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Reproductive dysfunction linked to alteration of endocrine activities in zebrafish exposed to mono-(2-ethylhexyl) phthalate (MEHP) Full text
2020
Park, Chang-Beom | Kim, Ko-ŭn | Kim, Yŏng-jun | On, Jiwon | Pak, Ch'ang-gyun | Kwon, Young-Sang | Pyo, Heesoo | Yeom, Dong-Huk | Cho, Sung Hee
This study aimed to investigate the effect of mono-(2-ethylhexyl) phthalate (MEHP), one of the major phthalate metabolites that are widespread in aquatic environments, on reproductive dysfunction, particularly on endocrine activity in adult male and female zebrafish. For 21 days, the zebrafish were exposed to test concentrations of MEHP (0, 2, 10, and 50 μg/mL) that were determined based on the effective concentrations (ECx) for zebrafish embryos. Exposure to 50 μg/mL MEHP in female zebrafish significantly decreased the number of ovulated eggs as well as the hepatic VTG mRNA abundance when those of the control group. Meanwhile, in female zebrafish, the biosynthetic concentrations of 17β-estradiol (E2) and the metabolic ratio of androgen to estrogen were remarkably increased in all MEHP exposed group compared with those in the control group, along with the elevated levels of cortisol. However, no significant difference was observed between these parameters in male zebrafishes. Therefore, exposure to MEHP causes reproductive dysfunction in female zebrafishes and this phenomenon can be attributed to the alteration in endocrine activities. Moreover, the reproductive dysfunction in MEHP-exposed female zebrafishes may be closely associated with stress responses, such as elevated cortisol levels. To further understand the effect of MEHP on the reproductive activities of fish, follow-up studies are required to determine the interactions between endocrine activities and stress responses. Overall, this study provides a response biomarker for assessing reproductive toxicity of endocrine disruptors that can serve as a methodological approach for an alternative to chronic toxicity testing.
Show more [+] Less [-]Atmospheric pollution revealed by trace elements in recent snow from the central to the northern Tibetan Plateau Full text
2020
Li, Yuefang | Huang, Ju | Li, Zhen | Zheng, Kui
In order to determine the current levels, spatial distribution patterns, and potential pollution of trace elements (TEs) in the atmosphere of the Tibetan Plateau (TP), snow pit samples were collected in May 2016 from five TP glaciers: Qiyi (QY), Hariqin (HRQ), Meikuang (MK), Yuzhufeng (YZF), and Xiaodongkemadi (XDKMD). Concentrations of 13 TEs (Al, Ba, Cd, Co, Cr, Cu, Fe, Li, Pb, Sb, Sr, U, and Zn) in the snow were measured. The spatial distribution patterns and depth profiles of TEs from the studies sites revealed that the influence of dust on TEs was more significant on the MK and YZF glaciers than on the QY, HRQ, and XDKMD glaciers. The spatial distributions of TE EFFₑ values differed from their concentrations, however. The enrichment factor (EF) values and concentrations of some TEs in the YZF, QY, and XDKMD glaciers revealed that the pollution levels of these elements were significantly lower than those found in previous research. Examination based on EFs, principal component analysis, as well as the calculated non-dust contributions of TEs, revealed that dust was the principal source for most TEs in all five glaciers, while biomass burning was another potential natural source for TEs in some glaciers, such as QY. In contrast, Cd, Ba, Sr, Cu, Pb, Zn, and Sb were occasionally affected by anthropogenic sources such as road traffic emissions, fossil fuel combustion, and mining and smelting of nonferrous metals in and beyond the TP. Air mass backward trajectories revealed that potential pollutants were transported not only from local sources but also from Xinjiang Province in northwestern China, as well as South Asia, Central Asia, the Middle East, and Europe.
