Environmental Science and Pollution Research最新文献

With the depletion of energy resources like coal, dependence on cleaner energy carriers like biomass is growing in the present century. Gasification is the most renowned and more energetically efficient technology for extracting this energy via the generation of syngas than other thermochemical conversion processes. It can produce power, liquid fuel, and valuable chemicals like methanol, upon which the present civilization relies. In contrast, other thermochemical processes can produce products (biochar or bio-oil) that do not hold value as high as syngas. Rice husk (RH) and cashew nut shells (CNS) are the two abundant biomasses predominantly found in India with extensive energy potential. RH and CNS gasification have several disadvantages that can be eliminated when gasified together, e.g., co-gasification can reduce the tar and ash content, which can cause serious operational issues during gasification. RH with significant lignin content and CNS with high volatile matter are ideal feedstocks for syngas production via gasification. The present study investigated the synergistic effect of co-gasification of the above feedstocks in a fixed-bed reactor. The mixtures of RH and CNS with blending ratios of 75:25, 50:50, and 25:75 were gasified using steam as the gasifying agent and N₂ as the carrier gas at a reaction temperature of 850 °C. The N₂ flow rate was kept at 20 LPM, and the steam flow rate was 0.825 mLPM in all the experiments. Syngas, with an optimum energy content (higher heating value) of 13.8 MJ/Nm³, the highest H₂ concentration of 43.5% volume (without considering N₂ and O₂), and the highest yield of 1.24 Nm³/kg obtained with gasification of a 50:50 blend, revealed the synergistic effect simultaneously. The char and tar yields were also the lowest in the case of 50:50 blend gasification.

In southwestern Nigeria, the increase in informal mining activities has raised environmental and public health concerns due to the potential mobilization of naturally occurring radioactive materials (NORMs) into surrounding ecosystems. In this study, 30 soil samples and 60 mine tailings were collected and analyzed to determine the activity concentrations of NORMs (⁴⁰K, ²³⁸U, and ²³²Th). Gamma spectrometry with a well-calibrated CsI(Tl) detector was used. Spatial distribution maps were generated via geostatistical interpolation techniques. The radiological health risks associated with NORMs in the study area were assessed. The mean activity concentrations of ⁴⁰K, ²³⁸U, and ²³²Th were 465.9 ± 267.5 Bq kq^-1, 30.3 ± 9.1 Bq kg^-1, and 48.7 ± 13.2 Bq kg^-1, respectively, in the soil samples, whereas the values were 607.3 ± 651.8 Bq kg^-1 for ⁴⁰K, 29.5 ± 24.6 Bq kg^-1 for ²³⁸U, and 53.0 ± 34.5 Bq kg^-1 for ²³²Th in the mine tailings. Compared with soil, mine tailings present slightly higher activity concentrations of radionuclides. Geospatial maps of the study area reveal distinct hotspots with elevated activity concentrations of radionuclides, particularly in areas in close proximity to mining sites. The results of the radiological health risk parameters evaluated in this study show that while most locations fall within internationally recommended safety limits, certain areas (with high activity concentrations of NORMs) can pose potential radiological health risks to local populations through prolonged exposure. There is a need for continuous environmental monitoring and the implementation of safety guidelines in the study area to mitigate radiological hazards associated with artisanal mining.

The rapid increase in global textile waste poses significant environmental and resource challenges, necessitating effective recycling strategies. This article provides a global perspective on textile waste recycling (TWR), including policies in major countries and initiatives by international organizations. Through bibliometric analysis, four key research themes were identified: dye removal, physical recycling methods, chemical recycling methods, and sustainable development and the circular economy. Based on bibliometric analysis, the article reviews various TWR approaches and their applications, such as physical methods for fiber and composite production, chemical methods for material synthesis, and thermochemical conversion methods for carbon material and energy recovery. The study also analyzes the economic and environmental benefits of various recycling methods, highlights current challenges, and offers recommendations to guide future research in TWR. This work represents a significant advancement in the valorization of textile waste and provides valuable insights for designing effective strategies for sustainable textile waste management.

Legacy industrial lead (Pb) contamination poses a public health problem worldwide. In Southeast Los Angeles, California, a history of concentrated industrial activity has raised concern about Pb contamination in the area's neighborhoods, particularly in Huntington Park. One former industrial facility in Huntington Park has attracted attention from both a local community environmental justice organization and the U.S. Environmental Protection Agency (USEPA). Although a 2023 report by the USEPA concluded that the Pb contamination from this site was "not significant," the 2024 reduction of the federal soil screening level for residential soil Pb-from 400 mg/kg to 200 mg/kg-prompted a reassessment. In a community-based participatory research effort,91 residential surface soil samples from Huntington Park were analyzed by XRF spectrometry and compared with 118 surface soil samples from broader Los Angeles. In Huntington Park, 85.7% and 57.2% of soils exceeded the state (80 mg/kg) and new federal (200 mg/kg) screening levels, respectively-compared to 55.9% and 19.6% citywide. Soil Pb concentration was found to be statistically significantly higher in the residential soils in Huntington Park compared to the rest of Greater Los Angeles (Mann-Whitney U, p < 0.01). Soil Pb concentrations in Huntington Park also correlated significantly with proximity to the industrial site. Notably, 49.5% of Huntington Park soils fell between the updated and the former federal screening level, highlighting the need for reevaluation of the area's contamination. These results also emphasize the need for remedial action to be taken in areas like Huntington Park, which serves as a clear example of disproportionate contaminant exposure faced by disadvantaged/minority communities.

