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1.
Build Environ ; 207: 108567, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36568651

RESUMEN

The COVID-19 pandemic has suddenly switched most education processes from face-to-face to remote mode, obliging millions of students to utilize their residences as study spaces. However, the characteristics of their residential built environments differ in terms of regional, social, cultural, and technological aspects. These differences should impact the students' performance and satisfaction which needs to be measured and studied. The present study aims to identify the effect of the residential built environment on students' satisfaction and academic performance during the COVID-19 pandemic. It was conducted in two countries, Kazakhstan (KZ) and Norway (NO), using a comprehensive online survey to gather data. An empirical assessment based on the structural equation model was employed to identify links between health, safety, and comfort of students' facilities and academic performance and satisfaction. We conclude that the built environment affects both satisfaction for remote education and their learning performance. Significant differences in readiness for remote education have been observed between urban and non-urban living areas: (1) The role of health-and-safety convenience seems to increase with the urbanization level of the respondents' living spaces; (2) in contrast, for non-urban residents, the provision of comfort facilities is dominant. In the meantime, an analysis "by regions" revealed that health-and-safety-related facilities in residences are more critical for remote education in Central Asia (KZ). In contrast, the comfort features of residences being more important for the students studying remotely in Northern Europe (NO). These results provide an understanding that would assist in improving remote education and preparing pandemic-ready living areas.

2.
Acta Biomater ; 151: 1-44, 2022 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-35921991

RESUMEN

For the first time, the present review critically evaluates biodegradable polymer matrix composites containing graphene-related materials (GRMs) for antibacterial applications while discussing their development, processing routes, mechanical properties, and antibacterial activity. Due to its suitable biological properties and processability, chitosan has been the most widely used biodegradable polymer for the fabrication of GRM-containing composites with antibacterial properties. The majority of biodegradable polymers (including cellulose-, gelatine-, PVA-, PCL-, and PHA-based polymers) exhibit little to no antibacterial effect alone; however, they show significant antibacterial activity (>70%) when combined with GRMs. In vitro and in vivo studies indicate that GRMs functionalization with biodegradable polymers also reduces potential GRM cytotoxicity. Overall, GRMs in biodegradable polymer matrices provide attractive antibacterial activity against a broad spectrum of bacteria (>30 different bacteria) along with improved mechanical properties over pristine polymers, where the type and the degree of improvement provided by GRMs depend on the specific matrix. For example, the addition of GRMs into chitosan, PVA, and PCL matrices increases their tensile strength by 80%, 180%, and 40%, respectively. Challenges remain in understanding the effects of processing routes and post-processing methods on the antibacterial activity and biocompatibility of biodegradable polymer/GRM composites. Given their promising properties and functionality, research on these composites is expected to further increase along with the implementation of new composite systems. These would include a wide range of applications, e.g., wound dressings, tissue engineering, drug delivery, biosensing, and photo-thermal therapy, as well as non-medical use, e.g., antibacterial food packaging, water treatment, and antibacterial fabrics. STATEMENT OF SIGNIFICANCE: Graphene-related materials (GRMs) in polymer matrices can provide excellent antibacterial activity against a broad spectrum of bacteria together with improved mechanical properties (e.g., tensile strength and elastic modulus) over pristine polymers; thus, research efforts and applications of biodegradable polymer matrix composites containing GRMs have increased notably in the last ten years. For the first time, the present review critically evaluates biodegradable polymer matrix composites containing GRMs for antibacterial applications while discussing their development, processing routes, mechanical properties, and antibacterial activity. Future research directions for each composite system are proposed to shed light on overcoming the existing challenges in composite performance (e.g., mechanical properties, toxicity) reported in the literature.


Asunto(s)
Quitosano , Grafito , Antibacterianos/farmacología , Celulosa , Quitosano/farmacología , Grafito/farmacología , Polímeros/farmacología , Resistencia a la Tracción
3.
Build Environ ; 219: 109234, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35645453

RESUMEN

COVID-19 pandemic has forced people to stay home and switch to the remote working mode, which - reportedly - affect job satisfaction and productivity. The present study investigates the relationship between the residential environment and worker's job satisfaction and productivity in the remote working mode during the COVID-19 pandemic. A hypothetical structural equation model (SEM) of the influencing factors is constructed based on a literature review and experts' opinions. A survey-based respondents' opinions (n = 2276) were then used to test and analyze the model. The model results reveal that a residential built environment has an indirect effect on both remote work satisfaction and productivity. However, among all the factors, comfortable space (separate space and ergonomic furniture) is found to be the most important. This study presents the importance of adopting a residential built environment to respond to a crisis like a pandemic in achieving the desired comfort level of remote work. Although this study provides a holistic approach, it also proposes a base for the future country-specific analysis by providing some possible countries' differences.

