Lichens as integrating air pollution monitors

In this work an attempt to combine the results of lichen mapping with the quantitative levels of certain trace elements in Hypogymnia physodes (L.) Nyl. collected on a national scale is presented. An Index of Atmospheric Purity (IAP) was calculated using a simple method of mapping lichens based on the assessment of the cover and frequency of crustose, foliose and fruticose lichens on different tree species. For determination of trace elements in lichens k0-instrumental neutron activation analysis was used. From the IAP results it can be concluded that the epiphytic lichen flora look quite poor with more than 70% of the territory in the fourth and third classes, which represent highly polluted and moderately polluted air. By comparing IAP results with elemental levels in H. physodes using multivariate statistical methods it was found that the elemental levels do not have a direct negative effect on the diversity of lichens but can help in identification of the type of possible pollution sources and their origin.     

Determination of sulfur oxides formed during the S(IV) oxidation in the presence of iron

The reaction products (i.e., sulfate (SO4(2-)) and dithionate (S2O6(2-))) of S(IV) oxidation in the presence of iron(III) under different experimental conditions were investigated. Ion-interaction chromatography was used for the separation of sulfate and dithionate using tetrabutylammonium hydroxide (TBAOH) as an ion-pair reagent. The chromatographic method was optimized by varying the composition of the mobile phase (i.e., concentration of TBAOH, acetonitrile and Na2CO3) and by varying the flow rate of the mobile phase. The method was successfully applied to the determination of dithionate formed during the S(IV) oxidation in the presence of Fe(III). In air-saturated solutions sulfate was observed as the only product, while in N2-saturated solutions dithionate was also determined, but it is the minor reaction product and represents about 4% of the total amount of oxidized HSO3- under the studied conditions.     

Toxicity of surfactants to green microalgae Pseudokirchneriella subcapitata and Scenedesmus subspicatus and to marine diatoms Phaeodactylum tricornutum and Skeletonema costatum

Ecotoxicity of different commercial surfactants (six anionic, two amphoteric and one nonionic), essential constituents of cleansing hair products (shampoos), as well as ecotoxicity of eight shampoos containing different combinations of these surfactants, were tested in order to evaluate their possible toxic effects on microalgae. Specific objective of this research was to compare the sensitivity of selected freshwater and marine microalgae to these widely used surfactants and well-known pollutants in surface waters. Internationally validated methods (ISO standards) for the determination of toxic effects on the growth of planktonic freshwater green algae Pseudokirchneriella subcapitata and Scenedesmus subspicatus and marine diatoms Skeletonema costatum and Phaeodactylum tricornutum, were used. The obtained results showed that the concentrations of tested surfactants and shampoos, which resulted in 50% growth reduction of planktonic freshwater green algae, when compared to the controls without test substances (EC50), were in the range from 0.32 to 4.4 mg l(-1) for surfactants and from 2.1 to 8.5 mg l(-1) for shampoos expressed as active substance. Marine diatoms were significantly more sensitive to the tested surfactants than freshwater green algae (EC50 0.14-1.7 mg l(-1) for surfactants and 0.35-1.25 mg l(-1) for shampoos). According to the classification on the basis of environmental effects, the obtained results suggested that all tested surfactants can be classified as having toxic effects on freshwater green alga Pseudokirchneriella subcapitata. Some of them indicated that they have a very toxic effect on Scenedesmus subspicatus and marine diatoms Skeletonema costatum and Phaeodactylum tricornutum.     

Growth of sea bass,Dicentrarchus labrax,larval and juvenile stages and their otoliths under quasi-steady temperature conditions

The relationship between somatic growth and growth of otoliths of sea bass larvae, postlarvae and juveniles under relatively steady temperature conditions was studied. Larvae were incubated at the constant ambient temperature of 13.5°C, whereas postlarvae and juveniles were reared at a comparatively steady temperature ranging from 18.6 to 20.4°C, with a mean of 19.67°C. The patterns of both somatic and otolith growth were found to be similar. Differentiated data on larvae length and otolith diameters indicated three periods of change in their growth rates. Since temperature was kept relatively steady during the experiment, and larvae fed ad libitum, these periods could be attributed with relative certainty to intrinsic changes which occur during stage-specific periods of growth. The third period of change in both growth rates indicates a specific phase of growth during metamorphosis. The changes in growth rates, as well as the raw time series of the growth of both larval lengths and otolith diameters, may be described by higher order polynomials with a high degree of probability levels. A non-linear relationship between body length and otolith diameters was established, indicating positive allometric growth of otoliths. It was also observed that the coefficient of allometric growth changed at the time estimated for the end of metamorphosis. Thus, a non-linear relationship and changes in the coefficients of allometry should be borne in mind when back-calculating somatic growth from the growth of otoliths.     

Radon in the spas of Croatia

Radon concentrations in air and geothermal water of the spa pools in Croatia were measured and the average values of 40.3 and 4.5 kBq/m3 were obtained, respectively. Great difference between radon concentrations in pool and spring water was considered as a result of mixing normal and geothermal water in the pool as well as the radon decay. Estimation of an effective dose, received by the personnel in the Bizovac spa, gave the value of 0.27 mSv/y. At the location Stubica, the transfer factor of the radon for air and thermal water in the pool was calculated, and the value of 4.9+/-0.7 x 10(-3) was obtained.     

