Search Results (206)

The presence of plastics in the soil environment is an undeniable global reality. Biodegradable plastics (BPs) possess several key properties that make them more environmentally sustainable compared to other categories of plastics. However, their presence induces significant changes in soil systems health where they are found, due to a combination of environmental, soil, and climatic factors, as well as the simultaneous presence of other pollutants, both inorganic and organic. In the present work, a review has been conducted on published research findings regarding the impact of various types of BPs on the parameters that regulate and determine soil health. In particular, the study examined the effects of BPs on physical, chemical, and biological indices of soil quality, leading to several important conclusions. It was observed that silty and loamy soils were significantly affected, as their physical properties were altered. Moreover, significant changes in both chemical and microbiological indicators were observed with increasing environmental temperatures. The presence of all types of biodegradable microplastics led to a significant reduction in soil nitrogen content as temperature increased. This study highlights the profound effects of the climate crisis on the properties of soils already contaminated with plastics, as the effects of rising temperatures on soil properties appear to be amplified in the presence of plastics. On the other hand, higher temperatures also trigger a series of chemical reactions that accelerate the degradation of BPs, thereby reducing their volume and mass in the soil environment. These processes lead to increased emissions of gases and higher ambient temperatures, leading to global warming. The types and quantities of plastics present, along with the environmental changes in a study area, are critical factors that must be taken into account by policymakers in order to mitigate the impacts of climate change on soil health and productivity. Full article

Groundwater contamination by nitrates (NO₃⁻) and nitrites (NO₂⁻) is an urgent problem in rural areas of Eastern Europe, with profound public health and sustainability implications. This paper presents an integrated assessment of groundwater vulnerability and water quality in rural wells in the Ceanu Mare commune, Cluj County, Romania—a representative area of the Northern Transylvania Basin, characterized by diverse geological structures, intensive agricultural activities, and incomplete public water infrastructure. This study combines detailed hydrochemical analyses, household-level studies, and geological context to identify and quantify key factors influencing nitrate and microbial contamination in rural wells, providing a comprehensive perspective on water quality challenges in the central part of Romania. This study adopts a multidisciplinary approach, integrating detailed geotechnical investigations conducted through four strategically located boreholes. These are complemented by extensive hydrogeological and lithological characterization, as well as rigorous chemical and microbiological analyses of nearby wells. The results reveal persistently elevated concentrations of NO₃⁻ and NO₂⁻, commonly associated with inadequate livestock waste management and the proximity of manure storage areas. Microbiological contamination was also frequent. In this study, the NO₃⁻ levels in well water ranged from 39.7 to 48 mg/L, reaching up to 96% of the EU/WHO threshold (50 mg/L), while the NO₂⁻ concentrations varied from 0.50 to 0.69 mg/L, exceeding the legal limit (0.5 mg/L) in 87% of the sampled wells. Ammonium (NH₄⁺) was detected (0.25–0.34 mg/L) in all the wells, below the maximum allowed limit (0.5 mg/L) but indicative of ongoing organic pollution. All the well water samples were non-compliant for microbiological parameters, with E. coli detected in 100% of cases (5–13 CFU/100 mL). The regional clay–marl substrate offers only limited natural protection against pollutant infiltration, primarily due to lithological heterogeneity and discontinuities observed within the clay–marl layers in the study area. This research delivers a replicable model for rural groundwater assessment and addresses a critical gap in regional and European water safety studies. It also provides actionable recommendations for sustainable groundwater management, infrastructure development, and community risk reduction in line with EU water directives. Full article

