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BTEX indoor air characteristic values in rural areas of Jordan: Heaters and health risk assessment consequences in winter season Полный текст
2020
Alsbou, Eid M. | Omari, Khaled W.
Benzene, toluene, ethylbenzene, and xylene isomers (BTEX) are known to affect environmental air and health quality. In this study, the levels of BTEX compounds were determined in indoor air environments during the winter generated by several different heaters: diesel pot-bellied heater with chimney (DH); electric heater (EH); unfluted gas heater (GH); kerosene heater (KH); and wood pot-bellied heater with chimney (WH). The samples were collected using a diffusion passive adsorbent (activated charcoal) and then analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the heaters differ in the quantity of BTEX released during operation. The KH was the most polluted heater based on BTEX measurement, followed by DH. The ∑BTEX for heaters were observed as follows: KH (290 μg m⁻³); DH (120 μg m⁻³); GH (84 μg m⁻³); WH (31 μg m⁻³); EH (16 μg m⁻³). Toluene was the predominant compound in all air samples. In KH and DH, the toluene to benzene ratios (T/B) were higher than 4 due to fuel evaporation, while GH had a T/B ratio of 3.9, indicating that the combustion of liquefied petroleum gas (LPG) was the main source. Moreover, a risk assessment was performed to evaluate where the cancer risks (CR) for benzene and ethylbenzene exceeded the critical values (10⁻⁶). KH was found to be the most harmful heater for residents, followed by DH and GH. For non-carcinogenic compounds, hazard quotients (HQ) were found to be less than one and thus unlikely to cause health problems.
Показать больше [+] Меньше [-]Fate of microplastics in wastewater treatment plants and their environmental dispersion with effluent and sludge Полный текст
2020
Edo, Carlos | González-Pleiter, Miguel | Leganés, Francisco | Fernández-Piñas, Francisca | Rossal S., J. Roberto (Julio Roberto Rossal Salazar)
This work studied the occurrence of microplastics in primary and secondary effluents and mixed sludge of a WWTP as well as in processed heat-dried sludge marketed as soil amendment. Sampled microparticles were divided into fragments and fibres, the latter defined as those with cylindrical shape and length to diameter ratio >3. We showed the presence of 12 different anthropogenic polymers or groups of polymers with a predominance of polyethylene, polypropylene, polyester and acrylic fibres together with an important amount of manufactured natural fibres. The smaller sampled fraction, in the 25–104 μm range, was the largest in both primary and secondary effluents. Fibres displayed lower sizes than fragments and represented less than one third of the anthropogenic particles sampled in effluents but up to 84% of heat-dried sludge. The plant showed a high efficiency (>90%) in removing microplastics from wastewater. However, the amount of anthropogenic plastics debris in the 25 μm - 50 mm range still released with the effluent amounted to 12.8 ± 6.3 particles/L, representing 300 million plastic debris per day and an approximate load of microplastics of 350 particles/m³ in the receiving Henares River. WWTP mixed sludge contained 183 ± 84 particles/g while heat-dried sludge bore 165 ± 37 particles/g. The sludge of the WWTP sampled in this work, would disseminate 8 × 10¹¹ plastic particles per year if improperly managed. The agricultural use of sludge as soil amendment in the area of Madrid could spread up to 10¹³ microplastic particles in agricultural soils per year.
Показать больше [+] Меньше [-]Kitchen concentrations of fine particulate matter and particle number concentration in households using biomass cookstoves in rural Honduras Полный текст
2020
Benka-Coker, Megan L. | Peel, Jennifer L. | Volckens, John | Good, Nicholas | Bilsback, Kelsey R. | L’Orange, Christian | Quinn, Casey | Young, Bonnie N. | Rajkumar, Sarah | Wilson, Ander | Tryner, Jessica | Africano, Sebastian | Osorto, Anibal B. | Clark, Maggie L.
