Potential Sources Of Contamination Research Articles

From Sea Water to Salt Crystals: An Onsite Investigation of Microplastics in a Conventional Sea Salt Farming System.

This study investigated microplastic (MP) contamination in conventional sea salt farming systems. Various crude sea salt samples (n = 22) that were traditionally produced were collected from salt farms and local vendors. Salt water (n = 15), macroalgae (n = 6), and clay of pond floors (n = 6) were collected from ponds subjected to different production (stabilization, evaporation, and concentration and crystallization concentration) processes. All samples were analyzed for MP abundance and characteristics. The potential sources of MP contamination in the salt were also investigated. The mean abundance of MPs in the salt water and clay of pond floor increased progressively throughout the production process and reached its highest level in the concentration and crystallization ponds (7400 MP particles/m3 in salt water and 19,336 MP particles/m2 in the clay of the pond floor). A maximum of 26,500 MP particles/kg of macroalgal material indicated the potential sink of MPs on the surface of the algae. Approximately 34-2377 MP particles/kg salt were found in the crude sea salt samples. However, the mean abundance (378 MP particles/kg of salt) indicated nonsignificant impacts of different harvesting processes on MP contamination. Most MP size distributions, shapes and polymer types in the salts were similar to those found in the salt water, macroalgae and clay of the pond floor. Approximately 99% of the MPs were fragments that were suspected to be decomposed from larger plastic debris and plastic machinery and tools used at the salt farm. Similar patterns of polymer distribution, in which PP > PE > PET > PS, were found for all samples studied.

Development of Salmonella enterica serovar Typhimurium, Listeria monocytogenes, and Pseudomonas aeruginosa multi-species in vitro dry surface biofilm models: Insights into resilience and persistence in low-moisture environments

Salmonella enterica serovar Typhimurium, Listeria monocytogenes, and Pseudomonas aeruginosa can persist as dry surface biofilms (DSB) and survive desiccation for prolonged periods of time. This could serve as potential sources of contamination in low-moisture food (LMF) processing environments. The objectives of this study were to develop in vitro mono-and mix-culture DSB models to better understand pathogen survival under dehydrated conditions as DSB. Mono-and mix-culture wet surface biofilms (WSB) of S. enterica ser. Typhimurium ATCC 14028, L. monocytogenes FSL R8-5318, and P. aeruginosa ATCC 15442 were developed following EPA MLB SOP MB-19 protocol on borosilicate glass coupons using a CDC® biofilm reactor. WSB were harvested and dried for 24, 48, and 72 h at 21 °C to form DSB. Mean log10 CFU/cm2 were calculated at each desiccation time point and compared to control (WSB) using LSM of PROC GLM to fit linear models (P = 0.05). Approximately 8.8 ± 1.7, 7.1 ± 1.1, 6.9 ± 0.6, and 6.3 ± 0.8 mean log10 CFU/coupon were recovered from mono-culture Salmonella DSB at 0, 24, 48, and 72 h, respectively. Overall, Salmonella mean log10 densities were limited when co-cultured with P. aeruginosa although there were no significant differences in Salmonella density over desiccation time points. Mean log10 CFU/coupon for L. monocytogenes monoculture DSB were comparatively lower i.e., 5.7 ± 0.4 (0 h), 3.8 ± 0.1 (24 h), and 3.4 ± 0.6 (48 h), and 2.6 ± 0.3 (72 h). However, when co-cultured with P. aeruginosa, L. monocytogenes exhibited consistently higher cell densities 6.7 ± 0.4, 6.0 ± 0.9, 5.6 ± 0.04, and 4.9 ± 0.6, at 0, 24, 48, and 72 h, respectively. On average, P. aeruginosa consistently exceeded six log10 at each desiccation time point in co-culture. Confocal laser scanning microscopy (CLSM) images confirmed biofilm development and persistence over time in mono and mixed cultures. This work provides foundational evidence toward better understanding pathogen survival under dehydrated conditions, interactions between different pathogens within desiccated biofilms, and their respective survival rates. Additionally, these data provide quantitative assessment of bacterial load within DSB under high-risk scenarios for LMFs. These models provide opportunities to explore targeted mitigation strategies, including efficacy of dry sanitation practices, to prevent the formation or remove DSB in LMF processing environments.