The popularity of small-scale and local fruit and vegetable production has increased in recent years due to perceived economic, environmental, and social benefits. However, these operations face contamination risks that both consumers and small-scale producers may underestimate. The present study aimed to assess the microbiological and chemical hazards on fruit, vegetables, soil, and water samples from small-scale farms in north-western Portugal during pre-harvest activities. Additionally, the study investigated farmers’ non-compliance with food safety regulations and good agricultural practices (GAPs), exploring how their behaviour might contribute to the identified hazards. A before-and-after analysis of non-compliant behaviours was conducted to determine the impact of training on improving food safety practices. The analysis identified the presence of pathogenic bacteria, pesticides, flame retardant residues, nitrates, and heavy metals. Lead (Pb) concentrations exceeded EU limits in organic carrots from one producer (0.156 ± 0.043 mg/kg) and in chard from another (0.450 ± 0.126 mg/kg). Cadmium (Cd) levels were also above regulatory thresholds in bell peppers (0.023 ± 0.009 mg/kg) and organic tomatoes (0.026 ± 0.015 mg/kg) from two different producers. Elevated levels of heavy metals were detected in irrigation water from two sites, with zinc (Zn) at 0.2503 ± 0.0075 mg/L and Pb at 0.0218 ± 0.0073 mg/L. Among food samples, the most prevalent microorganisms were Pseudomonas spp. (88.2%), Bacillus cereus (76.5%), and aerobic mesophilic bacteria (100%). Phosphorus flame retardants (PFRs), particularly tris(2-butoxyethyl) phosphate (TBEP), were detected in all food and soil samples. Some EU-banned pesticides were detected in food and soil samples, but at levels below the maximum residue limits (MRLs). Chlorpyrifos (35.3%) and p,p’-DDD (23.5%) were the most detected pesticides in food samples. After the training, GAP behaviour improved, particularly that related to hygiene. However, issues related to record-keeping and soil and water analyses persisted, indicating ongoing challenges in achieving full compliance. Full article

Microbial contamination and biofilm formation on food contact materials (FCMs) represent critical challenges within the food supply chain, compromising food safety and quality while increasing the risk of foodborne illnesses. Traditional materials often lack sufficient microbial resistance to contamination, creating a high demand for innovative antimicrobial surfaces. This study assessed the effectiveness of a nanosized deposited SiO_xC_yH_z coating approved for food contact on 3D-printed polyamide 12 (PA12) disk substrates, aiming at providing antimicrobial and anti-biofilm functionality to mechanical components and packaging material in the food supply chain. The coating was applied using plasma-enhanced chemical vapor deposition (PECVD) and characterized through Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and contact angle measurements. Coated PA12 samples exhibited significantly enhanced hydrophobicity, with an average water contact angle of 112.9°, thus improving antibacterial performance by markedly reducing bacterial adhesion. Microbiological assays revealed a significant (p < 0.001) bactericidal activity (up to 4 logarithms after 4 h, ≥99.99%) against Gram-positive and Gram-negative bacteria, including notable foodborne pathogens such as L. monocytogenes, S. aureus, E. coli, and S. typhimurium. SiO_xC_yH_z-coated PA12 surfaces exhibited strong antibacterial activity, representing a promising approach for coating additive-manufactured components and equipment for packaging production in the food and pharmaceutical supply chain able to enhance safety, extend product shelf life, and reduce reliance on chemical sanitizers. Full article

In Mexico, hospital wastewater (HWW) is a source of chemical and microbiological contamination, and it is released into the municipal sewage system without prior treatment. This water may contain pathogenic bacteria and antimicrobial resistance genes, which represent a risk to Public Health and the environment. So far, there are no studies that analyse this problem comprehensively, relating bacterial population structures, chemical contaminants, and seasonality. The aim of this work was to seasonally characterise the bacterial communities of HWW, including clinically relevant bacteria and resistance genes in Hospital Juárez de México (HJM), and to evaluate the impact of physicochemical factors on their composition. A one-year observational, cross-sectional study was conducted at five HWW discharge points of HJM. Fourteen physicochemical parameters were determined by using standard methodologies, and statistical differences between discharges and seasons were evaluated. Bacterial communities were analysed by targeted amplicon sequencing of the V3-V4 region of the 16S rRNA gene. In addition, the presence of eight antimicrobial resistance genes of local epidemiological importance was assessed. Data were analysed using alpha and beta diversity indices, principal component analysis, and multivariate statistical tests. HWW showed high taxonomic diversity, with Proteobacteria, Firmicutes, and Bacteroidetes standing out. Clinically relevant bacteria were identified in 73.3% of the analyses, with Enterobacter and Escherichia-Shigella predominating. Total and dissolved solids, temperature, nitrate, and pH significantly influenced the bacterial composition of HWW. Seven out of the eight genes evaluated were identified, with bla_KPC, bla_OXA-40, and mcr-1 being the most frequent, showing significant seasonal differences. This study underlines the microbiological and chemical complexity of HWW, highlighting the impact of clinically relevant bacteria and antimicrobial resistance genes on Public Health. The findings emphasise the need to implement hospital waste management programmes and ideally specific treatment plants to minimise the associated risks and protect the environment and human health. Full article

