Use of an activated carbon from antibiotic waste for the removal of Hg(II) from aqueous solution

Porous carbon has been prepared from waste antibiotic material by a chemical activation method using K(2)CO(3) as an activating reagent. Carbon was studied systematically by the adsorption of nitrogen and iodine. It was found that the process parameters such as activation temperature and activation time are crucial for preparing high-quality activated carbon. The proper choice of the preparation conditions allows to produce microporous activated carbon with a micropore volume up to 0.492 cm(3)/g and a BET surface area of 1260 m(2)/g. Adsorption of mercury(II) from an aqueous solution on antibiotic carbon was investigated under the varying conditions of agitation time, metal ion concentration and pH. The adsorption capacity of the carbon is 129 mg/g.     

Falls from height during the floor slab formwork of buildings: Current situation in Spain

Problem

One of the phases with the highest risk of falls from a height in the construction of a building is during the floor slab formwork stage. This paper analyzes this particular risk, as well as the most frequently used fall-protection systems.

Method

A survey was carried out to define the current situation in Spain with regard to falls from a height during floor slab formwork and the fall-protection systems used to prevent such a risk.

Results

The results of the survey clarified the current situation in Spain with regard to this risk, and made it clear that there is considerable risk of falling from a height during the floor slab formwork stage.

Discussion

All the safety systems analyzed presented a series of weak points that should be studied in detail before they can be used on building sites.

Impact on industry

The risk of falling associated with floor slab formwork and the most frequently used protection systems are analyzed. As no research had been carried out to date on this type of risk, we consider the research presented in this article to be a pioneer in the field.     

Environmental pollution by antibiotics and by antibiotic resistance determinants

Antibiotics are among the most successful drugs used for human therapy. However, since they can challenge microbial populations, they must be considered as important pollutants as well. Besides being used for human therapy, antibiotics are extensively used for animal farming and for agricultural purposes. Residues from human environments and from farms may contain antibiotics and antibiotic resistance genes that can contaminate natural environments. The clearest consequence of antibiotic release in natural environments is the selection of resistant bacteria. The same resistance genes found at clinical settings are currently disseminated among pristine ecosystems without any record of antibiotic contamination. Nevertheless, the effect of antibiotics on the biosphere is wider than this and can impact the structure and activity of environmental microbiota. Along the article, we review the impact that pollution by antibiotics or by antibiotic resistance genes may have for both human health and for the evolution of environmental microbial populations.     

Comparative study of degradation of toluene and methyl isobutyl ketone (MIBK) in aqueous solution by pulsed corona discharge plasma

Effectiveness of pulsed power plasma for the degradation of two toxic volatile organic compounds (VOCs), toluene and methyl isobutyl ketone (MIBK), in aqueous solution was evaluated. The plasma degradation of MIBK has been studied for the first time. The influence of initial concentration of target compound, solution pH and scavengers on percentage degradation was evaluated. 100% removal of 200 mg/L of toluene and MIBK was achieved both in liquid and gaseous phases after 12 and 16 min of plasma treatment, respectively. The first order rate constant of toluene and MIBK degradation (for 200 mg/L each) was 0.421 and 0.319 min^?1 respectively when they were treated individually, and these values decreased slightly during degradation of their mixture. MIBK degradation was slower than toluene and it might be due to semi volatile and hydrophilic nature of MIBK. The effect of initial concentration of toluene and MIBK showed different degradation patterns. Highest degradation of both the compounds was obtained in neutral pH and in absence of scavengers. ?OH radical was the major reactive species involved in their degradation. Their degradation in real environmental matrices showed that removal reduced significantly in secondary effluent due to scavenging of reactive species by various ions and organic matter. The total number of degradation intermediates identified in case of toluene and MIBK was 11 and 14 respectively and formate was the one recalcitrant byproduct generated. The degradation pathway of toluene and MIBK involving reactions of reactive oxygen and nitrogen species and reductive species is proposed.     

Interspecies and spatial trends in polycyclic aromatic hydrocarbons (PAHs) in Atlantic and Mediterranean pelagic seabirds

PAHs were analyzed in the liver of 5 species of pelagic seabirds (Procellariiformes) from the northeast Atlantic and the Mediterranean. The main objective was to assess the trophic and geographic trends of PAHs in seabirds to evaluate their suitability as bioindicators of chronic marine pollution by these compounds. Although higher levels of PAHs have been described in the Mediterranean compared to other oceanic regions, we did not find significant spatial patterns and observed only minor effects of the geographic origin on seabird PAHs. However, we found significant higher PAH levels in petrel compared to shearwater species, which could be related to differences in their exploitation of mesopelagic and epipelagic resources, respectively, and the vertical dynamic of PAHs in the water column. Overall, although this study enhances the need of multi-species approaches to show a more comprehensive evaluation of marine pollution, seabirds emerged as poor indicators of pelagic chronic PAH levels.     

