Retention Sites Research Articles

The Effect of Nanoparticles Against Streptococcus mutans in the Orthodontic Primer Used for Aligner Attachment: An In Vitro Study.

Objective This study investigates the antimicrobial properties of silver (1%) and chitosan (1%) nanoparticles against Streptococcus mutans (S. mutans) when added to an orthodontic primer used for aligner attachments. While aligner treatments are becoming increasingly popular for their aesthetics and convenience, their attachments can create retention sites for bacteria, potentially leading to white spot lesions (WSLs). This in vitro study aims to address this issue by enhancing the antimicrobial efficacy of aligner primers. Methodology Thirty freshly extracted teeth were classified into the following three groups: Group A with the standard primer, Group B with chitosan nanoparticles mixed in the primer, and Group C with silver nanoparticles mixed in the primer. The samples were incubated with S. mutans and bacterial colonies were counted at 12, 24, 48, and 72 hours. Results The results showed a significant reduction in colony-forming units (CFUs) in the groups with nanoparticles compared to the control group, with silver nanoparticles exhibiting a higher antimicrobial effect than chitosan. Conclusions This study suggests that incorporating silver nanoparticles into orthodontic primers can effectively reduce bacterial growth, potentially improving oral hygiene and reducing the risk of WSLs in patients undergoing aligner treatment.

Combination of magnesium modified biochar and iron oxides down-regulates phosphates transport in porous media

The practical effects of biochar on soil phosphate (P) transport are significantly affected by P adsorption capacity of biochar itself and its interaction process with iron oxides. Here, the ability of pyrolysis to shape P adsorption capacity of biochar was investigated, while the interaction of biochar and iron oxides on P transport was explored with quartz sand columns and numerical modeling. Adsorption experiments showed that pyrolysis increased P adsorption capacity of Mg-modified biochar (∼248 mg g−1) through enriching surface morphology and pore structures, optimizing composition of functional groups, and forming MgO crystals. It also caused that P adsorption at MgBC-700°C was mainly controlled by surface precipitation, electrostatic attraction and pore interception. Simultaneously, the desorption of P was sensitive to pH changes and with low-stability. Transport experiments showed that iron oxides reduced P transport, shown to be goethite > hematite (P leaching: 69.59 % vs 98.29 %). Further, MgBC-700°C continued to decrease P transport from 75.56 % to 31.50 %, and the effect of goethite was more effective, with ligand reaction playing an important role. This process was influenced by cation types (Ca2+ and K+), ionic strength (1 mM and 50 mM), and pH (5, 7 and 9) through changing available retention sites of columns. Furthermore, since P adsorption mechanisms were different in the presence of MgBC-700°C and goethite than MgBC-700°C only, the changes of pH could no longer cause the release of P, but surprisingly, citric acid and oxalic acid could activate and slowly release the retained P via chelation, ligand exchange, and solubilization, which suggested that MgBC-700°C, as an environmentally-friendly P adsorption and release material, has great potential in reducing P loss and facilitating P utilization.

Abundance and distribution of microplastics in benthic sediments and Cladocera taxa in a subtropical Austral reservoir.

Pollution of the natural environment by microplastics has become a global issue in ecosystems as it poses a potential long-term threat to biota. Microplastics can accrue in high abundances in sediments of aquatic ecosystems while also contaminating pelagic filter feeders, which could transfer pollutants up trophic webs. We assess the abundance and distribution of microplastics in benthic sediments and Cladocera taxa in a subtropical Austral reservoir using a combination of geospatial techniques, physicochemical analyses, diversity indices, and multivariate statistics between two seasons (i.e., hot-wet and cool-dry). We found particularly high densities of microplastics during the cool-dry season for both sediments (mean 224.1 vs. 189 particles kg-1 dry weight) and Cladocera taxa (0.3 particles per individual). Cladocera microplastic shapes were dominated by fibers with high densities of the transparent color scheme. Pearson correlation results indicated that sediment microplastic abundances were negatively correlated with chlorophyll-a concentration, temperature, and resistivity, whereas they were positively correlated with pH and salinity during the hot-wet season, with no variables significant in the cool-dry season. Cladocera microplastic abundances were positively correlated with conductivity and salinity during the cool-dry season, but no variables in the hot-wet season. These findings provide insights into the role of reservoirs as microplastic retention sites and the potential for uptake and transfer from lower trophic groups. These insights can be used to strengthen future monitoring and intervention strategies. Integr Environ Assess Manag 2024;20:2256-2270. © 2024 SETAC.

