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

Free living animals are sensitive indicators of the environment pollution by polychlorinated biphenyls (PCBs) and other organic pollutants. The aim of this study was to determine polychlorinated hydrocarbons in the depot fat of red foxes (Vulpes vulpes L.) living in the natural environment of south-western Slovakia. The analyses performed included dichlorodiphenyltrichloroethane (DDT), hexachlorobenzene (HCB) and polychlorinated biphenyls (PCBs). The gas chromatograph equipped with an electron capture detector (ECD) was used. The accumulation of pollutants in depot fat of animals followed the order PCB > DDT > HCB. Of all pollutants, the total concentration of PCBs was significantly higher (p < 0.05) in fat tissue of foxes (1.445 ± 0.174 mg/kg) in comparison to DDT (0.1120 ± 0.24 mg/kg) and HCB 0.052 ± 0.010 mg/kg). Compared to samples from females (0.962 ± 0.110 m/kg), significantly higher (p < 0.05) PCB levels were found in samples from males (1.751 ± 0.293 mg/kg). Moderate positive correlation (r = 0.5509) between PCB and HCB was detected. Wild animals can act as indicators of environmental pollution by polychlorinated hydrocarbons, making their monitoring an ongoing priority.

There are limited studies on air quality in the Southern United States, with even fewer assessing the health impacts of poor air quality on underserved communities. Jackson, the Mississippi state capital, has documented environmental injustices linked to drinking water quality and access to healthcare, but the impact of air pollution is underexplored. Fine particulate matter (PM_2.5), a complex mixture of air pollution, has associations with systemic health effects and the ability to induce oxidative stress. While federal regulations require monitoring PM_2.5 throughout the United States, there is limited characterization of health relevant components, including black carbon and polycyclic aromatic hydrocarbons (PAHs). This project utilizes PM_2.5 filters to investigate the chemical and toxicological profile of PM_2.5 at two intraurban sites using the dithiothreitol assay to measure oxidative potential and Gas Chromatography - Mass Spectrometry to quantify PAHs. Significant differences between sites in PM_2.5 concentration, oxidative potential, and PAH concentrations was observed. Additional research is needed to determine the potential human health risks that PM_2.5 poses to residents in Jackson, MS, but this work highlights pollutants of interest at levels that exceed similar studies for urban regions, encouraging more attention and action to protect the air of vulnerable populations.

This study investigates the optimization of alum dosing in surface water treatment at Ghana's Weija Water Treatment Plant using response surface methodology (RSM). By combining conventional jar tests, historical data (2002-2016) and 2018 seasonal experiments, the research evaluates the impact of raw water quality, especially turbidity, pH, color and polycyclic aromatic hydrocarbons (PAHs), on coagulation efficiency. While traditional jar tests required 90-100 mg/L of alum, RSM achieved better turbidity and color removal with just 71 mg/L, also reducing residual aluminum levels. The RSM approach demonstrated cost savings exceeding GHS 600,000 annually, cutting chemical usage by over 30% and ensuring compliance with WHO standards. Comparative analysis across treatment techniques confirmed RSM's superior performance and economic benefits. The findings highlight the importance of predictive, multivariate optimization in improving treatment reliability, reducing sludge generation and enhancing operational efficiency.

This study investigates the removal of nickel (II) from aqueous solutions using a biodegradable cellulose nanocrystal (CNC) nanocomposite. Fourier Transform Infrared (FTIR) analysis confirmed successful functionalization, with characteristic peaks observed at 1735 cm^-1 (C = O stretching of carboxyl groups) and 1050 cm^-1 (C-O-C stretching), indicating the effective incorporation of EDTA into the CNC structure. Scanning Electron Microscopy (SEM) revealed a rough and porous surface morphology, favorable for enhanced adsorption performance. Thermogravimetric Analysis (TGA) demonstrated the composite's thermal stability up to 320 °C, with a significant weight loss of 65% between 300-400 °C corresponding to cellulose decomposition. Batch adsorption experiments examined the effects of pH, contact time, adsorbent dosage, and initial nickel (II) concentration. The maximum removal efficiency of 98.3% was achieved at a pH of 6, a 120-min contact time, an 8 g/100 mL dosage, and an initial concentration of 150 mg/L. Film diffusion was identified as the rate-limiting step with an R² of 0.983. Machine learning models were also developed to predict adsorption performance. The Artificial Neural Network (ANN) model achieved R² of 0.987 and RMSE of 0.012, while the Adaptive Neuro-Fuzzy Inference System (ANFIS) demonstrated superior accuracy with R² of 0.995 and RMSE of 0.008. The nickel(II) adsorption is best represented by the Langmuir model, with an R² value of 0.996. The pseudo-second-order model governs the adsorption process; the Dubini-Radushkevich model confirms chemisorption with an energy of 9.375 kJ/mol. These findings confirm that the CNC nanocomposite is an efficient, thermally stable, and sustainable adsorbent for Ni(II) removal from aqueous media, with ANN and ANFIS models providing reliable predictive capability for process optimization.