Application and Experimental Substantiation of the Radioecological Model for Prediction in Behavior 90Sr in Cultivated Soil-Crop System: A Case Study of Two Experimental Agricultural Fields.

The radioactive fission product 90Sr has a sufficient half-life (28.8 years) to be detected long after its appearance in the environment. After its uptake into the soil-edible plant system, it enters the food chain and represents a potential source of contamination that threatens human health. Due to these facts, tracking the distribution of the artificial radionuclide 90Sr in the soil-edible plant system is a subject of intense research. The tracking of the 90Sr radionuclide distribution in the soil profile, as well as in the crops on the long-term experimental fields was carried out using beta radiation spectrometry. The radiochemical analytical method was used to analyze the 90Sr content in cultivated soil and crops. The conducted study focused on the experimental substantiation of the developed model for predicting the behavior of 90Sr in the cultivated soil-crop system. The results of using the applied radioecological model for the transfer of 90Sr from the soil to the above-ground part of crops showed a relatively good agreement with the experimentally determined values of the soil-crop transfer factor, which indicates that the used model can be successfully applied for the prediction of the behavior of 90Sr in the soil-soil solution-crop system.

Use of plasma process diagnostic sensors for the monitoring of in situ dry cleaning of plasma enhanced chemical vapor deposition chamber

A potential source of particle contamination due to poorly maintained PECVD chamber condition forces to perform in situ dry cleaning also actively employed before the wet-cleaning chamber maintenance period. In this paper, we demonstrate the use of plasma process diagnostic sensors, optical emission spectroscope, and quadrupole mass spectrometer for in situ plasma monitoring of the dry-cleaning step. It is worthwhile to know the thin film residue on the chamber’s inner wall, but it is difficult to collect the deposited thin film sample from the wall since the preparation of the sample from the equipment is impossible. To alleviate the concern, we prepared silicon wafer samples mounted on the chamber sidewall over the prolonged exposure of the SiO2 deposition process, and the collected sensory data were investigated under the dry-cleaning condition. The residue film obtained through the experiment was characterized by Fourier transform infrared, x-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy. We found a useful insight into the chamber dry-cleaning end point detection application through residual gas analysis, and the results contribute to process engineers setting up the in situ dry-cleaning recipe to make sure that subsequent deposition can be consistently maintained.

Atmospheric concentrations and potential sources of dioxin-like contaminants to Acadia National Park

Acadia National Park (ANP) is located on Mt. Desert Island, ME on the U.S. Atlantic coast. ANP is routinely a top-ten most popular National Park with over four million visits in 2022. The overall contribution and negative effects of long-range atmospheric transport and local sources of dioxin-like contaminants endangering natural and wildlife resources is unknown. Dioxin-like (DL) contaminants polychlorinated dibenzo-p-dioxins (∑PCDD) and polychlorinated dibenzofurans (∑PCDF), non-ortho coplanar PCBs (∑CP4), and polychlorinated naphthalenes (∑PCNs) were measured at the McFarland Hill air monitoring station (44.37⁰N, 68.26⁰W). On a mass/volume basis, total PCNs averaged 90.9 % (788 fg/m3) of DL contaminants measured annually, with 92.9 % of the collected total in the vapor-phase. Alternatively, total dioxin/furans (∑PCDD/Fs) represented 71.6 % of the total toxic equivalence (∑TEQ) (1.018 fg-TEQ/m3), with 69.7 % in the particulate-phase. Maximum concentrations measured for individual sampling events for ∑PCDD/F, ∑CP4, and ∑PCN were 159 (winter), 139 (summer), and 2100 (autumn), fg/m3 respectively. Whereas the maximum ∑TEQ concentrations for individual sampling events for ∑PCDD/F, ∑CP4, and ∑PCN were 2.8 (autumn), 0.38 (summer), and 0.71 (autumn), fg-TEQ/m3 respectively. Pearson correlations were calculated for ∑PCDD/Fs and ∑PCN particulate/vapor-phase air concentrations and PM2.5 wood smoke “indicator” species. The most significant correlations were observed in autumn for particulate-phase ∑PCDD/Fs suggesting a relationship between visitation-generated combustion sources (campfires and/or waste burning) or climate-change mediated forest fires. Significant Clausius-Clapeyron (C–C) correlations observed for particulate-phase ∑PCDDs (r2 = 0.567) as ambient temperatures decreased suggests a connection between localized domestic heating sources or visitor-based burning of wood/trash resources. Alternatively, highly significant C–C vapor-phase ∑CP4-PCBs correlations (r2 = 0.815) implies that the majority of ∑CP4-PCB loading to ANP is from long-range atmospheric transport processes. Based on these findings, Acadia National Park should be classified as a remote site with minor depositional impacts from ∑PCDD/Fs, ∑CP4-PCBs, and ∑PCN atmospheric transport or local diffuse sources.

