Indirect electrochemical degradation of acetaminophen: process performance, pollutant transformation, and matrix effects evaluation

Acetaminophen (ACE), a highly consumed pharmaceutical, was degraded in aqueous matrices by reactive chlorine species (RCS) electrogenerated using Ti/IrO2 electrodes. Although this pollutant has been extensively treated by electrochemical techniques, little information is known about its degradation in fresh urine by electrogenerated RCS, and the understanding of its transformations using analyses of atomic charge. In this work, these two topics were discussed. Initially, the effect of current (10-40 mA) and supporting electrolyte (considering typical ions present in surface water and urine (Cl- and SO42-)) on the electrochemical system was evaluated. Then, the kinetics and primary transformations products involved in the elimination of ACE were described. It was found that, in distilled water, the process at 40 mA in NaCl presence led to 100 % of ACE degradation (10 min, 0.056 Ah L-1). Theoretical analyses of atomic charge for ACE indicated that the amide group is the most susceptible to attacks by RCS such as HOCl. On the other hand, degradation of acetaminophen in synthetic fresh urine was slower (21% of degradation after 60 min of treatment) than in distilled water. This was attributed to the other substances in the urine matrix, which induce competition for the degrading RCS.

Molecular Signatures of Humic Acids from Different Sources as Revealed by Ultrahigh Resolution Mass Spectrometry

Humic acid (HA) is extremely important for understanding the geochemical cycle of pollutants in different environments. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has performed molecular-level analysis of two standard HAs from the Suwannee River (SRHA) and leonardite (LEHA) and HA from Jiufeng forest in Beijing (JFHA), which is impossible for other conventional instruments. Regardless of the source of HA, compounds containing more heteroatoms (such as nitrogen and sulfur) have a higher degree of unsaturation and aromaticity. JFHA, SRHA, and LEHA from soil, river, and leonardite, respectively, are arranged in order from the lowest to highest degree of humification, according to molecular unsaturation and aromaticity of HAs. Soil HA is more labile and contains many large molecular weight compounds with low unsaturation. Regardless of unsaturation, molecules of River HA have a homogeneous molecular mass distribution and contain many plant-derived lignin- and tannin-like compounds, which are more stable than lipid and more labile than condensed aromatics. Leonardite HA with a high degree of humification contains a large number of compounds with high aromaticity and more heteroatoms and has low lability. Our results reveal the diversity of humic acid at molecular level because of different degree of humification and the lability. These conclusions are significant for understanding the role of humic acid from different sources in pollutant transformation and the geochemical cycle at the molecular level.

Optimization of load norms for transfrontier water bodies taking into account natural processes of self-purification

In the paper is used the systems approach to justification and optimization ofnorms of the load on the transboundary water bodies. Special attention was given to evaluation of the factors determining the norms of load on the natural water systems for individualtransboundary water bodies. The effects of the pollutant transformation in the water bodiesare taken into account. The algorithm of attribution of quotas to various kinds of man-causedload along entire length of the water body in question is offered. The concrete methods ofmeeting the environmental norms for the priority-driven types of pollutants. It is offered tointroduce the norms attribution basing on environmental and emission approaches and takinginto account the use of the best technologies for industrial and natural systems.

Modelling the dispersion of benzene emissions from a proposed ethanol producing facility in Farewell-Oshawa of Toronto, Canada

The production and use of biofuels such as ethanol have been the target of intensive research. One source of ethanol is corn, which is abundant in many countries. In producing ethanol from corn, an assessment of the environmental impact of the process is needed. This study intends to provide insight into benzene emitted from a proposed biofuel plant, its dispersion behavior, and the effects it may have on the immediate environment. Three-season (January, April, and June) dispersion results of benzene emissions from the proposed ethanol-producing facility are evaluated by using the CALPUFF modelling system. Within the framework of the CALPro software, ambient benzene concentrations are modelled over a 24-hour period of exposure by considering the impact of pollutant transformation and removal, and meteorological factors such as wind direction and speed, and temperature. Simulations are performed for the plant area located in Farewell, Oshawa, Ontario, based on the emission and meteorological dataset for the year 2013. The modeling domain covers the area of 30 × 30 km2 with the grid spacing of 150 m. The number of grid lines is taken as 200 for each axis, and the dispersion of benzene emissions is simulated in nine vertical layers of the domain of study. Based on simulated one-hour and 24-hour average benzene concentrations, pollution dispersion results show that the maximum concentrations are recorded as 4.585 and 0.403 µg/m3 at 17h00 LST on hourly basis and on 24-hour basis, respectively, for the winter season. For the spring season, the highest concentrations are measured as 1.345 and 0.136 µg/m3 at 21h00 LST for one-hour and 24-hour periods, respectively. For the summer season, the peak benzene concentrations are found to be 1.085 and 0.277 µg/m3 at 01h00 LST. The results indicate that none of the months exceeds the half-hour limit of 7 µg/m3 set by Ontario Regulation 419/05, but they surpass the Ontario Regulation 419 Schedule 3 limit of 0.01 µg/m3 for a 24-hour dispersion period. This information may prove invaluable to further research on the impacts of the ethanol-production process on the environment.