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

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

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

Laboratory manual in teaching medical chemistry in english language course for the student of medicine and dental medicine

Chemistry is an experimental science. it is not an inanimate science, but one that help us to understand the behavior of living systems. This manual was designed especially to follow the lecture portion of the student class. The laboratory activities include materials that students may be familiar with, such as household products, drinks, and various medicines. in such way, chemical topics are related to the real world and to the student’s own science experience. Some of the lab exercises teach basic skills while others encourage students to extend scientific curiosity beyond the lab. The laboratory class gives an opportunity to go beyond the lectures and words in the textbook and experience the scientific processes from which conclusions and theories concerning chemical behavior are drawn. The concepts of some experiments have health and biological aspects

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

Evaluation of paralytic shellfish poisoning toxin profile of mussels from Bulgarian North Black Sea coast by HPLC-FlD with post and pre-column derivatization

Marine toxins are produced by certain toxic phytoplankton species. Harmful toxins may accumulate in the shellfish tissue, potentially impacting human health. Paralytic shellfish poisoning (PSP) is a syndrome caused by ingestion of shellfish contaminated with paralytic shellfish toxins (PST) that comprise saxitoxin and its variants (neosaxitoxin, gonyautoxins and their decarbamoyl and N-sulfocambamoyl analogs). The aim of this study was to evaluate the presence of paralytic shellfish toxins (PSTs) in plankton samples and in mussels intended for human consumption. Mussels collected in the main areas of production and recreational harvesting off the north coast of Bulgaria have been investigated for PSP toxins. Individual toxins were determined using two methods both involving fluorescence detection: ion pair-liquid chromatography with post-column derivatization (method 1) and high-performance liquid chromatographic procedure employing pre-column oxidation of the toxins (method 2). The results according method 1 demonstrated the presence of gonyautoxin 2 in 53% of the mussel samples and no toxins were detected in the plankton samples. The toxicity level - 1.6 μg STX.2HCl .kg-1 was far beneath the EU legislative limit of 800 μg STX.2HCl .kg-1 concluding in negligible risk for human health. Due to higher limits of detection no toxins were detected via method 2. Even though, considering method 2 is recognized by European Commission as official for regulatory purposes and the relative high value of the legislative threshold, thus obtained toxin levels are enough representative to conclude if mussels are safe for consumption or not. On the other hand, the more sensitive method 1 provides important data on extremely low toxin levels which would be useful for chronic exposure estimation and for completing the knowledge about occurrence of PSTs in certain locations

Health Risks Associated With Consumption Of Marine Biotoxin-Contaminated Seafood From The North Bulgarian Black Sea Coast

