DETECTED MARINE TOXINS IN DIFFERENT TROPHIC LEVELS – STUDY FROM BULGARIAN SOUTH COAST OF THE BLACK SEA
ZLATINA PETEVA*, MONA STANCHEVA, STANISLAVA GEORGIEVA
Department of Chemistry, Faculty of Pharmacy, Medical University “Prof. Dr. P. Stoyanov” Varna, Bulgaria
*Corresponding author: zlatina.peteva@mu-varna.bg
Keywords: domoic acid, lipophilic toxins, Black Sea, Bulgaria, phytoplankton, mussels
Abstract: Marine toxins originate in unicellular algae. About 2% (60-80 species) of the estimated 3400-4000 known phytoplankton taxa are toxic. In response to favorable conditions in their environment, toxic microalgae (dinoflagellates and diatoms) may proliferate and/or aggregate to form dense concentrations of cells called "harmful algal blooms" (HABs). Such cases, but also low cell concentration of toxic phytoplankton species may result in contamination of the whole food chain. Filter-feeding shellfish, zooplankton, and herbivorous fishes ingest these algae and act as vectors to humans either. The aim of this study was to summarize and review the marine toxin content along the Black Sea food chain levels (phytoplankton and mussels), to discuss the metabolic changes they may undergo as they move to higher trophic level and the potential impact to the apex consumer – the human. Plankton and mussels were sampled in the period 2016-2018 on the South Black Sea coast of Bulgaria. Lipophilic toxins and domoic acid were detected on LC-MS/MS and saxitoxins and its analogues on HPLC-Fl. Domoic acid (DA) was the toxin with the highest detected concentrations: in plankton - 962963.0 pg/net haul and in mussels – 618859.8 pg/g. In addition, yessotoxins (YTX), pectenotoxin-2 (PTX2) and gonyautoxin-2 (GTX2) were also found in the samples. Despite of the low toxin concentrations detected, distribution and mobility of toxin producing algae in harvest waters, toxin accumulation potential of mussels, etc. need to be considered to protect human from contamination.