The impact of kit, environment, and sampling contamination on the observed microbiome of bovine milk.

In low-microbial biomass samples such as bovine milk, contaminants can outnumber endogenous bacteria. Because of this, milk microbiome research suffers from a critical knowledge gap, namely, does non-mastitis bovine milk contain a native microbiome? In this study, we sampled external and internal mammary epithelia and stripped and cisternal milk and used numerous negative controls, including air and sampling controls and extraction and library preparation blanks, to identify the potential sources of contamination. Two algorithms were used to mathematically remove contaminants and track the potential movement of microbes among samples. Results suggest that the majority (i.e., >75%) of sequence data generated from bovine milk and mammary epithelium samples represents contaminating DNA. Contaminants in milk samples were primarily sourced from DNA extraction kits and the internal and external skin of the teat, while teat canal and apex samples were mainly contaminated during the sampling process. After decontamination, the milk microbiome displayed a more dispersed, less diverse, and compositionally distinct bacterial profile compared with epithelial samples. Similar microbial compositions were observed between cisternal and stripped milk samples, as well as between teat apex and canal samples. Staphylococcus and Acinetobacter were the predominant genera detected in milk sample sequences, and bacterial culture showed growth of Staphylococcus and Corynebacterium spp. in 50% (7/14) of stripped milk samples and growth of Staphylococcus spp. in 7% (1/14) of cisternal milk samples. Our study suggests that microbiome data generated from milk samples obtained from clinically healthy bovine udders may be heavily biased by contaminants that enter the sample during sample collection and processing workflows.IMPORTANCEObtaining a non-contaminated sample of bovine milk is challenging due to the nature of the sampling environment and the route by which milk is typically extracted from the mammary gland. Furthermore, the very low bacterial biomass of bovine milk exacerbates the impacts of contaminant sequences in downstream analyses, which can lead to severe biases. Our finding showed that bovine milk contains very low bacterial biomass and each contamination event (including sampling procedure and DNA extraction process) introduces bacteria and/or DNA fragments that easily outnumber the native bacterial cells. This finding has important implications for our ability to draw robust conclusions from milk microbiome data, especially if the data have not been subjected to rigorous decontamination procedures. Based on these findings, we strongly urge researchers to include numerous negative controls into their sampling and sample processing workflows and to utilize several complementary methods for identifying potential contaminants within the resulting sequence data. These measures will improve the accuracy, reliability, reproducibility, and interpretability of milk microbiome data and research.

