China is the biggest consumer of coal. Every year, half or more of China’s coal is used in the power industry. Most thermal power plants in China use electrostatic precipitators to treat solid particulate matter in flue gas. The efficiency of the electrostatic precipitator in removing dust has a considerable influence on atmospheric pollutants. However, the most important factor affecting the efficiency of the electrostatic precipitator in removing dust is the dielectric properties of the fly ash. Through the study of volt-ampere characteristics, electrical and capacitive properties, and electrical breakdown characteristics of coal-fired fly ash, it is found that the V–I characteristics of ash samples in thermal power plant do not strictly follow the formula ([Formula: see text]), the type of coal, and the chemistry of coal. Ingredients are related; disparate types of ash samples have disparate capacitances, and the measurement of capacitive contrast resistance has a certain influence.

The modern usage of pharmaceutical drugs has led to a progressive increase in their presence and environment concentrations, particularly in the aquatic compartment which is the most common final dumping location for this specific class of chemicals. These substances, due to their chemical and biological properties, can exert mostly uncharacterized toxic effects to non-target aquatic species, given the diverse pathways they activate, and the large number of putative targets in the wild. Among drugs in the environment, paracetamol assumes a leading role, considering its widespread therapeutic use and consequently, environmental presence. The present study aimed to assess the acute and chronic effects of paracetamol, in ecologically relevant levels, in the freshwater cladoceran Daphnia magna, namely focusing on biochemical and reproductive parameters. Considering the pro-oxidant effects of paracetamol, already described for a large set of aquatic organisms, specific enzymes involved in the anti-oxidant and metabolic responses were quantified, namely catalase (CAT) and glutathione S-transferases (GSTs) activities. Cholinesterases (ChEs) activity was quantified to evaluate the capacity of paracetamol to induce neurotoxicity, an indirect outcome of oxidative effects by paracetamol, that may affect feeding behavior and reproductive outcomes of this crustacean. Paracetamol in the tested levels showed no effect on reproductive traits of D. magna. Results obtained for organisms acutely exposed included significant increases in the activities of both GSTs and CAT, demonstrating a short-term pro-oxidative effect by paracetamol. On the contrary, ChEs activity was significantly decreased in organisms exposed to this drug, showing a possible interference with neurotransmission. On the contrary, no noteworthy effects were reported for organisms chronically exposed to ecologically realistic concentrations, evidencing the transient nature of the obtained biological response. These results demonstrate the responsiveness of D. magna to paracetamol, especially for high levels of exposure that, despite not being environmentally relevant, are able to trigger significant antioxidant responses. No population effects were likely to be caused by realistic levels of paracetamol, and the absence of biochemical changes after chronic exposure suggests that this specific organism may not be deleteriously affected by low levels of paracetamol, under real scenarios of contamination.

The aim of this study is to assess an innovative economic approach for the production of both fermentative hydrogen and biochar from fruit and vegetable peels (FVPs) via fermentation/pyrolysis process. Firstly, in fermentation batches, multi-fermentation of FVPs positively affected the harvested hydrogen yield and COD reduction efficiency, which reached their maximal values of 3.9 ± 0.6 mmol/gCOD and 56.2 ± 4.6% at batch of 25% pea + 25% tomato + 25% banana + 25% orange (M4). Secondly, digestates produced from all batches were pyrolyzed at 500 °C for investigating the potential for biochar production. Based on the characteristics of the pyrolyzed digestate, biochar produced from S1 (spinach) exhibited the highest specific surface area, density, pore volume, biochar production yield, and pyrolysis profit of 28.43 ± 3.95 m²/g, 1.93 ± 0.18 g/cm³, 0.59 ± 0.08 cm³/g, 59.04 ± 2.36%, and 3.66 $/kgfₑₑdₛₜₒcₖ, respectively. However, the maximum overall profit from both fermentation and pyrolysis processes was 5.21 $/kgfₑₑdₛₜₒcₖ and was denoted for M4.

Persistent environmental pollutants are a growing problem around the world. The effective control of the pollutants is of great significance for human health. Some microbes, especially Arthrobacter, can degrade pollutants into nontoxic substances in various ways. Here, we review the biological properties of Arthrobacter adapting to a variety of environmental stresses, including starvation, hypertonic and hypotonic condition, oxidative stress, heavy metal stress, and low-temperature stress. Furthermore, we categorized the Arthrobacter species that can degrade triazines, organophosphorus, alkaloids, benzene, and its derivatives. Metabolic pathways behind the various biodegradation processes are further discussed. This review will be a helpful reference for comprehensive utilization of Arthrobacter species to tackle environmental pollutants.

