Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering最新文献

Down-flow hanging sponge (DHS) reactors, employed in domestic wastewater treatment, have demonstrated efficacy in eliminating Escherichia coli and other potentially pathogenic bacteria. The aim of this study was to elucidate the mechanism of removal of E. coli by employing a cube-shaped polyurethane sponge carrier within a compact hanging reactor. An E. coli removal experiment was conducted on this prepared sponge. Escherichia. coli level was found to decrease by more than 2 logs after passing through five nutrient-restricted DHS sponges. Conversely, a newly introduced sponge did not exhibit a comparable reduction in E. coli level. Furthermore, under conditions of optimal nutritional status, the reduction in E. coli level was limited to 0.5 logs, underscoring the crucial role of nutrient restriction in achieving effective elimination. Analysis of the sponge-associated bacterial community revealed the presence of a type VI secretion system (T6SS), a competitive mechanism observed in bacteria. This finding suggests that T6SS might play a pivotal role in contributing to the observed decline in E. coli level.

A study was conducted to investigate the air deposition and explore the distribution of potentially toxic elements in the Mariovo region, North Macedonia, using moss samples as biomonitors of air pollution. The distribution of 44 chemical elements was detected in 20 moss samples collected in the area. The moss samples were analyzed after microwave digestion using inductively coupled plasma - atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). It was found that atmospheric deposition for some potentially toxic elements in the moss samples in the study area was influenced only by lithogenic origin. R-mode factor analysis was used to identify and characterize elemental associations. Three factors were separated from the group of macroelements determined by ICP-AES: Factor 1 (Cr, Fe, Ni, V, Al, Zn, Pb, and Li), F2 (Li, Sr, and Ba), and F3 (P, and K); and two associations were separated from the group of trace elements determined by ICP-MS: Factor 1 (Ga, Sc, Ti, Co, Zr, Rb, As, Cs, Ge, Y, Sn, Mo, and rare earth elements - REEs) and Factor 2 (Br, B, Cd, I, and Sb).

The leaching laboratory experiment uses the artificial neural network (ANN) to predict and evaluate copper and cobalt recovery. This study aimed to evaluate the efficacy of using the shrinking core model in conjunction with an artificial neural network (ANN) as part of a machine learning strategy to improve the leaching process of cobalt (II) and copper (II). The numerous factors in the leaching process, such as acid concentration, leaching time, temperature, soil-to-solution ratio, and stirring speed, are adjusted using an ANN with several layers, feed-forward, and back-propagation learning methods. These variables are in charge of the high cobalt recovery during the reduced sulfuric acid leaching procedure. The ANN algorithm has 10 hidden layers, 5 input variables describing the leaching parameters, and two neurons as output layers corresponding to copper and cobalt leaching recovery. The optimum conditions were found to be acid concentration of 100 g/L, leaching duration 120 min, temperature 55 °C, soil-to-solution ratio of 1:40 g/mL, and stirring speed 300 rpm. The optimized trained neural networks tested, trained, and validated steps are represented by R² values of 0.94, 0.99, 0.97, and 0.97, respectively, equating to 97.5% copper recovery and 95.4% cobalt recovery.

The study was carried out to define the distribution of mercury in surface soils in the Mitrovica region, Republic of Kosovo and to assess the level and extent of contamination. A total of 156 soil samples were collected from a depth of 5 cm at each grid point of 1.4 × 1.4 km in an area of 301.5 km². The mercury content was found to be between 0.02 mg/kg and 11.16 mg/kg. The average Hg content (0.49 mg/kg) exceeded the mean content in European (0.037 mg/kg) and world (0.06 mg/kg) soils by 13.2 and 8.2 times, respectively. From the calculated enrichment factors (EF) and the geo-accumulation index (I-geo), as well as from the distribution map of Hg content, it is evident that the soils of the study area are highly contaminated with mercury, with extremely high enrichment of Hg in the soils of Zone I, which was classified as the most contaminated zone with Hg and other potentially toxic elements in the study area as well as in the towns of Zveçan and Mitrovica. The higher Hg content is of anthropogenic origin, mainly due to lead and zinc mining and metallurgical activities in the study area. The mercury levels were also found to exceed the New Dutch List target value (0.3 mg/kg) in 90 km² of the study area.

The influx of insufficiently purified or untreated domestic wastewater into aquatic ecosystems raises the question of the production of environmentally friendly detergents. The purpose of this work was to investigate the toxicity of phosphonate-containing and phosphate-free dishwashing detergents for dishwashers according to the phytotest with a garden cress (Lepidium sativum L.). Dishwashing detergents for dishwashers ("All in 1"), widely available in the retail network of Ukraine, were used in concentrations the aqueous solutions from 0.005% to 10.0% for their effect on test indicators of garden cress: energy of seed germination, seed germination and biometric and morphometric indicators of seedlings, which were processed statistically. Some phytotoxic indices were determined for the tested aqueous solutions. It was established that the studied solutions of both phosphonate-containing and phosphate-free detergents are extremely and high toxic according to the calculated indices. The obtained data indicate the danger of the investigated detergents for the hydrosphere, the need to replace with a less toxic agents, in particular, based on biosurfactants.

