QSPR for prediction of subcooled vapor pressures (log PL) of polychlorinated trans-azobenzenes

In this study the values of subcooled vapor pressures (log P(L)) were estimated for 209 trans chloroazobenzenes (Ct-ABs) that fill some gaps in analytical and experimental data on these compounds. There are 209 chloro derivatives of trans azobenzenes that are relatively stable and more environmentally relevant than 209 chloro cis congeners. The calculations models were based on the Quantitative Structure-Property Relationship (QSPR) scheme using the semi-empirical method (PM6) in molecular package (MOPAC) software and density functional theory (DFT) method using B3LYP functional and 6-311++G** basis set) in Gaussian 03 software method and the artificial neural networks (ANNs) prediction. The values of log P(L) predicted by models used varied between -3.94 to -2.66 for Mono-; -4.85 to -2.97 for Di-; -5.18 to -3.17 for Tri-; -6.02 to -3.77 for Tetra-; -6.64 to -4.64 for Penta-; -7.36 to -4.76 for Hexa-; -7.54 to -5.79 for Hepta-; -7.75 to -6.64 for Octa-; -7.89 to -7.44 for Nona-Ct-Abs; and -8.09 and -8.13 for Deca-Ct-AB. Based on these values Ct-ABs can be grouped localized among relatively low (log P(L) -4 to -2) and low (log P(L) < -4) mobile Persistent Organic Pollutants (POPs). Both the calculation methods employed were characterized by similar prediction ability of subcooled vapor pressure values of Ct-ABs, while those of PM6 are much more efficient due to a cheaper hardware used and around 300-fold less time spent on calculations.     

Styrofoam debris as a potential carrier of mercury within ecosystems

The present paper falls within the trend of research into interactions between various pollutants emitted anthropogenically into the environment and focuses on mercury and styrofoam debris. The study covers part of the Southern Baltic’s drainage area. Apart from styrofoam and beach sand, the research involved mosses, which are bioindicators of atmospheric metal pollution. The research has shown that mercury present in the environment becomes associated with styrofoam debris. The median for mercury concentrations in virgin styrofoam samples (0.23 ng g^?1 dry weight (d.w.)) and in beach sand samples (0.69 ng g^?1 d.w.) was an order of magnitude lower than in the styrofoam debris (5.20 ng g^?1 d.w.). The highest mercury content observed in styrofoam debris (3,863 ng g^?1 d.w.) exceeded the standards for bottom sediment and soil. The binding of mercury to styrofoam debris takes place in water, and presumably also through contact with the ground. A significant role in this process was played by biotic factors, such as the presence of biofilm and abiotic ones, such as solar radiation and the transformations of mercury forms related to it. As a result, mercury content in styrofoam debris underwent seasonal changes, peaking in summertime. Furthermore, the regional changes of mercury content in the studied debris seem to reflect the pollution levels of the environment.     

Fuzzy control for the process of heat removal during the composting of agricultural waste

This paper shows the concept and preliminary test of the composting process control with fuzzy logic. The temperature in the compost heap during the process is greater than 80 °C. Because wastes of agricultural origin do not require hygienization, part of the heat can by retrieved, which lowers the temperature in the heap to 55 °C (this is also the optimum temperature for the composting process). The heat retrieved from a compost heap can be used in another place. Therefore, a composting system was developed in which the aeration rate and heat removal rate can be adjusted. There are two goals of this system: maximising the amount of the heat retrieved from the heap and minimising the duration of the composting process. In the preliminary experiments freshly mown grass with 50 % cabbage was used as the compost material. The results show that the fuzzy logic control system functions correctly with respect to calculations. During the study, a median 90 MJ of heat was produced by the bioreactor; the thermophilic phase was shortened to 12 days. There was also a reduction in the emission of ammonia.     