4.
Materials (Basel) ; 14(21)2021 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-34772101

RESUMEN

AA1050 Al alloy samples were shot-peened using stainless-steel shots at shot peening (SP) pressures of 0.1 and 0.5 MPa and surface cover rates of 100% and 1000% using a custom-designed SP system. The hardness of shot-peened samples was around twice that of unpeened samples. Hardness increased with peening pressure, whereas the higher cover rate did not lead to hardness improvement. Micro-crack formation and embedment of shots occurred by SP, while average surface roughness increased up to 9 µm at the higher peening pressure and cover rate, indicating surface deterioration. The areal coverage of the embedded shots ranged from 1% to 5% depending on the peening parameters, and the number and the mean size of the embedded shots increased at the higher SP pressure and cover rate. As evidenced and discussed through the surface and cross-sectional SEM images, the main deformation mechanisms during SP were schematically described as crater formation, folding, micro-crack formation, and material removal. Overall, shot-peened samples demonstrated improved mechanical properties, whereas sample surface integrity only deteriorated notably during SP at the higher pressure, suggesting that selecting optimal peening parameters is key to the safe use of SP. The implemented methodology can be used to modify similar soft alloys within confined compromises in surface features.

5.
Sustain Cities Soc ; 75: 103300, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34545318

RESUMEN

During COVID-19, the building and service characteristics of residential buildings turned out to be more critical due to lockdowns. The present research assesses the importance of new sustainability indicators for residential buildings in three categories (e.g., Health and Safety, Environmental Resources Consumption, and Comfort) that provide resilience for pandemic periods. The opinions of stakeholders on the identified indicators were collected and then analyzed. 'Health and Safety' category is found to be the most critical among the others. The prevention of virus propagation, mental health, and building air quality are three crucial indicators playing essential roles in the health and safety category. In more detail, innovative smart technologies, including touchless technologies, are identified as a priority in preventing virus propagation. Outdoor spaces and safe indoor places for socialization are weighted as essential in supporting the well-being and mental health of the resident. Finally, air filtration and segregation of medical waste indicators are considered critical in preventing the spread of viruses. There was a consensus among the local and international experts since they did not significantly report differing opinions for the majority of the indicators. However, there was a shift in experts' opinions towards pandemic-oriented indicators compared to conventional sustainability indicators.

6.
Environ Sci Pollut Res Int ; 28(19): 24406-24418, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-32266616

RESUMEN

A detailed characterization of municipal solid waste (MSW) beyond a standard compositional analysis may offer insights useful for improving waste management systems. The present paper contributes to the scarce literature in the field by presenting new data from a rapidly developing Central Asian city, the capital of Kazakhstan, Nur-Sultan. Three sampling campaigns (each 1 week long) have been conducted at the city landfill over a 1-year period (2018-2019), and a detailed characterization for selected waste components and sub-components has been performed. The major fractions of MSW were organics (46.3%), plastics (15.2%), paper (12.8%), and diapers (5.9%). The detailed composition analysis showed high LDPE (low-density polyethylene) content (5.5%) mostly comprised of plastic bags (4.5%), transparent glass (3.2%), pharmaceuticals (0.4%), and fine (i.e., < 12 mm) organic fraction content (29%). The MSW generation rate of Nur-Sultan was estimated as 1.47 kg capita-1 day-1 based on the field collection as well as literature data. Among sustainable waste management recommendations addressed for Nur-Sultan and applicable to other cities in Central Asia, composting is recommended due to high organics fraction in MSW and its great potential to reduce the landfilled waste volume and to help valorizing the waste.