Cooking and heating with solid fuels results in high levels of household air pollutants, including particulate matter (PM); however, limited data exist for size fractions smaller than PM₂.₅ (diameter less than 2.5 μm). We collected 24-h time-resolved measurements of PM₂.₅ (n = 27) and particle number concentrations (PNC, average diameter 10–700 nm) (n = 44; 24 with paired PM₂.₅ and PNC) in homes with wood-burning traditional and Justa (i.e., with an engineered combustion chamber and chimney) cookstoves in rural Honduras.The median 24-h PM₂.₅ concentration (n = 27) was 79 μg/m³ (interquartile range [IQR]: 44–174 μg/m³); traditional (n = 15): 130 μg/m³ (IQR: 48–250 μg/m³); Justa (n = 12): 66 μg/m³ (IQR: 44–97 μg/m³). The median 24-h PNC (n = 44) was 8.5 × 10⁴ particles (pt)/cm³ (IQR: 3.8 × 10⁴–1.8 × 10⁵ pt/cm³); traditional (n = 27): 1.3 × 10⁵ pt/cm³ (IQR: 3.3 × 10⁴–2.0 × 10⁵ pt/cm³); Justa (n = 17): 6.3 × 10⁴ pt/cm³ (IQR: 4.0 × 10⁴–1.2 × 10⁵ pt/cm³). The 24-h average PM₂.₅ and particle number concentrations were correlated for the full sample of cookstoves (n = 24, Spearman ρ: 0.83); correlations between PM₂.₅ and PNC were higher in traditional stove kitchens (n = 12, ρ: 0.93) than in Justa stove kitchens (n = 12, ρ: 0.67). The 24-h average concentrations of PM₂.₅ and PNC were also correlated with the maximum average concentrations during shorter-term averaging windows of one-, five-, 15-, and 60-min, respectively (Spearman ρ: PM₂.₅ [0.65, 0.85, 0.82, 0.71], PNC [0.74, 0.86, 0.88, 0.86]).Given the moderate correlations observed between 24-h PM₂.₅ and PNC and between 24-h and the shorter-term averaging windows within size fractions, investigators may need to consider cost-effectiveness and information gained by measuring both size fractions for the study objective. Further evaluations of other stove and fuel combinations are needed.
Показать больше [+] Меньше [-]Use of chemical concentration changes in coastal sediments to compute oil exposure dates Полный текст
2020
Xia, Junfei | Zhang, Wei | Ferguson, Alesia C. | Mena, Kristina D. | Özgökmen, Tamay M. | Solo-Gabriele, Helena M.
Oil spills can result in changes in chemical contaminant concentrations along coastlines. When concentrations are measured along the Gulf of Mexico over time, this information can be used to evaluate oil spill shoreline exposure dates. The objective of this research was to identify more accurate oil exposure dates based on oil spill chemical concentrations changes (CCC) within sediments in coastal zones after oil spills. The results could be used to help improve oil transport models and to improve estimates of oil landings within the nearshore. The CCC method was based on separating the target coastal zone into segments and then documenting the timing of large increases in concentration for specific oil spill chemicals (OSCs) within each segment. The dataset from the Deepwater Horizon (DWH) oil spill was used to illustrate the application of the method. Some differences in exposure dates were observed between the CCC method and between oil spill trajectories. Differences may have been caused by mixing at the freshwater and sea water interface, nearshore circulation features, and the possible influence of submerged oil that is unaccounted for by oil spill trajectories. Overall, this research highlights the benefit of using an integrated approach to confirm the timing of shoreline exposure.
Показать больше [+] Меньше [-]Environmental temperature and human epigenetic modifications: A systematic review Полный текст
2020
Xu, Rongbin | Li, Shuai | Guo, Shuaijun | Zhao, Qi | Abramson, Michael J. | Li, Shanshan | Guo, Yuming
The knowledge about the effects of environmental temperature on human epigenome is a potential key to understand the health impacts of temperature and to guide acclimation under climate change. We performed a systematic review on the epidemiological studies that have evaluated the association between environmental temperature and human epigenetic modifications. We identified seven original articles on this topic published between 2009 and 2019, including six cohort studies and one cross-sectional study. They focused on DNA methylation in elderly people (blood sample) or infants (placenta sample), with sample size ranging from 306 to 1798. These studies were conducted in relatively low temperature setting (median/mean temperature: 0.8–13 °C), and linear models were used to evaluate temperature-DNA methylation association over short period (≤28 days). It has been reported that short-term ambient temperature could affect global human DNA methylation. A total of 15 candidate genes (ICAM-1, CRAT, F3, TLR-2, iNOS, ZKSCAN4, ZNF227, ZNF595, ZNF597, ZNF668, CACNA1H, AIRE, MYEOV2, NKX1-2 and CCDC15) with methylation status associated with ambient temperature have been identified. DNA methylation on ZKSCAN4, ICAM-1 partly mediated the effect of short-term cold temperature on high blood pressure and ICAM-1 protein (related to cardiovascular events), respectively. In summary, epidemiological evidence about the impacts of environment temperature on human epigenetics remains scarce and limited to short-term linear effect of cold temperature on DNA methylation in elderly people and infants. More studies are needed to broaden our understanding of temperature related epigenetic changes, especially under a changing climate.
