خيارات البحث
النتائج 1 - 8 من 8
Focus topics on microplastics in soil: Analytical methods, occurrence, transport, and ecological risks
2020
Li, Jia | Song, Yang | Cai, Yongbing
Microplastics with extremely high abundances are universally detected in marine and terrestrial systems. Microplastic pollution in the aquatic environment, especially in ocean, has become a hot topic and raised global attention. However, microplastics in soils has been largely overlooked. In this paper, the analytical methods, occurrence, transport, and potential ecological risks of microplastics in soil environments have been reviewed. Although several analytical methods have been established, a universal, efficient, faster, and low-cost analytical method is still not available. The absence of a suitable analytical method is one of the biggest obstacles to study microplastics in soils. Current data on abundance and distribution of microplastics in soils are still limited, and results obtained from different studies differ significantly. Once entering into surface soil, microplastics can migrate to deep soil through different processes, e.g. leaching, bioturbation, and farming activities. Presence of microplastics with high abundance in soils can alter fundamental properties of soils. But current conclusions on microplastics on soil organisms are still conflicting. Overall, research on microplastics pollution in soils is still in its infancy and there are gaps in the knowledge of microplastics pollution in soil environments. Many questions such as pollution level, ecological risks, transport behaviors and the control mechanisms are still unclear, which needs further systematical study.
اظهر المزيد [+] اقل [-]A typical derivative and byproduct of tetrabromobisphenol A: Development of novel high-throughput immunoassays and systematic investigation of their distributions in Taizhou, an e-waste recycling area in eastern China
2020
Environmental distribution and concentration of tetrabromobisphenol A bis- (2-hydroxyethyl) ether (TBBPA-DHEE) and tetrabromobisphenol A mono- (hydroxyethyl) ether (TBBPA-MHEE), are obscure due to the lack of available analytical methods. Here two novel immunoassays were established to systematically investigate their distributions in Taizhou, Eastern China. Five monoclonal antibodies against pollutants were generated with two designed haptens through animal immunization. After matched with different coating antigens/antibodies, ELISAs were established (LOD for TBBPA-DHEE, 0.12 ng/mL, based on OVA-M3/mAb-D4G6; LOD for TBBPA-MHEE, 0.79 ng/mL, based on OVA-M3/mAb-D2G6) and applied for investigation of their occurrences at a typical e-waste recycling area after 2-year samples collection, where the total 33 water, 32 soil and 16 biological samples were collected with the highest concentrations of 3.46 ng/mL, 2.76 ng/g (dry weight, dw) and 5.01 ng/g (dw), respectively. Meanwhile, our study also indicated that at the centralizing e-waste recycling sites the serious pollution for both chemicals still existed despite of various efforts. Besides, obvious improvements were observed at an abandoned e-waste recycling region treated and remedied for many years by the local Chinese government. These findings highlight the importance of policy decisions in treatment of pollutants to reduce organic pollutant-related health risks.
اظهر المزيد [+] اقل [-]Transformation and degradation of polycyclic aromatic hydrocarbons (PAHs) in urban road surfaces: Influential factors, implications and recommendations
2020
Gbeddy, Gustav | Goonetilleke, Ashantha | Ayoko, G. A. (Godwin A.) | Egodawatta, Prasanna
Polycyclic aromatic hydrocarbons (PAHs) are prone to post-emission transformation and degradation to yield transformed PAH products (TPPs) that are potentially more hazardous than parent PAHs. This review provides a comprehensive evaluation of the potential environmental processes of PAHs such as sorption, volatilisation, photo- and bio-transformation and degradation on road surfaces, a significant accumulation point of PAHs. The review primarily evaluates key influential factors, toxicity implications, PAHs and TPPs fate and viable options for mitigating environmental and human health impacts. Photolysis was identified as the most significant transformation and degradation process due to the light absorption capacity of most PAHs. Climate conditions, physicochemical properties of road dust (sorbent), PAHs and TPPs and the existence of heavy metals such as Fe (III) are notable underlying factors for photolysis. Available data points to the predominance of carbonyl TPPs than other products such as nitro and hydroxyl TPPs with decreasing concentration trend of 9-fluorenone > 9,10-anthraquinone > benzo[a]fluorenone on road surfaces. The review recommends conducting future investigations targeting the influential factors pertaining to the fate of road deposited PAHs and TPPs. Furthermore, development of cost and time effective modern analytical methods is needed to quantify PAHs and TPPs present in minute quantities of samples. The review also identified that the unavailability of toxicity equivalency factors (TEF) for the most critical TPPs can be addressed using quantitative structure-activity relationship (QSAR) models and bioassays simultaneously. The content of this review is significant to the future work of researchers across various fields including analytical and environmental chemistry, stormwater pollution and toxicology.
