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Resultados 3711-3720 de 5,153
Association of phthalate exposure with anthropometric indices and blood pressure in first-grade children Texto completo
2018
Wu, Wei | Wu, Ping | Yang, Fang | Sun, Dan-ling | Zhang, De-Xing | Zhou, Yi-Kai
We aimed to assess the relationship of urine phthalate metabolite concentrations with anthropometric indices, and blood pressure in first-grade children. We detected 11 phthalate metabolites in urine and estimated anthropometric indices, including skinfold measurements, waist circumference (WC), and body mass index (BMI) in 276 children aged 6–8 years. Multivariate linear regression models were used to assess the associations between urinary phthalate metabolite levels, and anthropometric and blood pressure indices in a gender-specific manner. In boys, a 1-ng/mL increase in monobenzyl phthalate (MBzP) concentration was associated with a 0.027-cm decrease in the skinfold measurement (95% confidence interval [CI], − 0.053 to 0.001), whereas a 1-ng/mL increase in mono-ethyl-phthalate (MEP) concentration was associated with a 0.016-mm Hg decrease in systolic blood pressure (95% CI, − 0.031 to 0.001). MBzP, mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), and MEOHP concentrations were also inversely associated with WC. However, in girls, MEP concentrations were positively associated with chest measurements, but were inversely associated with WC. A 1-ng/mL increase in monomethyl phthalate concentrations was associated with a 0.039-cm increase in skinfold measurements (95% CI, 0.002 to 0.076), whereas a 1-ng/mL increase in MECPP concentrations was associated with a 0.050 cm decrease in skinfold measurements (95% CI, − 0.095 to − 0.005). In this exploratory, cross-sectional analysis, we identified various interesting associations between different phthalate metabolite levels and anthropometric indices, which suggest that some of phthalate metabolite should be considered in addition to the prevalence rates of overweight and obesity.
Mostrar más [+] Menos [-]Ultrasonic seed treatment improved physiological and yield traits of rice under lead toxicity Texto completo
2018
Rao, Gangshun | Ashraf, Umair | Huang, Suihua | Cheng, Siren | Muhammad, Abrar | Mo, Zhaowen | Pan, Shenggang | Tang, Xiangru
Lead (Pb) is a highly toxic metal that damages normal plant metabolism and often results in reduced crop growth and yield. To measure whether or not ultrasonic seed (US) treatment alleviates Pb stress in rice, the seeds of two rice cultivars, i.e., Guangyan1 and Huahang31, were exposed to 30 min of ultrasonic vibration and then the seedlings were transplanted to Pb-contaminated soil. Results revealed that the Pb contents in roots, stems, leaves, panicles (at heading), and brown rice (at maturity) were lower in US treatment than control (CK; without US treatment); the trend for accumulation of Pb in different plant parts was recorded as: root ˃ stems ˃ leaves ˃ panicles ˃ brown rice in both rice cultivars. Overall, the Pb contents in the brown rice of Huahang31 were higher than those in Guangyan1. Moreover, the contents of proline and soluble protein as well as the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were significantly higher while the malondialdehyde (MDA) contents were significantly reduced in US treatment compared to CK. The effective panicle number, seed set percentage, grains per panicle, 1000-grain weight, and grain yield were increased by 8.9%, 5.3%, 6.8%, 4.4%, and 26.6% in Guangyan1 and 3.2%, 5.7%, 5.7%, 5.0%, and 24.2% in Huahang31, respectively in US treatment compared to CK. Hence, seed treatment with ultrasonic waves could improve rice performance and reduce brown rice Pb accumulation under Pb-polluted soils.