Asunto(s)
Eliminación de Residuos , Administración de Residuos , Ciudades , Kazajstán , Residuos Sólidos/análisis , Instalaciones de Eliminación de Residuos
7.
MethodsX ; 8: 101577, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35004211

RESUMEN

The method presented in this paper aims to support the sustainability assessment methods of residential buildings under pandemic conditions. The main purpose of the study is to review existing criteria of the well-known assessment tools and then to suggest a set of assessment measures for the emerging pandemic-resilient indicators. Current sustainability assessment methodologies mostly focus on the conventional sustainability pillars (Environmental, Social, Economic), whereas the proposed emerging sustainability assessment indicators include changes in sustainability requirements brought by the current pandemic. Firstly, a set of indicators with possible measures was identified; then, we reviewed several existing green building certification systems to identify their gaps and developed a foundation for each indicator. Finally, several round table discussions involving various stakeholders (e.g., engineers, designers, health care experts, academics) were conducted to consolidate the identified measures. The findings of the present study indicate that certain pandemic-resilient indicators are not fully addressed by existing assessment tools, pointing out the importance of the development of new measures to make them more suitable to use under pandemic conditions. Thus, the present study contributes to the building assessment methods by proposing a set of emerging assessment indicators with measures, which can be used by various professionals that would contribute to more sustainable buildings in upcoming pandemics.•A 5-point scale was used to assess the indicators, and various stakeholders in a previous study identified their weights.•The methodology introduces new pandemic-related indicators into the conventional sustainability concept.•The assessment measures are rapid and economically efficient to apply for any residential building.

8.
Artículo en Inglés | MEDLINE | ID: mdl-33271828

RESUMEN

Mercury (Hg) emissions from anthropogenic sources pose a global problem. In Central Asia, Kazakhstan's central and northern regions are among the most severely Hg-contaminated territories. This is due to two former acetaldehyde (in Temirtau) and chlor-alkali (in Pavlodar) plants, discharges from which during the second half of the 20th century were estimated over 2000 tons of elemental Hg. However, the exact quantities of Hg released through atmospheric emissions to the environment, controlled discharges to the nearby aquatic systems, leakages in the cell plant, and contaminated sludge are still unknown. The present review is the initiation of a comprehensive field investigation study on the current state of these contaminated sites. It aims to provide a critical review of published literature on Hg in soils, sediments, water, and biota of the impacted ecosystems (Nura and Irtysh rivers, and Lake Balkyldak and their surrounding areas). It furthermore compares these contamination episodes with selected similar international cases as well as reviews and recommends demercuration efforts. The findings indicate that the contamination around the acetaldehyde plant site was significant and mainly localized with the majority of Hg deposited in topsoils and riverbanks within 25 km from the discharge point. In the chlor-alkali plant site, Lake Balkyldak in North Kazakhstan is the most seriously contaminated receptor. The local population of both regions might still be exposed to Hg due to fish consumption illegally caught from local rivers and reservoirs. Since the present field data is limited mainly to investigations conducted before 2010 and given the persisting contamination and nature of Hg, a recent up-to-date environmental assessment for both sites is highly needed, particularly around formerly detected hotspots. Due to incomplete site remediation efforts, recommendations given by several researchers for the territories of the former chlor-alkali and acetaldehyde plant site include ex-situ soil washing, soil pulping with gravitational separation, ultrasound and transgenic algae for sediments, and electrokinetic recovery for the former and removal and/or confinement of contaminated silt deposits and soils for the latter. However, their efficiency first needs to be validated. Findings and lessons from these sites will be useful not only on the local scale but also are valuable resources for the assessment and management of similar contaminated sites around the globe.


Asunto(s)
Restauración y Remediación Ambiental , Mercurio , Contaminantes Químicos del Agua , Animales , Canadá , Ecosistema , Monitoreo del Ambiente , Sedimentos Geológicos , Kazajstán , Mercurio/análisis , Contaminantes Químicos del Agua/análisis
9.
MethodsX ; 7: 101105, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33145182

RESUMEN

The presented method provides the details for how each indicator in "RSAM: A Rapid Sustainability Assessment Method" is scored using a residents' opinions-based sustainability assessment procedure that is specifically designed for the assessment of existing residential buildings. Existing methods in the literature mostly suggest indicator scores in construction sustainability assessments using highly technical data and require a high level of engineering and management expertise. This makes them elaborate but labor-, time-, and cost-intensive; and thus, their use is more frequently favored in new projects.•The presented method redefines a set of conventional environmental, social-functional, and economic indicators in a context which combines data from residents' opinions (e.g. perceived quality of indoor temperature comfort level) and easy-to-obtain information (e.g. annual utility bills).•All indicator ratings are represented within a 10-point scale, and their weights on the overall model are identified by stakeholders.•RSAM provides a rapid and low-cost assessment for existing buildings which normally may not go through a conventional sustainability assessment due to resource limitations.