Tributyltin (TBT) induces oxidative stress and modifies lipid profile in the filamentous fungus Cunninghamella elegans

To investigate the response of the tributyltin-degrading fungal strain Cunninghamella elegans to the organotin, a comparative lipidomics strategy was employed using an LC/MS-MS technique. A total of 49 lipid species were identified. Individual phospholipids were then quantified using a multiple reaction monitoring method. Tributyltin (TBT) caused a decline in the amounts of many molecular species of phosphatidylethanolamine or phosphatidylserine and an increase in the levels of phosphatidic acid, phosphatidylinositol and phosphatidylcholine. In the presence of TBT, it was observed that overall unsaturation was lower than in the control. Lipidome data were analyzed using principal component analysis, which confirmed the compositional changes in membrane lipids in response to TBT. Additionally, treatment of fungal biomass with butyltin led to a significant increase in lipid peroxidation. It is suggested that modification of the phospholipids profile and lipids peroxidation may reflect damage to mycelium caused by TBT.     

Lead accumulation and elimination in tissues of Prussian carp, Carassius gibelio (Bloch, 1782), after long-term dietary exposure, and depuration periods

We studied the bioaccumulation of lead in selected tissues of Prussian carp Carassius gibelio (Bloch, 1782) during 12 and 24 months exposure to different doses of this metal in feed and the elimination of lead from tissues during the following 12-month depuration period. Lead concentration was determined using atomic absorption spectrometry method. The highest lead concentrations were observed at 2.0?±?0.54 to 7.4?±?1.1 mg?kg^?1 in the kidney, 3.0?±?0.13 to 5.2?±?0.17 mg?kg^?1 in the bone, and 4.5 (±0.4)?mg?kg^?1 in the hepatopancreas of fish from groups exposed to lead dietary concentration from 8 to 49 mg?kg^?1 for 24 months. The rate of accumulation were generally the highest at the beginning of exposure as evidenced by the highest monthly increments of bioaccumulation observed after 3 months of contamination for muscles, hepatopancreatic gland, intestine, and gills. Also analysis of the monthly increments of lead bioaccumulation in bone tissue and the highly significant coefficients of correlation indicate that the dynamics of accumulation are clearly dependent on dose of exposure. Depuration of accumulated lead from the organs depended mainly on tissue and duration of elimination period. Very rapid depuration was observed in soft tissues such as the intestine or muscles. Very low elimination was observed for scales and bones where until the end of the experiment highly significant lead concentration differences were observed in all groups in relation to the control group. Chronic dietary exposure in the range of 8–49 mg Pb?kg^?1 resulted in no significant effects on the growth and survival of Prussian carp females.     

Assessment of boscalid and pyraclostrobin disappearance and behavior following application of effective microorganisms on apples

ABSTRACT

The aim of this study is to assess the disappearance of boscalid (IUPAC name: 2-chloro-N-[2-(4-chlorophenyl)phenyl]pyridine-3-carboxamide) and pyraclostrobin (IUPAC name: methyl N-[2-[[1-(4-chlorophenyl)pyrazol-3-yl]oxymethyl]phenyl]-N-methoxycarbamate) residues in apple fruit, and to verify whether an organic fertilizer enriched with strains of antagonistic microorganisms can reduce pesticide residue levels. Field trials were conducted in a commercial orchard on apples of the Gloster variety, during 21 days after the treatment with Bellis 38 WG and the subsequent application of Zumba Plant formulation containing Bacillus spp., Trichoderma spp. and Glomus spp. In control samples, the decrease rate of boscalid and pyraclostrobin residue levels followed an exponential function, described by formulae R_t = 0.2824e^?0.071t and R_t = 0.1176e^?0.060t, with the coefficient of determination of r² = 0.8692 and r² = 0.9268, respectively. These levels dropped to half (t_1/2) of their initial values after 9.8 and 11.5 days, respectively. The treatment with Zumba Plant resulted in a reduction in boscalid and pyraclostrobin residue levels by 52% and 41%, respectively. The results of this study are of importance for horticulture sciences and for producers of apples using plant protection products (PPPs).     

