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.     

基于QSAR模型的蒙特卡洛方法分析有机化学物质对大型蚤(Daphnia magna)的毒性

本文建立一系列758种有机化合物对大型蚤(Daphnia magna)毒性的定量结构-活性关系(QSARs)。用简化的分子线性输入系统(SMILES)代表分子结构。用CORAL(关联和逻辑)软件作为工具来开发QSAR模型。这些模型使用蒙特卡罗方法建立,依据的原理是QSAR是一个“随机事件”,假设检验一组随机数据分布在可见的训练集和不可见的验证集。检验了三组分布于可见的训练、校准、测试集中的数据以及不可见的验证集。最佳模型的预测潜能,也就是其不可见的验证集的统计特征如下:n = 87,r² = 0.8377,RMSE = 0.564。建议和讨论了所构建模型的机械解释和适用领域。
精选自Alla P. Toropova, Andrey A. Toropov, Aleksandar M. Veselinovi?, Jovana B. Veselinovi?, Danuta Leszczynska, Jerzy Leszczynski. Monte Carlo based QSAR models for toxicity of organic chemicals to Daphnia magna. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2691–2697, November 2016. DOI: 10.1002/etc.3466
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3466/full
     

The practical societal problem of pollution and public health as the source of a variety of problems regarding chance mechanisms operating in living organisms

The essence of the societal problem which justifies the expenditure of large sums on studies of pollution and health is illustrated by three figures included in this paper. The first two of these figures illustrate the contemporary publicity favoring the two competing energy-producing technologies, the nuclear and the conventional fossil-burning technologies. The very existence of this costly publicity demonstrates that the decisions affecting public health are now frequently made without due regard to the relevant scientific findings. The third figure illustrates the most laudable effort of the Environmental Protection Agency to establish a relationship between hoped-for decreases in mortality and the dollar cost of removing from the environment any one of the several investigated pollutants, e.g., “particulates”, krypton-85, tritium, etc.The subsequent parts of this presentation tend to document the fact that the reliability of the EPA chart published in 1973 is illusory. The same applies to the large number of other official publications, including those of the National Academy of Sciences. The results of more modern studies brought to the fore a variety of biological chance mechanisms, such as competing risks, dose-rate effects, synergisms, etc., which make the problem attacked by EPA much more difficult than was originally anticipated.The basic research, combining the laboratory experimentation on animals and theoretical considerations, results in a better understanding of a variety of phenomena. However, this better understanding seems to imply that the solution of the practical societal problem requires a large multipollutant and multilocality epidemiological study.     

Acceleration of tributyltin chloride (TBT) degradation in liquid cultures of the filamentous fungus Cunninghamella elegans

In this study, we have examined the effects of synthetic medium ingredients and culture incubation conditions on growth and tributyltin chloride (TBT) degradation activity of the fungus Cunninghamella elegans. The best efficiency of TBT conversion to less toxic derivatives: dibutyltin and monobutyltin was noticed on media which contained glucose, NH(4)Cl, K(2)HPO(4) and MgSO(4). Next, the constructed M3 medium (with the above components) ensured vigorous growth of C. elegans and allowed the reduction of 80% of the initial TBT content (10 mg l(-1)), after 3d of biodegradation. The further acceleration of the biocide utilization by C. elegans was achieved by additional oxygen supply (pO(2) >or = 20%) to the growing fungus (89% after 2d of incubation in the BioFlo II bioreactor). The efficient xenobiotic biodegradation was related to the intensity of fungal growth. The obtained results suggest a cometabolic nature of TBT utilization by C. elegans.     

Butyltin compounds in sediment and fish from the Polish Coast of the Baltic Sea

Concentrations of mono- (MBT), di- (DBT), and tri-(TBT) butyltin compounds were measured in eggs, liver, and muscle of nine species of fish from four regions of the Baltic Sea - the Firth of Vistula, the Gulf of Gdańsk, Puck Bay, and the mouth of the Vistula River. The overall concentration ranges among all the fish sampled from the four sites were: < 7 to 79 ng/g for MBT, 6 to 1100 ng/g for DBT, 7 to 3600 ng/g for TBT, and 16 to 4800 ng/g for total BTs, on a wet wt basis. The highest concentration of total BTs was found in herring liver from the Firth of Vistula (4800 ng/g, wet wt) and in roach muscle from Puck Bay (3300 ng/g, wet wt), while the least concentration was found in burbot eggs and liver from the Vistula River (39 and 32 ng/g, wet wt, respectively). TBT was the major form of BTs present in most samples analyzed. Sediment samples collected from shipyards in the Gulf of Gdańsk contained butyltin concentrations ranging from 1.2 to 46 μg/g (dry wt) for MBT, 2.0 to 42 μg/g for DBT, and 2.6 to 40 μg/g for TBT. As with the fish, the majority of the BTs in sediment were present as TBT, which suggested recent exposure of the aquatic environment of the region to TBT.     