Mostrar más [+] Menos [-]Seasonal distributions of heavy metal concentrations in different snail (Helix pomatia) tissues from an urban environment in Serbia Texto completo
2018
Ciric, Jelena | Cerić, Olgica | Marković, Radmila | Janjić, Jelena | Spirić, Danka | Popović, Milka | Pećanac, Biljana | Baltić, Branislav | Baltić, Milan Ž
The aim of this study was to evaluate the differences between concentrations of heavy metals (cadmium, copper, zinc, iron, and manganese) in terrestrial gastropods, Helix pomatia, collected in four different environment locations in Pančevo city, Serbia. Metal concentrations in the foot and in the digestive gland were measured. Heavy metals cadmium, copper, zinc, iron, and manganese were measured in triplicate by atomic absorption spectrophotometry. Also, this study investigated correlations between the trace element content in the soft tissues and different seasons (summer and fall). The results showed that heavy metal concentrations of the measured elements in both snail tissues were significantly higher in polluted sites when compared to the background levels in the city. In digestive gland tissues, the concentration of heavy metals was higher compared with that in foot tissues. The bioaccumulation (heavy metal concentrations in soft tissues) of heavy metals (Cd, Cu, Zn, Fe, and Mn) in snails, Helix pomatia, has been assessed and related to seasons and sites. Heavy metal accumulation in the soft tissues of snails could provide a powerful monitoring tool for the assessment of environmental heavy metal pollution.
Mostrar más [+] Menos [-]Removal of hexavalent chromium from water by modified sponge iron particles and insights into mechanism Texto completo
2018
Zhu, Guilin | Song, Junde | Dong, Weihong | Lu, Jingfeng | Wang, Yan | Jiang, Weinan | Guo, Ping
Sponge iron particles modified with expanded graphite and Cu were used to purify solutions contaminated with aqueous Cr(VI). A removal mechanism that involved physical adsorption and a redox reaction is proposed. The reaction, which consisted of rapid adsorption, a desorption stage, and an adsorption–desorption equilibrium stage, corresponded to a first-order kinetic model. The properties of the adsorption materials before and after use were investigated by X-ray diffraction, scanning electron microscopy–energy-dispersive spectroscopy, Fourier-transform infrared spectroscopy, energy-dispersive X-ray fluorescence spectroscopy, and surface area measurements. Changes in the surface properties, e.g., attachment of material to the surface and filling of pores with Cr, were clearly observed. The Langmuir model best described Cr(VI) adsorption on the sponge iron and its modified particles. Removal efficiencies of 98.7, 98.8, and 100% were achieved in 7 h at a Cr(VI) dosage of 10 mg/L. Sponge iron particles are therefore potential adsorbents and after modification give good removal of Cr(VI) ions from contaminated water.
Mostrar más [+] Menos [-]Stage-specific testicular protein levels of the oestrogen receptors (ERα and ERβ) and Cyp19 and association with oestrogenic contamination in the lambari Astyanax rivularis (Pisces: Characidae) Texto completo
2018
Weber, André Alberto | Moreira, Davidson Peruci | Melo, Rafael Magno Costa | Vieira, Augusto Bicalho Cruz | Bazzoli, Nilo | Rizzo, Elizete
Oestrogens participate in various biological processes such as oogenesis, vitellogenesis and testicular development, but studies regarding the distribution and protein levels of oestrogen receptors (ERα and ERβ) and aromatase (Cyp19) in testis are rarely investigated in fish species. The aim of the present study was to analyse the expression pattern of ERα, ERβ and Cyp19 in testis of Astyanax rivularis and, in addition, to verify if oestrogenic contamination interferes in the expression levels of these proteins. Quarterly, field samplings were carried out during a reproductive cycle in a stream of the Upper Velhas River with a good conservation status (site S1). In the gonadal maturation peak (June), when ripe stage was most abundant, fish collection was made in three streams: S1, reference site, and S2 and S3, sites contaminated by untreated sewage. The results of immunohistochemistry demonstrated labelling of Cyp19 in Leydig cells and acidophilic granulocytes, but spermatogonia, Sertoli cells, spermatids and spermatozoa were also labelled. ERα was more widely distributed than ERβ being found in all developmental germ cell phases. On the other hand, ERβ was found only in spermatogonia and spermatocytes. During testicular maturation, ELISA levels for Cyp19, ERα and ERβ followed the gonadosomatic index (GSI) with significant higher values in the ripe stage. Regarding to endocrine disruption, the males exposed to domestic sewage presented significant higher expression of Cyp19 and ERα when compared to the non-exposed fish. Together, our results demonstrate expression patterns of Cyp19, ERα and ERβ in the testis of A. rivularis. In addition, we indicate ERα and Cyp19 as sensitive biomarkers for monitoring of oestrogenic contamination in freshwater environments.