Assessment of microbial contamination within working environments of different types of composting plants

The objective of the study was to determine the degree of microbiological contamination, type of microflora, bioaerosol particle size distribution, and concentration of endotoxins in dust in different types of composting plants. In addition, this study provides a list of indicator microorganisms that pose a biological threat in composting facilities, based on their prevalence within the workplace, source of isolation, and health hazards. We undertook microbiological analysis of the air, work surfaces, and compost, and assessed the particle size distribution of bioaerosols using a six-stage Andersen sampler. Endotoxins were determined using gas chromatography–mass spectrometry (GC-MS). Microbial identification was undertaken both microscopically and using biochemical tests. The predominant bacterial and fungal species were identified using 16S rRNA and ITS1/2 analysis, respectively.?The number of mesophilic microorganisms in composting plants amounted to 6.9 × 10²–2.5 × 10⁴ CFU/m³ in the air, 2.9 × 10²–3.3 × 10³ CFU/100 cm² on surfaces, and 2.2 × 10⁵–2.4 × 10⁷ CFU/g in compost. Qualitative analysis revealed 75 microbial strains in composting plants, with filamentous fungi being the largest group of microorganisms, accounting for as many as 38 isolates. The total amount of endotoxins was 0.0062–0.0140 nmol/mg of dust. The dust fraction with aerodynamic particle diameter of 0.65–1.1 μm accounted for 28–39% of bacterial aerosols and 4–13% of fungal aerosols. We propose the following strains as indicators of harmful biological agent contamination: Bacillus cereus, Aspergillus fumigatus, Cladosporium cladosporioides, C. herbarum, Mucor hiemalis, and Rhizopus oryzae for both types of composting plants, and Bacillus pumilus, Mucor fragilis, Penicillium svalbardense, and P. crustosum for green waste composting plants. The biological hazards posed within these plants are due to the presence of potentially pathogenic microorganisms and the inhalation of respirable bioaerosol. Depending on the type of microorganism, these hazards may be aggravated or reduced after cleaning procedures.

Implications:?This study assessed the microbial contamination in two categories of composting plants: (1) facilities producing substrates for industrial cultivation of button mushrooms, and (2) facilities for processing biodegradable waste. Both workplaces showed potentially pathogenic microorganisms, respirable bioaerosol, and endotoxin. These results are useful to determine the procedures to control harmful biological agents, and to disinfect workplaces in composting plants.     

Variation in oxidative stress and photochemical activity in Arabidopsis thaliana leaves subjected to cadmium and excess copper in the presence or absence of jasmonate and ascorbate

We have presented changes in the photosynthetic apparatus activity of Arabidopsis thaliana plants occurring within 15-144 h of 100 microM Cu or Cd action with regard to jasmonate (JA) as well as expression of the oxidative stress and non-enzymic defense mechanisms. The inhibitory effect of both heavy metals related to developing dissipative processes and lipid peroxide formation was expressed in dark-adapted state after the longest time as a decrease in potential quantum yield of PSII. In dark- and light-adapted state the heavy metals affected the enzymic phase of photosynthesis already from the 15th hour, which was related to the lipid peroxide formation. Photochemical quenching decrease was induced after 48th hour and did not show a close correlation with the JA pathway. Blockade of endogenously formed JA by propyl gallate decreased the effect of Cu and Cd on both the whole photosynthetic apparatus starting from the 48th hour and on the primary photochemistry of PSII after 144 h. In the case of Cu the effect was related to a lipid peroxidation decrease and to an increase in glutathione and phytochelatin (PC) levels, but in the case of Cd to lipid peroxidation, O.2- and especially to PCs increase. The obtained results indicated that JA after the longest time might enhance the sensitivity of A. thaliana to Cu and Cd stress. Asc enhanced toxic action of Cu and Cd after 15 h, but after a longer time it diminished the influence of Cd (but not Cu) on photosynthetic activity.