2-ethylhexyl 4-methoxycinnamate (EHMC), a UV filter commonly used in sunscreen products, is also an emerging environmental pollutant that interferes with the structure and function of bovine serum albumin (BSA). A study was conducted on the interaction between EHMC and BSA when they coexist and are encapsulated within β-cyclodextrin (β-CD). Multiple spectra demonstrate, both qualitatively and quantitatively, that β-CD coexistence and encapsulation weaken the interaction between EHMC and BSA, resulting in a more difficult binding process between the two and inhibiting EHMC-induced conformational changes in BSA. Once encapsulated by β-CD, the inclusion complex (IC) was weakly bound to BSA (K_b=(7.63 ± 0.01)×10⁴ M^-1), and it had no significant impact on BSA's structure. Despite this, β-CD did not significantly alter EHMC's UV shielding ability.

High level of aluminum content in Enteromorpha prolifera posed a growing threat to both its growth and human health. This study focused on exploring the factors, impacts, and process of removing aluminum from Enteromorpha prolifera using humic acid. The results showed that under experimental conditions of 0.0330 g·L^-1 humic acid concentration, pH 3.80, 34 °C, and a duration of 40 min, the removal rate was up to 80.18%. The levels of major flavor components, proteins, and amino acids in Enteromorpha prolifera increased significantly after treatment, while polysaccharides and trace elements like calcium and magnesium decreased significantly. Infrared spectroscopy demonstrated that the main functional groups involved in binding with Al³⁺ during humic acid adsorption were hydroxyl, carboxyl, phenol, and other oxygen-containing groups. The adsorption process of Al³⁺ by humic acid was a spontaneous phenomenon divided into three key stages: fast adsorption, slow adsorption, and adsorption equilibrium, which resulted from both physical and chemical adsorption effects. This study provided a safe and efficient method in algae metal removal.

The photocatalytic technology for indoor air disinfection has been broadly studied in the last decade. Selecting proper photocatalysts with high disinfection efficiency remains to be a challenge. By doping with the incorporation of metals, the bandgap can be narrowed while avoiding the recombination of photogenerated charge. Three photocatalysts (Ag-TiO₂, MnO₂-TiO₂, and MnS₂-TiO₂) were tested in photocatalytic sterilization process. The results revealed that Ag-TiO₂ had the best antibacterial performance. Within 20 min, the concentration of Serratia marcescens (the tested bacteria) decreased log number of ln 4.04 under 640 w/m² light intensity with 1000 µg/mL of Ag-TiO₂. During the process of inactivating bacteria, the cell membranes of bacterial was destructed and thus decreasing the activity of enzymes and releasing the cell contents, due to the generation of reactive oxygen species (O₂•^- and •OH) and thermal effect. Spectral regulation has the greatest impact on the sterilization efficiency of MnO₂-TiO₂, which reduces the probability of photocatalytic materials being excited.

Despite incineration is an important emission source of toxic pollutants, such as heavy metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), it is still one of the most widely used methods for the management of municipal solid waste. The current paper summarizes the results of a 20-year follow-up study of the emissions of PCDD/Fs by a municipal solid waste incinerator (MSWI) in Sant Adrià de Besòs (Catalonia, Spain). Samples of ambient air, soils and herbage were periodically collected near the facility and the content of PCDD/Fs was analyzed. In the last (2017) survey, mean levels in soil were 3.60 ng WHO-TEQ/kg (range: 0.40-10.6), being considerably higher than the mean concentrations of PCDD/Fs in soil samples collected near other MSWIs in Catalonia. Moreover, air PCDD/F concentrations were even higher than those found in a previous (2014) survey, as they increased from 0.026 to 0.044 pg WHO-TEQ/m³. Ultimately, the PCDD/F exposure would be associated to a cancer risk (2.5 × 10^-6) for the population living in the surrounding area. Globally, this information indicates that the MSWI of Sant Adrià de Besòs could have had a negative impact on the environment and potentially on public health, being an example of a possible inappropriate management for years. The application of Best Available Techniques to minimize the emission of PCDD/Fs and other chemicals is critical.

Heavy metal ions are acknowledged to impact the environment and human health adversely. CNCs are effective materials for removing heavy metal ions in industrial applications and process innovations since they can be used in static and dynamic adsorption processes. Cost-effective, uncomplicated water treatment technologies must be developed using biodegradable polymers, namely, modified cellulose nanocrystals. Adaptive neuro-fuzzy inference systems (ANFISs) and artificial neural networks (ANNs) were used to evaluate and examine the efficacy of modified cellulose nanocrystals in removing lead(II) from wastewater. The research indicated that the maximum adsorption capacity attained was 260 mg/g at a pH of 6, an initial concentration of 200 mg/L, a contact duration of 300 min, and a 5 g/200 mL dose. Influence of four input variables on the Pb(II) adsorption capacity: The experimental data were juxtaposed with the outcomes from ANN and ANFIS to ascertain the pH, contact time, starting concentration, and dose. The correlations of 0.9916 for the created artificial neural network (ANN) and 0.9953 for the adaptive neuro-fuzzy inference system ANFIS indicate that the study data may be predicted with precision. ANFIS had a Pearson's chi-square value of 0.638, surpassing the ANN's score of 0.979.