Equid milk (donkey or mare) has traditionally been consumed raw or fermented due to its distinctive chemical composition, which closely resembles human milk, and its nutritional benefits. Nowadays, interest in it is increasing, despite limited research on its microbiological risk. Coxiella burnetii (C. burnetii), a globally re-emerging zoonotic agent, has rarely been investigated in equid milk. The objective of this study was to demonstrate the applicability of selected analytical methods for detecting C. burnetii in raw equid milk. A commercial molecular assay was tested on three serial dilutions of one donkey milk sample contaminated with a C. burnetii plasmid, which showed no interference of donkey milk with real-time PCR detection. The commercial molecular assay and a serological assay routinely used in the laboratory were also applied to screen a total of 106 equid milks from 16 farms to assess their applicability to diagnostic samples. No C. burnetii DNA or anti-C. burnetii antibodies were detected in these screenings. In our study, the implemented methods appeared to be suitable for C. burnetii investigation in equid milk. While the overall low prevalence recorded in Italy among domestic species is reassuring, strategic surveillance and risk assessment remain essential considering the low infectious dose of C. burnetii and its zoonotic potential. Full article

Black soldier fly (BSF) larvae are increasingly used in sustainable waste management, offering potential for the bioconversion of organic waste into insect-derived fertilizer and animal feed. This study investigates the impact of varied substrate mixtures percentages of sludge and chicken feed on heavy metal accumulation, pathogen reduction, and nutrient composition in BSF frass. Methods: The experiment was conducted with four substrate treatments (100% sludge, 75% sludge + 25% chicken feed, 25% sludge + 75% chicken feed, and 100% chicken feed) over a 20-day period. Chemical and microbiological analyses were performed on the feed mixture before adding larvae and on the frass produced in each treatment. Heavy metal concentrations, including cobalt (Co), chromium (Cr), nickel (Ni), and lead (Pb), pathogen levels (Escherichia coli, total coliform, and fecal coliform), and nutrient composition, including moisture content, pH, ash, nitrogen, phosphorus, calcium, potassium, sodium, magnesium, and chlorine, were assessed. Statistical analysis was used to determine significant differences across treatments. Results: Heavy metal levels in frass varied with substrate composition, with significantly higher concentrations of cobalt (Co), chromium (Cr), nickel (Ni), and lead (Pb) in sludge-dominant treatments (p < 0.05). Treatments with higher chicken feed content were associated with lower metal levels, indicating organic feed’s potential in limiting heavy metal accumulation (p < 0.001). Pathogen analysis showed high microbial levels in sludge-based treatments, while the 100% chicken feed treatment exhibited minimal contamination, highlighting its safety profile (p < 0.05). Nutrient characterization revealed that chicken feed-enhanced treatments produced frass with higher nitrogen and potassium levels, suggesting improved nutrient density and potential for agricultural use. Conclusions: Tailoring BSF substrates by combining sludge with organic feed can enhance the nutritional quality of frass while reducing environmental risks associated with heavy metal and pathogen presence. This study supports the potential of BSF as a sustainable bioconversion tool, promoting circular agriculture. Full article

This article explores how the location of a building in an urban area, the level of external air pollution, and the way a residence is used can affect indoor air quality. To assess this, this study used measurements of physical and chemical pollutants, as well as microbiological measurements, including counts of various bacteria and microscopic fungi. These included counts of mesophilic and psychrophilic bacteria, mannitol-positive and mannitol-negative Staphylococcus, Actinobacteria, Pseudomonas fluorescens, and microscopic fungi. The research involved analysing indoor and outdoor air quality in 38 selected spaces within buildings in the city of Poznań during the heating season. The study found that the eastern part of the city showed the highest levels of fungal contamination in the external environment. Furthermore, distinct differences were observed between the presence of microorganisms indoors and outdoors based on the results of bacterial and fungal aerosol studies. The authors advocate for including microbiological studies as part of standard air quality assessment indicators to reveal the extent and source of contamination, as similar issues may be present in cities around the world. Full article