Show more [+] Less [-]Insights into acetate-mediated copper homeostasis and antioxidant defense in lentil under excessive copper stress Full text
2020
Shahadat Hossain, Md. | Abdelrahman, Mostafa | Tran, Cuong Duy | Nguyen, Kien Huu | Chu, Ha Duc | Watanabe, Yasuko | Hasanuzzaman, Mirza | Mohsin, Sayed Mohammad | Fujita, Masayuki | Tran, Lam-son Phan
Gradual contamination of agricultural land with copper (Cu), due to the indiscriminate uses of fungicides and pesticides, and the discharge of industrial waste to the environment, poses a high threat for soil degradation and consequently food crop production. In this study, we combined morphological, physiological and biochemical assays to investigate the mechanisms underlying acetate-mediated Cu toxicity tolerance in lentil. Results demonstrated that high dose of Cu (3.0 mM CuSO₄. 5H₂O) reduced seedling growth and chlorophyll content, while augmenting Cu contents in both roots and shoots, and increasing oxidative damage in lentil plants through disruption of the antioxidant defense. Principle component analysis clearly indicated that Cu accumulation and increased oxidative damage were the key factors for Cu toxicity in lentil seedlings. However, acetate pretreatment reduced Cu accumulation in roots and shoots, increased proline content and improved the responses of antioxidant defense (e.g. increased catalase and glutathione-S-transferase activities, and improved action of glutathione-ascorbate metabolic pathway). As a result, excess Cu-induced oxidative damage was reduced, and seedling growth was improved under Cu stress conditions, indicating the role of acetate in alleviating Cu toxicity in lentil seedlings. Taken together, exogenous acetate application reduced Cu accumulation in lentil roots and shoots and mitigated oxidative damage by activating the antioxidant defense, which were the major determinants for alleviating Cu toxicity in lentil seedlings. Our findings provide mechanistic insights into the protective roles of acetate in mitigating Cu toxicity in lentil, and suggest that application of acetate could be a novel and economical strategy for the management of heavy metal toxicity and accumulation in crops.
Show more [+] Less [-]Developmental toxicity and neurotoxicity of penconazole enantiomers exposure on zebrafish (Danio rerio) Full text
2020
Jia, Ming | Teng, Miaomiao | Tian, Sinuo | Yan, Jin | Meng, Zhiyuan | Yan, Sen | Li, Ruisheng | Zhou, Zhiqiang | Zhu, Wentao
Penconazole is a widely used chiral triazole bactericide that may adversely affect the environment. It contains two corresponding enantiomers and there may be differences in toxicity between the isomers. Therefore, in this study, we exposed zebrafish embryos to different concentrations of the penconazole enantiomer to study the developmental toxicity and neurotoxicity of penconazole on zebrafish and the difference in toxicity between enantiomers. The results showed that penconazole exposure caused adverse effects on zebrafish embryos, such as autonomous motor abnormalities, heart rate slowing, and increased deformity, resulting in significant developmental toxicity. Meanwhile, also caused the zebrafish larvae to slow movement, the neurotransmitter content and nervous system related gene expression significantly changed, which proved that penconazole also caused neurotoxicity to zebrafish. Interestingly, our results also clearly show that (+)-penconazole is significantly more toxic to zebrafish than (−)-penconazole at the same concentration, whether it is developmental toxicity or neurotoxicity, which suggests that we should focus on (+)-penconazole more when conducting toxicological studies on penconazole.
Show more [+] Less [-]Effects of treatment agents during acid washing and pH neutralization on the fertility of heavy metal-impacted dredged marine sediment as plant-growing soil Full text
2020
Kim, Kibeum | Yoon, Sangwon | Kwon, Hyun-ah | Choi, Yongju
The present study was aimed at investigating the effects of different acids and pH neutralizers applied to dredged marine sediment for the treatment of heavy metals, and the resulting influence on the sediment quality as a plant growth medium. The inspection of barley germination in the dredged marine sediment revealed that residual salts are critical plant stressors whose adverse effects exceed those exhibited by high-level heavy metals and petroleum hydrocarbons present in the sediment. Acid washing and pH neutralization reduced not only the heavy metal contents but also the sediment salinity (by factors of 6.1–9.5), resulting in 100% germination of barley. For acid-washed and calcium-oxide-neutralized sediment, the barley growth was comparable to that observed in untreated and water washed sediment despite factors of 5.2–8.0 greater sediment salinity in the former. This result represents the protective effect of residual calcium against sodium and chloride toxicity. Water washing of acid-washed and pH-neutralized sediments further enhanced barley growth owing to the reduction in osmotic pressure. This study showed the effect of different sediment-washing reagents on the product quality. It also indicated the significance of balancing the enhancement of product quality and economic cost of further treatment requirements.