Urban stormwater green infrastructure: Evaluating the public health service role of bioretention using microbial source tracking and bacterial community analyses

Bioretention cells (BRCs) control stormwater flow on-site during precipitation, reducing runoff and improving water quality through chemical, physical, and biological processes. While BRCs are effective in these aspects, they provide habitats for wildlife and may face microbial hazards from fecal shedding, posing a potential threat to human health and the nearby environment. However, limited knowledge exists regarding the ability to control microbial hazards (e.g., beyond using typical indicator bacteria) through stormwater biofiltration. Therefore, the purpose of this study is to characterize changes in the bacterial community of urban stormwater undergoing bioretention treatment, with the goal of assessing the public health implications of these green infrastructure solutions. Samples from BRC inflow and outflow in Columbus, Ohio, were collected post-heavy storms from October 2021 to March 2022. Conventional culture-based E. coli monitoring and microbial source tracking (MST) were conducted to identify major fecal contamination extent and its sources (i.e., human, canine, avian, and ruminant). Droplet digital polymerase chain reaction (ddPCR) was utilized to quantify the level of host-associated fecal contamination in addition to three antibiotic resistant genes (ARGs): tetracycline resistance gene (tetQ), sulfonamide resistance gene (sul1), and Klebsiella pneumoniae carbapenemase resistance gene (blaKPC). Subsequently, 16S rRNA gene sequencing was conducted to characterize bacterial community differences between stormwater BRC inflow and outflow. Untreated urban stormwater reflects anthropogenic contamination, suggesting it as a potential source of contamination to waterbodies and urban environments. When comparing inlet and outlet BRC samples, urban stormwater treated via biofiltration did not increase microbial hazards, and changes in bacterial taxa and alpha diversity were negligible. Beta diversity results reveal a significant shift in bacterial community structure, while simultaneously enhancing the water quality (i.e., reduction of metals, total suspended solids, total nitrogen) of urban stormwater. Significant correlations were found between the bacterial community diversity of urban stormwater with fecal contamination (e.g. dog) and ARG (sul1), rainfall intensity, and water quality (hardness, total phosphorous). The study concludes that bioretention technology can sustainably maintain urban microbial water quality without posing additional public health risks, making it a viable green infrastructure solution for heavy rainfall events exacerbated by climate change.

Prevention is the Only Cure: Health Effects of the Uranium Cycle on Women, Fetuses and Children

There are many sources of potential contamination throughout the uranium cycle, which can affect the health of families for generations to come. Children and fetuses are especially vulnerable due to rapid cell division during physical growth. This is documented internationally through outcomes such as increased incidence in spontaneousabortions,childhoodleukemiaandotherchildhoodcancers. Researchonthistopicaroseoutofa local concern in eastern Ontario due to proposed uranium mines at the watershed of major rivers, which may pose arisktomidwiferyclients wholiveneartailingponds,incommunitieswhorelyontheriversfortheirsourceof water, or who work in reprocessing and nuclear power plants. As Canada is the world's largest producer and exporter of uranium, the health impacts extend to the most recent use of depleted uranium in weapons abroad. As primary health practitioners, midwives can play a role in promoting public health through becoming better informed, and supporting local and international initiatives which address the threat posed to human and environmental health by the uranium cycle.

Evaluation of Hydrogeochemical Processes for Irrigation Use and Potential Nitrate Contamination Sources in Groundwater Using Nitrogen Stable Isotopes in Southwest, India: A Case Study

Evaluation of Hydrogeochemical Processes for Irrigation Use and Potential Nitrate Contamination Sources in Groundwater Using Nitrogen Stable Isotopes in Southwest, India: A Case Study

Shiga Toxin-Producing Escherichia coli O157:H7 Illness Outbreak Associated with Untreated, Pressurized, Municipal Irrigation Water - Utah, 2023.

During July-September 2023, an outbreak of Shiga toxin-producing Escherichia coli O157:H7 illness among children in city A, Utah, caused 13 confirmed illnesses; seven patients were hospitalized, including two with hemolytic uremic syndrome. Local, state, and federal public health partners investigating the outbreak linked the illnesses to untreated, pressurized, municipal irrigation water (UPMIW) exposure in city A; 12 of 13 ill children reported playing in or drinking UPMIW. Clinical isolates were genetically highly related to one another and to environmental isolates from multiple locations within city A's UPMIW system. Microbial source tracking, a method to indicate possible contamination sources, identified birds and ruminants as potential sources of fecal contamination of UPMIW. Public health and city A officials issued multiple press releases regarding the outbreak reminding residents that UPMIW is not intended for drinking or recreation. Public education and UPMIW management and operations interventions, including assessing and mitigating potential contamination sources, covering UPMIW sources and reservoirs, indicating UPMIW lines and spigots with a designated color, and providing conspicuous signage to communicate risk and intended use might help prevent future UPMIW-associated illnesses.

