Karakterisanje hemijskog sastava sedimenta bokokotorskog zaliva korišćenjem energetski disperzivne rendgenske fluorescentne spektrometrije (ED-HRF)

Abstract

Prostorna raspodela glavnih oksida (Na2O, K2O, SiO2, Al2O3, Fe2O3, CaO, MgO, MnO, TiO2, P2O5) i velikog broja elemenata (Cr, Co, Ni, Cu, Zn, As, Se, Pb, Sn, Sb, Ba, Sr, Br, Rb, Zr, Mo, Cs, Y, V, Ga, La, U, Th, Nb, W, Sc, Ge, Gd, Yb, Hf i Ce) u uzorcima površinskog sedimenta Bokokotorskog zaliva odreĊena je merenjem njihovih koncentracija primenom metode energetski disperzivne rendgenske fluorescentne spektrometrije (ED-XRF) na osnovu prethodno determinisanog sadrţaja organske materije i karbonata u ispitivanim uzorcima površinskog sedimenta. Optimalni uslovi primene i promenljive ED-XRF metode za ispitivane okside i elemente odreĊeni su korišćenjem pet standardnih referentnih materijala. OdreĊen je tip i kvalitet površinskog sedimenta (aluminosilikatni ili karbonatni; kao i nezagaĊeni ili zagaĊeni). Ovim ispitivanjem utvrĊeno je da karbonatni tip sedimenta karakterišu veoma visoke koncentracije Sr, Sc, La, Nb, Hf i Yb. TakoĊe je utvrĊeno prisustvo negativne Ce-anomalije (fenomena koji karakteriše vrlo niska koncentracija Ce u sedimentu u odnosu na sve ostale retke zemne elemente) za razliku od aluminosilikatnog tipa sedimenta. Ispitivani površinski sedimenti klasifikovani su kao nezagaĊeni ili zagaĊeni na osnovu Faktora obogaćenja (EF), Kontaminacionog faktora (CF), Indeksa opterećenja zagaĊenjem (PLI), Indeksa zagaĊenja elementima (EPI) i Geoakumulacionog indeksa (Igeo). Ovi parametri su izraĉunati na osnovu literaturnih podataka o elementarnom nivou analiziranih elemenata u sedimentnim stenama, ili „background”-vrednosti. Na osnovu vrednosti po smernicama za kvaltiet sedimenta (SQG) od strane USEPA praćen je negativan uticaj elemenata na morske organizme. Na osnovu izraĉunatih indeksa i faktora vezanih za zagaĊenje površinskog sedimenta u zalivu, procenjena je zagaĊenost površinskog sedimenta koja se menja od nezagaĊenog do jako zagaĊenog, u zavisnosti od primenjenih vrednosti „background”-a ispitivanih elemenata u proraĉunima. Na osnovu indeksa i faktora zagaĊenja ne mogu se izvršiti potpune procene zagaĊenja...

The spatial distribution of major oxides (Na2O, K2O, SiO2, Al2O3, Fe2O3, CaO, MgO, MnO, TiO2, P2O5) and numerous elements (Cr, Co, Ni, Cu, Zn, As, Se, Pb, Sn, Sb, Ba, Sr, Br, Rb, Zr, Mo, Cs, Y, V, Ga, La, U, Th, Nb, W, Sc,Ge, Gd, Yb, Hf, and Ce) was determined by using energy dispersive X-ray fluorescence spectrometry (ED-XRF) on the basis of previously measured content of organic matter and carbonates in the investigated surface sediments of the Bay. The optimal measuring variables for the investigated oxides and elements were determined by using five standard reference materials. Based on measurements of ED-XRF method were determined by the type and quality of surface sediment (aluminosilicate or carbonated; and unpolluted or polluted). Oxides, minor and rare earth elements were measured for the first time in surface sediments at twelve locations in the Bay by ED-XRF technique. In this research found that the carbonated sediment type is characterized by very high concentrations Sr, Sc, La, Nb, Hf, and Yb. It was also found the presence of negative Ce-anomaly (the phenomenon in which the concentration of Ce in the sediment rather small compared to all the other rare earth elements) as opposed to , unlike the aluminosilicate type of sediment. Sediments were classified as non-polluted or polluted by counting Enrichment Factor (EF), Contamination Factor (CF), Pollution Load Index (PLI), Element Pollution Index (EPI) and Geo-accumulation index (Igeo). These parameters were calculated on the basis of literature data on the elementary level of the analyzed elements in sedimentary rocks, or "background"-values. Based on the literature elemental background level of the analyzed elements or on the sediment quality guidelines (SQG) of USEPA followed possible negative impact on marine organisms. On the basis of the calculated indexes and factors related to the pollution of surface sediments in the Bay, the assessment of sediment pollution of surface changing from unpolluted to very polluted, depending on the applied values of „background” tested elements in the calculations