Milica Arsenović

Analysis of trace elements in surface sediments, mussels, seagrass and seawater along the southeastern Adriatic coast – a chemometric approach

Abstract Surface sediments, mussels, seagrass, surface and bottom seawater samples were collected from the costal area of the southeastern Adriatic Sea and analyzed in order to determine the concentration and origin of the following elements: Fe, Mn, Zn, Ni, Cu, Ni, Co, As, Cd, Cr and Hg. The complexity of the obtained data was reduced by principal component analysis (PCA) and cluster analysis (CA), methods well known and accepted for the identification of the quality of marine environments. Both PCA and CA analysis were used to discriminate groups of samples according to the similarity of their chemical composition. The results revealed good diversity between the various samples, expressed by their distinctive positions of points in factor space. PCA indicated that the first two PC components explained about 73, 48, 43, 48, and 50 % of the total variance of the data for sediments, mussels, seagrass, and surface and bottom water, respectively. The results showed good discrimination capabilities between the samples taken from different locations, and also different seasons, which was especially evident in the surface and bottom water samples. Simultaneously, PCA/CA analysis of the amounts of trace elements found in the marine organisms could explain the manner of their bioaccumulation.

The Effects of Chemical Composition and Firing Temperature in Heavy Clay Brick Production — Chemometric Approach

Factors influencing final clay brick properties are numerous, since the raw materials are highly heterogeneous. The chemometric approach is rarely used in analysis in this field, although it could significantly improve understanding of the overall system behavior and the quality of products. Principal component analysis (PCA) was used on a group of 139 samples collected in Serbia to discriminate groups of samples according to similarity of chemical composition and fired laboratory products properties. The focus of this study was to determine the importance of parameters that describe clay brick production and quality, depending on final usage of raw material in the clay brick industry. A fuzzy synthetic evaluation, using a membership trapezoidal function with defined optimal interval values for different types of heavy clay products, is chosen for the study. The optimal sample’s chemical composition and firing temperature were chosen by the fuzzy synthetic evaluation, regarding the kind of the heavy clay product.