Skin reactions to latex in dental professionals – first Croatian data

Purpose. To determine the prevalence of undesirable skin reactions to latex in dental professionals and students of the School of Dental Medicine in Zagreb, Croatia. Methods. Our research included 444 participants, of which 200 agreed to undergo a skin prick test (SPT). All participants answered a questionnaire in which we asked about incidence of skin lesions, duration of occupational exposure to latex, localization of skin lesions and symptoms. Statistical analysis of the questionnaire and test results was then carried out. Results. Of the total 444 participants surveyed, 249 (56.1%) reported lesions on their skin (professionals 64.8%, students 6.1–58.5%). From the questionnaire, 239 (96.0%) respondents reported lesions on the hands and fingers, mostly in the form of erythema (37.0%) and occasional dryness of skin (29.0%). Positive SPT results were found in 14 (7.0%) out of the 200 respondents who underwent the test. Conclusions. While a large number of subjects (56.1%) reported skin lesions when using latex products at their workplace, the SPT test was positive only in 7.0%. The results show that the prevalence of self-reported skin lesions was significantly related to the length of occupational exposure, with a substantial effect size (p?<?0.001; V?=?0.334).     

Multi-criteria ranking of copper concentrates according to their quality – An element of environmental management in the vicinity of copper – Smelting complex in Bor,Serbia

The results of multi-criteria ranking of copper concentrates by their quality, according to their content of useful and harmful components, are presented in this paper. Cu, Ag and Au were taken as useful components, while Pb, Zn, As, Cd, Hg, Bi and Sb were considered as harmful with adequate weight parameters. Considering its specific role in copper metallurgy, sulfur in the concentrate was considered in two scenarios. In the first scenario S was considered as a useful and in the other one as a harmful component. The ranking is done by implementing the PROMETHEE/GAIA method with an additional implementation of the special PROMETHEE V method, using the standard limitations of the heavy metals content in the concentrate. In this way, it is possible to perform an optimization of the input charge for the copper extraction from two aspects. The first aspect covers benefits from the content of useful metals, while the second deals with the protection of the environment, considering the content of harmful components of the charge.Using multi-criteria decision making for the sake of ranking the quality of copper concentrates, as described in this paper, could be considered as a contribution to the methodology of forming the market price of this product.     

Impact of a native Streptomyces flavovirens from mushroom compost on green mold control and yield of Agaricus bisporus

ABSTRACT

Thirty-five actinobacterial isolates, obtained from button mushroom (Agaricus bisporus) substrates (i.e., compost in different phases of composting, black peat or casing layer) in Serbia in 2014–2016 were tested in vitro against the causal agents of green mold in cultivated mushroom. Out of six most promising isolates, A06 induced 42.4% in vitro growth inhibition of Trichoderma harzianum T54, and 27.6% inhibition of T. aggressivum f. europaeum T77. The novel strain A06 was identified as Streptomyces flavovirens based on macroscopic and cultural characteristics and 16S rDNA sequence and used in mushroom growing room experiments. Actinobacteria had no negative influence on mycelial growth of the cultivated mushroom in compost in situ. Isolate S. flavovirens A06 enhanced mushroom yield significantly, up to 31.5%. The A06 isolate was more efficient in enhancing yield after inoculation with the compost mold T. aggressivum (26.1%), compared to casing mold T. harzianum (8%). Considering disease incidence, actinobacteria significantly prevented green mold in compost caused by T. aggressivum (6.8%). However, fungicide prochloraz-Mn had a more significant role in reducing symptoms of casing mold, T. harzianum, in comparison with actinobacteria (24.2 and 11.8%, respectively). No significant differences between efficacies of S. flavovirens A06 and the fungicide prochloraz-Mn against T. aggressivum were revealed. These results imply that S. flavovirens A06 can be used to increase mushroom yield and contribute to disease control against the aggressive compost green mold disease caused by Trichoderma aggressivum.     

Comparative environmental assessment of natural and recycled aggregate concrete

Constant and rapid increase in construction and demolition (C&D) waste generation and consumption of natural aggregate for concrete production became one of the biggest environmental problems in the construction industry. Recycling of C&D waste represents one way to convert a waste product into a resource but the environment benefits through energy consumption, emissions and fallouts reductions are not certain. The main purpose of this study is to determine the potentials of recycled aggregate concrete (concrete made with recycled concrete aggregate) for structural applications and to compare the environmental impact of the production of two types of ready-mixed concrete: natural aggregate concrete (NAC) made entirely with river aggregate and recycled aggregate concrete (RAC) made with natural fine and recycled coarse aggregate. Based on the analysis of up-to-date experimental evidence, including own tests results, it is concluded that utilization of RAC for low-to-middle strength structural concrete and non-aggressive exposure conditions is technically feasible. The Life Cycle Assessment (LCA) is performed for raw material extraction and material production part of the concrete life cycle including transport. Assessment is based on local LCI data and on typical conditions in Serbia. Results of this specific case study show that impacts of aggregate and cement production phases are slightly larger for RAC than for NAC but the total environmental impacts depend on the natural and recycled aggregates transport distances and on transport types. Limit natural aggregate transport distances above which the environmental impacts of RAC can be equal or even lower than the impacts of NAC are calculated for the specific case study.     

Processing of whey from dairy industry waste

An investigation carried out in 11 dairies in Serbia has shows that 78.75 % of whey, a by-product of cheese industry, is emitted into river systems, thus contributing to the organic pollution of the environment. This pollution can be avoided by processing of whey into food and pharmaceuticals. It is shown that low-temperature regime of whey concentration and fractionation, based on vacuum concentration and diafiltration, preserves whey proteins undenaturated, as proved by differential scanning calorimetry method. Functional native whey proteins based food products, with potentially high immunomodulatory activity, are obtained.