Μm Filter Research Articles

Transformation and fate of Fe(III) in petroleum-hydrocarbon-contaminated soil and groundwater

In anoxic subsurface environments, low Fe(III) bioaccessibility greatly limits in situ biodegradation of petroleum hydrocarbons (PHCs). Ferric ammonium citrate is a soluble compound that has the potential to increase the bioaccessibility of Fe(III). However, in neutral to alkaline environments, Fe(III) hydrolysis can produce Fe(III) (oxyhydr)oxides that may subsequently transform or recrystallize to relatively stable and less bioaccessible phases. Accordingly, the objective of this study was to elucidate the transformation and fate of Fe(III) contributed by ferric ammonium citrate in a gasoline-contaminated subsurface environment that was undergoing in situ bioremediation. Ferric ammonium citrate, together with sodium tripolyphosphate, magnesium sulphate, and nitric acid, was continuously injected into the contaminated groundwater for about 22 weeks. Colloids in the groundwater (solid particles retained on a 0.45 μm filter) and soil cores were collected from the site. Fe speciation in these samples was characterized using X-ray absorption near edge structure (XANES) and Fourier transform infrared (FTIR) spectroscopy. The groundwater colloids (GWCs) contained mostly octahedrally coordinated Fe(III), but the subsoils contained both octahedrally coordinated Fe(III) and Fe(II). The fraction of Fe(II) in the subsoils generally increased after about 22 weeks of continuous amendment injection. Ferric ammonium citrate did not persist in the PHC-contaminated subsurface: the Fe(III) it contained was transformed to solid phases. Fe(III)-organic-matter (Fe(III)-OM) complex/coprecipitate and sulfate green rust were the major phases present in the GWCs; akaganeite, chloride green rust, vivianite, ferrihydrite, Fe(III)-silicate, and magnetite were present as minor phases. The subsoils contained three major phases: Fe(III)-OM complex/coprecipitate, magnetite, and calcium ferric silicate. The presence of major Fe(II) phases in the subsoils strongly indicate that secondary Fe(III) phases (especially Fe(III)-OM complex/coprecipitate) served as terminal electron acceptors during the microbial degradation of PHCs in the contaminated subsurface.

Comparative analysis of bioaccessibility tests for metals and metalloids: Methodological advancements and implications for consumer product safety.

Bioaccessibility is crucial in human health risk assessment as it predicts the fraction of metals and metalloids absorbed by the human body. This study compared the modified RIVM method, which includes acid digestion, with the ERU 19899 EN method to assess the oral bioaccessibility of certified reference materials. The modified RIVM method showed higher bioaccessibility, offering more conservative health risk values. Adding a filtration step after centrifugation with a 0.45 μm filter reduced the error in the results from 66.7 % to 19.9 % by removing small particles that were not separated during centrifugation. Dermal bioaccessibility was evaluated using two artificial sweat solutions: one with five amino acids at pH 5.5 and the EN 1811 method at pH 6.5. The pH 5.5 solution leached more metals due to complexation between amino acids and metal ions, increasing solubility. Sebum decreased the leached amount of cationic metals (Cd, Cr, and Pb), as fatty acids can form complexes with metal ions. Therefore, a solution with five amino acids at pH 5.5, without sebum, is suggested for assessing dermal bioaccessibility. Various consumer products, including seven toys, were tested for both oral and dermal bioaccessibility to provide more reliable health risk assessment information. The oral bioaccessibility results of the toys aligned with other studies. The dermal bioaccessibility of the consumer products ranged from 0.001 % to 1.414 %, with the highest Cr concentration measured in a brown watch strap.

Dissolved beryllium (< 1 kDa) mobilized as a major element in groundwater in legacy mine waste.

