Diets of fan shells (Pinna nobilis) of different sizes: fatty acid profiling of digestive gland and adductor muscle

Pinna nobilis is a large bivalve, endemic to the Mediterranean Sea that was shown in a previous study to ingest significantly different proportions of different food items according to its shell height. Fatty acid profiling of total lipids was used to examine these differences in diet in relation to shell size. Small (shell height 23.0 ± 3.3 cm), medium (SH 41.5 ± 5.5 cm) and large (SH 62.7 ± 4.8 cm) P. nobilis were collected from Mali Ston Bay, Adriatic Sea, in March 2010, and fatty acid analysis was performed on digestive gland and adductor muscle tissues. Based on the analysis of the digestive gland, small P. nobilis were associated with a detrital food chain, characterized by saturated and branched-chain fatty acids, while the diets of medium and large individuals had a greater proportion of polyunsaturated fatty acids. This likely reflects the fact that smaller individuals feed within the benthic boundary layer where the detritus concentrations are high. Fatty acid incorporation into the adductor muscle, likely representative of food taken up over a longer time period, was reversed, that is, larger individuals had lower levels of polyunsaturated fatty acids. This most probably reflects energy expenditure, which typically increases with increasing organism size.     

Air pollution protection by waste amorphous SiO2 utilization in Portland cement production

This papers deals with waste amorphous silica obtained from AlF₃ production. This is a waste material that could be used as additive in cement production. Results are encouraging although there are no large quantities of this material available (about 4000 t/yr). Experiments were performed with the addition of 2.5%, 5.0%, 7.5% and 10.0% mass of amorphous silica obtained from AlF₃ production. Flexural and compressive strengths of the prepared mortar samples with w/c = 0.50 and with the constant flow were determined. Experiments show that optimal quantity for the amorphous silica addition is 5% of the cement mass.     

Environmental human silver exposure

Environmental exposure to silver (Ag) was assessed in occupationally non-exposed adult human population by analyzing Ag in the hair (H?·?Ag) and whole blood (WB?·?Ag). H?·?Ag was analyzed in 311 (123 men, M; 188 women, W); while WB?·?Ag was determined in 235 of these individuals (90 M, 145 W). Women had more H?·?Ag than men (M 0.05 vs. W 0.076), whereas WB?·?Ag concentrations in men and women were not significantly different. A natural distribution of the median derivatives was utilized to generate the dataset to fit the logistic sigmoid curve to assess the current human body burden of environmental Ag population exposure for M and W separately. The H?·?Ag (µg?g^?1) below 0.0105 for M and 0.0145 for W, reflects low level of environmental Ag exposure. The adaptive physiological saturation phase followed where H?·?Ag rose rapidly, first for M and then for W in parallel with biological assay. Both parallel saturation curves converged and plateaued at 0.215 for M and 0.965 for W (µg?g^?1). The current level of human environmental Ag exposure is low, but cases of high Ag exposure occurred sporadically. In conjunction with the medical histories overt clinical neural toxicity may be expected for H?·?Ag at 4?µg?g^?1and higher. There were no significant correlation between the H?·?Ag and WB?·?Ag.     

Genotoxicity screening of the river Rasina in Serbia using the Allium anaphase–telophase test

Evaluation of the presence of genotoxic substances is especially important in rivers that serve as a source of drinking water. Nine water samples collected along the river Rasina in Serbia were analyzed for potential toxic and genotoxic effects using the Allium anaphase-telophase test. Inhibition of root growth relative to the negative control (synthetic water) was observed in all samples. Analysis of the genotoxic potential, through scoring anaphase and telophase aberrations, showed that in seven of the nine samples the level of aberrations was significantly increased relative to the negative control but was lower than that obtained for the positive control (methyl methanesulfonate). Changes in the relation between spindle and chromosome types of aberrations were found in some samples, indicating differences in the potential genotoxic substances present at the analyzed sites. The data, which were obtained from samples collected at the highest level of river water, warn that during periods of low flow the values could reach genotoxic activity. The Allium anaphase-telophase test can be recommended as an monitoring system, that can serve as the first alert for the presence of genotoxic environmental pollutants.     

Heavy metal concentration in fish tissues inhabiting waters of “Buško Blato” reservoar (Bosnia and Herzegovina)

Heavy metals concentration (mercury, lead, cadmium, arsenic, copper, zinc and chromium) in tissues (muscles, liver, kidney and gonads) of Dalmatian barbelgudgeon, the nase, the souffie and brown trout, inhabiting waters of Busko Blato reservoir in Bosnia and Herzegovina, has been determined by atomic absorption spectrophotometry. The meat of the tested fish sorts does not contain elevated concentration of most analyzed heavy metals with exception of lead (higher than MAC in Italy, Germany and Denmark) and mercury (in muscles of brown trout higher than MAC in most countries). The lowest level of all heavy metals is always detected in gonads, with higher values in fry compared to milt for copper, zinc, chromium and arsenic. The highest copper concentration is observed in the liver from the souffie which is suggested as a suitable biomonitor for copper intoxication. In muscles of all fish sorts, lead was always present in much higher concentration than cadmium, while in kidneys of most fish sorts, lead and cadmium concentrations were similar. We showed that bioaccumulation of some heavy metals in the fish sorts analyzed is tissue and sex dependent. Also, we concluded that the small water exchange in reversible shallow reservoir does not induce elevated concentration of heavy metals in fish tissues inhabiting Busko Blato.     