Показать больше [+] Меньше [-]Tossed ‘good luck’ coins as vectors for anthropogenic pollution into aquatic environment Полный текст
2020
Martínez, Alejandro | Di Cesare, Andrea | Mari-Mena, Neus | García-Gómez, Guillermo | Garcia-Herrero, Alvaro | Corno, Gianluca | Fontaneto, Diego | Eckert, Ester M.
Superstition has it that tossing coins into wells or fountains brings good luck, thereby causing a potential accumulation of microbially contaminated metal particles in the water. Here, we characterized the microbiota and the resistance profile in biofilm on such coins and their surrounding sediments. The study site was a tidal marine lake within a touristic center located in a natural reserve area. Notwithstanding the fact that coin-related biofilms were dominated by typical marine taxa, coin biofilms had specific microbial communities that were different from the communities of the surrounding sediment. Moreover, the communities were different depending on whether the coin were made mainly of steel or of copper. Sequences affiliated with putative pathogens were found on every third coin but were not found in the surrounding sediment. Antibiotic resistance genes (ARGs) were detected on most of the coins, and interestingly, sediments close to the area where coins accumulate had a higher frequency of ARGs. We suggest that the surface of the coins might offer a niche for ARGs and faecal bacteria to survive, and, thus, tossed coins are a potential source and vector for ARGs into the surrounding environment.
Показать больше [+] Меньше [-]An epifluorescence-based technique accelerates risk assessment of aggregated bacterial communities in carcass and environment Полный текст
2020
Mahmoud, M.A.M. | Zaki, R.S. | Abd- Elhafeez, H.H.
The severe and pervasive effects of multispecies foodborne microbial biofilms highlight the importance of rapid detection and diagnosis of contamination risk in the field using epifluorescence-based techniques (EBT) combined with automatic image-counting software. This study screened the hygiene quality of the environment, the carcass and the slaughtering equipment in the El-Kharga abattoir, New Valley Province, Egypt, to assess possible contamination during slaughter process. In addition, biofilm was assessed, and bacteria was enumerated by epifluorescence microscopy. Using both conventional and EBT, the highest bacterial counts were observed for the slaughtering equipment (6.6 and 5.2 cfu/cm2, respectively), followed by different parts of the carcass (4.1 and 4.4 cfu/cm2, respectively) and environmental samples (3.9 and 4.1 cfu/cm2, respectively). A high prevalence of E. coli O157:H7 was observed on the slaughtering equipment (25%), which also led to carcass (1%) contamination. Moreover, Enterobacteriaceae members were detected during examination, such as Klebsiella pneumoniae, Enterobacter aerogenes, and Raoultella ornithinolytica. Despite the relatively good hygiene quality of the abattoir environment, there is also a high risk associated with biofilm formation by pathogenic microorganisms on the slaughtering equipment. Moreover, EBT showed different structures of the biofilm, including those formed at different maturation stages, such as voids, microbubbles, channels and mushroom shapes. (EBT) microscopy combined with image-counting software could be a candidate substitute to estimate efficiently, precisely and rapidly the microbial aggregation and exposure risk in field than the conventional counting techniques.