Anthropogenic particle abundance and characteristics in seawater and intertidal sediments of the Tonkin Bay Coast (North Vietnam).

Microplastics (MPs, plastic items from 1µm to 5mm in size) are present in all environmental compartments. The evaluation of their concentration, fate, and spatial distribution is still a challenge for the scientific community. This concern is just debuting in developing countries, (i.e., Asia, South America, and Africa). This study deals with the MP contamination in the abiotic marine compartments of Northern Vietnam: seawater and intertidal sediments. Four sites located in the intertidal zone or near the coastline in Tonkin Bay, Vietnam were studied. A total of 16 samples (eight for each compartment) were collected in July 2020 (rainy season) and January 2021 (dry season). Anthropogenic particles (total observed fibers and fragments) were found at levels ranging from 3 to 303 particles/m3 in seawater and from 63 to 955 particles/kg dry weight in sediments. Most of these were fibers less than 300-µm long. Higher levels of seawater at the Nam Dinh site were found in the rainy season compared to the dry one. As the river flow was estimated six times higher during the rainy season than during the dry season, these results suggest the river discharge is a potential source of contamination for the coastal zone. The temporal variability was lower for the sediments than for the seawater, suggesting the long-term integration of the anthropogenic particles in this compartment. A small portion of sorted particles were analyzed by µFTIR (8.35%), and this sub-sample was only composed of fragments. Still, fragments were mostly composed of polypropylene (PP, 82%), polyethylene (PE, 9%), and polystyrene (PS, 9%). The fragment size was similar in the two studied compartments, but it was dependent on polymer types since PS fragments (140 ± 17µm) were smaller than those made of PE (622 ± 123µm) and PP (869 ± 905µm). Future works should investigate the smallest fraction of MP (even nanoplastics) as well as find solutions in order to mitigate MP contamination in the marine environment.

Significance of the apiary location for the content of copper and zinc in the bee pollen

Bee pollen is one of the most valuable direct products of honey bees. Bees as well as humans use pollen in their nutrition as a high-quality supplement. Therefore, information about the mineral content of pollen is valuable. The aim of this study was to determine the amounts of copper (Cu) and zinc (Zn) in the bee pollen collected from the three locations (Kozarska Dubica, Petrovo, and Srbac). Quantification of copper and zinc was done by atomic absorption spectrophotometry after acid digestion (HNO3+HClO4) of pollen. The highest contents of both elements were found in the bee pollen from Kozarska Dubica (8.41 mg Cu/kg, 29.52 mg Zn/kg). The lowest Cu content was found in the samples from Petrovo (6.19 mg/kg), while the lowest Zn content was determined in the pollen from Srbac (22.06 mg/kg). Additionally, there were statistically significant differences in the content of both elements between pollen originating from different locations. As the location of the apiary was mainly determined by its proximity to potential sources of metal contamination, botanical origin of pollen and technology of pollen collection, it is important to investigate their impact in more detail on the elemental content of pollen in the future.

Estimation of potential health risks on metals and metalloids contaminants in black goby (Gobius niger) consumption in selected niger delta coast, nigeria

