SEDIMENTOLOGICAL CHARACTERISTICS AND ANTHROPOGENIC PRESSURES ON SURFACE SEDIMENTS, PLOMIN BAY, ISTRIA

Analizirani su površinski sedimenti morskog dna Plominskog zaljeva, Istra. Uzorkovano je 7 lokacija po pravcu duž zaljeva, od najdubljeg prema najplićem djelu. Područje je odabrano radi obližnjeg drenažnog tunela koji aktivno sudjeluje u sedimentaciji zaljeva te zbog blizine termoelektrane Plomin. Ciljevi su: određivanje karakteristika sedimenata morskog dna i određivanje mogućeg antropogenog opterećenja tog sedimenta (prisustvo mikroplastike i ugljene prašine). Prilikom određivanja karakteristika sedimenata utvrđena je boja uzoraka, mjeren je udio karbonatne komponente te je utvrđen sastav rendgenskom difrakcijom na prahu (XRPD). Prilikom određivanja antropogenog opterećenja korištena je separacija na temelju gustoće pomoću SPT otopine, lupa te analiza infracrvenom spektroskopijom Fourierove transformacije (FTIR). Rezultati XRPD analize ukazuju na kvarc i kalcit kao glavne faze u uzorcima te sporadičnu pojavu muskovita, klorita i halita. Izdvajanjem lake frakcije u uzorcima pronađene su sintetičke niti i 5 fragmenata mikroplastike te ugljena prašina. Fragmenti su FTIR analizom identificirani kao poliviniliden-klorid i polipropilen, a sintetičke niti kao polietilen niske gustoće. Spektrogrami ugljene prašine upućuju na lignit i bituminozni ugljen. Porijeklo ugljene prašine povezano je s obližnjom TE Plomin. Rezultati ovog rada pridonijeli su boljem uvidu u karakteristike sedimenta na istraživanom lokalitetu, iako ne upućuju na značajnije antropogeno opterećenje, stalan donos novog sedimenta može utjecati na točnost antropogenog opterećenja.Surface sediments of the seabed of Plomin Bay, Istria were analyzed. 7 locations along the bay, from the deepest to the shallowest, were sampled. The area was chosen because of the nearby drainage tunnel that actively participates in the sedimentation of the bay and because of the proximity of the Plomin thermal power plant. The objectives are: to determine the characteristics of seabed sediments and to determine the possible anthropogenic load of that sediment (the presence of microplastics and coal dust was analyzed). During the determination of sediment characteristics, the color of the samples was determined, the carbonate content was measured and the composition was determined by X-ray powder diffraction (XRPD). Density-based separation using SPT solution, magnifying glass, and Fourier transform infrared spectroscopy (FTIR) were used to determine anthropogenic load. The results of XRPD analysis indicate quartz and calcite as the main phases in the samples and the sporadic occurrence of muscovite, chlorite and halite. By isolating the light fraction in the samples, synthetic threads and 5 fragments of microplastics and coal dust were found. The fragments were identified by FTIR analysis as polyvinylidene-chloride and polypropylene, and the synthetic threads as low density polyethylene. Coal dust spectrograms indicate lignite and bituminous coal. The origin of coal dust is connected with the nearby TPP Plomin. The results of this work contributed to a better insight into the characteristics of the sediment at the investigated site, although they do not indicate a significant anthropogenic load, the constant yield of new sediment may affect the accuracy of anthropogenic load