Clinical Characteristics of Children With Foreign Bodies in the Digestive Tract and Analysis of Risk Factors for Serious Complications.

Foreign bodies (FBs) in the digestive tract are common in children, we analyzed the clinical characteristics of children with FBs in the digestive tract and discuss the risk factors for serious complications. We retrospectively reviewed clinical data of 139 children with FBs in the digestive tract. Based on the severity of complications caused by FBs, the patients were divided into risk and general groups for analysis and comparison. Significant differences were observed in the retention sites of FBs, the diameter of FBs retained in the esophagus, FBs retention time exceeding 24 h, and the absence of witnesses between the 2 groups. Inadequate care, button batteries (BBs), ingested mmFBs, FBs retained in the esophagus, long-term retention, and giant gastric bezoars may cause serious complications. In addition to treating FBs and the complications, clinicians should emphasize the importance of childcare to prevent the ingestion of FBs.

Anthropogenic particle concentrations and fluxes in an urban river are temporally variable and impacted by storm events.

Anthropogenic particles (AP), which include microplastics and other synthetic, semisynthetic, and anthropogenically modified materials, are pollutants of concern in aquatic ecosystems worldwide. Rivers are important conduits and retention sites for AP, and time series data on the movement of these particles in lotic ecosystems are needed to assess the role of rivers in the global AP cycle. Much research assessing AP pollution extrapolates stream loads based on single time point measurements, but lotic ecosystems are highly variable over time (e.g., seasonality and storm events). The accuracy of models describing AP dynamics in rivers is constrained by the limited studies that examine how frequent changes in discharge drive particle retention and transport. This study addressed this knowledge gap by using automated, high-resolution sampling to track AP concentrations and fluxes during multiple storm events in an urban river (Milwaukee River) and comparing these measurements to commonly monitored water quality metrics. AP concentrations and fluxes varied significantly across four storm events, highlighting the temporal variability of AP dynamics. When data from the sampling periods were pooled, there were increases in particle concentration and flux during the early phases of the storms, suggesting that floods may flush AP into the river and/or resuspend particles from the benthic zone. AP flux was closely linked to river discharge, suggesting large loads of AP are delivered downstream during storms. Unexpectedly, AP concentrations were not correlated with other simultaneously measured water quality metrics, including total suspended solids, fecal coliforms, chloride, nitrate, and sulfate, indicating that these metrics cannot be used to estimate AP. These data will contribute to more accurate models of particle dynamics in rivers and global plastic export to oceans. PRACTITIONER POINTS: Anthropogenic particle (AP) concentrations and fluxes in an urban river varied across four storm events. AP concentrations and fluxes were the highest during the early phases of the storms. Storms increased AP transport downstream compared with baseflow. AP concentrations did not correlate with other water quality metrics during storms.

Étude de l'adsorption des ions de Nickel sur des argiles naturelles locales dans les effluents hydrométallurgiques