Research regarding the geochemistry of beryllium (Be) in terrestrial environments is hindered by its high toxicity to humans and the low concentrations normally occurring in the environment. Although Be is considered an immobile element, extremely high dissolved concentrations have been detected in groundwater in the legacy Tailings Storage Facility (TSF) of Smaltjärnen, Sweden. Therefore, a detailed study was conducted to determine physiochemical parameters affecting the speciation of Be in the groundwater. Groundwater was sampled from 2016-2024 and filtered through 0.2 μm filters, whereas truly dissolved fraction (<1 kDa) samples were collected with dialysis membrane tubes in situ at groundwater wells. Secondary minerals on the tailings shore were studied by mineralogical methods and sequential extraction to trace the pathway whereby Be entered the downstream surface water. In part of the tailings, dissolved Be was detected in very high concentrations (average: 4.8 mg/L) in suboxic groundwater with pH from 6.0 to 6.4. Dialysis sampling in 2024 showed that more than 90% occurred as truly dissolved Be (<1 kDa). A significant correlation between Be and S was found, suggesting that sulfate complexes kept Be mobile in these pH conditions. Dissolved Be increased with decreased pH, and there is risk that the concentrations will increase further since sulfide oxidation with subsequent decrease in pH will continue for 100 of years in the TSF. In another part of the TSF, the pH was > 6.4 and dissolved Be was below the detection limit, possibly due to formation of Al(OH)3 (>0.2 μm) together with F and Zn. Secondary minerals on the shore of the tailings functioned as a temporary chemical barrier, scavenging Be primarily by secondary gypsum when present and otherwise by Fe hydr(oxides).

A comprehensive pyrolysis-gas chromatography/mass spectrometry analysis for the assessment of microplastics in various salts

Analytical pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS) was chosen to quantify microplastics(MPs) in edible salts: sea salt(SS), deep-sea salt(DSS), rock salt(RS), and lake salt(LS). Samples were filtered by two-step using 20 μm(MPs20) and 1 μm(MPs1) filters. Two Py-GC/MS methods with split ratios of 100/1 for high-level and 10/1 for low-level MPs were used. Quality control measures were taken to avoid pre-contamination. Methods showed high linearities (R2 > 0.995) and recoveries (84.2–118.1 %) for standards, polyethylene(PE), polypropylene(PP), polystyrene(PS), and polyethylene terephthalate(PET). SS showed highest MPs concentration (584.5 ± 204.4 μg/kg), followed by RS(34.2 ± 16.7 μg/kg) and LS(6.2 μg/kg). Over 7.2 % of detected MPs in SS and RS were smaller than 20 μm. PE, PP, and PET comprised 98.4 % of MPs in SS and 88.1 % in RS. MPs contamination from packaging materials was experimentally confirmed by the presence of similarly shaped PS particles in RS. MPs annual exposure was highest in SS(2304 μg/person), followed by RS(135 μg/person), and LS(24 μg/person), indicating substantial variation in exposure based on salt type.

The preliminary study of antifungal and antibacterial properties of wine by-products

Background: Nowadays, the search for novel alternative antimicrobials has gained significant popularity. This surge is driven by the vast array of adverse effects of synthetic antimicrobials on human health and the environment. Consequently, the study of new natural sources of comparably ecologically safe and simultaneously effective antimicrobials is extremely important. In this context, the interest in wine by-products is growing due to their diverse beneficial properties. Traditionally considered industrial waste, wine by-products now offer promising opportunities. Notably, the unique climatic and geographical features of Armenian black grape varieties, such as Areni sev, make their by-products an attractive subject for study, with potential applications in agriculture. Objective: The study aims to investigate the antifungal and antibacterial properties of wine by-products obtained from the Areni sev grape variety. Methods: For the extraction of bioactive compounds, frozen and dry samples were homogenized. The maceration was performed in 70% hydroethanolic solution after incubation on a magnetic stirrer at room temperature. The obtained extracts were filtered through a 0.45 µm filter and evaluated for antifungal and antibacterial activity by disco-diffusion method. Results: Hydroethanolic extracts of wine by-products have exhibited antifungal and antibacterial activities. Specifically, the frozen samples demonstrated low antifungal activity against the Penicillium canescens with a 7.5 mm growth inhibition zone. In contrast, dried samples showed no antifungal activity. The highest antifungal activity was observed against Aspergillus niger with growth inhibition zones of 18 mm (frozen samples) and 15 mm (dried samples), respectively. Regarding antibacterial activity, wine by-product hydroethanolic extracts showed extremely low efficacy. Notably, frozen samples exhibited an 8 mm growth inhibition zone against Curtobacterium flaccumfaciens and 6.35 mm against Xanthomonas vesicatoria. Extracts from dried samples demonstrated a 6.35 mm inhibition zone against Curtobacterium flaccumfaciens and a 7 mm growth inhibition zone against Xanthomonas vesicatoria. Conclusion: Summarizing the results of the conducted experiments, it can be concluded that the used wine by-product derived from Areni sev grape has demonstrated notable antimicrobial activities, with a stronger emphasis on antifungal properties. The extracts obtained from frozen samples exhibited greater efficacy than those derived from dried samples. Future research plans include a more detailed investigation of Areni sev grape wine by-products. Keywords: wine by-product, grape pomace, Areni sev, bioactive compounds, antimicrobial properties