Nanoparticles: Their potential toxicity,waste and environmental management

This literature review discusses specific issues related to handling of waste containing nanomaterials. The aims are (1) to highlight problems related to uncontrolled release of nanoparticles to the environment through waste disposal, and (2) to introduce the topics of nanowaste and nanotoxicology to the waste management community. Many nanoparticles used by industry contain heavy metals, thus toxicity and bioaccumulation of heavy metals contained in nanoparticles may become important environmental issues. Although bioavailability of heavy metals contained in nanoparticles can be lower than those present in soluble form, the toxicity resulting from their intrinsic nature (e.g. their size, shape or density) may be significant. An approach to the treatment of nanowaste requires understanding of all its properties – not only chemical, but also physical and biological. Progress in nanowaste management also requires studies of the environmental impact of the new materials. The authors believe Amara’s law is applicable to the impact of nanotechnologies, and society might overestimate the short-term effects of these technologies, while underestimating the long-term effects. It is necessary to have basic information from companies about the level and nature of nanomaterials produced or emitted and about the expectation of the life cycle time of nanoproducts as a basis to estimate the level of nanowaste in the future. Without knowing how companies plan to use and store recycled and nonrecycled nanomaterials, development of regulations is difficult. Tagging of nanoproducts is proposed as a means to facilitate separation and recovery of nanomaterials.     

Biodegradation and sorption of nodularin (NOD) in fine-grained sediments

Nodularin (NOD) is a cyclic pentapeptide hepatotoxin produced by the bloom forming cyanobacterium Nodularia spumigena. The fate of the toxin in the aquatic environment has not been fully evaluated. In the current study the changes in NOD concentration caused by biodegradation and sorption in samples from the Baltic were studied. Seawater of various salinities (0, 4, 8 and 12 PSU) and three forms of fine-grained sediment (sterile wet sediment, non-sterile wet sediment, and combusted sterile sediment) were incubated with 34.7 μg of NOD. The toxin was seen to be highly stable both in sterile and non-sterile seawater. During the 21-day experiment NOD concentrations in solutions overlying the combusted sediment and the sterile wet sediment were reduced to 12.5 ± 2.6% and 59.8 ± 2.4% of the initial value. The greatest loss of the toxin (up to 100%) was observed in the non-sterile seawater incubated with non-sterile wet sediment. These results indicate an important role of benthic microbial community in nodularin removal. Two biodegradation products with similar spectral characteristics to NOD were detected; one of which was identified as Adda amino acid.     

Survey on composition and bioconcentration potential of 12 metallic elements in King Bolete (Boletus edulis) mushroom that emerged at 11 spatially distant sites

This paper provides data on baseline concentrations, interrelationships and bioconcentration potential of 12 metallic elements by King Bolete collected from 11 spatially distant sites across Poland. There are significant differences in concentrations of metals (Al, Ba, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Sr, Zn) and their bioconcentration potential in King Bolete Boletus edulis at 11 spatially distant sites surveyed across Poland. These have resulted from significant geographical differences in trace metal concentrations in a layer (0-10 cm) of organic and mineral soil underneath to fruiting bodies and possible local bioavailabilities of macro- (Ca, K, Mg, Na) and trace metals (Al, Ba, Cd, Cu, Fe, Mn, Sr, Zn) to King Bolete. The use of highly appreciated wild-grown edible King Bolete mushroom has established a baseline measure of regional minerals status, heavy metals pollution and assessment of intake rates for wild mushroom dish fanciers against which future changes can be compared. Data on Cd, Cu and Zn from this study and from literature search can be useful to set the maximum limit of these metals in King Bolete collected from uncontaminated (background) areas. In this report also reviewed are data on Al, Ba, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, Sr and Zn accumulation in King Bolete.     

Forest health status in the Carpathian Mountains over the period 1997-2001

The results of forest health status assessments in the Carpathian Mountains from the monitoring networks developed by the European Union Scheme on the Protection of Forest Against Atmospheric Pollution (EU Scheme) and International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP-Forests), have led to a better understanding of the impact of air pollution and other stressors on forests at the regional scale. During the period 1997-2001, forests in the Carpathian Mountains were severely affected by air pollution and natural stresses with 29.7-34.9% of the trees included in defoliation classes 2-4. The broadleaves were slightly healthier than the conifers, and European beech (Fagus sylvatica) was the least affected species. Norway spruce (Picea abies) has poor health status, with 42.9-46.6% of the trees damaged (2-4% defoliation classes). Silver fir (Abies alba) damage was also high, with 46.0-50.9% in defoliation classes 2-4. Pines (primarily Pinus sylvestris) were the least affected of the conifers, with 24.9-33.8% in defoliation classes 2-4. The results from the transnational networks (16 x 16 km) show that the Carpathian forests are slightly more damaged than the average for the entire Europe. The correlative studies performed in individual European countries show the relationships between air pollution stressors with trends in defoliation and a possible effect of natural stresses at each site. More specific, effects of tree age, drought, ozone and acid deposition critical level exceedances were demonstrated to affect crown condition.