This research focuses on the treatment of hydrometallurgical effluents, specifically studying the adsorption of metallic ions such as Nickel, Copper, Cobalt, Mercury, and lead on natural clays from the Democratic Republic of Congo (DRC). Twelve clay samples, six activated with a strong acid and six non-activated, were characterized using various techniques including X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, X-Ray Fluorescence, Transmission Electron Microscopy, and chemical dosage. The characterization revealed that the clays are mixed with several clayey minerals, enriched in aluminum silicate; contain absorption and water retention sites, and exhibit heterogeneities at the interfaces between grains and exchangeable ions. Activating the clays increased their cation exchange capacities, removed impurities, and increased pore size and specific area. Two aqueous solutions were used in the experiments: a laboratory-prepared nickel sulfate solution and a hydrometallurgical aqueous solution from a factory, both initially containing 15 mgL-1 of Ni2+ ions. Results showed that the adsorption of Ni2+ ions increased with the quantity of clay in the solution. The activated clays adsorbed more ions than non-activated clays at the same Ni2+ ion concentration. Additionally, adsorption was weaker in the hydrometallurgical solution compared to the nickel sulfate solution, suggesting competition from other metallic ions. The optimal adsorption occurred with chemically activated clays containing high Na+, Fe2+, and Al3+ ion content and low K+ ion content. The Hill-Langmuir model was used to describe the adsorption results, revealing that minimal quantities of activated clay were needed to adsorb a large quantity of Ni2+ ions in the solution, whereas large quantities of non-activated clays were insufficient. In conclusion, the research demonstrates the potential of natural clays from the DRC to adsorb metallic ions from hydrometallurgical effluents, providing insights for effective treatment methods in the future. The model revealed that the clay samples A2a clay, A6a and A3na have the very elevated reactional sites concentrations.

Novel three-dimensional fibrous covalent organic frameworks constructed via silver amalgam bridging for efficient organic dye adsorption and removal.

The construction of covalent organic frameworks (COFs) with unique structures has great significance in exploring the structure-function relationship and extending their potential applications. Fibrous COFs have demonstrated superior performance in specific application scenarios owing to the distinctive three-dimensional (3D) structure. Herein, we report a facile strategy for the fabrication of 3D COF nanofiber by exploiting silver amalgam as a bridging agent to assemble one-dimensional-extended PA-COF modules into a tubular structure. Dimensions of the obtained 3D COF nanofiber were predicted by DFT calculations, and the nanofiber was endowed with the merits of favorable uniformity and high stability. Due to the enhanced exposure of conjugatable binding sites for dye retention offered by the novel 3D architecture, the PA-COF nanofiber exhibits fast adsorption (within 5 min) and superior adsorption capacity to various organic dyes, e.g., 1717 mg g-1 for methylene blue (MB) and 978.3 mg g-1 for methyl orange (MO). Moreover, the PA-COF nanofiber shows excellent reusability in dye adsorption, which makes it a potential medium for removing dye pollutants from wastewater. This work presents an effective strategy to construct COF materials with unique architecture and potential prospects in the fields of separation and wastewater treatment.

Phylogenetic study of some major Dendrobium species of Eastern Himalaya using internal transcribed spacer marker

The entire internal transcribed spacer (ITS) region sequencing was used to determine the phylogenetic relationship of 44 Eastern Himalayan Dendrobium species using the Sanger method and MEGA 11. The combined length of ITS-I and ITS-II varies between 623 and 644 base pairs (bp). Among them, there are 403 polymorphic, 91 unique, and 223 conserved nucleotides. In addition, 337 nucleotides are parsimony informative, with a mean of 0.51 that supports the presence of genetic variation in the genome of the selected species. Overall composition distance is 0.32, transition and transversion bias (R) 1.444, and mean evolutionary divergence (d) 0.16. The length of ITS-2 sequences is bigger than that of ITS-I. ITS-II exhibits a higher G+C% content, and the K2+G model is the most suitable, with the lowest penalty for nucleotide substitutions. The average consistency, retention, composite value, and parsimony-informative sites (in parentheses) are 0.5028 (0.4571), 0.6545 (0.6545), and 0.3290 (0.2992), respectively. The mean value of the disparity indices is 0.192, which measures the variation in evolutionary trends between two sequences. In addition, the ratio of non-synonymous to synonymous substitutions (dN/dS) is −0.33 promotes purifying species selection. The prevalence of the TGT codon is abundant across the sequences, with the UCG codon exhibiting the highest relative synonymous codon usage (RSCU). Conversely, the GAC codon has the lowest RSCU value. The greatest genetic divergence occurred between Dendrobium aphyllum and Dendrobium denudans. The Breviflorus species group has the most genetic diversity, whereas Formosae has the least. Between Grastidium and Stachyobium group sequences had the highest evolutionary distance, whereas Dendrobium and Grastidium had the least. The negative value of Tajima’s D, Fu and Li’s D*, F*, and Fu’s Fs tests indicated current population is growing after facing a recent bottleneck. This study suggests that ITS sequencing could be a major focus of comparative sequencing at the generic level in Dendrobium plants and could provide valuable phylogenetic reconstruction for clarifying the evolutionary relevance of the taxa studied.