Optimizing RT-qPCR Detection of Enveloped and Non-enveloped Viruses in Wastewater: A Comparative Study in Grenada

Abstract Introduction/Objective Wastewater-based epidemiology (WBE) is an effective methodology to monitor the community spread of pathogens and has successfully been used to identify potential outbreaks. Most standardized methodologies used in WBE for the detection of viruses have been validated for non-enveloped viruses; therefore, there is a need for the development of a standardized protocol for the detection of both enveloped (such as SARS- CoV-2) and non-enveloped viruses (such as Hepatitis A). Wastewater seeded with Pseudomonas syringae bacteriophage (Φ6), an enveloped virus surrogate, and coliphage MS2, a non-enveloped virus surrogate, were used to evaluate the efficiency of four different aluminium flocculation methods. Untreated wastewater spiked with known amounts of surrogates was used as a control for viral recovery. Methods/Case Report Four different viral concentration methods were used. Method 1: AlCl3 flocculation at pH 3.5 followed by centrifugation, resuspension with 10% beef extract and filtered with a 0.22 μm filter. Method 2: AlCl3 flocculation at pH 6.0 followed by room temperature agitation, centrifugation, and resuspension with 3% beef extract. Method 3: Mixed method protocol-AlCl3 flocculation at pH 3.5 followed by room temperature agitation, centrifugation, resuspension with 3% beef extract. Method 4: Mixed method protocol-AlCl3 flocculation at pH 6.0 followed by centrifugation, resuspension with 10% beef extract filtered with a 0.22 μm filter. Viral RNA was extracted after concentration, and reverse-transcription quantitative polymerase chain reaction (RT- qPCR) was performed. Results (if a Case Study enter NA) The average Ct reduction of untreated wastewater compared to spiked was calculated for each method. The highest recovery of both Φ6 and MS2 was obtained using Method 3 (mixed protocol) with a significant difference at 95% confidence in the recovery of Φ6 (p= 0.0029) and MS2 (p= 0.0225). Conclusion Previous results from our lab demonstrate the importance of pH during the flocculation step of viral concentration using different methods of concentration. Here, the results suggest that the increased contact time between virus and the flocs is also critical. This can facilitate the implementation of WBE in Grenada to monitor and track potential viral outbreaks of both enveloped and non-enveloped viruses such as SARS-CoV-2 and Hepatitis A.

Are you filtering enough? Unveiling the impact of water sample volumes on eukaryotic microbial community in freshwater lakes

The appropriate volume of filtered water samples is crucial for accurately reflecting microbial community characteristics. Previous research has shown that changes in water sample volumes significantly affect bacterial diversity and the relative abundance of dominant taxa in marine environments. However, the specific impact on freshwater microbial diversity and community structure, particularly for eukaryotic microorganisms, remains unclear. To address this gap, we collected water samples from eutrophic Lake Taihu and mesotrophic Lake Bosten. We filtered the samples through 0.2 μm filters using volumes ranging from 0.1 to 2 L for Lake Taihu and 0.1 to 3.2 L for Lake Bosten. Analysis of 18S rRNA gene amplicons revealed that variations in filtered water sample volume significantly affected the diversity, community structure, and composition of eukaryotic microorganisms. In light of these findings, we recommend using a filtered water sample volume of approximately 0.2 L for eutrophic aquatic ecosystems and 0.8 L for mesotrophic aquatic ecosystems in microbial analyses. These recommendations underscore the importance of selecting the appropriate filtered water sample volume to ensure representative and reliable results in the study of eukaryotic microorganisms in freshwater ecosystems.