IntroductionThe Niger Delta in Nigeria is subject to anthropogenic influences, impacting the quality of its water bodies, including the Sombrero River. This study aims to investigate the concentrations of metals and metalloids in Gobius niger from the Sombrero River, as these contaminants can pose risks to human health through seafood consumption. Specifically, zinc (Zn), iron (Fe), copper (Cu), lead (Pb), arsenic (As), and cadmium (Cd) were analyzed using atomic absorption spectroscopy (AAS). Materials and MethodsSamples were collected from three different stations along the Sombrero River. The concentrations of Zn, Fe, Cu, Pb, As, and Cd were determined using AAS. Hazard Quotients (HQ), Chronic Daily Intake (CDI), Hazard Index (HI), and Individual Lifetime Cancer Risk (ILCR) values were calculated to assess the potential health risks associated with consuming fish contaminated with these metals and metalloids. ResultsStation 1 had the highest Zn concentration, followed by Fe, Cu, Pb, Cd, and As, with Zn reaching 104.8 ± 1.37 mg kg−1. Station 2 exhibited a similar trend, while Station 3 had Zn as the predominant metal and metalloid. Notably, Pb, As, and Cd levels were consistently low at all stations. While Pb was within permissible limits set by FAO/WHO for contaminants in the fish samples, Zn exceeded regulatory guidelines, suggesting a potential source of contamination. Hazard Quotients (HQ) highlighted a significant risk associated with zinc, especially for children. Chronic Daily Intake values showed metals in fish consumed by adults and children were generally within safe limits, except for Zn, which exceeded Maximum Tolerable Daily Intake (MTDI). Hazard Index values pointed to a substantial long-term health risk, particularly for children due to high zinc levels. However, Individual Lifetime Cancer Risk (ILCR) values were generally below 1, indicating relatively low cancer risks from G. niger consumption for both age groups. ConclusionThis study emphasizes the need for monitoring and managing metals and metalloid pollution in the Niger Delta region to ensure safe seafood consumption and community well-being. While certain metals pose minimal health risks, it highlights the necessity of specific interventions to reduce excessive zinc exposure and safeguard long-term health in the region.

Listeria monocytogenes Contamination Leads to Survival and Growth During Enoki Mushroom Cultivation

Two recent outbreaks of listeriosis have been linked to the consumption of enoki mushrooms. After the first outbreak, import sampling by the U.S. FDA identified that 43% of the samples evaluated were positive for Listeria monocytogenes (Lm). These observations raised questions about the potential sources of Lm contamination of enoki mushrooms. One potential source of contamination is during enoki mushroom cultivation, as growing conditions are comparatively cool and moist to induce mushroom germination, to which Lm is well adapted. Two varieties of enoki mushrooms were evaluated to determine the potential for Lm to contaminate enoki cultures when introduced at various points during cultivation (inoculation, scraping, pinning, and collaring). The results of two trials showed that Lm established contamination and grew to similar levels in the substrate regardless of when Lm was introduced and, with one exception, did not alter the rate of mushroom generation to below the control. Enumeration of Lm in enoki mushroom cultures at harvest found an average contamination of 103 cfu/g, though the results were variable. Refrigerated storage for six weeks was found to result in an increase in Lm. Additionally, no statistically significant difference in the levels of Lm was observed based on proximity to the substrate, though levels of Lm in the different enoki samples correlated with levels of Lm in the substrate at harvest, but not at scraping. The ability of Lm to grow independently in the media used to culture enoki was assessed, and Lm was found to be unable to grow but could sporadically survive in Masters Mix. No growth of Lm was observed in potato dextrose broth, though growth could occur on the agar. Overall, the data indicate a high potential for the establishment of Lm contamination at any point during enoki cultivation to result in Lm-contaminated mushrooms. These data indicate a need for active control mechanisms to prevent the introduction of Lm to enoki cultures.

Composting manure in the poultry farm harbours multidrug-resistance Salmonella

ABSTRACT Salmonella is one of the leading foodborne pathogens that cause gastroenteritis. It is imperative to monitor Salmonella contamination within poultry farms. This study focuses on the prevalence of Salmonella in composting manure at poultry farms a potential and persistent contamination sources. A batch of manure samples (n = 10) were collected from a local poultry farm, and half of the manure samples were detected to be Salmonella-positive. Serotyping results showed four serotypes among different isolated strains, including Typhimurium, Typhi, Newport, and Dublin. Isolates from manure generally demonstrated a high ciprofloxacin resistance and biofilm formation capacity. Multi-drug resistance was found in isolates from organic manure that had been fermented using high-temperature aerobic technology. Our study indicated that composting manure harboured Salmonella and might facilitate the transmission of Salmonella and the development of antimicrobial resistance. Proper composting strategies are needed to reduce the transmission of antimicrobial resistance and Salmonella.

