Refinar búsqueda
Resultados 1011-1020 de 7,921
Effects of environmental norfloxacin concentrations on the intestinal health and function of juvenile common carp and potential risk to humans
2021
Zhao, Xue-Li | Li, Ping | Zhang, Si-Qi | He, Shu-Wen | Xing, Shao-Ying | Cao, Zhi-Han | Lu, Rong | Li, Zhi-Hua
Antibiotics are emerging pollutants in our environment. These treatments have been widely used for their low cost, convenient use, and prominent effects. However, the prolonged or excessive use of such drugs can cause toxicity in aquatic organisms. These effects include genotoxicity, metabolic alteration, delayed development and decreased immunity, which carry further risks for ecological systems. In the present study, juvenile common carp (Cyprinus carpio) were exposed to norfloxacin (NOR) for 42 days, with NOR concentrations ranging from 100 ng/L to 1 mg/L, to assess the effects of environmental concentrations of antibiotics, to investigate the effects of NOR on intestinal morphology, enzymatic activity, and transcriptomic levels of RNA in fish, as well as a risk assessment on human health was carried out. The results demonstrated that oxidative stress was induced, the barrier function of the intestine was damaged, and changes occurred in the expression of immune-related genes in fish chronically exposed to antibiotics. Moreover, NOR could affect the regulation of the NF-κB signaling pathway. Thus, environmental concentrations of antibiotics can influence the intestinal health of fish and potentially posing health risks to humans.
Mostrar más [+] Menos [-]Third-hand smoke exposure is associated with abnormal serum melatonin level via hypomethylation of CYP1A2 promoter: Evidence from human and animal studies
2021
Jiang, Wenbo | Wu, Huanyu | Yu, Xinyang | Wang, Yu | Gu, Wenbo | Wei, Wei | Li, Bai | Jiang, XiTao | Wang, Yue | Hou, Wanying | Dong, Qiuying | Yan, Xuemin | Li, Ying | Sun, Changhao | Han, Tianshu
This study aimed to examine whether and how third-hand smoke (THS) exposure would influence serum melatonin level. 1083 participants with or without exposure to THS were enrolled. Serum ROS, SOD, GSH-Px, and melatonin were measured by ELISA. Methylation microarrays detection and WGCNA were performed to identify hub methylated-sites. The methylation levels of hub-sites were validated in addtional samples. Moreover, mice were exposed to THS for 6 months mimicking exposure of human and the serum, liver, and pineal were collected. Oxidative stress-related indicators in serum, pineal, and liver were measured by ELISA. The expressions of mRNA and protein and methylation levels of hub-gene discovered in human data were further explored by RT-PCR, western-blot, and TBS. The results showed the participants exposed to THS had lower melatonin-level. 820 differentially methylated sites associated with THS were identified. And the hub-site located on the CYP1A2 promoter was identified, which mediated the association between THS and decreased melatonin-level. Decreased peak of serum melatonin, increased ROS and reduced SOD and GSH-Px in pineal and liver, and elevated CYP1A2 expression in liver was also found in the THS-exposed mice. Hypo-methylation of 7 CPG sites on the CYP1A2 promoter was identified, which accelerated the catabolism of melatonin. Overall, THS exposure is associated with abnormal melatonin catabolism through hypo-methylation of CYP1A2-promoter.