Long-term seasonal changes of the Danube River eco-chemical status in the region of Serbia

Seasonal spatial and temporal changes of selected eco-chemical parameters in section of the Danube River flowing through Serbia were analyzed. Data for electrical conductivity (EC), dry and suspended matter, residue on ignition, chemical oxygen demand (COD), biochemical oxygen demand (BOD-5), ultraviolet extinction, dissolved oxygen (DO), oxygen saturation, pH, nitrates, total phosphorus, and nitrogen were collected between 1992 and 2006. The use of monthly medians combined with linear regression and two-sided t test has been proven to be the best approach for resolving trends from natural variability of investigated parameters and for determining trend significance. Patterns of temporal changes between different months were examined. It was also determined that spatial trends of some parameters oscillate in predictable manner, increasing in one part of the year and declining in the other. Regression slope coefficients, an excellent indicator for determining when the water quality is changing the most along the course of the Danube, reach their maximum during summer for temperature (t), electric conductivity, nitrates, and total N, while in the same season suspended matter, COD, BOD-5, DO, and oxygen saturation coefficients reach their minimum. Correlations for used data sets of selected parameters were analyzed for better understanding of their behavior and mutual relations. It was observed that as Danube flows through Serbia, its general eco-chemical status either stagnates or improves, but the rate of river self-purification often depends on the season of the year.     

Edaphic factors affecting the vertical distribution of radionuclides in the different soil types of Belgrade, Serbia

The specific activities of natural radionuclides ((40)K, (226)Ra and (232)Th) and Chernobyl-derived (137)Cs were measured in soil profiles representing typical soil types of Belgrade (Serbia): chernozems, fluvisols, humic gleysols, eutric cambisols, vertisols and gleyic fluvisols. The influence of soil properties and content of stable elements on radionuclide distribution down the soil profiles (at 5 cm intervals up to 50 cm depth) was analysed. Correlation analysis identified associations of (40)K, (226)Ra and (137)Cs with fine-grained soil fractions. Significant positive correlations were found between (137)Cs specific activity and both organic matter content and cation exchange capacity. Saturated hydraulic conductivity and specific electrical conductivity were also positively correlated with the specific activity of (137)Cs. The strong positive correlations between (226)Ra and (232)Th specific activities and Fe and Mn indicate an association with oxides of these elements in soil. The correlations observed between (40)K and Cr, Ni, Pb and Zn and also between (137)Cs and Cd, Cr, Pb and Zn could be attributed to their common affinity for clay minerals. These results provide insight into the main factors that affect radionuclide migration in the soil, which contributes to knowledge about radionuclide behaviour in the environment and factors governing their mobility within terrestrial ecosystems.     

The responses of the hepatosomatic index (HSI), 7-ethoxyresorufin-O-deethylase (EROD) activity and glutathione-S-transferase (GST) activity in sea bass (Dicentrarchus labrax, Linnaeus 1758) caged at a polluted site: implications for their use in environmental risk assessment

The present study investigates the response of three hepatic biomarkers in adult sea bass (Dicentrarchus labrax, Linnaeus 1758) caged at a wastewater outlet of an oil refinery with fish caged at a pristine site used as controls. The biomarkers that were investigated were the hepatosomatic index (HSI), 7-ethoxyresorufin-O-deethylase (EROD) activity and glutathione-S-transferase (GST) activity. In addition, we have measured the levels of polycyclic aromatic hydrocarbons (PAHs) and selected heavy metals (lead, cadmium, mercury, copper and zinc) in sediment samples at the polluted site. Although the polluted site had high environmental levels of PAHs and heavy metals, there was no difference in hepatic EROD activity and HSI between fish caged at the polluted site and controls. On the other hand, GST activity was significantly lower in fish caged at the polluted site compared to controls. Our results point out that the studied biomarkers have limited use in environmental risk assessment studies, at least when caged adult sea bass is used as the sentinel species and complex toxicant mixtures are involved.     

Exposure of microplastics to organic matter in waters enhances microplastic encapsulation into calcium carbonate

Environmental Chemistry Letters - Plastic pollution in water ecosystems is threatening the survival of wildlife. In particular, microplastics may be encapsulated into calcium carbonate, a crucial...