Mostrar más [+] Menos [-]Transient dispersion of an initial point pollutant concentration in wetland flows Texto completo
2018
Wang, Ping | Zeng, Li | Huai, Wenxin
Initial point pollutant transport in wetland flows acts as a typical form in various applications. Accurate determination of the basic characteristics for dispersion fundamentally supports the predication of pollutant transport especially in the transient stage. This work analytically studies the transient dispersion of an initial point pollutant concentration in wetland flows through the phase average technique and the method of concentration moments. The characteristics including the vertical mass distribution, longitudinal displacement, dispersivity, skewness, and kurtosis corresponding to the zeroth- to fourth-order concentration moments are accurately illustrated in their full-time dependance for the first time. Present results show to be distinctive from those of initial uniform concentration in the transient dispersion process. The temporal evolutions of the five characteristics are all dependent of the initial point release position. The results further demonstrate that the timescale 3.0 as measured by the skewness, rather than 0.5 as measured by the dispersivity, should be characterized as the transient period for the dispersion of initial point concentration in comparison with that of initial uniform. Furthermore, the longitudinally distributed mean concentration is as well analyzed through the Hermite polynomials. The results imply that strict criteria for environmental and ecological implications should be established by further accounting for the five characteristics.
Mostrar más [+] Menos [-]Combined Fe/P and Fe/S ratios as a practicable index for estimating the release potential of internal-P in freshwater sediment Texto completo
2018
Wang, Jingfu | Chen, Jingan | Guo, Jianyang | Sun, Qingqing | Yang, Haiquan
Release of phosphorus (P) from sediment is a major source of P in many freshwater lakes. Currently, assessing the ability of sediment to release P, which is valuable to the management of water eutrophication, remains a challenge. Thus, the purpose of this study was to find effective indexes for predicting the release potential of internal-P. In this study, high-resolution diffusive gradients in thin films (DGT) and conventional sequential extraction were used to characterize the distribution and speciation of P, iron (Fe), and sulfur (S) in the surface sediment of a mildly eutrophic reservoir in southwestern China. Sediment samples exhibited large variations in Fe, S, and P, thereby providing favorable conditions for investigating the effects of Fe and S on sediment P mobilization. In contrast to traditional knowledge, our results show that total P (TP) and redox-sensitive P(BD-P) are poorly correlated with releasable P(DGT-P). This implies that high levels of sedimentary TP and BD-P do not necessarily result in an elevated release of internal-P under anaerobic conditions. Sedimentary P release was greatly suppressed at ratios of Fe/P > 30 and Fe/S > 6. Significant positive correlations between DGT-P and DGT-Fe or DGT-S suggest that Fe and S play an important role in governing the mobility of sedimentary P. These results support the combined Fe/P and Fe/S ratios as an effective and practicable index for assessing the ability of sediment to release P. Thus, our study provides a new and simple method for assessing sedimentary P pollution in freshwater ecosystems.