Show more [+] Less [-]Early life exposure to air pollution, green spaces and built environment, and body mass index growth trajectories during the first 5 years of life: A large longitudinal study Full text
2020
de Bont, Jeroen | Hughes, Rachael | Tilling, Kate | Díaz, Yesika | de Castro, Montserrat | Cirach, Marta | Fossati, Serena | Nieuwenhuijsen, Mark | Duarte-Salles, Talita | Vrijheid, Martine
Urban environments are characterized by multiple exposures that may influence body mass index (BMI) growth in early life. Previous studies are few, with inconsistent results and no evaluation of simultaneous exposures. Thus, this study aimed to assess the associations between exposure to air pollution, green spaces and built environment characteristics, and BMI growth trajectories from 0 to 5 years. This longitudinal study used data from an electronic primary care health record database in Catalonia (Spain), including 79,992 children born between January 01, 2011 and December 31, 2012 in urban areas and followed until 5 years of age. Height and weight were measured frequently during childhood and BMI (kg/m²) was calculated. Urban exposures were estimated at census tract level and included: air pollution (nitrogen dioxide (NO₂), particulate matter <10 μm (PM₁₀) and <2.5 μm (PM₂.₅₎), green spaces (Normalized Difference Vegetation Index (NDVI) and % green space) and built environment (population density, street connectivity, land use mix, walkability index). Individual BMI trajectories were estimated using linear spline multilevel models with several knot points. In single exposure models, NO₂, PM₁₀, PM₂.₅, and population density were associated with small increases in BMI growth (e.g. β per IQR PM₁₀ increase = 0.023 kg/m², 95%CI: 0.013, 0.033), and NDVI, % of green spaces and land use mix with small reductions in BMI growth (e.g. β per IQR % green spaces increase = −0.015 kg/m², 95%CI: −0.026, −0.005). These associations were strongest during the first two months of life. In multiple exposure models, most associations were attenuated, with only those for PM₁₀ and land use mix remaining statistically significant. This large longitudinal study suggests that early life exposure to air pollution, green space and built environment characteristics may be associated with small changes in BMI growth trajectories during the first years of life, and that it is important to account for multiple exposures in urban settings.
Show more [+] Less [-]Respirable inorganic fibers dispersed in air and settled in human lung samples: Assessment of their nature, source, and concentration in a NW Italy large city Full text
2020
Capella, Silvana | Bellis, Donata | Fioretti, Elena | Marinelli, Roberto | Belluso, Elena
The present investigation represents a new approach useful to evaluate the general population risk correlated with environmental exposure to air dispersed inorganic fibers. The used method is based on the evaluation of the respirable inorganic fibers both air dispersed in a big city and contained in lungs of the general population following their respiration. Moreover, these data allow to identify the sources of dispersion (anthropogenic or natural) in air of the inorganic fibers and therefore to apply strategies to improve air quality. To describe this approach, we investigated air samples from a big city in NW Italy and lung inorganic burden of people here lived. This paper reports the data of the airborne inorganic fibers detected in two sampling campaign (2014 and 2016), in 24 districts of Torino (Piemonte - NW Italy), and in some autoptic lungs of general population lived here. The airborne fibers (collected on mixed-cellulose esters membrane) were characterized by SEMEDS. The identified inorganic fiber species were assigned to 5 classes, one of these including 2 types of asbestos. These last are grouped as tremolite/actinolite asbestos. They are dispersed from natural sources (i.e. certain kinds of rocks outcropping in the city surrounding areas). In no-one of the 24 districts of Torino their concentration highlighted a situation of asbestos pollution in place.A correlation with inorganic fibers (collected on mixed-cellulose esters membrane and characterized by SEM-EDS) detected in lung tissue samples of 10 subjects lived in Torino all their life and without professional exposure to asbestos were attempted. The only types of fibers identified as asbestos are tremolite/actinolite asbestos, and they match those detected in air sampling. The number of fibers per 1 g of tissue dry weight is lower than the quantities reported as indicative of significant asbestos exposure. We observed interesting gender differences.
Show more [+] Less [-]Maximizing HBr/Br2 in the flue gas and prevention of secondary pollution during the oxy-combustion of brominated waste electrical and electronic equipment part 1- thermodynamic considerations Full text
2020
Farshchi Tabrizi, Farshad | Dunker, Martin | Hiller, Andreas | Beckmann, Michael
Organobromine compounds comprise between 3 and 8% by weight of WEEE and mainly converted to HBr and Br₂ in the incinerator. However, these compounds, during the cooling of the flue gases, can form the PBDD/Fs in the post-combustion area of the furnace. Due to the many benefits of Oxy-combustion process, our group has developed a fluidised bed incinerator for burning the WEEE and plan to maximise HBr/Br₂ in the flue gas. Experimental results presented in the recent papers show that the combustion of the WEEE particles attains quickly to thermodynamic equilibrium. Thermodynamic modelling can, therefore, predict the concentration of brominated pollutants, particularly HBr, Br₂, HgBr₂, and Br˙ in the flue gas. In this paper, the effect of various parameters for increasing the HBr/Br₂ ratio in the flue gas has been investigated. The model shows that the addition of very small amounts of hydrogen in the post-combustion area can convert Br₂ and Br˙ into HBr.