STUDY OF CLINICAL AND MICROBIOLOGICAL PARAMETERS IN PATIENTS WITH NON-REMOVABLE ORTHODONTIC EQUIPMENT DURING THE USE OF DENTAL GELS IN A COMPARATIVE ASPECT

Inflammatory periodontal disease is the second most common pathology after dental caries, affecting up to 95% of the population of different age groups. The main etiological factor in the occurrence of this pathology is periodontopathogenic microflora. During orthodontic intervention, there is an exacerbation of inflammatory processes in the periodontium due to the accumulation of microbial biofilm, due to the appearance in the oral cavity of patients of additional retention sites in the form of fixed structures. The use of conventional hygiene products is not enough to eliminate deposits of microbial origin. Therefore, to reduce the inflammatory process in the periodontium during orthodontic intervention, it is necessary to use additional hygiene products that provide an adequate antimicrobial effect. These funds should mainly have a specific effect on the periodontopathogenic microflora. In the course of the conducted studies, the effectiveness of the antimicrobial action of dental gels "Bergisept" and "Metrogil-Denta" was proved. At the same time, "Bergisept-gel" has the advantages of specifically inhibiting the growth of P. gingivalis and A. actinomycetemcomitans and practically does not have an antimicrobial effect against Str. salivarius.

Comparative evaluation of Chlorhexidine and Triphala with Rajat Bhasma jelly as against Chlorhexidine mouth rinse in prevention of bacterial accumulation in fixed orthodontic assembly: A randomized interventional study

Background: By offering numerous mechanical retention sites, fixed orthodontic treatment increases the build-up of bacterial plaque, rendering teeth more susceptible to gingivitis and periodontitis. Chlorhexidine is a frequently utilised adjuvant to mechanical oral hygiene techniques and is regarded as the gold standard. As compared to chemicals and allopathy, nowadays patients are showing great inclination for the herbal products. Commercially available herbal mouhrinses are emerging in the market. Due to their lack of purity, these is a need for more herbal alternative mouthrinses like Triphala. As known, silver coated wire has antimicrobial and antiadherent properties, still not commercially available. Some reasons could be cost, toxicity levels, etc. Thereby, to evaluate the effects herbal mouthwashes in adjunct with herbal form of silver i.e. Rajat bhasma, present study has been taken up to check the antimicrobial and anti-adherent properties with various combinations Objectives: 1. To evaluate the efficacy of chlorhexidine mouthrinse and Rajat bhasma jelly as an antimicrobial agent 2. To evaluate the efficacy of Triphala mouthrinse and Rajat bhasma jelly as an antimicrobial agent 3. To compare the antimicrobial potency of chlorhexidine, triphala with rajat bhasma jelly combinations as against chlorhexidine on bacterial accumulation (streptococcus mutans and lactobacillus). Methods: Plaque will be collected from the left molar to right molar of the upper arch with a disinfected curette at 3 time periods: T 0 = just prior bonding, following full prophylaxis. T 1 = one month following bonding. T 3 = two months following bonding Streptococcus mutans and lactobacilli will be quantified by colony count procedure. Expected results: Patients receiving orthodontic treatment experience a greater reduction in plaque buildup attributable to the synergistic effects of rajat bhasma and different mouthrinses. Conclusion: It is expected that, Rajat bhasma and triphala being ayurvedic products cause no harm and show plaque reduction. Trial number: CTRI/2022/07/044130