Cacao mucilage is a rich medium for microbial development due to the presence of various sugars, water, pectin, mineral salts, and yeasts of the Saccharomyces cerevisiae type. This study aims to provide added value to this commonly discarded residue, thereby contributing to the economic growth of the Rio Chila area in the Valencia Canton of Los Ríos Province. The methods applied for developing beer consist of malting, grinding, mashing, filtering, boiling, cooling, fermentation (during which cacao mucilage is added), and maturation, followed by physical–chemical analyses. The Fine aroma cacao mucilage presented values of 0.66% acidity, 7.63 °Brix, pH 4.43, absorbance 1.13, transmittance 23.67%, suspended solids 0.04 g: 2.66%, density 1.07 g/mL, turbidity 6.94 NTU, °GL 8.47% vol., foam quantity 1.70 cm, colorimetry L* 50.77, colorimetry a* 18.08, colorimetry b* 50.53, and bitterness degree 39.00. The analyses presented values within the normal parameters applied to beers at the national level (INEN standards). Escherichia coli, Salmonella, and total microorganisms showed no contamination in the microbiological analyses. In the sensory analyses, appearance, aroma, flavour, and mouthfeel were evaluated, with the best experiment being the combination of Fine aroma cacao with a concentration of 30% mucilage and added Cascade hops. This study took into account the concentrations of cacao mucilage (20% and 30%) from the varieties (Fine aroma and CCN-51), as well as the addition of the brewing hops Cascade and Northern Brewer. Regarding the physicochemical characteristics, adding this cacao derivative did not affect craft beer and conformed to the ranges of the NTE INEN 2262 standard. Thus, this research proposes an alternative use for cocoa mucilage, contributing to waste reduction and broadening its potential applications. Full article

Spills involving fuels and lubricating oils in industrial environments caused by the fueling of machines, inadequate storage and the washing of equipment are significant sources of environmental pollution, impacting soil and water bodies. Such incidents alter the microbiological, chemical and physical properties of affected environments. The use of biosurfactants is an effective option for the cleaning of storage tanks and the remediation of contaminated soils and effluents. The scope of this work was to assess the production and application of a Starmerella bombicola ATCC 22214 biosurfactant to remediate marine and terrestrial environment polluted by oil. The production of the biosurfactant was optimized in terms of carbon/nitrogen sources and culture conditions using flasks. The performance of the biosurfactant was tested in clayey soil, silty soil, and standard sand, as well as smooth surfaces and industrial effluents contaminated with oils (fuel oils B1 for thermal power generation, diesel, and motor oil). The ideal culture medium for the production of the biosurfactant contained 2% glucose and 5% glycerol, with agitation at 200 rpm, fermentation for 180 h and a 5% inoculum, resulting in a yield of 1.5 g/L. The biosurfactant had high emulsification indices (86.6% for motor oil and 51.7% for diesel) and exhibited good stability under different pH values, temperatures and concentrations of NaCl. The critical micelle concentration was 0.4 g/L, with a surface tension of 26.85 mN/m. In remediation tests, the biosurfactant enabled the removal of no less than 99% of motor oil from different types of soil. The results showed that the biosurfactant produced by Starmerella bombicola is a promising agent for the remediation of environments contaminated by oil derivatives, especially in industrial environments and for the treatment of oily effluents. Full article

This study proposes an innovative framework integrating geographic information systems (GISs), water quality index (WQI) analysis, and advanced machine learning (ML) models to evaluate the prevalence and impact of organic and inorganic pollutants across the urban–industrial confluence zones (UICZ) surrounding the National Capital Territory (NCT) of India. Surface water samples (n = 118) were systematically collected from the Gautam Buddha Nagar, Ghaziabad, Faridabad, Sonipat, Gurugram, Jhajjar, and Baghpat districts to assess physical, chemical, and microbiological parameters. The application of spatial interpolation techniques, such as kriging and inverse distance weighting (IDW), enhances WQI estimation in unmonitored areas, improving regional water quality assessments and remediation planning. GIS mapping highlighted stark spatial disparities, with industrial hubs, like Faridabad and Gurugram, exhibiting WQI values exceeding 600 due to untreated industrial discharges and wastewater, while rural regions, such as Jhajjar and Baghpat, recorded values below 200, reflecting minimal anthropogenic pressures. The study employed four ML models—linear regression (LR), random forest (RF), Gaussian process regression (GPR), and support vector machines (SVM)—to predict WQI with high precision. SVM_Poly emerged as the most effective model, achieving testing CC, RMSE, and MAE values of 0.9997, 11.4158, and 5.6085, respectively, outperforming RF (0.9925, 29.8107, 21.7398) and GPR_PUK (0.9811, 68.4466, 54.0376). By leveraging machine learning models, this study enhances WQI prediction beyond conventional computation, enabling spatial extrapolation and early contamination detection in data-scarce regions. Sensitivity analysis identified total suspended solids as the most critical predictor influencing WQI, underscoring its relevance in monitoring programs. This research uniquely integrates ML algorithms with spatial analytics, providing a novel methodological contribution to water quality assessment. The findings emphasize the urgency of mitigating the fate and transport of organic and inorganic pollutants to protect Delhi’s hydrological ecosystems, presenting a robust decision-support system for policymakers and environmental managers. Full article