Show more [+] Less [-]Associations between persistent organic pollutants and endometriosis: A multipollutant assessment using machine learning algorithms Full text
2020
Associations between persistent organic pollutants and endometriosis: A multipollutant assessment using machine learning algorithms Full text
2020
Endometriosis is a gynaecological disease characterised by the presence of endometriotic tissue outside of the uterus impacting a significant fraction of women of childbearing age. Evidence from epidemiological studies suggests a relationship between risk of endometriosis and exposure to some organochlorine persistent organic pollutants (POPs). However, these chemicals are numerous and occur in complex and highly correlated mixtures, and to date, most studies have not accounted for this simultaneous exposure. Linear and logistic regression models are constrained to adjusting for multiple exposures when variables are highly intercorrelated, resulting in unstable coefficients and arbitrary findings. Advanced machine learning models, of emerging use in epidemiology, today appear as a promising option to address these limitations. In this study, different machine learning techniques were compared on a dataset from a case-control study conducted in France to explore associations between mixtures of POPs and deep endometriosis. The battery of models encompassed regularised logistic regression, artificial neural network, support vector machine, adaptive boosting, and partial least-squares discriminant analysis with some additional sparsity constraints. These techniques were applied to identify the biomarkers of internal exposure in adipose tissue most associated with endometriosis and to compare model classification performance. The five tested models revealed a consistent selection of most associated POPs with deep endometriosis, including octachlorodibenzofuran, cis-heptachlor epoxide, polychlorinated biphenyl 77 or trans-nonachlor, among others. The high classification performance of all five models confirmed that machine learning may be a promising complementary approach in modelling highly correlated exposure biomarkers and their associations with health outcomes. Regularised logistic regression provided a good compromise between the interpretability of traditional statistical approaches and the classification capacity of machine learning approaches. Applying a battery of complementary algorithms may be a strategic approach to decipher complex exposome-health associations when the underlying structure is unknown.
Show more [+] Less [-]Associations between persistent organic pollutants and endometriosis: A multipollutant assessment using machine learning algorithms Full text
2020
Matta, Komodo | Vigneau, Evelyne | Cariou, Véronique | Mouret, Delphine | Ploteau, Stéphane | Le Bizec, Bruno | Antignac, Jean-Philippe | Cano-Sancho, Germán | Laboratoire d'étude des Résidus et Contaminants dans les Aliments (LABERCA) ; École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Statistique, Sensométrie et Chimiométrie (StatSC) ; École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Centre hospitalier universitaire de Nantes (CHU Nantes)
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Show more [+] Less [-]In vitro avian bioaccessibility of metals adsorbed to microplastic pellets Full text
2020
Microplastics are known to be associated with co-contaminants, but little is understood about the mechanisms by which these chemicals are transferred from ingested plastic to organisms. This study simulates marine avian gastric conditions in vitro to examine the bioaccessibility of authigenic metals (Fe, Mn) and trace metals (Co, Pb) that have been acquired by polyethylene microplastic pellets from their environment. Specifically, different categories of pellet were collected from beaches in Cornwall, southwest England, and exposed to an acidified saline solution of pepsin (pH ∼ 2.5) at 40 °C over a period of 168 h with extracted metal and residual metal (available to dilute aqua regia) analysed by ICP-MS. For Fe, Mn and Co, kinetic profiles consisted of a relatively rapid initial period of mobilisation followed by a more gradual approach to quasi-equilibrium, with data defined by a diffusion model and median rate constants ranging from about 0.0002 (μg L⁻¹)⁻¹ h⁻¹ for Fe to about 7 (μg L⁻¹)⁻¹ h⁻¹ for Co. Mobilisation of Pb was more complex, with evidence of secondary maxima and re-adsorption of the metal to the progressively modified pellet surface. At the end of the time-courses, maximum total concentrations were 38.9, 0.81, 0.014 and 0.10 μg g⁻¹ for Fe, Mn, Co and Pb, respectively, with maximum respective percentage bioaccessibilities of around 60, 80, 50 and 80. When compared with toxicity reference values for seabirds, the significance of metals acquired by microplastics from the environment and exposed to avian digestive conditions is deemed to be low, but studies of a wider range of plastics and metal associations (e.g. as additives) are required for a more comprehensive risk assessment.
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