Assessment of the content,occurrence, and leachability of arsenic,lead, and thallium in wastes from coal cleaning processes

The aim of the study was to evaluate the content, occurrence, and leachability of arsenic (As), lead (Pb), and thallium (Tl) in wastes from coal cleaning processes with respect to the safe management of this waste. The study focused on wastes resulting from the wet gravitation and flotation processes employed for the purposes of coking coal cleaning in four coal mines situated in the Upper Silesian Coal Basin (Poland). The scope of the study included (i) determination of the content of these elements in the investigated wastes using atomic absorption spectrometry, (ii) evaluation of their mode of occurrence using electron microprobe analysis, and (iii) preliminary assessment of their leachability in deionized water. The content of the analyzed elements in the examined samples of coal waste was twice as high as the average content of these elements in the Earth’s crust. The contents of As and Pb, however, did not exceed their permissible contents in inert waste in accordance with Polish legal regulations based on EU directives. The limit on the content of Tl is not specified by these regulations, but its amount in the examined samples was similar to that occurring in the soils. Moreover, leaching tests have shown that these elements are hardly eluted from the analyzed material. Their content in the water leachates was generally lower than the detection limit of the analytical method, complying with the standards for good and very good water quality. Low leachability of these elements most probably results from their mode of occurrence in the investigated wastes. The chemical analysis using an electron microprobe and the analysis of the correlation between these elements, e.g., total and pyritic sulfur, have shown that Pb, As, and Tl are mainly found in sulfide minerals which are characterized by negligible solubility. In conclusion, the investigated hard coal processing waste does not constitute a threat to the environment and can be commercially used or safely neutralized, e.g., by landfilling.

     

Evaluation of vulnerability of Suillus variegatus and Suillus granulatus mushrooms to sequester mercury in fruiting bodies

This work determined the mercury (Hg) contents and bioconcentration potential of two Suillus mushrooms, and the probable dietary intake of this element from a mushroom meal. The determination of total Hg content of fungal and soil samples was performed using cold-vapour atomic absorption spectroscopy by a direct sample thermal decomposition coupled with gold wool trap of Hg and its further desorption and quantitative measurement at a wavelength of 253.7 nm. The median values of Hg contents (mg kg^?1 dry biomass) in 213 specimens of S. variegatus from 12 background areas varied widely from 0.087 to 0.51 for caps and from 0.041 to 0.24 for stipes. In 52 specimens of S. granulatus, the Hg contents ranged from 0.30 to 0.41 for caps and from 0.058 to 0.14 for stipes. Both species could be classified as moderate accumulators of Hg and the median bioconcentration factor values ranged from 7.0 to 14 (caps) and 2.1 to 13 (stipes) for S. variegatus and 9.5 (caps) and 1.3 (stipes) for S. granulatus. The estimated intake rates of Hg with the consumption of 300-g caps were from 0.0026 to 0.015 per capita or from 0.000037 to 0.00022 mg kg^?1 body mass and this do not indicate any cause for concern associated with eating a meal once or more in a week during the mushrooming season.     

Alkyl polyglucosides as cell surface modification factors: influence of the alkyl chain length

The use of surfactants in a bioremediation process is aimed at increasing the efficiency of the removal of hydrophobic contaminants from the environment. The subjects of the study were three alkyl polyglucosides (APGs) of different alkyl chain length: Glucopon 215 CS UP, Glucopon 600 CS UP, and Glucopon 650 EC. The impact of these surfactants on the surface properties of the test strain Pseudomonas fluorescens ATCC 14700, as well as on the biodegradation of diesel was tested. It was observed, that the length of alkyl chain has an influence on the cell surface properties. The modification of the cell surface hydrophobicity and the electrokinetic potential on the bacteria cells is dependent on the structure of Glucopon molecules. The elongation of alkyl chains in surfactant molecule caused an increase of the hydrophobic properties and a reduction of the electrokinetic potential on the bacteria cells. Moreover, the use of APGs below critical micelle concentration caused an increase of diesel oil biodegradation, especially in the case of Glucopons with longer alkyl chain (Glucopon 600 CS UP and 650 EC). The better diesel oil removal by tested strain after surfactant addition was correlated with the hydrophobic properties of bacteria strain.     

Facilitators and barriers to occupational health and safety in small and medium-sized enterprises: a descriptive exploratory study in Ontario,Canada

Purpose. The purpose of this particular study was to test a newly created instrument in describing the facilitators and barriers to occupational health and safety in small and medium-sized enterprises (SMEs) in Ontario, Canada. Methods. A cross-sectional design was used to identify the occupational health and safety culture of SMEs in public and private sectors in Ontario. Results. A total of 153 questionnaires were completed. The majority of respondents were female (84%) with a mean age of 49.8 years (SD 10.6). Seventy-four percent were supervisors. Seventy percent of respondents were from the private sector while 30% derived from the public sector including healthcare, community services, and non-profit organizations. Further, conducting regular external safety inspections of the workplace was found to be statistically associated with a safe work environment 2.88 95% CI [1.57, 5.27]. Conclusions. Strategies and training opportunities that focus on how to adapt occupational health and safety legislation to the nature and diversity of SMEs are recommended. Furthermore, employers may use such information to improve safety in their SMEs, while researchers can hopefully use such evidence to develop interventions that are applicable to meeting the occupational health and safety needs of SMEs.     

云南疣柄牛肝菌属真菌中汞含量及食用健康风险分析

汞(Hg)对人类健康有明显的毒害作用,多数野生食用菌对Hg有很强的富集能力,测定野生食用菌中总Hg含量,并对其进行食用安全评估有重要意义。采用冷原子吸收光谱法测定云南常见疣柄牛肝菌属真菌菌盖、菌柄中总汞(Hg)含量,分析样品对Hg的富集特征;以FAO/WHO现行每周Hg允许摄入量(provisional tolerable weekly intake,PTWI)标准,评估疣柄牛肝菌属真菌的食用安全性。结果显示,不同产地、种类及不同采集时间疣柄牛肝菌属真菌的总Hg含量差异明显,菌盖中总Hg含量在0.54~4.80 mg·kg-1dw之间,菌柄总Hg含量在0.32~2.80 mg·kg~(-1)dw之间,同一种牛肝菌菌盖总Hg含量均大于菌柄(Q(C/S)1),表明疣柄牛肝菌属真菌对Hg的积累量与生长环境、种类、部位等有关。根据FAO/WHO暂行的每周Hg允许摄入量标准(0.004 mg·kg-1bw),成年人(60 kg)每周食用300 g(鲜重)采自云南的疣柄牛肝菌属真菌,Hg摄入量远低于PTWI标准,对人体Hg暴露风险较低。     

The challenges in the identification of Escherichia coli from environmental samples and their genetic characterization

Environmental Science and Pollution Research - Escherichia coli bacteria are an essential indicator in evaluations of environmental pollution, which is why they must be correctly identified. This...