The illegal treatment of tuna with nitrite is a significant food safety concern. The risk may be due to not only the high nitrite levels and the possible formation of N-Nitrosamines but also to the possible increase in biogenic amines and microbial load and also pathogens. This study optimized the treatment of red tuna (Thunnus thynnus) with nitrite solutions and then determined several chemical (histamine, total volatile basic nitrogen (TVBN), biogenic amines, nitrite/nitrate, ascorbic acid, and sulfites) and microbiological (total microbial count, Enterobacteriaceae, Vibrionaceae, coagulase-positive staphylococci, Salmonella, Escherichia coli) parameters, comparing the results obtained with fresh samples with those obtained with treated samples after 5 days of storage (4 °C). The effect of such treatment on samples voluntarily contaminated with some pathogens was also investigated. The results indicate that if the products are characterized by suitable hygienic quality, the total microbial load and the levels of histamine and TVBN after 5 days of storage are below the legal limits, and no health risk subsists. The growth of pathogens/histaminogens (Salmonella and Morganella morganii) was also substantially inhibited during storage. Thus, this work confirmed that the high nitrite amounts and the possible development of N-nitrosamines represent the only significant food safety concerns. Full article

The importance of assessing the microbiological safety of food products is beyond doubt, which is also true for milk and dairy products. The goal of this work was to evaluate the changes in the composition of the gas phase in milk based on signals from chemical sensors to predict the quantity of the bacteria in the milk samples. The gas phase in raw milk samples and samples during pasteurization, as well as for a standard (a model aqua solution of macronutrients and minerals), was studied using an array of sensors with polycomposite coatings, including those contaminated with E. coli bacteria. Assessment of microbiological indicators was carried out according to GOST in parallel with the gas-phase analysis. The applicability of the results obtained on model systems was assessed using milk samples, including those containing other types of pathogenic microorganisms (Staphylococcus aureus, Klebsiella spp., etc.). It was found that the obtained models can be used to assess the presence and quantity of E. coli in milk at the pasteurization stage. Full article

This study examines the microbiological and mycotoxicological quality of common wheat in Romania in the extremely dry 2023–2024 agricultural year. Common wheat grown in the West Plain, Southern Hilly Area, Transylvania, and northern Moldavia (45–48° N, 21–27° E) had higher moisture content, water activity, Fusarium-damaged kernels, and deoxynivalenol levels. This was due to moderate temperatures, abundant precipitation, and soil water reserves in May, followed by moderate drought from June to August. Conversely, common wheat from the Oltenia Plain, the Southern Plain, and southern Moldavia (43–46° N, 23–28° E) had the lowest contamination levels, attributed to extreme temperatures and drought during June–August. Common wheat from Dobrogea (45° N, 28° E) showed the highest total fungi contamination, which was influenced by precipitation at harvest. Although microbiological and mycotoxicological contamination was low, it negatively affected the physico-chemical and sensory–colorimetric parameters of common wheat, particularly in the West Plain, Oltenia Plain, and Dobrogea. Consequently, there could be significant economic losses for farmers, storekeepers, millers, and bakers, as well as a decline in the quality of finished foods. Moreover, the coexistence of deoxynivalenol and total aflatoxins in common wheat grown in the northwest of the country indicates the spread of contamination due to dry conditions and climate change. Full article

Currently, solid waste storage systems generate secondary pollutants such as leachates, derived from rainwater infiltration or produced during their storage, which affect water quality, human health, and the environment. This study evaluated a bioremediation system for leachates from the “Rancho Triste” landfill using Spirulina sp. as a microalgal strain. Its rapid adaptation to the leachate was identified through respirometry based on CO₂ measurement, allowing the modeling of microalgal adaptation using a Log-Normal Peak Shifted with Offset function. Tests conducted in a 0.5 L reactor determined an optimal treatment time of 10 days, achieving removals of 87.17% for iron, 28.96% for magnesium, and 90.74% for manganese. Subsequently, a 2³ factorial design was implemented to optimize the reduction of chemical oxygen demand (COD), evaluating agitation, lighting, and nitrogen supplementation, achieving a COD removal efficiency exceeding 50% under optimal conditions. The fed-batch technique enabled an enrichment of microbiological populations, which, together with bio-stimulation, bioventilation, and photoperiods, demonstrated the scalability of the bioprocess and the significant reduction of metallic and recalcitrant contaminants present in the leachate. This approach proposes an ecological alternative with potential application in water treatment industries aiming for carbon neutrality and optimal transformation of high-effluent volumes. Full article