Detection and Screening of Organic Contaminants in A Riverine System of Georgia Using Non-Targeted Analysis

Numerous organic chemicals exist within aquatic environments, yet effectively screening and prioritizing them is a huge challenge. This study provides a comprehensive investigation into the ecological dynamics of the North Oconee River within Athens-Clarke County, Georgia, with a specific focus on the distribution of 33 identified compounds, including a prominent pesticide. The research, conducted in the riverine ecosystems proximal to the Firefly trail, employs advanced analytical techniques to elucidate potential contamination sources arising from agricultural and urban runoff. Intriguingly, the study reveals North Oconee River near the Firefly Trail as a notable site for heightened pesticide contamination, warranting a meticulous exploration of its origins. Furthermore, the investigation unveils the intricate microbial degradation processes of malathion within the North Oconee River, elucidating the pivotal role played by microbial activity in river water. The detection of degradant byproducts prompts the considerations of bioavailability and toxicity, associating potential implications for the river’s overall ecological health. Ongoing research endeavors to precisely quantify environmental risks and unravel indigenous microbial degradation pathways, presenting pivotal contributions to the scientific community’s understanding of complex riverine ecosystems. This research serves as a foundational piece in informing sustainable environmental management practices and emphasizes the urgency of comprehensive stewardship in safeguarding aquatic ecosystems.

Resource utilization of gasified fine ash from entrained flow bed via thermal modification-melting combustion: A pilot study

China generates substantial quantities of gasified fine ash (GFA) annually through entrained flow bed coal gasification processes. These GFAs are laden with significant amounts of poorly reactive carbon and abundant ash resources, including silica, aluminum. Typically GFA represent not only a gross squandering of resources but also a potential source of environmental contamination. In order to use both ash and carbon of GFA, our team has developed the thermal modification -melting combustion method. The study conducted thermal modification-melting combustion experiments of GFA with auxiliary heating fuel and varying moisture content on a pilot-scale experimental platform. The aim was to ascertain the influence of operating conditions on the physical and chemical properties of GFA fuel, as well as the carbon conversion rate of GFA and the potential for reusing ash after melting combustion in the entire system. The results indicate that an increase in the moisture content of GFA allows the thermally modified fine ash (MFA) to possess smaller particle sizes and more reactive sites in carbon structures, along with higher combustible gas yield and calorific value. Post-melting combustion, the residual carbon conversion rate in GFA surpassed 96.88 %, indicative of a high recovery potential. Moreover, the ash slag, rich in inorganic non-metallic glassy phases, emerged as a promising candidate for material reuse and application.

Identification of microbial communities and multi-species biofilms contamination in seafood processing environments with different hygiene conditions

Biofilms formed by spoilage and pathogenic bacteria increase microbial persistence, causing an adverse influence on the quality of seafood. The mono-species biofilms are widely reported, however, the contamination of multi-species biofilms and their matrix in food environments are still not fully understood. Here, we assessed the contamination of multi-species biofilms in three seafood processing environments with different hygiene levels by detecting bacterial number and three biofilm matrix components (carbohydrates, extracellular DNA (eDNA), and proteins). Samples comprising seven food matrix surfaces and eight food processing equipment surfaces were collected from two seafood processing plants (XY and XC) and one seafood market (CC). The results showed that the bacterial counts ranged from 1.89 to 4.91 CFU/cm2 and 5.68 to 9.15 BCE/cm2 in these surfaces by cultivation and real-time PCR, respectively. Six biofilm hotspots were identified, including four in CC and two in XY. Among the three processing environments, the amplicon sequence variants (ASVs) of Proteobacteria, Bacteroidetes, and Actinobacteria decreased with improved processing hygiene, while Firmicutes showed a decrease in the four most abundant phyla. The most prevalent bacteria belonged to genera Psychrobacter, Acinetobacter, and Pseudomonas, demonstrating the significant differences and alteration in bacterial community composition during different environments. From the biofilm hotspots, 15 isolates with strong biofilm forming ability were identified, including 7 Pseudomonas, 7 Acinetobacter, and 1 Psychrobacter. The Pseudomonas isolates exhibited the highest production of EPS components and three strong motilities, whose characteristics were positively correlated. Thus, this study verified the presence of multi-species biofilms in seafood processing environments, offering preliminary insights into the diversity of microbial communities during processing. It highlights potential contamination sources and emphasizes the importance of understanding biofilms composition to control biofilms formation in seafood processing environments.