10.
Materials (Basel) ; 13(19)2020 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-33008035

RESUMEN

Ti6Al4V alloy was shot peened by using stainless-steel shots with different sizes (0.09-0.14 mm (S10) and 0.7-1.0 mm (S60)) for two durations (5 and 15 min) using a custom-designed peening system. The shot size was the main parameter modifying the roughness (0.74 µm for S10 vs. 2.27 µm for S60), whereas a higher peening time slightly increased roughness. Hardness improved up to approximately 35% by peening with large shots, while peening time was insignificant in hardness improvement. However, longer peening duration with large shots led to an unwanted formation of micro-cracks and delamination on the peened surfaces. After dry sliding wear tests, the mass loss of peened samples (S60 for 15 min) was 25% higher than that of un-peened samples, while the coefficient of friction decreased by 12%. Plastically deformed regions and micro-scratches were observed on the worn surfaces, which corresponds to mostly adhesive and abrasive wear mechanisms. The present study sheds light on how surface, subsurface and tribological properties of Ti6Al4V vary with shot peening and peening parameters, which paves the way for the understanding of the mechanical, surface, and tribological behavior of shot peened Ti6Al4V used in both aerospace and biomedical applications.

11.
Environ Pollut ; 264: 114627, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32375089

RESUMEN

Contamination by potentially toxic elements (PTEs) in children's toys and jewelry is an ongoing problem where PTEs can become bioavailable especially via oral pathway (ingestion as a whole or of parts, and mouthing) and may cause adverse health effects for children. In the present review, legislation updates from the last decade in the United States (U.S.), Canada, and the European Union (E.U.) on PTEs in toys and jewelry are presented. Then, a literature review mostly covering the last decade on the total concentration, bioavailability, children's exposure, and bioaccessibility of PTEs in toys and jewelry is provided. The U.S. and Canadian legislations mainly focus on lead (Pb) and cadmium (Cd) total/soluble concentration limits to prevent exposure and have received several updates within the last decade, extending particularly the covered span of children's products. It seems that the introduction, subsequent enforcement, and update of regulations in developed countries have shifted the problem towards developing countries. In terms of categories, metallic toys and children's jewelry still have the most severe PTE contamination and the presence of Pb and Cd in these articles is an ongoing issue. Some studies suggest that color can be used as an indicator for the potential presence of PTEs (linked to chemicals such as lead chromate, cadmium sulfide) but the evidence is not always clear. Another concern is vintage/second-hand toys and jewelry as those items might have been produced before the legislation was present. As total and bioaccessible concentrations of PTEs in toys and jewelry do not always correlate, approaches considering bioaccessibility (e.g. of the E.U.) are more scientifically appropriate and help with better estimation of risk from exposure. Studies on toy and jewelry contamination using in vitro bioaccessibility techniques has become more common, however, there is still no in vitro test specifically designed and validated for toys and jewelry.


Asunto(s)
Joyas , Disponibilidad Biológica , Cadmio , Canadá , Niño , Humanos , Juego e Implementos de Juego
12.
Environ Sci Pollut Res Int ; 27(17): 21071-21083, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32266620