Mostrar más [+] Menos [-]The combined effects of macrophytes (Vallisneria denseserrulata) and a lanthanum-modified bentonite on water quality of shallow eutrophic lakes: A mesocosm study
2021
Zhang, Xiumei | Zhen, Wei | Jensen, Henning S. | Reitzel, Kasper | Jeppesen, Erik | Liu, Zhengwen
Establishment of submerged macrophyte beds and application of chemical phosphorus inactivation are common lake restoration methods for reducing internal phosphorus loading. The two methods operate via different mechanisms and may potentially supplement each other, especially when internal phosphorous loading is continuously high. However, their combined effects have so far not been elucidated. Here, we investigated the combined impact of the submerged macrophyte Vallisneria denseserrulata and a lanthanum-modified bentonite (Phoslock®) on water quality in a 12-week mesocosm experiment. The combined treatment led to stronger improvement of water quality and a more pronounced reduction of porewater soluble reactive phosphorus than each of the two measures. In the combined treatment, total porewater soluble reactive phosphorus in the top 10 cm sediment layers decreased by 78% compared with the control group without Phoslock® and submerged macrophytes. Besides, in the upper 0–1 cm sediment layer, mobile phosphorus was transformed into recalcitrant forms (e.g. the proportion of HCl–P increased to 64%), while in the deeper layers, (hydr)oxides-bound phosphorus species increased 17–28%. Phoslock®, however, reduced the clonal growth of V. denseserrulata by 35% of biomass (dry weight) and 27% of plant density. Our study indicated that Phoslock® and submerged macrophytes may complement each other in the early stage of lake restoration following external nutrient loading reduction in eutrophic lakes, potentially accelerating the restoration process, especially in those lakes where the internal phosphorus loading is high.
Mostrar más [+] Menos [-]Sources, environmental levels, and health risks of PM2.5-bound polycyclic aromatic hydrocarbons in energy-producing cities in northern China
2021
Guo, Li | Hu, Jian | Xing, Yanfeng | Wang, Hao | Miao, Shengjie | Meng, Qingqing | Wang, Xiaohong | Bai, Shuping | Jia, Jing | Wang, Pengjie | Zhang, Rui | Gao, Peng
We collected 170 samples of airborne fine particulate matter from five coal-producing cities and one oil-producing city in northern China during both heating and non-heating periods to quantify the concentrations of 12 polycyclic aromatic hydrocarbons, estimate their bioaccessible fraction, and calculate the incremental lifetime cancer risk (ILCR) of this fraction. The major sources of the particulate matter were analyzed using the chemical mass balance model. We found that the main emission sources were coal combustion during the heating period and open sources during the non-heating period. The ILCR was initially calculated as 2.65 × 10⁻⁹ for coal-producing cities and 4.60 × 10⁻⁹ for the oil-producing city during the heating period and 1.17 × 10⁻⁸ and 3.34 × 10⁻⁸, respectively, during the non-heating period. When only the bioaccessible fraction was used, the ILCR in coal-producing cities and the oil-producing city decreased by 87.2% and 82.1%, respectively, for the heating period and by 89.0% and 80.1%, respectively, for the non-heating period. The findings suggest that bioaccessibility should be considered when assessing the carcinogenic risk of polycyclic aromatic hydrocarbons. This study provides insights into the contribution of major emission sources to air pollution related to the long-term exploitation, transportation, and use of coal and oil.
Mostrar más [+] Menos [-]Endocrine-disrupting chemicals in a typical urbanized bay of Yellow Sea, China: Distribution, risk assessment, and identification of priority pollutants
2021
Lü Shuang, | Lin, Chunye | Lei, Kai | Xin, Ming | Wang, Baodong | Ouyang, Wei | Liu, Xitao | He, Mengchang
Endocrine-disrupting chemicals (EDCs) in water are receiving particular attention as they pose adverse effects on aquatic systems, even at trace concentrations. A comprehensive study was conducted on 14 EDCs (five estrogens and nine household and personal care products (HPCPs)) in the water of the urbanized Jiaozhou Bay in the Yellow Sea during summer and winter. Results showed that the total concentration of 14 EDCs ranged from 100 to 658 ng L⁻¹ and 56.7–212 ng L⁻¹ in the estuarine and bay water, respectively. The average total concentration of five estrogens in summer was significantly (p < 0.05) lower than that in winter due to the higher precipitation dilution and degradations during summer, whereas the average total concentration of nine HPCPs was significantly (p < 0.05) higher during the summer than that during the winter because of the higher usage and emissions during the summer. Estrogens and HPCPs were dominated by 17α-ethinylestradiol and p-hydroxybenzoic acid (PHBA), respectively. High PHBA concentrations may be related to the hydrolysis of parabens. The total concentrations of EDCs were higher in the eastern coastal seawater of the bay due to the strong influence of domestic and industrial wastewater discharge. Estrogens may interfere with the endocrine system of aquatic organisms in the bay because the total estradiol equivalent concentration exceeded 1 ng L⁻¹. 17α-ethinylestradiol was the main contributor to the estrogenic activity. The EDC mixtures posed high risks (RQ > 1) to mollusks, crustaceans, and fish, and low to moderate risks (RQ < 1) to algae. Fish was the most sensitive aquatic taxon to the EDC mixtures. Given the concentration and frequency of EDCs, the optimized risk quotient method revealed that 17α-ethinylestradiol, estrone, triclocarban, triclosan, and 17β-estradiol should be prioritized in ecological management because of their high risks (prioritization index of >1).