Examining ingested microplastics in fish: Considerations on filter pore size, analysis time, and material costs to design cost-effective projects

In recent years the microplastics research community has called for methods harmonization and standardized metrics of reporting microplastic attributes. While alignment of research practices is essential in obtaining robust microplastic data, resource managers need to balance how the cost and effort of methodologies compare to data output. The intention of this study is to compare two recommended methods for isolating anthropogenic microparticles in fish gastrointestinal tracts. Using Icelandic capelin (Mallotus villosus) as a study species, with potassium hydroxide (KOH) digestion, we compared a 1.2 μm filtration and 45 μm sieving protocols for isolating ingested anthropogenic microparticles. We compared methods based on the amount of time they took to conduct, the cost of the materials and equipment required, levels of procedural contamination, and data output. We found no significant differences in the materials costs or procedural contamination between the two methods. However, the two protocols resulted in anthropogenic microparticles with significantly different characteristics (i.e. colour, length, morphology), and the 45 μm sieving protocol took longer to conduct per sample. Our results contribute towards a more holistic understanding of microplastic research methods, their relative costs, and how they contribute to data outputs and development of large-scale monitoring programs.

Challenges in using 0.45 µm filters to assess potentially bioavailable trace elements in the dissolved fraction of river and peat bog waters of the Boreal Zone

Passing through a 0.45 µm filter can significantly alter the concentrations of dissolved trace elements (TEs) in organic-rich waters of the Boreal Zone. However, little evidence has been provided about the impacts of filtration on the size distribution of dissolved TEs. This limitation hinders our comprehension of how filtration affects the assessment of the potentially bioavailable forms of dissolved TEs (i.e. ions and small molecules). Using AF4-UV-ICP-MS, this study systematically investigates such artefacts and their influence on the concentrations of dissolved, primarily ionic, and colloid-associated TEs in river waters and peat bog waters of the Boreal Zone. In river waters (circumneutral pH), membrane filtration had a significant impact on TEs that are associated with inorganic colloids such as Al, Mn, Fe, As, the rare earth elements, Pb, and Th. Approximately 20–80 % of primarily ionic TEs (< 0.5 kDa) and 100 % of large inorganic (ca. 40–300 nm) TEs were excluded from the filtrates under clogged conditions. In contrast, little impact of filtration was observed for bog waters (pH 4). Similarly, cartridge filtration of river waters also led to a decrease in concentrations and size distributions of dissolved TEs. However, cartridge filtration demonstrated a higher efficiency in allowing the passage of ions and excluding colloids than membrane filtration. On average, the ratio of the dissolved concentrations between a cartridge and a membrane filtrate was 1.0 ± 0.2. For primarily ionic species, the average ratio was 1.4 ± 0.4, while for colloidal species, it was 0.4 ± 0.1. Therefore, despite having similar dissolved concentrations, filtration methods with the same nominal pore size can yield different concentrations of bioavailable forms of TEs. These findings may be important for studies of the environmental relevance of dissolved TEs in surface waters of the Boreal Zone, and organic-rich waters elsewhere.

Use of a nanoplastic carrier for assessing the aquatic toxicity of an organo-phosphite polymer additive

This work reports the production of nanoplastics (NPs) from polypropylene (PP) free of the antioxidant Irgafos® 168 (IRG) and alkane oligomers (ALK). PP pellets were milled into a powder with particle sizes in the 100–500 μm range. Additives and oligomers were removed using dichloromethane, and the powder exposed to UV irradiation, followed by filtration through 1 μm filters. PP suspensions, free of antioxidant and oligomers, were reloaded with IRG and ALK to their original commercial concentrations. This approach allowed testing the aquatic toxicity of IRG at concentrations compromised by water solubility limits. Toxicity assays using the cladoceran Daphnia magna with 24–48 h immobilization of neonates as endpoint showed toxicity for NPs containing IRG, with EC20 (48 h) in the 1.8–3.5 mg/L range, that corresponded to IRG exposure <1.2 μg/L. Suspensions of PP containing ALK, but not IRG, exhibited low toxicity (EC20 > 20 mg/L). The results allowed estimating the toxicity of IRG with a EC50 value of 3.3 ± 1.1 μg/L. Assays with different proportions of IRG and its oxidized form showed no differences. This work demonstrated the aquatic toxicity of IRG, for which there were no previous data, and developed a method for testing the toxicity of non-polar additives without being limited by their solubility.