اظهر المزيد [+] اقل [-]Study of Arsenic-Contaminated Soil Bacterial Community Using Biochip Technology
2020
Bunin, Evgeni | Khatisashvili, Gia | Varazi, Tamar | Kartvelishvili, Tamar | Asatiani, Nino | Sapojnikova, Nelly
The ecosystems near arsenic mining industrial areas are characterized with an elevated level of pollutants. In Caucasus region, such a hotspot is presented in Western Georgia: Uravi and Tsana abandoned arsenic production facilities and nearby mining tailings stored in deteriorating conditions that pose a threat to the population. The research presents a study of the local bacteria community of highly arsenic-contaminated soils (from 400 mg/kg at Uravi arsenic sulfide mineral processing facility to 11.3 g/kg at arsenic oxide storage area in Tsana) using an innovative, multitasking microscale bioanalytical method for environmental enquiries – DNA biochip (microarray). The detected Shewanella spp., Bacillus spp., and sulfate-reducing bacteria were considered as promising objects for future projects on in situ recovery of vast arsenic-contaminated areas applying remediation methods.
اظهر المزيد [+] اقل [-]A New Contaminant Superhighway? A Review of Sources, Measurement Techniques and Fate of Atmospheric Microplastics
2020
Mbachu, Oluchi | Jenkins, Graham | Pratt, Chris | Kaparaju, Prasad
Microplastic pollution is a significant and growing environmental issue. Recent studies have evaluated the atmosphere as an important pathway of microplastic contamination. Airborne microplastics can be transported long distances and accumulate in various terrestrial and aquatic environmental matrices, where they represent a threat to the biosphere. This review systematically summarizes the existing knowledge on airborne microplastics, including the different sampling and analytical techniques, occurrence and sources. We investigate the different sample collection techniques from street dust to indoor and outdoor air and examined sample preparation, pre-treatment and characterization techniques. We further explored the key factors with respect to their occurrence in the environment such as concentration levels, polymer composition, size distribution, shape and colour characteristics. The sources of airborne microplastics were also summarized. The results show that microplastics are ubiquitous in all atmospheric compartments including street dust and indoor and outdoor air at various concentrations, which is influenced by the community’s lifestyle choices, anthropogenic activities and meteorological conditions. Various forms of microplastics including spherules, film, fragments, fibres and granules were identified with fibrous microplastics being the most dominant. Additionally, microplastics of 20 different polymers and varying colour characteristic have been reported in studies focusing on airborne microplastic contamination. The size distribution of microplastics varied among the studied air compartments; however, they were mostly distributed towards the smaller size ranges, less than 1 mm. Our review highlights a need to consider atmospheric pathways in addition to soil and water migration dispersion processes for any holistic assessments of microplastic threats to the biosphere. Moreover, standardization of airborne microplastic sampling methods is needed to optimize the effectiveness of future work in this area. Graphical Abstract Microplastics in atmospheric environments
اظهر المزيد [+] اقل [-]A Green Analytical Method for Pre-concentration of Uranium in Water Samples Using Minicolumn with Sugarcane Bagasse
2020
de S. Dias, Fábio | Carvalho, Marcos A. | Carneiro, Candice N. | da Silva, Rodrigo F.
