzed were 57 samples by different analytical techniques - liquid chromatography tandem mass spectrometry (LC-MS/MS) and high-performance liquid chromatography with fluorescent detection followed by postcolumn derivatization. Domoic acid (DA), yessotoxin (YTX), pectenotoxin-2, PTX-2sa/ epi-PTX-2sa and gonyautoxin-2 (GTX2) were detected in the studied samples. Results revealed huge seasonal variations in the phycotoxin profiles of the mussels investigated. Spring 2017 profile is dominated by domoic acid present in 67% of the samples and reaching highest level of 618.9 ng. g-1. In summer 2017 samples YTX is prevalent (60%) reaching a level of 8.3 ng.g-1. No phycotoxins were detected in samples from fall 2017. The epimer pair PTX-2sa/ epi-PTX-2sa was with highest seasonal abundance in winter-spring 2018 – 47%. Its maximum detected level was 7.1 ng.g-1. No statistically significant differences in mean phycotoxin levels of different sampling locations were determined. Generally, the herein reported marine toxins levels are comparable or even lower than in other European studies and much lower than legislative limits set in EU. Nevertheless, the huge seasonal variations in the phycotoxin profile show that for protection of consumers’ health a further surveillance on marine toxins content in edible mussels is required