Long-Term Monitoring of Microplastics in a German Municipal Wastewater Treatment Plant

Wastewater treatment plants (WWTPs) have been identified as important point sources for microplastics (MPs) in the environment; monitoring MP emissions in the WWTP effluent is therefore essential for contamination control. The aim of this study is to acquire a large number of samples (320) over a period of two years and three months to determine the temporal variations in microplastic contamination in the outlet of the municipal WWTP Landau-Mörlheim. The effluent of the third cleaning stage is sampled with a 10 µm filter cartridge, processed in the laboratory using a hydrogen peroxide treatment, and MPs are then detected by fluorescence staining. The results show high temporal variations in the microplastic concentrations in the effluent of the WWTP. This indicates that high numbers of samples are necessary to obtain a representative assessment of the microplastic emissions; single samples are not representative. The average microplastic concentration in the effluent was 27.8 ± 29.8 MP/L, ranging from 0.6 MP/L to 194.0 MP/L. This leads to a yearly emission of 1.5 × 1011 MP for the WWTP Landau-Mörlheim, corresponding to an emission of 2.8 × 106 MP/inhabitant and year. Statistically significant seasonal variations could not be observed, although there is a trend towards lower MP concentrations in summer. Further, no correlations with other wastewater or weather parameters could be found.

Radiological Analyses of 226Ra and 238U in Surface Water and Sediments from the Jackpile Member of the Morrison Formation, Pueblo of Laguna, New Mexico.

Surface water and sediments from the Jackpile mine, St. Anthony mine, Rio Paguate, Rio Moquino, and Mesita Dam areas near Pueblo of Laguna, New Mexico, were analyzed for 226Ra and U using gamma (γ) spectroscopy and inductively coupled plasma mass spectroscopy, respectively. Activity ratios for 226Ra/238U for solid samples range from 0.34 ± 0.13 to 16 ± 2.9, which reflect uranium transport and accumulation (<1), relatively pristine material in secular equilibrium (1), and removal of uranium by weathering (>1). Concentrations ranging from 80 to 225 μg L-1 U were detected in unfiltered water samples near the Jackpile mine. Water samples upstream and downstream from the mine contained concentrations ranging from 12 to 15 μg L-1 U. Water samples collected from the North Pit standing pond in the Jackpile mine contained as much as 1560 pCi L-1 of 226Ra, and passing the water through a 0.2 μM filter did not substantially reduce the activity of 226Ra in the water. 234Th and 226Ra are in secular equilibrium in this water, while radon gas was lost from the water. The results of the current study provide insight into the distribution of U-series radionuclides in the Pueblo of Laguna area, including detection of high levels of radioactivity in water at some locations within the Jackpile mine.

A rapid on-site loop-mediated isothermal amplification technology as an early warning system for the detection of Shiga toxin-producing Escherichia coli in water.

Shiga toxin-producing Escherichia coli (STEC) is an important waterborne pathogen capable of causing serious gastrointestinal infections with potentially fatal complications, including haemolytic-uremic syndrome. All STEC serogroups harbour genes that encode at least one Shiga toxin (stx1 and/or stx2), which constitute the primary virulence factors of STEC. Loop-mediated isothermal amplification (LAMP) enables rapid real-time pathogen detection with a high degree of specificity and sensitivity. The aim of this study was to develop and validate an on-site portable diagnostics workstation employing LAMP technology to permit rapid real-time STEC detection in environmental water samples. Water samples (n=28) were collected from groundwater wells (n=13), rivers (n=12), a turlough (n=2) and an agricultural drain (n=1) from the Corrib catchment in Galway. Water samples (100 ml) were passed through a 0.22 µm filter, and buffer was added to elute captured cells. Following filtration, eluates were tested directly using LAMP assays targeting stx1, stx2 and E. coli phoA genes. The portable diagnostics workstation was used in field studies to demonstrate the on-site testing capabilities of the instrument. Real-time PCR assays targeting stx1 and stx2 genes were used to confirm the results. The limit of detection for stx1, stx2 and phoA LAMP assays were 2, 2 and 6 copies, respectively. Overall, stx1, stx2 and phoA genes were detected by LAMP in 15/28 (53.6 %), 9/28 (32.2 %) and 24/28 (85.7 %) samples, respectively. For confirmation, the LAMP results for stx1 and stx2 correlated perfectly (100 %) with those obtained using PCR. The portable diagnostics workstation exhibited high sensitivity throughout the on-site operation, and the average time from sample collection to final result was 40 min. We describe a simple, transferable and efficient diagnostic technology for on-site molecular analysis of various water sources. This method allows on-site testing of drinking water, enabling evidence-based decision-making by public health and water management authorities.