Polycyclic aromatic hydrocarbons (PAHs) pose a significant environmental challenge due to their toxicity that are harmful to living organisms, and commonly found in various ecosystems. Degradation using natural indigenous bacteria is the most cost-effective solution to remove PAHs in the environment. This study examines Sdt-1, an isolated bacterial consortium from agricultural soil in Wakabayashi-ward, Sendai, Japan, capable of degrading PAHs. Sdt-1 was incubated to a solution containing fluorene, phenanthrene, and pyrene in Bushnell Hass Medium (BHM) with 100 mg/L concentration of each compound. Fluorene degraded at the fastest rate, then phenanthrene, while pyrene was the slowest due to its higher molecular weight. Cloning of the 16S rRNA gene showed that Sdt-1 consists primarily of 48% Castellaniella, 16% Mycobacterium, 14% Desulfonatronum, 10% Azospirillum, and 2% each of several other genera. The dynamics of the Sdt-1 was tracked over the 15-d incubation periods through the PCR-DGGE analysis, showing Mycobacterium as the dominant PAH degrader. Correlation between bacterial activity and PAH-degrading genes (nidA and gram-positive PAH-RDH) demonstrates that specific microbes are in charge of various degradation phases. This study enhanced our understanding of the mechanics, characteristics, and the potential role for bioremediation applications of aerobic PAH-degrading bacteria from paddy soil in agricultural land.

The ketamine (KET) and its analogs consumed by humans are becoming emerging contaminants (ECs), as they at present in surface waters after being carried through wastewater systems. Drugs in wastewater can be analyzed using the direct-injection method, a simple wastewater analysis (WWA) method that can provide objective, continuous and nearly to real-time findings. This article describes an ultra-high-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantification and confirmation of seven KET-based ECs in wastewater by direct injection. After optimization of the UPLC-MS/MS and sample pretreatment conditions, the method was validated and applied to samples (n = 157) collected from several wastewater treatment plants (WWTPs) in southern China in which KET had the highest detection rate. The established direct-injection method was not only simple to perform but also had better sensitivity, shorter detection times, and analyzed more KET-based ECs than currently published methods, meeting the requirements for the monitoring and high-throughput analysis of common KET-based ECs. We also analyzed the fragmentation pathway of KET-based ECs to obtain product ion information on other unknown substances. Additional studies are needed to establish a comprehensive direct-injection screening method of ECs in wastewater on model-based assessment.

The distribution of antibiotic resistance genes (ARGs) in Laizhou Bay affects the local socio-economic development. The study aimed to investigate the distribution of ARGs in the rivers that flow into the sea around Laizhou Bay's southern shore. Water and sediment samples were collected from different typical sites of rivers entering the sea in Weifang, including Mi River, Bai Lang River, Yu River, Wei River, Jiaolai River, Xiaoqing River and Di River. The species and abundance of ARGs in the sediments were characterized and quantified by macro-genome high-throughput sequencing technology. The species distribution of ARGs was compared. In two sediment samples and seven water samples, 24 ARGs types and 1244 subtypes of ARGs were detected, in which multidrug-resistant class was the main ARGs type and FBJ murine osteosarcoma viral oncogene homolog B (fosB) was the dominant ARGs. The types of ARG in the top ten of these samples were the same, although the proportion was different. Dominant ARG subtypes accounted for more than 50% of all the nine samples. This article provides basic data support for pollution status and environmental risk assessment as well as remediation of ARGs in rivers entering the sea along the south coast of Laizhou Bay.

Cellulose was isolated from recycled pulp and paper sludge and used to synthesize cellulose nanocrystals. Response surface methodology and Box-Behnken design model were used to predict, improve, and optimize the cellulose isolation process. The optimal conditions were a reaction temperature of 87.5 °C, 180 min with 4% sodium hydroxide. SEM and TEM results revealed that the isolated cellulose had long rod-like structures of different dimensions than CNCs with short rod-like structures. The crystallinity index from XRD significantly increased from 41.33%, 63.7%, and 75.6% for Kimberly mill pulp sludge (KMRPPS), chemically purified cellulose and cellulose nanocrystals, respectively. The TGA/DTG analysis showed that the isolated cellulosic materials possessed higher thermal stability. FTIR analysis suggested that the chemical structures of cellulose and CNCs were modified by chemical treatment. The cellulose surface was highly hydrophilic compared to the CNCs based on the high water holding capacity of 65.31 ± 0.98% and 83.14 ± 1.22%, respectively. The synthesized cellulosic materials portrayed excellent properties for high-end industrial applications like biomedical engineering, advanced materials, nanotechnology, sustainable packaging, personal care products, environmental remediation, additive manufacturing, etc.

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).