As filter feeders, bivalves and ascidians can accumulate contaminants present in the environment and pass them on to higher food chain levels as vectors. The consumption of bivalves contaminated with the potent neurotoxin domoic acid (DA) can cause amnesic shellfish poisoning in humans. The aim of this study was to determine seasonal differences in occurrence and accumulation of this phycotoxin in European oysters (Ostrea edulis Linnaeus, 1758) (n = 46), Queen scallops (Aequipecten opercularis Linnaeus, 1758) (n = 53), and edible ascidians of the Microcosmus spp. (n = 107), originating from the same harvesting area in the Northern Adriatic Sea. The quantification was performed using ultra-performance liquid chromatography–tandem mass spectrometry (LC-MS/MS) preceded by derivatization with dansyl chloride. DA was found in very low concentrations throughout the year, with a maximum value of 810 μg/kg in Queen scallops. This study reveals differences in the occurrence and accumulation of DA between Queen scallops and the other two investigated species (oysters and ascidians) and the highest concentrations during the colder part of the year. Even though DA was detected in all of them, Queen scallops showed higher DA accumulation compared to the other two (p < 0.001), hence representing a sentinel species suitable for the monitoring of DA level in seafood.

Honey is a natural product producedby honeybees valued for its nutritional andhealth benefits. However, contaminationwith veterinary drug residues, such as ni-troimidazoles (NMZ), poses a health risk toconsumers. Nitroimidazoles, banned in theEuropean Union due to their carcinogenicand genotoxic properties, have been mis-used in beekeeping to treat diseases suchas nosemosis. The aim of this study was todetect nitroimidazole residues in rare uni-floral honey species from Croatia, Ailanthusaltissima (Mill) Swingle and Mentha spp.,using a validated ultra-performance liquidchromatography-tandem mass spectrometrymethod. Although the applied method wasoriginally developed for the determinationof NMZs in poultry muscle and eggs, the re-sults of the validation study show that it isalso suitable for determination in honey withsome modifications. For all analytes, the de-cision limit and detection capability valueswere between 0.33 and 0.71 µg/kg, which isbelow the minimum method performancerequirement for NMZs in honey of 1 µg/kgset by the European Union Reference Labo-ratories. Ten nitroimidazoles were analysedin 11 honey samples and no residues weredetected, confirming compliance with Eu-ropean regulations. These results are in linewith broader studies showing rare NMZ con-tamination in the global honey market. How-ever, they emphasise the need for continuousHoney is a natural product producedby honeybees valued for its nutritional andhealth benefits. However, contaminationwith veterinary drug residues, such as ni-troimidazoles (NMZ), poses a health risk toconsumers. Nitroimidazoles, banned in theEuropean Union due to their carcinogenicand genotoxic properties, have been mis-used in beekeeping to treat diseases suchas nosemosis. The aim of this study was todetect nitroimidazole residues in rare uni-floral honey species from Croatia, Ailanthusaltissima (Mill) Swingle and Mentha spp.,using a validated ultra-performance liquidchromatography-tandem mass spectrometrymethod. Although the applied method wasoriginally developed for the determinationof NMZs in poultry muscle and eggs, the re-sults of the validation study show that it isalso suitable for determination in honey withsome modifications. For all analytes, the de-cision limit and detection capability valueswere between 0.33 and 0.71 µg/kg, which isbelow the minimum method performancerequirement for NMZs in honey of 1 µg/kgset by the European Union Reference Labo-ratories. Ten nitroimidazoles were analysedin 11 honey samples and no residues weredetected, confirming compliance with Eu-ropean regulations. These results are in linewith broader studies showing rare NMZ con-tamination in the global honey market. How-ever, they emphasise the need for continuousmonitoring, especially as the possible use ofbanned NMZs in honey production cannot becompletely ruled out. Future studies shouldalso investigate the transfer of NMZs frombeeswax to honey, emphasising the impor-tance of good beekeeping practises to avoidcontamination.monitoring, especially as the possible use ofbanned NMZs in honey production cannot becompletely ruled out. Future studies shouldalso investigate the transfer of NMZs frombeeswax to honey, emphasising the impor-tance of good beekeeping practises to avoidcontamination.

Praćenjem stanja okoliša putem mjerenja sadržaja različitih onečišćujućih tvari (kontaminanata) u školjkašima ujedno se mogu pratiti biološke promjene i štetni učinci onečišćujućih tvari kojima su ti organizmi izloženi te se može procijeniti utjecaj ljudskih aktivnosti na određeni ekosustav. Akumulacija različitih onečišćujućih tvari u školjkašima namijenjenim za prehranu je stalna opasnost za ljude, kao potrošače na vrhu hranidbenog lanca. Mikroplastika je složeni kontaminant, koji uključuje vrlo širok skup čestica koje u procjeni rizika zbog njihove iznimne raznolikosti (veličina, oblik, topljivost, sastav polimera, adsorbirane kemikalije, biološki materijal, itd.) predstavljaju jedinstveni izazov. Glavni razlog opasnosti konzumacije školjkaša leži u biologiji njihovog organizma budući se oni hrane filtriranjem vode ili mora u kojem se uzgajaju ili prirodno žive, nakupljajući u svom organizmu različite tvari iz okoline. U razumijevanju kemijskog rizika mikroplastike koristi se model profila polimera, odnosno toksičnosti njihovih monomera. Nesumnjivo, analiza mikroplastike uključuje uz kemijsku karakterizaciju i određivanje ukupnog broja čestica kako bi se procijenila izloženost ljudi mikroplastici temeljem podataka o prehrambenim navikama ciljane populacije. U ovom radu dan je pregled literaturnih spoznaja o istraživanjima mikroplastike u dvoljušturnim mekušcima, kemijskoj karakterizaciji mikroplastike i pojavnosti u različitim vrstama školjkaša.