The Impact of Chloroform on Viability of Temperate Bacteriophage Lambda and Survival of its Host, Escherichia coli

Background: This study investigates the effect of chloroform, an organic compound with anti-bacterial properties, produced both naturally and due to anthropogenic activities on the viability of temperate bacteriophage lambda (phage lambda) and its host, Escherichia coli (E. coli). The study was initiated while repurposing phage lambda for testing efficacy and efficiency of disinfectants. Results: Plaque assays and Polymerase Chain Reaction (PCR) using primers specific to the Lambda Tail Protein (LTP) demonstrated a decrease in plaque-forming units and the log copy number of phage lambda following chloroform treatment of phage lysates. Interestingly, PCR with 16 S rRNA primers detected the presence of bacteria in both chloroform-treated and untreated lysates, suggesting that E. coli lysogens, small enough to pass through 0.2 μm filters, which is commonly used for sterilization, were present in the phage lysates. The presence of lysogens in the phage lysates was further supported by the absence of a 16 S rRNA amplicon in lysates prepared without phage lambda infection and the presence of an amplicon in DNase-treated lysates. Additionally, PCR and microscopy revealed that chloroform treatment of phage lysates increased the lysogen copy number, decreased lysogen size, and altered lysogens phage-producing ability. Conclusion: In summary, while chloroform had a slight effect on the viability of phage lambda, most of the phage remained resistant to chloroform because they lack a lipid coat. Phage lambda transitioned to a lysogenic life cycle under sub-optimal growth conditions, leading to the formation of E. coli lysogens. These lysogens were more resistant to stresses like chloroform, ensuring the survival of both the phage and the host during adverse conditions

Detection and Characterization of Extracellular Vesicles in Sputum Samples of COPD Patients.

Only one study has reported the presence of extracellular vesicles (EVs) in COPD patients' sputum. Thus, we aimed to isolate and characterize EVs from COPD and healthy individuals' sputum. A total of 20 spontaneous sputum samples from COPD patients (m/f: 19/1) and induced sputum samples from healthy controls (m/f: 8/2) were used for EV isolation. The sputum supernatants were resuspended in PBS, precleared by centrifugation at 800× g for 10 min at 4 °C, and passed through a 0.22 μm filter (Millipore, Burlington, MA, USA). EVs were isolated by a standard membrane affinity spin column method (exoEasy maxi kit, Qiagen, Hilden, Germany). The EVs were then characterized by assessing their morphology and size using Transmission Electron Microscopy (TEM) and determining the CD9 and CD81 EV-markers with Western blot analysis. The EVs had a spherical shape and their mean diameter in the COPD patients was significantly greater than in the controls. Enrichment of the EV markers, CD9 and CD81, were detected in both the healthy and COPD individuals. Total EV-associated protein was significantly increased in the COPD patients compared to the controls. ROC analysis showed that total EV-associated protein in the sputum could be used to differentiate between the controls and COPD patients, with a sensitivity of 80% and a specificity of 70% at a cut-off point of 55.59 μg/mL (AUC = 0.8150). EVs were detectable in both the COPD and healthy individuals' sputum. The ratio of EVs in the 150-200 nm range was twice as high in the COPD patients than in the controls. The COPD patients' sputum contained increased total EV-associated protein as compared to controls, highlighting their value as a new source of specific exoproteins.

Tracking of microplastics distribution patterns and their characterisation in deposited road dust from Dhaka city, Bangladesh