RESUMEN

Contamination by potentially toxic elements (PTEs) in children's toys and jewelry is an ongoing problem, and there is evidence in the literature that the issue is shifting towards developing countries and small markets. The present research aims (1) to characterize total concentrations of eleven PTEs (As, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Se, and Zn) in children's jewelry and toys purchased from the Central Asian market (n = 65), and (2) to investigate the relationship between the extent of contamination and sample categories/properties. The laboratory analyses showed that the majority of the samples had PTEs above the total and soluble limits for PTEs stated in the USA, Canadian, and the EU legislation. Particularly for metallic toys and jewelry (n = 46), the total concentrations in 45 samples exceeded the EU migration limits for one or more PTEs. In particular, Cu and Zn concentrations were extremely high (up to 100%) in many samples and highly toxic Cd and Pb were present in elevated quantities in several articles. Contamination was also present, albeit to a much lesser extent, in other toy categories: brittle/pliable toys for Co and Cr, plastic toys and jewelry for Pb, and other toys for Co. Although average values and visual observations suggested evidence, no statistically significant relationship between PTE concentrations and sample properties (color, price, and degree of appeal) could be found. The findings supported the evidence that the contamination issue in children's jewelry and toys by PTEs is an ongoing issue in developing countries. Very high total concentrations of PTEs particularly found in several metallic samples warrant further investigation of migratable concentrations. Thus, conducting bioaccessibility tests and a subsequent human health risk characterization is recommended. Overall, there is a potential risk for children in the case of exposure to PTEs from children's jewelry and toys sold on the Central Asian market. More effective enforcement of legislation for consumer goods in the region and raising public awareness regarding chemicals in children's products are recommended.


Asunto(s)
Joyas , Metales Pesados/análisis , Canadá , Niño , Humanos , Plásticos , Juego e Implementos de Juego , Medición de Riesgo
13.
Environ Monit Assess ; 192(1): 50, 2019 Dec 17.
Artículo en Inglés | MEDLINE | ID: mdl-31848713

RESUMEN

Arsenic (As) is among the most harmful toxic elements to human health with severe carcinogenic and non-carcinogenic effects. The present study aims to (1) characterize a site with geogenic As anomaly (Emet basin) in Kutahya, Turkey via soil (urban, agriculture, forest; n = 53 total), water (n = 11), and agricultural product (n = 19) samples; and, (2) characterize human health risks for different receptors under specific exposure scenarios. Soil As levels were very high (range, 22.4-765 mg kg-1). Previous literature suggested some evidence of Sb and Hg combined with As in mineral forms in the region; the present study found elevated Sb (up to 76.0 mg kg-1) in two regions with very high As levels, but Hg concentrations were low in the region. Soils from urban/agricultural zones (representing anthropogenic impact) did not have statistically different As levels compared with forest soils (representing low/no human impact). As water concentrations were also very high (range, 14.0-729 µg L-1), however, uptake by agricultural products was low, mostly limited to wheat (up to 0.7 mg kg-1). Exposure assessment/risk characterization showed that non-carcinogenic risk following exposure to soils was very high for children (hazard index up to 37 under reasonable maximum exposure) as well as carcinogenic risk (probability up to 1.19E-3). The risk was even higher considering intake of water, and in this case, both for children and adults (HI, 4.0-66.6; cancer risk, 1.29E-4-1.84E-2). The potential adverse outcomes of the As anomaly in the region may be grave, thus further geochemical investigation of As speciation and mobile fractions as well as gastrointestinal As bioaccessibility supplementing probabilistic human health risk characterization are recommended.


Asunto(s)
Antimonio/análisis , Arsénico/análisis , Exposición a Riesgos Ambientales/análisis , Mercurio/análisis , Contaminantes del Suelo/análisis , Adulto , Carcinógenos , Niño , Exposición a Riesgos Ambientales/estadística & datos numéricos , Monitoreo del Ambiente , Humanos , Medición de Riesgo , Suelo/química , Triticum , Turquía
14.
Sci Total Environ ; 692: 595-601, 2019 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-31539967