Mostrar más [+] Menos [-]Diagnosis and ecotoxicological risk assessment of 49 elements in sludge from wastewater treatment plants of Chongqing and Xiamen cities, China Texto completo
2018
Suanon, Fidèle | Chi, Qiaoqiao | Yang, Xiaoyong | Wang, Hongjie | Rashid, Azhar | Asefi, Bahareh | Mama, Daouda | Yu, Chang-Ping | Sun, Qian
Limited information about the sludge quality is a major constraint for its usage and proper disposal. This study investigated the occurrence of 49 elements in sludge from 11 wastewater treatment plants (WWTPs) in Chongqing and Xiamen cities of China. The concentration of 46-detected elements ranged from 16.2 μg kg⁻¹ (Pt) to 55.0 g kg⁻¹ (Al) on dry solid basis in the sludge. The enrichment factor of most of the elements was > 1.5, indicating their possible anthropogenic origin. The precious metals had considerably higher enrichment factor ranging from 56.3 to 200,000. Principal component analysis clustered the samples from Chongqing and Xiamen separately to suggest strong spatial variations. Contamination factor, pollution loading index, and integrated pollution degree were calculated to evaluate the elemental pollution risk. The pollution loading index indicated unpolluted to highly polluted levels of the elements in the sludge. In addition, results from the ecotoxicological risk index showed an individual low to very high ecotoxicological risk posed by eight metal(loid)s (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in the WWTPs.
Mostrar más [+] Menos [-]Chrysotile and rock wool fibers induce chromosome aberrations and DNA damage in V79 lung fibroblast cells Texto completo
2018
Cui, Yan | Ma, Ji | Ye, Wei | Han, Zhixia | Dong, Faqin | Deng, Jianjun | Zhang, Qingbi
According to global estimates, at least 107,000 people die each year from asbestos-related lung cancer, mesothelioma, and asbestosis resulting from occupational exposure. Chrysotile accounts for approximately 90% of asbestos used worldwide. Artificial substitutes can also be cytotoxic to the same degree as chrysotile. But only a few researchers focused on their genetic effects and mutagenicity information which is useful in evaluating the carcinogenicity of chemicals. In this study, chrysotile from Mangnai, Qinghai, China, and an artificial substitute, rock wool fiber were prepared as suspensions and were tested at concentrations of 50, 100, and 200 μg/ml in V79 lung fibroblasts. Chromosome aberrations were detected by micronucleus assay after exposure for 24 h, and DNA damage were estimated by single cell gel electrophoresis after exposure for 12, 24, or 48 h. According to the results, chrysotile and rock wool fibers caused micronuclei to form in a dose-dependent manner in V79 cells; olive tail moment values increased in a dose- and time-dependent manner. When V79 cells were exposed to a concentration of 200 μg/ml, the degree of DNA damage induced by chrysotile fibers was greater than rock wool fibers. Our study suggests that both chrysotile and rock wool fibers could induce chromosome aberrations and DNA damage. These materials are worthy of further study.
Mostrar más [+] Menos [-]Comparisons of three plant species in accumulating polycyclic aromatic hydrocarbons (PAHs) from the atmosphere: a review Texto completo
2018
Huang, Shaojian | Dai, Chunhao | Zhou, Yaoyu | Peng, Hui | Yi, Kexin | Qin, Pufeng | Luo, Si | Zhang, Xiaoshan
Plant leaves play a key role in the accumulation of PAHs, as they are able to capture PAHs from the air. In this paper, the mechanism, including absorption and adsorption, for plants to scavenge PAHs from the air was reviewed. Moreover, the differences of PAHs accumulating capability are mainly compared among three representative plant species, including pine needles, Holm oak leaves, and moss. On the whole, it is shown that oak leaves present the strongest PAHs accumulating capability for total PAHs among three plants species. Oak leaves and pine needles show higher accumulating tendency for light and medium molecular weight PAHs, whereas moss presents stronger accumulating tendency for heavy molecular weight PAHs. Environmental factors (i.e., temperature, seasonality, and photolysis) also account for the process of PAHs transferred from air to plants. With the temperature climbing, the concentration of PAHs in the air will increase. Due to the meteorological conditions and the human activities changed with seasons, it was shown that the PAHs were greatly accumulated in leaf surface in winter than in summer. Photolysis was also able to influence the PAHs on leaf surface, which are significant to this process. In conclusion, oak, pine, and moss can be used to filter PAHs when considering urban landscaping. Besides combining the traditional analytical methods with in situ determination, there might be able to provide a novel method to further study the specific absorption mechanisms. The accumulation of PAHs in crop leaf surface related to the application of surfactants is also worth studying.
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