Mostrar más [+] Menos [-]Estimating uncertainties of source contributions to PM2.5 using moving window evolving dispersion normalized PMF
2021
Song, Lilai | Dai, Qili | Feng, Yinchang | Hopke, Philip K.
Conventional factor analyses can present problems in cases with changing numbers of sources and/or time-dependent source compositions. There is also lack of a reliable method to estimate uncertainties in the source contributions derived by positive matrix factorization (PMF). Applying a moving window evolving PMF to hourly PM₂.₅ composition dataset from a field campaign in Tianjin China that included the Spring and Lantern Festivals and the start of COVID-19 pandemic has substantially improved the apportionment compared to a conventional analysis using the entire data. Festival-related sources (e.g., fireworks and residential burning here) have been clearly identified and estimated during both the Spring and Lantern Festivals. During this period, the sources changed because the time period overlaps with the outbreak of COVID-19 and related reductions in activity during the lockdown that began on Lunar New Year. Multiple PMF runs providing source contribution estimates made it possible to estimate the uncertainties in these values. Our results show that winds-dependent sources like dust and distant point sources have larger uncertainties than the other sources. Compared with conventional PMF analyses, the current method may better reflect the actual emissions as well as being able to estimate uncertainties. Thus, this approach appears to be an improvement if the appropriate data are available.
Mostrar más [+] Menos [-]Elevated CO2 concentration affects survival, but not development, reproduction, or predation of the predator Hylyphantes graminicola (Araneae: Linyphiidae)
2021
Li, Wei | Zhao, Yao | Li, Yingying | Zhang, Shichang | Yun, Yueli | Cui, Jinjie | Peng, Yu
Elevated CO₂ concentrations can change the multi-level nutritional relationship of the ecosystem through the cascading effect of the food chain. To date, few studies have investigated the effects of elevated CO₂ concentration on the Araneae species through the tritrophic system. Hylyphantes graminicola (Araneae: Linyphiidae) is distributed widely in Asia and is a dominant predator in cotton fields. This study investigated chemical components in the food chain of cotton (Gossypium hirsutum)—cotton aphid (Aphis gossypii)—predator (H. graminicola) and compared the development, reproduction, and predation of H. graminicola under ambient (400 ppm) and elevated concentration of CO₂ (800 ppm). The results showed that the elevated CO₂ concentration increased the chemicals of cotton and cotton aphid, but it did not affect the nutrients, development, reproduction, and predation of the spider. However, the survival rate of the spider was significantly decreased in elevated CO₂. The results will further our understanding of the role of natural enemies in an environment with elevated CO₂ concentration.