Морските храни, включително риби, миди и др., са здравословен източник на протеини и дълговерижни омега-3 мастни киселини, важни например за ранното развитие, за състоянието на очите и сърцето на човека. В България се увеличава консумацията на миди през последните години. Но изследвания показват, че морските дарове съдържат някои замърсители като метилживак, арсен, устойчиви органични замърсители (POPs) – ДДТ (DDTs), полихлорирани бифенили (PCBs) и морски биотоксини (фикотоксини). Всички те могат да повлияят неблагоприятно на човешкото здраве, ако се приемат, например с храната, над определени нива, при или без продължителна експозиция.Целта на това изследване беше да се определят нивата на фикотоксини в миди, предназначени за консумация от човека, и да се оценят рисковете за здравето, свързани с тяхната консумация.Проби миди (диви и култивирани) бяха осигурени от рибни пазари и магазини през 2016, 2017 и 2018 г. Анализът на риска за здравето беше извършен, както следва: 1) определяне на нивата на фитотоксини чрез течна хроматография с мас детекция (LC-MS); 2) сравнение на нивата на морските биотоксини с нормативните стойности за ЕС; 3) оценка на острата и хронична експозиция; 4) заключение за рисковете за здравето, свързани с консумацията на изследваните миди. Резултатите от изследванията показват наличие на домоена киселина (DA), йесотоксини (YTXs), пектентооксин-2 (PTX-2) и азаспирациди (AZAs) в пробите. Здравните рискове– амнезиево и азаспирацидно отравяне, се дължат съответно на наличието на DA и AZAs. YTXs и PTX-2 нямат доказан ефект върху човешкото здраве, но са силно токсични за мишки при i.p. инжектиране. Тъй като регистрираните нива на фитотоксини и изчислената остра и хронична експозиция бяха много по-ниски от референтната стойност, може да се направи заключение, че здравният риск, свързан с консумацията на изследваните миди, съдържащи морски биотоксини от северния бряг на Българското Черноморие, е нисък.Seafood, defined as marine and freshwater fish and shellfish, is recognized as a healthy food choice because it is a low-fat protein source that provides long-chain omega-3 fatty acids important for early development along with eye and heart health. In Bulgaria, the consumption of shellfish has been increasing recently. However, seafood is also known to contain certain contaminants, such as methylmercury, arsenic, persistent organic pollutants (POPs) – DDTs and PCBs and marine biotoxins (phycotoxins). They all may adversely affect human health if ingested over certain levels with or without prolonged exposure. The aim of this research was to evaluate the phycotoxin levels in mussels intended for human consumption and to comment the health risks associated with their consumption. Mussel (wild and farmed) samples were provided from seafood markets in 2016, 2017 and 2018. The health risk analysis has been conducted as follows: 1) determination of phycotoxin levels via LC-MS technique; 2) comparison the marine biotoxins levels with the EU legislative limit; 3) estimation of acute and chronic exposure; 4) conclusion about the health risks associated with consumption of investigated species. Results indicate the presence of domoic acid (DA), yessotoxins (YTXS), pectenotoxin-2 (PTX-2) and azaspiracids (AZAs) in the samples. The health risks that could be associated – amnesic shellfish and azaspiracid poisoning are due to availability of DA and AZAs, respectively. YTXs and PTX-2 have no proven effect on human health but are acutely toxic to mice via i.p. injection. As the registered phycotoxin levels and the calculated acute and chronic exposure were much lower than the reference limit, in general, it could be concluded that the health risk associated with consumption of marine biotoxin-contaminated seafood from North Bulgaria would be low

Detection of marine biotoxin in plankton net samples from the Bulgarian coast of Black Sea

Some diatoms and dinoflagellates can produce marine toxins, which can accumulate in, e.g. filter-feeding bivalves, posing a potent treat to seafood consumers. In this study, concentrated net plankton samples were collected from mussel cultivation regions (Kavarna bay) and zones for wild catch (Varna bay) in two periods - winter to fall 2018 and spring 2019. A method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed to analyze domoic acid (DA), okadaic acid, dinophysistoxins, yessotoxin, pectenotoxin-2 (PTX2), gymnodimine A (GYM), 13-desmethyl spirolide C (SPX1), and goniodomin A (GDA). Paralytic shellfish toxins (PSTs) were investigated by high performance liquid chromatography with post-column derivatization and fluorescence detection. Results indicated the presence of DA, PTX2, SPX1 and GDA reaching maximum levels of 1.4 ng.NH-1.m-1 DA, 115.5 ng.NH-1.m-1 PTX2, 0.2 ng.NH-1.m-1 SPX1 and 8.6 ng.NH-1.m-1 GDA. No PSTs were detected in the investigated samples. The maximum toxin load of the samples was due to the presence of PTX2. Detection of DA, PTX2, SPX1 and GDA in the samples points to the possible toxigenic nature of phytoplankton species along the Bulgarian coast. These data may be used to evaluate the probability of potential risks to local aquaculture and seafood from wild catch

Empirical determination of conversion factor for depicting phycotoxin concentration in whole mussel Mytilus galloprovincialis meat