To investigate the effects of antibiotics on nitrogen removal and uptake by wetland plants, four typical macrophyte species, Cyperus alternifolius L., Typha angustifolia L., Lythrum salicaria L., and Acorus calamus L., were grown in hydroponic cultivation systems and fed wastewater polluted with 10 μg L⁻¹ Ofloxacin (OFL) and Tetracycline (TET). Biomass production, nitrogen mass concentration, chlorophyll content, root exudates, and nitrogen removal efficiency of hydroponic cultivation were investigated. The results indicated that in all hydroponic systems, NH₄⁺–N was entirely removed from the hydroponic substrate within 1 day and plant nitrogen accumulation was the main role of the removed NO₃⁻. OFL and TET stimulated the accumulation of biomass and nitrogen of A. calamus but significantly inhibited the NO₃⁻–N removal ability of L. salicaria (98.6 to 76.2%) and T. augustifolia (84.3 to 40.2%). This indicates that A. calamus may be a good choice for nitrogen uptake in wetlands contaminated with antibiotics. OFL and TET improved the concentrations of total organic carbon (TOC), total nitrogen (TN), organic acid, and soluble sugars in root exudates, especially for oxalic acid. Considering the significant correlation between TOC of root exudates and nitrogen removal efficiency, the TOC of root exudates may be an important index for choosing macrophytes to maintain nitrogen removal ability in wetlands contaminated with antibiotics.

This study assessed the contaminant removal potential of a low-cost alum synthesized from bauxite slime waste compared to industrial grade alum [Al₂(SO₄)₃.18H₂O] in treating car wash wastewater using standard jar tests. The synthesized alum was subsequently applied as a coagulant to test the short-term performance of a bench scale flocculation–flotation system for treating car wash wastewater. Coagulant dosages and mixing intensities were optimized for both coagulants and differences were analyzed with R using two-way ANOVA with Tukey’s (HSD) post hoc testing. Per the jar tests, percentage removal of up to 99%, 34%, and 75% of turbidity, anionic surfactants (AS), and COD, respectively, was achieved with 90 mg/L of the synthesized alum compared to 100%, 37%, and 74% for industrial grade alum. Contaminant removal efficiencies of both coagulants were comparable (p > 0.05). However, coagulant dosage strongly influenced the removal of turbidity, AS, and COD (p < 0.05) while mixing intensity influenced all but COD. The bench-scale flocculation–flotation system completely removed turbidity (100%) and reduced AS and COD by up to 92% and 99% respectively. The results of this study demonstrate the potential of alum synthesized from bauxite slime waste as a cheaper alternative for industrial grade alum in wastewater recycling for the car wash industry.

Lead is one of the most widely used elements in the world. Lead can cause acute and chronic complications such as abnormal hemoglobin synthesis, kidney damage, abortion, nervous system disorders, male infertility, loss of learning ability, behavioral disorders, and even death. The aim of this study was to carry out quantitative and semi-quantitative risk assessments of exposure to lead among the solderers of the Neyshabur electronics industry. This cross-sectional, descriptive, and analytical study was conducted in 2017 and 2018 on 40 female soldering workers exposed to lead. Semi-quantitative risk assessment was carried out according to the Singapore Health Department and quantitative risk assessment according to the Office of Environmental Health Hazard Assessment (OEHHA) method. The average occupational exposure to lead in the electronics manufacturing industry was 93.89 ± 33.40 μg m⁻³ with a range from 9 to 150 μg m⁻³. Occupational exposure to lead in the industrial groups of initial soldering with an average of 130.37 ± 40.23 μg m⁻³ and cutting wires, electroplating, and coating bare parts with an average of 110.24 ± 30.11 μg m⁻³ was higher than the secondary soldering groups with an average of 90.78 ± 20.22 and shift supervisors with an average of 43.86 ± 10.97 μg m⁻³. The mean excess lifetime cancer risk (ELCR) was 0.11 per 1000 people and the mean non-carcinogenic risk (HQ) was 7.20. The results of this study indicate that there is a risk of non-carcinogenic complications among electronic solderers. Therefore, managers and employers should reduce lead exposure through engineering controls (substituting lead-free alloys, efficient ventilation) and management strategies such as reducing exposure hours.