Chitosan has been extensively investigated as a natural feed additive in ruminant diets; however, its effects on ruminal fermentation and enteric methane (CH₄) mitigation remain inconsistent. This study aimed to evaluate the impacts of graded chitosan supplementation on in vitro digestibility, gas and CH₄ production, rumen fermentation characteristics, protozoal populations, and the phylogenetic affiliation of the recovered methanogens. A total mixed ration (50% forage:50% concentrate) was incubated for 24 h with three chitosan doses-CHI4, CHI8, and CHI12 (4, 8, and 12 g/kg DM, respectively)-and a control. Gas production kinetics were assessed using a semi-automated in vitro gas production system, and methanogen-specific 16S rRNA genes were amplified by nested PCR and sequenced using Sanger sequencing to generate individual consensus sequences for phylogenetic analysis rather than operational taxonomic units (OTUs) derived from high-throughput sequencing. Chitosan at 8 and 12 g/kg DM linearly reduced net gas production (P < 0.001) and CH₄ output (P = 0.008), with CHI8 yielding the greatest reduction (11%) in CH₄ compared to the control. True dry matter degradation (TDDM; P = 0.032) and true organic matter degradation (TDOM; P = 0.012) were significantly decreased by CHI8 and CHI12. Partitioning factor (PF) values were increased with CHI8 supplementation (P < 0.001 linear; P = 0.021 quadratic). All chitosan treatments elevated ammonia-N concentrations (P < 0.001). CHI12 significantly increased total volatile fatty acids (VFAs; P = 0.001), acetate (P = 0.016), propionate (P = 0.016), valerate (P = 0.001), and branched-chain VFAs (P < 0.01), whereas CHI8 reduced butyrate levels (P = 0.018), and selectively modulated protozoal populations (with reductions in Epidinium spp. and Eudiplodinium spp.). Phylogenetic analysis of methanogen 16S rRNA sequences revealed treatment-associated differences in the affiliation of the limited number of sequences recovered, with CHI4 and the control grouped with Uncultured Methanobacteriaceae, while CHI8 and CHI12 aligned with Uncultured Methanobrevibacter strains. Comparative analysis showed high sequence similarity between chitosan-derived isolates and reference sequences from North America. In conclusion, chitosan supplementation induced qualitative shifts in the phylogenetic affiliation of the sampled methanogens, with supplementation at 8 g/kg DM effectively reduced CH₄ emissions, whereas 12 g/kg DM provided additional improvements in ruminal fermentation characteristics.

Street dust is a major sink for organic pollutants, yet their spatial distribution in cities remains poorly understood. This study quantified 59 organic pollutants in street dust from 19 districts across metropolitan Barcelona, Spain. We detected 41 compounds, including polycyclic aromatic hydrocarbons (PAHs), phthalates, bisphenol A (BPA), organophosphorus flame retardants (OPFRs), nicotine, and chlorpyrifos (CPS). Samples were collected via a standardized protocol and analyzed using gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). We applied generalized linear models (GLMs) and used Akaike Information Criterion (AIC) to test hypotheses on anthropogenic, environmental, and management-related influences on contamination patterns. PAH concentrations were higher in areas exposed to regional winds from the airport and harbour. Local winds correlated with lower levels of phthalates, BPA, and CPS. BPA increased with population density but dropped in sun-exposed plots. PAH and OPFR levels were lower in areas cleaned with water. Nicotine was higher in plots exposed to water runoff. Results suggest pollutant persistence and redistribution, rather than emission intensity, largely shape spatial patterns. These findings highlight the need to incorporate environmental and urban-management variables into pollution assessments and offer a methodological framework applicable to other European cities facing similar environmental challenges.

Agriculture is an important part of the Brazilian economy; however, its production is extremely dependent on agricultural chemicals which may reach non-target locations, such as water and sediment from surface water bodies, and accentuate their risks and their permanence in the environment. This study aimed to evaluate the occurrence of pesticides in water samples from the Ijuí river basin (Rio Grande do Sul, Brazil), a region with intensive agricultural activities. Experiments were conducted in 12 sites in the basin. The Solid Phase Extraction (SPE) technique and the QuEChERS-acetate methodology were used for preparing water samples and sediment samples, respectively. Besides, to determine the chemical compounds under study, Liquid Chromatography coupled to Mass Spectrometry (LC-MS) was conducted. The ecological risk of quantified pesticides was also calculated. In surface waters, pesticide concentrations ranged from < LOQ to 0.078 µg⋅L^-1; cyproconazole, atrazine and penoxsulam exhibited the highest concentrations. In sediments, metsulfuron-methyl was found at the highest concentration, i. e., 189 µg⋅kg^-1. There is high diversity and concentration of pesticides downstream from the basin, a fact which may be related to hydroelectric lakes and increase in agricultural areas towards the mouth. Furthermore, these locations were found to pose great ecological risks, which ranged from low to moderate, regarding the sediment. Concerning water, sites close to the mouth posed high risk for aquatic plants due to atrazine and cyproconazole. Results highlight the contamination of waters and sediments in the Ijuí river basin with pesticides and should warn people of the extent of the impact of agricultural activities on the environment.