Designing multivariate porphyrin-based metal-organic frameworks with Ni/Co dual-metal atom sites for cooperative NO2 capture and NO retention

Selective adsorption using porous materials is a promising approach to removing ambient nitrogen dioxide (NO2). However, the highly reactive nature of NO2 and the often-associated release of nitric oxide (NO) render a formidable challenge in developing effective and stable adsorbents. Here, we designed multivariate porphyrin-based metal–organic frameworks (MTV-PMOFs Al-PMOF(NixCoy)) featuring atomically dispersed Ni/Co dual-metal centers in the porphyrin ring as active adsorption sites, as robust adsorbents capable of synergistically boosting NO2 adsorption capability and retaining the evolved NO. The introduction of the Ni/Co dual-metal sites in MTV-PMOFs greatly enhanced the NOx adsorption performance. Under dry conditions, Al-PMOF(Ni1Co1) exhibited a NO2 adsorption capacity of 3.66 mmol/g (100 ppm NO2 in feed), among the highest under similar conditions, a high NO retention ability, and good regenrability (85%). Under wet conditions, its NO2 removal capacity was further elevated by more than 50% (5.65 mmol/g). Moreover, the Ni/Co ratio in MTV-PMOFs dictates a structure–property relationship between the released amount of NO and adsorbed capacity of NO2. Such a corporative NO2 and NO adsorption was for the first time established in MOFs. The material stability and potential economic value were also investigated to demonstrate the applicability of MTV-PMOFs as NO2 adsorbents. This work provides new perspectives for the development of adsorption-based technology for mitigating ambient NO2 pollution and managing other corrosive and toxic gases.

Responses of understory vascular plant communities up to 6 years after retention harvesting in planted Abies sachalinensis forests

Planted forests managed to supply timber are usually harvested by clearcutting but are also expected to contribute to biodiversity conservation. The retention forestry approach that retains important forest structures, such as trees and decayed logs at harvest, can be applied in planted forests to mitigate the negative impacts of clearcutting. Planted forests are disturbed by harvesting and postharvest silvicultural management activities, such as site preparation, planting, and weeding. The responses of understory vascular plant communities to various retention harvesting and postharvest silvicultural management were studied by comparing the composition of understory plant species before and after harvesting at the Retention Experiment for plantation FoREstry in Sorachi, Hokkaido, Japan (REFRESH). Dispersed and aggregated retention sites were established in planted Abies sachalinensis forests. In the dispersed retention sites, broad-leaved trees established in conifer plantations were retained. Clearcut and unharvested stands were used as controls and patch-cutting sites (one third of the area was clearcut by patches of 1-ha) were also established. Harvesting took place the year after the preharvest survey, and postharvest surveys were conducted in the first, third, and sixth years thereafter. The effects on species richness, the persistence of species occurrence in the preharvest survey, and the species composition of understory plants were then examined. Colonization by early seral species resulted in changes to the understory plant communities after harvesting and site preparation, irrespective of overstory tree retention. The species composition within aggregated retention patches was not altered, even though most overstory trees were blown down and are expected to provide a refuge for forest species. The presence of retained trees and steep slopes enhanced preharvest species persistence, which was presumed to be due to hampered soil disturbance. Harvesting and site preparation methods that avoid soil disturbance may help to maintain habitats for more understory plants in planted forests. The effects of weeding on the persistence of understory species differed from that of harvesting and site preparation. The trajectories for each site in the Non-metric multidimensional scaling ordination space were almost parallel from the preharvest to postharvest surveys, suggesting that the preharvest vegetation left a legacy. The direction of movement was reversed in the survey six years after harvesting. It is necessary to determine the resistance and resilience of understory plants within the management cycle (planting through harvesting) to establish management practices that maintain the diversity of understory plants in planted forests.