The inspiration for this study was the anxiety of Warsaw beekeepers, who raised the question whether location of hives in large urban agglomerations results in changes in concentrations of xenobiotics, toxic elements, and micronutrients in honey bees. Preliminary studies required elaboration of the research methodology, as the studied object is characterized by a low degree of homogeneity and the method of sample preparation affects obtained results. From many tested approaches, the use of washed and milled abdomens of the bees is recommended. Results obtained for such prepared samples are slightly lower than for whole bees, but their repeatability is higher, which enables easier interpretation of the trends and comparison of different locations. The contents of selected elements (As, Al, Cd, Co, Cr, Cu, Mn, Pb, and Zn) were compared in bees from urban and rural areas. The studies were supported by pesticides analysis. Also, it was checked whether these substances are accumulated on the surface or inside the bee’s body. The research indicates the markers of contamination: Al, As, and Cr on the surface and Cd inside the bodies of honey bees. The location of the hives does not influence significantly the content of “toxic,” nutrient metals and metalloids in bees (slightly higher levels of As, Al, Pb, and Cd were found in bees from urban areas). In terms of exposure to these elements and pesticides, the large city environment is not harmful for honey bees.

Many areas in the Southern African Development Community are data-poor and poorly accessible. Water quality assessment in these areas therefore has to rely on the limited available data, coupled with restricted field sampling. This paper documents the first evaluation of the main geochemical processes and impact of anthropogenic and natural sources of contamination on the groundwater quality of the aquifer system used for domestic and agricultural purposes in Limpopo National Park, Gaza Province, Southern Mozambique. Twenty-five groundwater and surface water samples were collected during two field campaigns, one in October 2016 (the end of the arid period) and the other in March 2017 (the end of the wet period). In the field, the researchers analysed chemical–physical parameters such as temperature, pH and EC. In the laboratory, the major ions (boron, Na⁺, Ca²⁺, K⁺, Mg²⁺) and anions (Cl⁻, SO₄²⁻, NO₃⁻, HCO₃⁻, CO₃²⁻) were determined, and almost all groundwater samples fall into the brackish water category. The B/Cl ratio and δ¹¹B concentrations were then measured to better understand the origin of these brackish waters. The direct relationship between boron and chlorine and δ¹¹B concentrations above 40‰ suggests the presence of fossil water in the aquifer. The groundwater in this area was found to be above the limits stated as desirable by the Department of Water and Sanitation (DWS) and the World Health Organisation for domestic and irrigation purposes. The suitability of the groundwater for drinking purposes was also evaluated, with the results indicating that it is not suitable. The values of the sodium absorption ratio, sodium percentage and electrical conductivity show that most of the groundwater samples are also not suitable for agricultural purposes. However, the surface waters have higher quality for both domestic and irrigation purposes. The water of Massingir Lake turns out to be the most suitable resource for a possible rural development plan for the area.

Simulation and prediction of the pollution transport is one of the major problems in environmental and rivers engineering studies. The numerical tools have been used in simulation of the concentration profile transmission for description of river water quality. The one-dimensional advection-dispersion equation (ADE) is used in applied water quality modeling and requires the accurate estimation of longitudinal dispersion coefficient (Dₓ). This paper develops a hybrid numerical-intelligence model for dispersion modeling in open-channel flows. The main contribution of this paper is to improve the results of 1D numerical simulation of pollutant transport in steady flows by estimation of dispersion coefficient (Dₓ) based on artificial intelligence models and subset selection of maximum dissimilarity (SSMD). The developed hybrid model uses an intelligence module based on optimized adaptive neuro fuzzy inference system (ANFIS) and artificial neural networks (ANNs) for longitudinal dispersion estimation, in which their structures are optimized by genetic algorithm (GA). Intelligence estimates of Dₓ by ANN, ANFIS, ANFIS-GA, ANN-GA, multiple linear regression (MLR), and empirical equation are compared with observed values of Dₓ available in 505 river section, and the ANFIS-GA, as the most accurate, is incorporated and integrated with developed 1D-ADE numerical module. The numerical solution of 1D-ADE is done using physically influenced scheme (PIS) for face flux estimation in finite volume method. The performance of hybrid models PIS-ANFIS-GA, PIS-ANFIS, and PIS-empirical is compared using the R², RMSE, MAE, and NSE values in comparison with analytical solution and measured concentration hydrographs. The results revealed that the hybrid numerical-intelligence model is more accurate than the other classical methods for sediment/pollutant dispersion prediction in open-channel flows. The developed hybrid numerical-intelligence model can accurately simulate the dispersion processes in rivers and is a novel step in applicability of ANFIS-GA and ANN-GA models. Graphical abstract ᅟ