Mostrar más [+] Menos [-]Identification of novel halogenated naturally occurring compounds in marine biota by high-resolution mass spectrometry and combined screening approaches
2021
Belova, Lidia | Fujii, Yukiko | Cleys, Paulien | Śmiełowska, Monika | Haraguchi, Koichi | Covaci, Adrian
Marine animals, plants or bacteria are a source of bioactive naturally-occurring halogenated compounds (NHCs) such as bromophenols (BPs), bromoanisoles (BAs) and hydroxylated or methoxylated analogues of polybrominated diphenyl ethers (HO-PBDEs, MeO-PBDEs) and bromobiphenyls (HO-BBs, MeO-BBs). This study applied a comprehensive screening approach using liquid chromatography high-resolution mass spectrometry and combining target, suspect and non-target screening with the aim to identify new hydroxylated NHCs which might be missed by commonly applied gas chromatographic methods. 24 alga samples, 4 sea sponge samples and 7 samples of other invertebrates were screened. Target screening was based on 19 available reference standards of BPs, (di)OH-BDEs and diOH-BBs and yielded seven unequivocally identified compounds. 6-OH-BDE47 was the most frequently detected compound with a detection frequency of 31%. Suspect screening yielded two additional compounds identified in alga samples as well as 17 and 8 compounds identified in sea sponge samples of Lamellodysidea sp. and Callyspongia sp., respectively. The suspect screening results presented here confirmed the findings of previous studies conducted on sea sponge samples of Lamellodysidea sp. and Callyspongia sp. Additionally, in Lamellodysidea sp. and Callyspongia sp. 13 and 4 newly identified NHCs are reported including heptabrominated diOH-BDE, monochlorinated pentabrominated diOH-BDE, hexabrominated OH–MeO-BDE and others. Non-target screening allowed the identification of 31 and 20 polyhalogenated compounds in Lamellodysidea sp. and Callyspongia sp. samples, respectively. Based on the obtained fragmentation spectra, polybrominated dihydroxylated diphenoxybenzenes (diOH-PBDPBs), such as hepta-, octa- and nonabrominated diOH-BDPBs, could be identified in both species. To our knowledge, this study is the first report on the environmental presence of OH-PBDPBs.
Mostrar más [+] Menos [-]Toward a unified framework for investigating micro(nano)plastics in packaged beverages intended for human consumption
2021
Shruti, V.C. | Pérez-Guevara, Fermín | Elizalde-Martínez, I. | Kutralam-Muniasamy, Gurusamy
The continuously increasing presence of micro- and nanoplastics contamination in numerous food products for human consumption is threatening and their potential health effects towards humans remain uncertain. At present, investigations on packaged beverages (e.g. bottled drinking water, beer, milk and refreshments) have received scientific attention and represent an important part of microplastic research as humans are orally exposed to these anthropogenic contaminants every day. Rapid and effective detection methods are important to quantify micro- and nanoplastic particles with a great accuracy as well as to identify their sources and characteristics. A number of methods are currently in use to assess microplastics in packaged beverages; however, the great variations in methods and data acquisition render difficulties when comparing the results and developing the protocols. Based on the challenges, this paper aims to provide a comprehensive understanding of emerging technological approaches, points out the current limitations from sample preparation to quantification and present recommendations. From the results of our analysis, we postulate an example framework that can be applied to different types of drinking products for investigating micro- and nanoplastics. Overall, this review will serve as a first step towards harmonization of micro- and nanoplastic monitoring efforts and a point of reference to help direct future researches focusing on drinking products intended for human consumption.
Mostrar más [+] Menos [-]The fate of anthropogenic Pb in soils; years after Pb terminated as a fuel additive; Northern Israel
2021
Harlavan, Yehudit | Shirav, Moshe | Ilani, Shimon | Halicz, Ludwik | Yoffe, Olga
The source for Lead (Pb) pollution in soils from the heavily industrialized area located along the coast of the Eastern Mediterranean, Haifa Bay, Northern Israel, is studied using the lead isotopic composition. The uniqueness of the studied data set is that it includes samples of soils, road-wash, and storm-dust sampled for nearly three decades (1988–2017). Road-wash sediments are similar in both elemental and Pb isotopic composition to soils sampled in the same year (2010), indicating re-suspension of local soil, as its origin. Soils sampled during and before 1993 show no evidence for Pb contamination (bulk soil values), although Pb as an additive was already in use. Furthermore, soil overturns hinder the possibility to trace changes in the Pb isotopic composition with time in soils of the same location. Soils sampled from 1995–8 to 2013 were significantly dominated by Post-1992 Pb additive, pointing to Pb’s peak as an additive. Soils Pb and Zn Enrichment factors for most samples are below 5, and their anthropogenic source is likely common. Forest fire enriched Pb and Zn in the soil, and their Pb isotope compositions reflect this enrichment. Lead from the Hod Assaf recycling plant detected up to some 2.5 km away, and although not analyzed in the current study, dioxin-like compounds possibly accompanied Pb.
Mostrar más [+] Menos [-]