Changes in the structure and D desorptive release from W-D co-deposit layers caused by thermal annealing

The annealing of ∼1 μm thick tungsten–deuterium co-deposit layers produced at 320 ± 25 K is found to induce changes in the desorptive release behavior and crystal structure. The changes in co-deposits were revealed by annealing in the temperature range 273–1273 K, examining the crystal structure with glancing angle X-ray diffraction, re-populating traps remaining following the anneal, by D plasma exposure at 373 K, then re-examining the co-deposits with glancing angle X-ray diffraction and scanning electron microscopy, before performing thermal desorption mass spectrometry to ascertain the effect of annealing on trap concentrations. The results indicate that low temperature W-D co-deposit layers are prone to the development of a significant fraction of deuterium retention sites, with a predominant thermal release that begins at ∼400 K and ceases approaching ∼1000 K. Increased annealing temperature is found to progressively depopulate and remove low temperature deuterium retention sites, as suggested by an inability to re-populate those sites with the deuterium plasma. Scanning electron micro-graphs show marked differences at the anneal temperature extremes, with surface conversion from a dendritic appearance at 320 K to a nodular appearance at 1273 K. X-ray diffraction reveals two W phases initially present as 320 K, namely the α-W BCC and β-W A15 crystal phases, the latter of which rapidly anneals out above 490 K leaving only increased Bragg reflection from the α-W phase at the higher annealing temperature.

The impacted oro-pharnygeal fish bone-surgeon’s dilemma

Pisces are a delicacy on the table of almost every non-vegetarian household. Unfortunately, pharyngeal impaction of fish bones is a frequent emergency in the oto-rhino-laryngological clinics or trauma units of tertiary health care facilities. Sequentially the sites of retention noted are the lymphoid tissue of tonsillar fauces, the coffin corner, the base of the tongue, either valleculae and the pyriform sinuses. Lancinating pain on deglutition with a typical history is diagnostic, therapy necessitating timely intervention to avoid an untoward sequel. It poses a queer situation for the laryngologist whether to go ahead and straightaway attempt to extract the same under local anesthesia or wait for the requisite 6 hrs for administration of general anesthesia. The waiting duration being equally painful and a testing period for the patient and the surgeon alike. The latter is more apprehensive about deeper migration of the bone. The out-patient extraction in a cooperative individual was undertaken with a three-handed modality, adopting an angled viewing telescope and respective instrumentation.

Mini-Implants Retaining Removable Partial Dentures in Subjects without Posterior Teeth: A 5-Year Prospective Study Comparing the Maxilla and the Mandible

Background and objectives: Long-term studies of clinical outcomes of mini-implants (MDIs) in the first premolar/canine sites retaining a bilateral free-ending removable partial dentures (RPD) in Kennedy class I subjects have not been well documented. The aim was to assess clinical outcomes in a prospective 5-year cohort study comparing the mandible and maxilla. Material and Methods: Participants (n = 92) who received two MDIs each and a new RPD were reviewed after one, three and five years. A total of 71 participants (82 mini-implants in the mandible; 58 in the maxilla) completed the study. Marginal bone level change, success, survival rates, Modified Plaque (MPI) and Bleeding Indices (MBI) were assessed. Results: The five-year success rate was 93.3% and 93.4% (p > 0.05), in the mandible and the maxilla, respectively. Mean peri-implant bone loss (MBL) increased significantly over five years (p < 0.01) to 0.50 mm in the mandible and 0.52 mm in the maxilla. Age had a significant effect on the MBL (higher rates in younger participants), while jaw of insertion, gender, and antagonistic jaw status did not. MPI and MBI were not significantly correlated with MBL. Conclusions: The insertion of two MDIs in previous first premolar/canine sites for retention of a free-end saddle RPD can be a successful treatment modality in subjects with narrow alveolar ridges.