Показать больше [+] Меньше [-]Effect of dibutyl phthalate on microbial function diversity and enzyme activity in wheat rhizosphere and non-rhizosphere soils Полный текст
2020
Gao, Minling | Dong, Youming | Zhang, Ze | Song, Zhengguo
The pollution of farm soils by the plasticizer dibutyl phthalate (DBP) should be researched owing to the extensive use of plastic film. We investigated the influence of DBP on microbial communities and enzyme activities in rhizosphere and non-rhizosphere soil during the different growth stages of wheat and determined the response through simulations. The results indicated that protease, polyphenol oxidase, and β-glucosidase activity in soil decreased with increasing DBP dosage, while dehydrogenase, urease, and acid phosphatase activities increased. Moreover, the effects of DBP on soil enzyme activity gradually weakened with DBP degradation. Dibutyl phthalate has a certain inhibitory effect on the activity, diversity, and heterogeneity of microorganisms in soil. In addition, DBP can increase the utilization of amines and carboxylic acids and decrease the utilization of carbohydrates and amino acids by soil microorganisms. According to the Gaussian and molecular docking analysis, we considered that monobutyl phthalate and DBP could affect the utilization of amino acids by Proteobacteria. The enzyme activity, microbial activity, and heterogeneity of rhizosphere soil were higher than those of non-rhizosphere soil. Microbial carbon source utilization in rhizosphere and non-rhizosphere soils depends on wheat growth, soil type, and DBP dosage. Owing to the widespread presence of DBP in agriculture, negative effects of phthalic acid esters should be considered in relation to soil quality and food safety in future.
Показать больше [+] Меньше [-]Microplastic ingestion rates are phenotype-dependent in juvenile anemonefish Полный текст
2020
Nanninga, Gerrit B. | Scott, Anna | Manica, Andrea
The potential influence of microplastic debris on marine organisms is an issue of great ecological and socioeconomic concern. Experiments exposing fishes and invertebrates to constant concentrations of microplastics often yield high variation in particle ingestion rates among individuals. Yet, despite an increasing interest in microplastic ingestion in the wild, the potential intrinsic drivers of inter-individual variation have received little attention so far. Here we assessed individual-level ingestion of Polyethylene microspheres by laboratory-reared juvenile anemonefish, Amphiprion ocellaris, in relation to (a) ambient particle concentrations and (b) repeatable behavioural traits. We show that microplastic ingestion is highly variable at all tested particle concentrations and that this variation can partially be explained by individual activity levels. Moreover, the relationship between ingestion and behavioural variation increased notably when only the most behaviourally consistent individuals (n = 40 out of 60) were considered in the analysis. Our findings indicate that microplastic ingestion rates in juvenile reef fishes may be less dependent on ambient concentrations than expected; instead they are to some degree phenotype-dependent. Care should thus be taken when reporting mean responses to microplastic exposure treatments, because some individuals may not be affected in the same way as others due to differential ingestion behaviour. We also discuss potential ramifications of non-random ingestion variability on population- and community-level responses.
Показать больше [+] Меньше [-]Biochar induced modification of graphene oxide & nZVI and its impact on immobilization of toxic copper in soil Полный текст
2020
Mandal, Sandip | Pu, Shengyan | He, Lingling | Ma, Hui | Hou, Deyi
Biochar has recently been fascinating for research in many environment areas due to its potential applications. In this research, graphene, and nano zero-valent iron (nZVI) were integrated with biochar and used for copper immobilization in the soil. Initially, the biomass feedstock was pyrolyzed under N₂ atmosphere from 150 to 650 °C and immersed in an aqueous solution containing graphene, and then impregnated with nZVI. Laboratory characterization with different instruments (eg. SEM, TEM, XRD, UV–Vis, VSM, and XPS) showed that graphene sheets and reactive nZVI were loaded on the biochar surface during the development process. The 450 °C was considered as optimum pyrolysis temperature based on the effective surface properties of the obtain biochar material. Boehm titration and functional group analysis confirmed the presence of carboxylic groups, phenolic groups in the corn stack biochar supported graphene oxide/nZVI (CTBC-GO/nZVI). Thermogravimetric analysis showed that nZVI incorporation to biochar surface could improve thermal stability as compared to graphene oxide incorporated biochar and pristine biochar. The material was utilized for copper (Cu) immobilization in the soil and a comparative evaluation was established on the basis of efficiency. The soil experiment showed that the CTBC-GO/nZVI has a superior immobilization efficiency of copper than pristine biochar and GO@BC. The available Cu content decreased by > 65% in CTBC-GO/nZVI amended soil after 14 days. Sequential extraction procedure (SEP) results suggested that CTBC-GO/nZVI promoted the conversion of more accessible Cu into the less accessible and bioavailable forms to reduce the toxicity of Cu. Therefore, CTBC-GO/nZVI composite is a promising and effective amendment for immobilizing Cu in contaminated soils and improving soil properties.This work can put forward a strategy to develop magnetic biochar composites and an application towards toxic heavy metals immobilization in soil.
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