The widespread presence of microplastics (MPs) in road dust has considerable concern regarding their potential risks to ecosystems and human health. Despite the massive production of plastic, the erudition of MPs distribution patterns in various sizes of deposited road dust is still limited around the globe. Thus, the aim of this research is to provide an unambiguous picture of MPs distributional pattern, identification, classification, quantification, and features from road dust in various zones and types of roadways in Dhaka, Bangladesh. This study examined MPs in road dust samples with particle sizes ranging from 300 to 150 μm (Group-A), 149-75 μm (Group-B), and <75 μm (Group-C). This work extracted MPs from road dust using 30 % H2O2, 1.6 g/cm3 ZnCl2, and 0.45 μm filter paper. A fluorescent microscope (Motic B410E, Germany), Motic Pictures, and 3.0 ML software were utilized to identify MPs visually. Additionally, FTIR and SEM were utilized to determine the chemical composition of MPs. Group-A Road dust samples had a significantly higher concentration of MPs (38945 items/kg) compared to Group-B and <75 μm Group-C dust (16720 and 5945 items/kg, respectively). The distribution hierarchy for total MPs on average by location and type of road is as follows: paved road (355 items/5 g) > unpaved road (325 items/5 g) > soil samples (294 items/5 g), roadside dust samples (284 items/5 g), and mid-road (283 items/5 g). By taking into account all sizes of road dust samples, the MPs were classified as fiber (70.26 %), fragment (26.12 %), beads (0.66 %), films (1.32 %), and foams (1.58 %). It was found that adults inhaled MPs an average of 1612 items/day, while they ingested an average of 880 items/day. Children had an inhalation rate of 1232 items/day and an ingestion rate of 10267 items/day, which was 4–17 times greater than in other countries. This study identified 22 MPs polymer types, and SEM results show that MPs surfaces are being weathered into nanoplastics, creating a more hazardous environment.

Assessing eDNA capture method from aquatic environment to optimise recovery of human mt-eDNA

Previous studies have shown that environmental DNA (eDNA) from human sources can be recovered from natural bodies of water, and the generation of DNA profiles from such environmental samples may assist in forensic investigations. However, fundamental knowledge gaps exist around the factors influencing the probability of detecting human eDNA and the design of optimal sampling protocols. One of these is understanding the particle sizes eDNA signals are most strongly associated with and the most appropriate filter size needed for efficiently capturing eDNA particles. This study assessed the amount of mitochondrial eDNA associated with different particle sizes from human blood and skin cells recovered from freshwater samples. Samples (300 mL) were taken from experimental 10 L tanks of freshwater spiked with 50 µL of human blood or skin cells deposited by vigorously rubbing hands together for two minutes in freshwater. Subsamples were collected by passing 250 mL of experimental water sample through six different filter pore sizes (from 0.1 to 8 µm). This process was repeated at four time intervals after spiking over 72 hours to assess if the particle size of the amount of eDNA recovered changes as the eDNA degrades. Using a human-specific quantitative polymerase chain reaction (qPCR) assay targeting the HV1 mitochondrial gene region, the total amount of mitochondrial eDNA associated with different particle size fractions was determined. In the case of human blood, at 0 h, the 0.45 µm filter pore size captured the greatest amount of mitochondrial eDNA, capturing 42 % of the eDNA detected. The pattern then changed after 48 h, with the 5 µm filter pore size capturing the greatest amount of eDNA (67 %), and 81 % of eDNA at 72 h. Notably, a ten-fold dilution proved to be a valuable strategy for enhancing eDNA recovery from the 8 µm filter at all time points, primarily due to the PCR inhibition observed in hemoglobin. For human skin cells, the greatest amounts of eDNA were recovered from the 8 µm filter pore size and were consistent through time (capturing 37 %, 56 %, and 88 % of eDNA at 0 hours, 48 hours, and 72 hours respectively). There is a clear variation in the amount of eDNA recovered between different cell types, and in some forensic scenarios, there is likely to be a mix of cell types present. These results suggest it would be best to use a 5 µm filter pore size to capture human blood and an 8 µm filter pore size to capture human skin cells to maximize DNA recovery from freshwater samples. Depending on the cell type contributing to the eDNA, a combination of different filter pore sizes may be employed to optimize the recovery of human DNA from water samples. This study provides the groundwork for optimizing a strategy for the efficient recovery of human eDNA from aquatic environments, paving the way for its broader application in forensic and environmental sciences.

Preliminary studies on the effect of excretory secretory (ES) Ascaris lumbricoides antigens on colorectal cell line viability.