Mussels accumulate marine biotoxins (phycotoxins) produced by certain phytoplankton species. In EU are set limits for toxin concentration (e.g. domoic acid, okadaic acid, yessotoxins etc.) beyond that mussels are safe for consumption. Marine biotoxins tend to accumulate in the digestive gland (hepatopancreas) of the mussel. Consequently, this tissue is preferred for toxin concentration determination. Normally the whole shellfish is consumed and therefore the occurrence data for phycotoxins need to be expressed in terms of whole shellfish meat. A theoretical factor of 5 is used to convert the value to whole shellfish meat. The aim of this study was to determine an empirical factor in order to convert phycotoxin concentrations from hepatopancreas to whole shellfish meat of main marine aquaculture in Bulgaria- mussels Mytilus galloprovincialis. Wild and cultivated mussels were collected from the north Black Sea coast of Bulgaria in 2017. In total 13 mussel samples were studied whereas in each sample subsamples of hepatopancreas only and whole mussel meat are prepared. Phycotoxins were extracted for all types of phycotoxins by means of liquid-liquid extraction and their concentration was determined via LC/MS. Yessotoxins appeared in most of the samples and therefore seemed most suitable for empirical conversion factor determination. It is calculated as ratio between determined concentration in hepatopancreas and whole shellfish meat. Mean defined value was 5.36. Determination and application of empirical conversion factor is important when establishing very low concentration for chronic exposure assessment. It will be advantageous when taking into account interspecies differences and to avoid phycotoxin omission if preparing whole shellfish sample.</jats:p

Lipophilic Marine Biotoxins in Mussels from Bulgarian coast and Dietary Intake of Different Population Groups

AbstractIntroductionLipophilic phycotoxins, produced by toxic phytoplankton species, accumulate in digestive glands of mussels. If contaminated mussels containing marine biotoxins over regulatory levels are consumed, it is assumed that this could result in e.g. gastrointestinal disorders.ObjectivesThe aim of the study was to report contamination level of lipophilic marine biotoxins and to assess the potential health risk based on dietary intake for regular consumers and recreational harvesters from Bulgaria.Method/DesignWild and cultivated mussels were sampled in spring seasons of 2017 and 2018 from the North Black Sea coast. Positive phycotoxins concentrations determined via LC-MS/MS in extracts from digestive glands of the mussels were converted in phycotoxin levels for whole mussel meat (mm) by applying a factor of 5 proposed by EFSA. Dietary intakes were calculated by multiplying the mean positive phycotoxin levels (mg /kg mm) by the food consumption data for an average body weight (bw) of the investigated population group.Results and discussionIn total 20 farmed and 15 wild mussel samples were investigated. Yessotoxins and pectenotoxin-2 were detected. The mean YTX levels in cultivated mussels were measured about two times higher in spring 2018 (1.64 mg/kg) than in 2017 (0.70 mg/kg). The mean YTX level in wild mussels was found much lower - 0.46 mg/kg (spring 2017). In this regard, estimation of mean dietary YTX intake show that exposure of both population groups by consumption of cultivated mussels from spring 2018 is highest. Nevertheless, the regulatory threshold – acute reference dose of 25 μg/kg bw, is much above the highest calculated dietary intake (0.006 μg/kg female consumers). The mean PTX2 level in wild mussel samples from spring 2017 (0.71 mg/kg) was found about six times higher than in farmed mussels.The calculation of mean dietary PTX2 intake indicate that most exposed are females if wild mussels from spring 2017 were consumed. Still, the calculated value – 0.003 μg/kg bw were much lower than the ARfD - 0.8 μg/kg bw. All wild mussel samples from spring 2018 were negative. Lowest exposure to detected toxins were established for recreational harvesters.ConclusionThis study showed in general low contamination level with YTX and PTX2 of investigated mussel samples. Thereon, the estimated dietary intake of selected population groups is also much lower than the regulatory thresholds.</jats:sec