The roles of Fe oxyhydroxide coating and chemical aging in pyrogenic carbon nanoparticle transport in unsaturated porous media

Pyrogenic carbon (PyC) nanoparticles are widespread in the environment, which is important to global carbon cycle. PyC can exist for millions of years and undergo various environmental aging processes. To better understand the roles of Fe oxyhydroxides and water content on the pristine and aged PyC transport, adsorption and column experiments were conducted under three saturations (100%, 70%, and 40%) and three pH (5, 7, and 9) in both clean and Fe oxyhydroxide-coated sand. At high water saturations (100% and 70%), the mobility of both the pristine and aged PyC was enhanced at high pH due to strong electrostatic repulsion, and the aged PyC showed higher mobility than the pristine PyC because of its more negative charge and hydrophilic surface. The coating of Fe oxyhydroxides on sand decreased the mobility of both the pristine and aged PyC due to weak electrostatic repulsion, large specific surface area, and high roughness. At low saturation (40%), solution pH showed little effect on both the pristine and aged PyC mobility, and water saturation became the main factor affecting PyC mobility. Almost no pristine or aged PyC transported out from the Fe oxyhydroxide-coated sand column because Fe oxide increased the roughness of the sand surface, which led to a sharp increase in the air-water-solid interface and retention sites. This study demonstrates that water content, environmental aging, and Fe oxyhydroxides are significant in the fate and transport of PyC nanoparticles in environments, which provides a good fundamental understanding for the assessment of pyrogenic carbon application in environmental protection and carbon sequestration.

RAINWATER RETENTION SITE ASSESSMENT FOR URBAN FLOOD RISK REDUCTION AND FLOOD DEFENCE IN MANDAUE CITY, PHILIPPINES

Abstract. This study utilized a geospatial approach to identify suitable sites for rainwater retention areas in Mandaue City, a highly urbanized city in Cebu, Philippines. Based on the integrated use of remote sensing and Geographic Information System (GIS), ideal sites for rainwater retention were produced to divert surface water runoff from flooding the streets and obstructing traffic. Ideally, the chosen sites should have low infiltration capacity and be within open spaces. For the hydrological planning of the study, we considered the amount of surface runoff, elevation, soil characteristics, land use, and present drainage status of the study area. The Digital Elevation Model (DEM) derived from LiDAR technology is used to obtain the slope raster and generate small streams. Land cover and curve number (CN) of the area were used to compute the surface runoff. The soil textures were converted based on their infiltration rate and runoff potential. Finally, the weighted overlay tool in GIS created a layer identifying potential areas for rainwater retention sites. The findings indicate that 54.8% of the research area was ideal for water harvesting, with open land areas making up 2.3% of the best locations. In addition, a major portion of the appropriate locations lies in clay loam soils and within 0–25 meters in elevation. These results will hugely benefit policymakers and urban planners in helping create solutions to the city’s flooding problem and the looming water crisis.

Facilitated transport of microplastics and nonylphenol in porous media with variations in physicochemical heterogeneity

Nonylphenol (Noph) has garnered worldwide concern as a typical endocrine disruptor due to its toxicity, estrogenic properties, and widespread contamination. To better elucidate the interaction of Noph with ubiquitously existing microplastics (MPs) and the potential interdependence of their transport behaviors, batch adsorption and column experiments were conducted, paired with mathematical modeling. Compared with sand, MPs and soil colloids show stronger adsorption affinity for Noph due to the formation of hydrogen bonding and the larger numbers of interaction sites that are available on solid surfaces. Limited amount of soil-colloid coating on sand grains significantly influenced transport behaviors and the sensitivity to solution chemistry. These coatings led to a monotonic increase in Noph retention and a nonmonotonic MPs retention in single systems because of the altered physicochemical properties. The mobility of both MPs and Noph was enhanced when they coexisted, resulting from their association, increased electrostatic repulsion, and competition on retention sites. Limited release of MPs and Noph (under reduced ionic strength (IS) and increased pH) indicated strong interactions in irreversible retention. The retention and release of Noph were independent of IS and solution pH. A one-site model with a blocking term and a two-site kinetic model well described the transport of MPs and Noph, respectively. Our findings highlight the essential roles of coexisting MPs and Noph on their transport behaviors, depending on their concentrations, IS, and physicochemical properties of the porous media. The new knowledge from this study refreshes our understanding of the co-transport of MPs and organic contaminants such as Noph in the subsurface.