RESUMEN

Dermal exposure to metals has previously received less attention than oral/inhalation exposure. Nonetheless, human health risk is significant for certain contaminants and exposure scenarios. The present study aims to (1) characterize two certified reference soils (SQC001, BGS 102); and (2) assess Cr, Ni, Pb, and Zn dermal bioaccessibility via in vitro assays using three synthetic sweat formulations (EN 1811, pH 6.5 (Sweat A), NIHS 96-10, pH 4.7 (Sweat B), and a more complex pH 5.5 formulation containing amino acids (Sweat C)) and two sebum formulations. Metals bioaccessibility in sweat followed Sweat B > Sweat C > Sweat A, attributed to sweat B lower pH. Dermal bioaccessibility in both sebum formulations was lower than 1% for Ni and Pb and below 9% for Cr and Zn, possibly due to low affinity of metals for non-polar lipids. It must be noted that bioaccessible Zn in BGS 102 was higher when extracted with synthetic sebum compared to any of the synthetic sweat formulations. Metal bioaccessibility in sweat was considerably higher for SQC001 (up to 76.6% for Zn using Sweat B) than for BGS 102 (ranging between 0.02 and 1.3% for all elements and all sweat formulations), attributed to higher pH, higher organic carbon, and higher cation exchange capacity of reference soil BGS 102. Sebum formulations spiked with metals generally entailed low metal recovery (except for Zn), which may explain overall low bioaccessibility values for sebum. Sebum and sweat formulation, and soil properties seem to control in vitro dermal bioaccessibility of metals.


Asunto(s)
Monitoreo del Ambiente/métodos , Metales Pesados/metabolismo , Contaminantes del Suelo/metabolismo , Disponibilidad Biológica , Piel Artificial
16.
Chemosphere ; 197: 42-49, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29331717

RESUMEN

Dermal exposure to contaminated sites has generally received less attention than oral/inhalation exposure due to limited exposure scenarios and less perceived potential for toxicity, however, the risk can be significant for specific contaminants and scenarios. The present study aims to (1) measure Cr, Ni, Pb, and Zn contamination in soil and mine tailings samples (n = 7), (2) determine the dermal bioaccessibility of these metals via in vitro tests using two synthetic sweat formulations (EN 1811; NIHS 96-10), and (3) obtain dermal absorbed doses (DADs) for children's and adults' exposure scenarios and compare them to derived dermal reference values. The NIHS 96-10 formulation yielded higher bioaccessibility values for all metals than EN 1811, possibly due to its lower pH. Zn had the highest bioaccessibility for both formulations whereas Cr had the lowest. There was some evidence of adsorption of initially mobilized Pb and Zn to soil with longer test times, resulting in slightly lower bioaccessibility after 8 h of testing with respect to 2 h. The calculated DADs showed that the risk for exposure was acceptable (DAD < derived dermal reference value) for all metals except for Cr(VI) considering exposure to two of the samples. The risk in the case of children's exposure scenario (play on contaminated medium) was significantly higher than the case for the adults' exposure scenario (exposure in industrial context). Additional bioaccessibility research is recommended on additional samples with differing properties/contamination profiles, on additional contaminants with high dermal affinity (especially As), and on the development/validation of in vitro dermal bioaccessibility tests.


Asunto(s)
Exposición a Riesgos Ambientales/análisis , Metales/análisis , Contaminantes del Suelo/análisis , Adulto , Niño , Exposición a Riesgos Ambientales/estadística & datos numéricos , Monitoreo del Ambiente/métodos , Contaminación Ambiental/estadística & datos numéricos , Humanos , Metales Pesados/análisis , Minería , Medición de Riesgo/métodos , Suelo/química
17.
Sci Total Environ ; 579: 378-386, 2017 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-27887839

RESUMEN

The present study aims (1) to characterize contaminated soils (n=6) and mine tailings samples (n=3) for As, Cu, Fe, Mn, Ni, Pb, and Zn content; and (2) to assess elemental lung bioaccessibility in fine fraction (d<20µm which might contribute to airborne particulate matter (PM) and thus be inhaled) by means of in vitro tests using Gamble's solution (GS) and an artificial lysosomal fluid (ALF). Elemental concentrations were high in the majority of samples, particularly for As (up to 2040mg·kg-1), Fe (up to 30.7%), Mn (up to 4360mg·kg-1), and Zn (up to 4060mg·kg-1); and elemental concentrations (As, Cu, and Ni) in the sieved fraction (d<20µm) obtained from contaminated soils were significantly higher than in the bulk fraction (<160µm). In vitro tests with ALF yielded much higher bioaccessibility than tests with GS, and the use of ALF in addition to GS is recommended to assess lung bioaccessibility. Bioaccessibility in ALF was high for all elements after 2weeks of testing both in terms of concentration (e.g. up to 1730mg·kg-1 for As) and percentages (e.g. up to 81% for Pb). The elemental solubilization rate generally declined rapidly and continuously with time. Similarly, bioaccessibility increased rapidly and tended to reach a plateau with time for most samples and metals. However, it is not possible to recommend a general testing duration as the solubilization behavior was highly element and sample-specific.