Is paper bag plastic-free, without plastic in colourful logo area?

The concern over plastic contamination has led to bans on plastic shopping bags, often replaced by paper ones. However, logos painted or printed on paper bags may still contain plastics, as investigated herein. In some logos, for example, white pigment of titanium dioxide (TiO2) nanoparticles are bound with plastic binder onto the cellulose surface of the paper. This hybrid of plastic and nanoparticle is examined using scanning electron microscope (SEM) to characterise morphology physically, and Raman imaging to identify and visualise them chemically. Raman imaging scans the sample to separate images and identify not only plastic but also the co-formulated pigment. The scan generates a hyperspectral matrix containing hundreds to thousands of spectra, and subsequent analysis can enhance the signal-to-noise ratio. Decoding the hyperspectral matrix using chemometrics like principal component analysis (PCA) can effectively map plastic and pigment separately with increased certainty. The image can be further refined through 3-dimensional surface fitting for deconvolution, providing direct visualisation of the plastic-nanoparticle hybrid at a density of approximately 7.3 million particles per square millimetre. Overall, caution should be exercised when using paper bags, as they may not be entirely free of plastics. Raman imaging proves to be an effective method for identifying and visualising complex components, including plastics and nanoparticles. Environmental ImplicationThe concern over plastic contamination has led to bans on plastic shopping bags, replaced by paper alternatives. However, some logos on paper bags may still contain plastics, which is investigated to confirm the presence of plastic-nanoparticle hybrid using SEM and Raman imaging. By employing decoding algorithms such as PCA to separately map plastic and pigment, and utilising 3D surface fitting to deconvolute the image, the hybrid plastic-nanoparticle is estimated at a density of approximately 7.3 million particles per square millimetre. It's important to exercise caution and not assume these items are plastic-free. This aspect of plastics may have been overlooked as another potential source of contamination.

Microbial dynamics of South Korean beef and surroundings along the supply chain based on high-throughput sequencing

Microbiological safety and quality of beef is crucial as beef can serve as a reservoir for a variety of bacteria, including spoilage-related and foodborne pathogens. Controlling microbial contamination is a critical aspect of food quality and safety, but it is difficult to prevent as there are several potential sources of contamination from production to distribution. In this study, the microbiological ecology of cattle/beef and associated environmental samples (n = 69) were trace-investigated to reveal microbiome shifts in cattle/beef and possible cross-contaminants throughout the entire supply chain using 16S rRNA gene sequencing. Pseudomonas, Psychrobacter, and Acinetobacter, known as spoilage bacteria, opportunistic pathogens, or antibiotic-resistant bacteria, were the main microorganisms present in cattle/beef, and Staphylococcus became abundant in the final products. The dominance of Acinetobacter and Pseudomonas was noticeable in the slaughtered carcasses and slaughterhouse environment, indicating that the slaughterhouse is a critical site where hygienic practices are required to prevent further contamination. Taxonomic similarities between cattle/beef and several environmental samples, as well as diversity analysis, presented a high potential for microbial transmission. Source tracking identified environmental samples that primarily contributed to the microbiota of cattle/beef. Farm floor (48%), workers' gloves (73%), and carcass splitters (20%) in the slaughterhouse were found to be major sources influencing the microbiome of cattle/beef at the farm, slaughterhouse, and processing plant, respectively. These findings demonstrated the dynamics of bacterial communities in cattle/beef according to stage and detected potential contamination sources, which may aid in a better understanding and control of microbial transmission in beef production.