Short-term effects of retention forestry on the diversity of root-associated ectomycorrhizal fungi in Sakhalin fir plantations, Hokkaido, Japan

We have examined the effects of dispersed and aggregated retention on the diversity of root-associated ectomycorrhizal fungi (EcMf) in Sakhalin fir (Abies sachalinensis) plantations, 4 years after logging. Roots of Sakhalin fir seedlings and the adjacent broadleaved or Sakhalin fir trees were sampled in broadleaved dispersed retention sites (10, 50, or 100 trees/ha), conifer aggregated retention sites (a single 60 × 60 m square patch of Sakhalin fir trees per site), clear-cut sites, unharvested Sakhalin fir plantations, and natural broadleaved forest stands. The EcMf on the roots were grouped into operational taxonomic units based on the similarity of the internal transcribed spacer sequences within the nuclear ribosomal DNA. Clear-cutting significantly reduced the species richness and diversity of the EcMf and altered the species composition when compared with the unharvested Sakhalin fir plantations and natural broadleaved forests. In contrast, both the aggregated and dispersed retention sites maintained higher levels of EcMf diversity, as well as different EcMf communities when compared with the clear-cut sites. Aggregated retention was effective at conserving EcMf diversity at the unharvested Sakhalin fir plantations, but the effects were limited within retained patches. Broadleaved dispersed retention did not retain the EcMf communities that were present prior to logging even at high retention levels, but they could retain unique EcMf communities, which differed between the Sakhalin fir plantations, natural broadleaved forests, and clear-cut sites. The species richness and diversity values for some of the dispersed retention sites were comparable to the values for the unharvested Sakhalin fir plantations and tended to be greater than the values for the aggregated retention sites. The results indicate that dispersed retention could be an effective strategy by which to preserve a larger number of EcMf species and unique EcMf communities in logged conifer plantations, although the positive effects were likely limited spatially within the rooting zones of the retained broadleaved trees. Finally, naturally regenerating Sakhalin fir seedlings were found to share a large amount of their EcMf with adjacent broadleaved retention trees, indicating that multi-host EcMf of retained trees largely contribute to ectomycorrhizal colonization of the surrounding regenerated seedlings in the logged areas. Our findings demonstrated that both dispersed and aggregated retention methods could be used to mitigate the impacts of logging on EcMf diversity in Sakhalin fir plantations, in Japan, and that there were large differences in the effects among the different retention methods.

Sensitivity of the Transport of Plastic Nanoparticles to Typical Phosphates Associated with Ionic Strength and Solution pH.

The influence of phosphates on the transport of plastic particles in porous media is environmentally relevant due to their ubiquitous coexistence in the subsurface environment. This study investigated the transport of plastic nanoparticles (PNPs) via column experiments, paired with Derjaguin–Landau–Verwey–Overbeek calculations and numerical simulations. The trends of PNP transport vary with increasing concentrations of NaH2PO4 and Na2HPO4 due to the coupled effects of increased electrostatic repulsion, the competition for retention sites, and the compression of the double layer. Higher pH tends to increase PNP transport due to the enhanced deprotonation of surfaces. The release of retained PNPs under reduced IS and increased pH is limited because most of the PNPs were irreversibly captured in deep primary minima. The presence of physicochemical heterogeneities on solid surfaces can reduce PNP transport and increase the sensitivity of the transport to IS. Furthermore, variations in the hydrogen bonding when the two phosphates act as proton donors will result in different influences on PNP transport at the same IS. This study highlights the sensitivity of PNP transport to phosphates associated with the solution chemistries (e.g., IS and pH) and is helpful for better understanding the fate of PNPs and other colloidal contaminants in the subsurface environment.