Asunto(s)
Contaminantes Atmosféricos/análisis , Exposición a Riesgos Ambientales/análisis , Metales/análisis , Material Particulado/análisis , Contaminantes del Suelo/análisis , Exposición a Riesgos Ambientales/estadística & datos numéricos , Humanos , Pulmón , Minería
19.
Environ Sci Pollut Res Int ; 23(24): 24422-24434, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27080406

RESUMEN

Human exposure to particulate matter (PM) has been associated with adverse health effects. While inhalation exposure to airborne PM is a prominent research subject, exposure to PM of geological origin (i.e., generated from soil/soil-like material) has received less attention. This review discusses the contaminants in PM of geological origin and their relevance for human exposure and then evaluates lung bioaccessibility assessment methods and their use. PM of geological origin can contain toxic elements as well as organic contaminants. Observed/predicted PM lung clearance times are long, which may lead to prolonged contact with lung environment. Thus, certain exposure scenarios warrant the use of in vitro bioaccessibility testing to predict lung bioavailability. Limited research is available on lung bioaccessibility test development and test application to PM of geological origin. For in vitro tests, test parameter variation between different studies and concerns about physiological relevance indicate a crucial need for test method standardization and comparison with relevant animal data. Research is recommended on (1) developing robust in vitro lung bioaccessibility methods, (2) assessing bioaccessibility of various contaminants (especially polycyclic aromatic hydrocarbons (PAHs)) in PM of diverse origin (surface soils, mine tailings, etc.), and (3) risk characterization to determine relative importance of exposure to PM of geological origin.


Asunto(s)
Exposición por Inhalación/análisis , Pulmón/química , Material Particulado/análisis , Animales , Disponibilidad Biológica , Humanos , Pulmón/metabolismo , Material Particulado/metabolismo , Contaminantes del Suelo/análisis
20.
Environ Monit Assess ; 188(4): 222, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26969154

RESUMEN

The present study aims to transform a treated soil (TS) into a more desirable resource by modifying physico-chemical properties via amendments while reducing toxic metals' mobility and oral bioaccessibility. A hydrocarbon-contaminated soil submitted to treatment (TS) but still containing elevated concentrations of Cu, Ni, Pb, and Zn has been amended with compost, sand, and Al2(SO4)3 to render it usable for horticulture. Characterization and sequential extraction were performed for TS and four amended mixtures (AM1-4). P and K availability and metal bioaccessibility were investigated in TS and AM2. Amendment improved soil properties for all mixtures and yielded a usable product (AM2 20 % TS, 49 % compost, 30 % sand, 1 % Al2(SO4)3) satisfying regulatory requirements except for Pb content. In particular, AM2 had improved organic matter (OM) and cation exchange capacity (CEC), highly increased P and K availability, and reduced total metal concentrations. Furthermore, amendment decreased metal mobile fraction likely to be plant-available (in mg kg(-1), assumed as soluble/exchangeable + carbonates fractions). For AM2, estimated Pb bioavailability decreased from 1.50 × 10(3) mg kg(-1) (TS) to 238 mg kg(-1) (52.4 % (TS) to 34.2 %). Bioaccessible concentrations of Cu, Ni, and Zn (mg kg(-1)) were lower in AM2 than in TS, but there was no significant decrease for Pb. The results suggest that amendment improved soil by modifying its chemistry, resulting in lower metal mobile fraction (in %, for Cu and Zn) and bioaccessibility (in %, for Cu only). Amending soils having residual metal contamination can be an efficient valorization method, indicating potential for reducing treatment cost and environmental burden by rendering disposal/additional treatment unnecessary. Further studies including plant bioavailability are recommended to confirm results.


Asunto(s)
Exposición a Riesgos Ambientales/estadística & datos numéricos , Contaminación Ambiental/estadística & datos numéricos , Restauración y Remediación Ambiental/métodos , Metales Pesados/análisis , Contaminantes del Suelo/análisis , Suelo/química , Zinc/análisis , Disponibilidad Biológica , Cobre/análisis , Monitoreo del Ambiente , Humanos , Plomo/análisis , Níquel/análisis
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