This study proposes a method based on solid-phase extraction using a minicolumn with sugarcane bagasse for pre-concentration uranium in water samples. The first optimization step was used factorial design in two levels (2⁵) for the preliminary assessment of factors: elution flow, sample flow, pH, buffer concentration, and eluent concentration. From this design, it was found that all variables showed significant influence. In the second stage, using the Doehlert design with 5 variables, the optimal conditions were determined: pH 8.3, flow elution 5.5 mL min⁻¹, buffer concentration 0.045 mol L⁻¹, sample flow 5.5 mL L⁻¹, and eluent solution (ascorbic acid 0.6% w/v in medium of hydrochloric acid at a final concentration of 0.06 mol L⁻¹). The method was applied to the determination of uranium with a detection limit (LD) of 0.41 μg L⁻¹ and quantification (LOQ) of 1.40 μg L⁻¹, Relative standard deviation (RSD) 2.5 and 1.3% uranium concentration of 20 and 60 μg L⁻¹, respectively. The factor of pre-concentration for the system is 46 for a sample volume of 50 mL. The accuracy was confirmed by the spike test. The procedure was applied for the determination of uranium in tap water, well water, and human consumption; the samples were collected in the municipalities of Caetité, Cruz das Almas, Itabuna, Aramari-BA, and seawater samples from Todos os Santos Bay. Uranium concentrations were found in the analyzed samples varying from 7.0 to 16.5 μg L⁻¹.
اظهر المزيد [+] اقل [-]An innovative approach for the simultaneous quantitative screening of organic plastic additives in complex matrices in marine coastal areas
2020
Castro-Jiménez, Javier | Ratola, Nuno
Aiming the simultaneous determination of widely used organic plastic additives in complex marine matrices, this work proposes a fast and “green” analytical protocol based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) technology. The validation of this innovative method on real matrices (i.e., sediments, mussel, fish, and Posidonia oceanica) indicated a general good performance in all of them for phthalate esters (PAEs), with low blank levels and average method recoveries varying from 54 ± 11 to 71 ± 12%. The best method performance for organophosphate ester (OPE) flame retardants and plasticizers was in biotic matrices (recoveries 52 ± 31 to 86 ± 38%). This application represents an innovative QuEChERS sequence of two dispersive solid-phase extraction (SPE) steps enabling this approach for the determination of important families of organic plastic additives in the marine environment. Indeed, our method allowed the fast screening and simultaneous determination of OPE and PAEs in various sites and matrices subject to different anthropogenic pressure in coastal NW Mediterranean Sea for the first time. ∑₇PAE and ∑₉OPE concentrations of 19–83 and 27–116 ng g⁻¹ dw (fish), of 80–714 and 42–71 ng g⁻¹ dw (mussels), of 192–908 and 47–151 ng g⁻¹ dw (Posidonia oceanica), and of 11–328 and 4–10 ng g⁻¹ dw (sediment) were measured, respectively. Our approach was sensible enough as to detect differences in the (bio)accumulation patterns of the target compounds in various species and/or sites. This application opens new perspectives for environmentally friendly marine environment monitoring and screening campaigns for organic plastic additives. Graphical abstract
اظهر المزيد [+] اقل [-]Remediation of brownfields contaminated by organic compounds and heavy metals: a bench-scale test of a sulfur/vermiculite sorbent for mercury vapor removal
2020
Topka, Pavel | Soukup, Karel | Hejtmánek, Vladimír | Hlásenský, Ivo | Kaštánek, František | Šolcová, Olga
In this study, we report for the first time a novel type of sorbent that can be used for mercury adsorption from the air-based off-gasses—vermiculite impregnated with alkali polysulfides and thiosulfates. In contrast to other sorbents, vermiculite exhibits superior thermal stability in air and low adsorption capacity for organic vapors. This allows for a more favorable design of the soil remediation unit—direct coupling of thermal desorber with catalytic oxidizer using air as a carrier gas. In the bench-scale test at 180 °C, the sulfur/vermiculite sorbent exhibited significantly higher efficiency for the adsorption of mercury vapor from the off-gasses than the commercial sulfur/activated carbon sorbent at its highest operating temperature (120 °C). The average mercury concentration in the adsorber off-gas decreased from 1.634 mg/m³ for the sulfur/activated carbon to 0.008 mg/m³ achieved with impregnated vermiculite. The total concentration of organic compounds in the soil after thermal desorption was below the detection limit of the employed analytical method.
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