Helminth parasites are a group of complex metazoans from various taxonomic families. Excretory secretory (ES) by-products, secreted by living parasites from the surface, appeared to modulate the host immunological response towards helminth infection. This study aims to investigate the effect of ES antigen from helminth parasite on colorectal cell viability. Worm were cultured in phosphate-buffered saline (PBS x1) at 37°C for 24 hours after being rinsed in sterile PBS. Using a mortar and pestle, the worm was crushed vigorously using PBS. The obtained excretory secretory (ES) antigens were extracted and filtered using a 0.22 µM filter and stored at -20°C for further assay. For LCMS, 100 µl of the extract was analysed using Agilent ZORBAX Eclipse Plus C18 Rapid Resolution HT. The extraction of ES antigen (10 µg/ml and 20 µg/ml) was used for cell viability studies using CRC cell line HCT 116. Cell viability and MTT assay were conducted as per the protocol mentioned in the MTT kit. The liquid chromatography and mass spectrometry (LCMS) data indicated that the ES antigen contained metabolic compounds, namely fatty acid, amino alcohol, indoles, sterols, glycosides, and sphingoids. For the Ascaris lumbricoides LCMS analyses, around 405 metabolic peaks were detected. Out of which, 58 were detected via the database were identified, while several compounds detected have anticancer properties. The MTT assay indicated that after 24 hours and 48 hours of exposure, all treated cells showed a decrease in cell viability compared to the control group. The preliminary studies demonstrated that the ES antigen from Ascaris lumbricoides has some ability to decrease the cell viability of the HCT116 CRC cell line. Further studies are needed to examine the cell cycle arrest and apoptosis effect of the ES antigen towards the CRC cell line.

Synthesis, MTT assay, 99m-Technetium radiolabeling, biodistribution evaluation of radiotracer and in vitro magnetic resonance imaging study of P,N-doped graphene quantum dots as a new multipurpose imaging nano-agent

Abstract In this study, a new nano-structure, N,P-doped graphene quantum dots (N,P-GQDs), were synthesized as multipurpose imaging agent for performing scintigraphy and magnetic resonance imaging (MRI). Some standard characterization methods were used to identify the nano-structure. In vitro cytotoxicity evaluation using MTT assay revealed that N,P-GQDs nanoparticles had no significant cytotoxicity after 24 and 48 h against normal (MCF-10A) and cancerous (MCF 7) human breast cell line in concentration up to 200 μg/mL. The N,P-GQDs were radiolabeled with Technetium-99m as 99mTc-(N,P-GQDs) and the radiochemical purity was assayed by ITLC concluding RCP ≥ 95 %. The passing of 99mTc-(N,P-GQDs) through 0.1 µm filter demonstrated that 70.8 % of particles were &lt;0.1 µm. In order to perform scintigraphy, the 99mTc-(N,P-GQDs) were injected to female healthy Wistar rats. The results showed that the radio-complex was captured and eliminated just by kidneys. Moreover, in vitro T1-weighted phantom MRI imaging showed that the N,P-GQDs have proper relaxivity in comparison to Dotarem® as a clinically available contrast agent. The results showed that the N,P-GQDs have potential to be considered as a novel and encouraging agent for both molecular MRI and nuclear medicine imagings.

Ultrafiltration of anaerobically digested sludge centrate as key process for a further nitrogen recovery process

In a wastewater treatment plant, the centrate generated in the dehydration process of the anaerobically digested sludge has a high potential for nutrients recovery because of its high nutrients concentration (specifically nitrogen and phosphorous). However, the high organic matter and solids content may make difficult its management. Membrane fouling is the most significant challenge limiting the application of membrane techniques for wastewater treatment. Results in this article highlight the potential of conventional filtration followed by ultrafiltration as pretreatment for further nutrients recovery using emerging membrane technologies (as membrane contactor, membrane distillation or forward osmosis). Thus, a conventional filtration (with 1, 5 and 60 μm filters) followed by an ultrafiltration process were tested. The UF membranes studied were two PES membranes (5 kDa and 0.01 μm) and one PVDF membranes (100 kDa). Results demonstrated that a conventional filtration with a cartridge filter of 60 μm and a subsequent UF process with a 0.01 μm RAY100 membrane (Orelis, France) achieved the best results in terms of the maximum organic matter (66% COD removal) and solids (over 97% suspended solids removal) separation, hardly varying nutrients concentration (13% NH4+ removal). Concerning membrane fouling, FESEM-EDX confirmed salt precipitation on the membrane surface, which has to be controlled to avoid loss of performance.