Standardized emissions inventory methodology for open-pit mining areas

INTRODUCTION: There is still interest in a unified methodology to quantify the mass of particulate material emitted into the atmosphere by activities inherent to open-pit mining. For the case of total suspended particles (TSP), the current practice is to estimate such emissions by developing inventories based on the emission factors recommended by the USEPA for this purpose. However, there are disputes over the specific emission factors that must be used for each activity and the applicability of such factors to cases quite different to the ones under which they were obtained. There is also a need for particulate matter with an aerodynamic diameter less than 10?μm (PM(10)) emission inventories and for metrics to evaluate the emission control programs implemented by open-pit mines. STANDARDIZED EMISSION INVENTORY METHODOLOGY: To address these needs, work was carried out to establish a standardized TSP and PM(10) emission inventory methodology for open-pit mining areas. The proposed methodology was applied to seven of the eight mining companies operating in the northern part of Colombia, home to the one of the world's largest open-pit coal mining operations (～70?Mt/year). RESULTS: The results obtained show that transport on unpaved roads is the mining activity that generates most of the emissions and that the total emissions may be reduced up to 72% by spraying water on the unpaved roads. Performance metrics were defined for the emission control programs implemented by mining companies. It was found that coal open-pit mines are emitting 0.726 and 0.180?kg of TSP and PM(10), respectively, per ton of coal produced. It was also found that these mines are using on average 1.148?m(2) of land per ton of coal produced per year.     

Relationship between occupational social class and exposure to organochlorine pesticides during pregnancy

Background

Little evidence is available on the influence of socioeconomic factors on exposure to persistent organic pollutants, especially during vulnerable periods such as pregnancy and early life.

Objective

To investigate the relationship of maternal social class with placental concentrations of organochlorine pesticides (OCPs) and their combined estrogenic activity measured with a biomarker of exposure.

Methods

Exposure to 16 OCPs (DDTs, endosulfans, and seven other compounds) and the total effective xenoestrogenic burden (TEXB) were analyzed in placentas from a mother-child cohort. OCP concentrations were quantified by gas chromatography and mass spectrometry, and TEXB was assessed with the E-Screen bioassay. Social class was classified according to maternal occupation. Multivariate regression analysis was conducted to examine variations in pesticide exposure and TEXB as a function of maternal social class in 257 subjects.

Results

Placental p,p′-DDT concentrations were higher in social classes III and IV than in classes I-II (the most affluent); concentrations of the sum of DDTs were higher in class IV; and exposure to the sum of endosulfans was greater in class III. HCB concentrations were higher among women in class IV than in classes I-II and among manual (classes III-V) than non-manual workers. However, the trend across social classes was only statistically significant for HCB. Social class significantly explained 10% of the variability in concentrations of the sum of endosulfans.

Conclusion

There is a need to explore whether more disadvantaged populations suffer higher levels of exposure to pesticides or other environmental chemicals and how different social processes contribute to this exposure.     

Degradation of organic pollutants in Mediterranean forest soils amended with sewage sludge

The degradation of two groups of organic pollutants in three different Mediterranean forest soils amended with sewage sludge was studied for nine months. The sewage sludge produced by a domestic water treatment plant was applied to soils developed from limestone, marl and sandstone, showing contrasting alkalinity and texture. The compounds analysed were: linear alkylbenzene sulphonates (LAS) with a 10–13 carbon alkylic chain, and nonylphenolic compounds, including nonylphenol (NP) and nonylphenol ethoxylates with one and two ethoxy groups (NP1EO + NP2EO). These compounds were studied because they frequently exceed the limits proposed for sludge application to land in Europe. After nine months, LAS decomposition was 86–96%, and NP + NP1EO + NP2EO decomposition was 61–84%, which can be considered high. Temporal trends in LAS and NP + NP1EO + NP2EO decomposition were similar, and the concentrations of both types of compounds were highly correlated. The decomposition rates were higher in the period of 6–9 months (summer period) than in the period 0–6 months (winter + spring period) for total LAS and NP + NP1EO + NP2EO. Differences in decay rates with regard to soil type were not significant. The average values of decay rates found are similar to those observed in agricultural soils.