The development of effective ways and new molluscicides for snail management are currently priority goals to reduce agricultural and financial losses. Saponin is a type of secondary plant metabolites that has greater potential because it is eco-friendly, biodegradable, cost-effective and has a broad spectrum of promising biological activities. Therefore, for the first time, this study investigated the molluscicidal and biochemical effects of soyasaponin on the land snail, Theba pisana. The results showed that saponin had a contact molluscicidal potential against T. pisana with LD₅₀ = 262.76, 213.05, and 166.11 μg/g body weight after 24, 48, and 72 h of treatment, respectively. Using two sublethal doses, saponin increased acetylcholinesterase (AChE) activity post exposure to 1/50 LD₅₀ for 24, 48, and 72 h, whereas an inhibition was observed after exposure to 1/2 LD₅₀. Both doses led to a significant elevation in glutathione-S-transferase (GST) activity after 24 and 48 h. γ-glutamyl transferase (γ-GT) activity was significantly higher at both doses compared to control after all exposure intervals. Moreover, a significant increase in alanine aminotransferase (ALT) activity was occurred following exposure to both tested doses, except after 72 h of exposure to 1/2 LD₅₀. At all exposure times, there was a significant augmentation in aspartate aminotransferase (AST) activity, except for low dose post 24 h. Saponin-treated snails exhibited higher alkaline phosphatase (ALP) activity compared to control group. It also elicited an elevation in glucose level, whereas an opposite effect was occurred in cholesterol level post 24, 48, and 72 h of exposure to both saponin doses. Overall, saponin showed a promising toxicity, suggesting that it could be used as an effective natural alternative for synthetic molluscicides. Our findings also provide a novel insight into how biochemical alterations can be exploited to explore the mechanism underlying saponin toxicity against land snails.

The contamination of water by heavy metals, particularly hexavalent chromium (Cr(VI)), poses a serious threat to aquatic life and human health. Developing low-cost and eco-friendly adsorbents from agricultural waste offers a sustainable solution to this problem. In this context, potato peels, an abundant agro-waste, can serve as an efficient biosorbent for Cr(VI) removal. This study investigates the potential of potato peels (RPP) as a cost-effective and sustainable material for the removal of Cr(VI) from aqueous systems. The RPP was characterized using several techniques including FTIR, pH_pzc, TGA/DTG, and XRD. The effect of various adsorption parameters was examined, such as initial pH (2-5), contact time (0-360 min), initial concentration (10-200 mg L^-1), and solution temperature (30-50 °C). A maximum chromium (VI) adsorption capacity of 15.09 mg g^-1 was achieved under optimal conditions of pH 2, initial concentration 100 mg L^-1, adsorbent dosage of 4 g L^-1, and contact time of 360 min. Isotherm analysis showed that the Langmuir model fit the data (R² = 0.98), indicating monolayer adsorption behavior. Kinetic data followed a pseudo-second-order model indicating a chemisorption process. Furthermore, thermodynamic analysis revealed negative ΔG° < 0, while ΔH° = 44.13 kJ mol^-1 > 40 kJ mol^-1 and ΔS° = 145.80 kJ mol^-1 K^-1, suggesting that the process is spontaneous and endothermic. Desorption and reusability studies confirmed successful adsorbent reuse for three cycles. These findings indicate that potato peel waste is an environmentally friendly and effective biosorbent for the removal of chromium (VI) from aqueous media.

Trichloroethene (TCE) is a widespread toxic groundwater contaminant; thus, the development of inexpensive and accessible remediation materials is needed. Bioremediation of TCE under field conditions often requires the addition of carbon amendments. This study examines the use of biosolids at a field site as a sustainable carbon-rich and microbial amendment. A trench with amendments was installed upstream of a TCE-contaminated site, which was filled with biosolids, limestone, and biochar. Field monitoring of water quality parameters was compared with microbial community changes in soil samples collected 9 months after amendment. The results showed that the TCE concentration decreased from 91 µg/L to below the detection limit, with the presence of TCE biodegradation products indicating anaerobic reductive dehalogenation occurring in the trench. Analysis of the microbial community data also provided predictions about the metabolic activities and showed the presence of acetogenic activity. This activity is required for complete TCE dehalogenation and suggests the presence of different dehalogenase enzymes that can contribute to the degradation of chlorinated contaminants. Thus, the application of the waste product for sustainable TCE bioremediation in the field was successful in decreasing the contaminant levels by upcycling an organic waste product (biosolids).