Water and sediments have become a major threat. Heavy metals, some of which are potentially toxic, are distributed in different areas by different routes. Tafna river was studied upstream and downstream under contrasting hydrological conditions during the year 2020.The different levels and sources of pollution are assessed by combining geochemical indicators: geoaccumulation index (GI-go), contamination factor (CF), pollutant loading index (PLI) and supplemented by correlation matrix (CM) as statiscal analyses added principal component analysis (PCA). The elements analysed were physical and chemical parameters (pH, DO, electrical conductivity CE and, COD BOD5), and the metallic elements (Fe, Cd, Pb, Cu, Mn and Zn). They were classified based on how contaminated they were: for the water compartment (Fe> Mn>Cu>Pb>Cd>Zn), while for sediments (Zn> Pb>Fe>Cd>Cu >Mn). The results suggest that the chemical composition of the waters of the Tafna river is influenced by the lithology, which contributes to the enrichment of the sediments. All of the indicators suggest an average levels of sediment and water pollution at the Tafna's summit, then decreases towards the bottom due to the geomorphology with multiple sources of pollution. As a result, our study offers the first comprehensive information on the amount of heavy metals present in the riverbed's sediment and water.

Mussels (Mytilus galloprovincialis) were collected from the locality in the vinicity of the Institute for Marine Research in Kotor (Montenegro, Yugoslavia). The concentration of Cu (copper), Cr (chromium), Fe (iron), Zn (zinc), Ni (nickel), Mn (manganese), Pb (lead), Cd (cadmium), Al (aluminium), Ca (calcium) and Mg (magnesium) were determined in whole mulles, gills, pedal muscle and in rest of soft tissues. The data obtained in this research were compared with the results reported by other investigators.

The determination of main and some biogenic and trace elements in the sea water of the Boka Kotorska Bay (Adriatic sea, Montenegro, Yugoslavia) was carried out by the atomic apsorption and emission spectrometric method (FAAS) and by the hydride technique AAS (HGAAS).

MPI - Metal Pollution Index is being proposed with an aim improving the freshwater pollution control, monitoring and classification based on fish metal body burden. This is a simple mathematical model which enables presentation of Cd, Pb, Cu, Zn and Al fish liver concentration as a single value. After thorough studies of bioaccumulation, biomagnification and tissue distribution patterns, liver of Carassius auratus gibelio has been chosen as sentinel organ. Normal distribution and biological variation assessment is being achieved by using normalizers - reference values (liver concentrations of selected elements in fish from reference sites Vruje and Moharac micro water reservoirs, Serbia (Yugoslavia)). Selected representative sites have been evaluated according to new classification of freshwater ecosystem based on MPI values.

Activities of rat brain synaptic plasma membrane (SPM)Na(+)/K(+)-ATPase and Mg(2+)-ATPase were investigated by in vitro individual and simultaneous exposure to ions of the first transition series metals (Cu(2+), Zn(2+), Fe(2+)). All investigated metals produced a larger maximum inhibition of Na(+)/K(+)-ATPase than Mg(2+)-ATPase activity. Metal concentrations causing 50% inhibition of Na(+)/K(+)-ATPase activities were: Cu(2+) 7.1 microM Zn(2+) 19 microM Fe(2+) 25 microM. Simulataneous exposure to metal combinations: Cu(2+)/Zn(2+), Cu(2+)/Fe(2+) and Zn(2+)/Fe(2+) inhibited both the Na(+)/K(+)-ATPase and Mg(2+)-ATPase activity synergistically, i.e., more than the sum of the metal induced inhibitions assayed separately. It is also established that the plot of logarithm IC50 values of Na(+)/K(+)-ATPase activity vs. the ionic radius of (Cu(2+), Zn(2+), Fe(2+)) is a straight line that enables to predict the value IC50 for other metals of the first transition series. The results obtained show that Na(+)/K(+)-ATPase is promising as a biological component of biosensor.

Ambient PM2.5 (particulate matter less than 2.5 μm) samples, collected in a 8-week wintertime sampling program in two residential sites of Bhilai, India during the Indian Diwali festival in November 2012, were chemically characterized for 38 chemical species including eight speciated carbonaceous fractions (SCFs) of elemental (EC) and organic carbon (OC), twenty one metallic elements, and nine water soluble ionic species. Our objectives were to investigate: 1) relative abundances of SCFs contained in PM2.5during the Diwali festival period compared to normal days, and 2) enrichment pattern of potential inorganic markers of firework emission in ambient PM2.5during the festival days. Eight-fold increase inPM2.5mass concentrations were measured during the Diwali festival days compared to concentrations occurring in normal days. Bursting of firecrackers in the residential streets have shown significant contribution to the emission markers (K, Mg, Zn, S, EC and OC) along with crustal markers (Ca, Fe, Al) in ambient PM2.5aerosol samples. Concentrations of water soluble ionic species were found to be 10 times greater than those found in normal days. Further, the anion/cation ratios were found to reach a factor of 2; indicating the acidic character of emissions resulting from fireworks. The relative abundance of SCFs and higher ratios of OC to EC during the Diwali episode suggested the significant formation of secondary organic carbon (SOC) aerosols. We estimate that aerosols emitted from firework bursting contribute up to 32% of total ambient PM2.5 during the Diwali festival.

Mauritania is a fishing country. However, the Mauritanian coast is increasingly exposed to environmental issues mainly due to anthropogenic activities such as the mining, gas, oil, and fishing industries, as well as new agricultural practices that unreasonably use inputs. Environmental monitoring of the Mauritanian coast faces several challenges; thus, improving the fisheries sector begins with enhancing the state of marine ecosystems and implementing environmental monitoring adapted to climatic conditions and local needs. This study aims to evaluate the quality of the sediments of the “Baie du Repos” in the town of Nouadhibou, Mauritania, through the study of organic matter and the quantification of trace metallic elements in the Quaternary sediments of the Bay. Six samples deemed representative of this Bay were taken and transported to the laboratory. The physicochemical analysis of these samples shows that the superficial horizons of 30 cm depth have overall organic matter contents higher than the average threshold value proposed by the literature for 4 out of 6 of the points studied. The contents recorded for the different metallic trace elements indicate that point 1 is the most exposed to contamination, with the highest concentrations of cadmium, lead, copper, iron, and zinc. The ACP (Principal Component Analysis) showed that the metallic trace elements Pb, Cu, Fe, Cd, and Zn are closely related and evolve positively in the same direction. Additionally, it was found that the points studied are divided into three groups: Group 1 contains only point 1, which is the most exposed to contamination by these toxic elements (Pb, Cu, Zn, Fe, and Cd). Group 2 contains points 3, 5, and 6, which are moderately contaminated by metallic elements with a significant dominance of organic matter (OM). Finally, Group 3 is the least contaminated, with a very high content of organic matter (OM).