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Development of a comprehensive understanding of aggregation-settling movement of CeO2 nanoparticles in natural waters Texto completo
2020
Lv, Bowen | Wang, Chao | Hou, Jun | Wang, Peifang | Miao, Lingzhan | Xing, Baoshan
Parameters such as the settling rate, aggregation rate, and collision frequency in predictive models used to describe the fate of nanoparticles (NPs) are very important for the risk assessment of NPs in the environment. In this study, CeO₂ NPs were chosen as the model particles to investigate such parameters through aggregation-settling experiments under environmentally relevant conditions. The results indicate that natural colloids (Ncs) have no effect on the settling of NPs in seawaters, whereas they stabilize the NPs at a low initial particle concentration and promote the heteroaggregation of NPs at a high initial particle concentration in lake waters. In all cases, a suspended sediment absorbs the NPs and Ncs as mixed aggregates, resulting in a rapid settling. Furthermore, the calculation results of the model indicate that the shear force increases the collision frequency of the NPs by 4–5 orders of magnitude higher than that in quiescent waters. However, the break-up effect by the shear force is more obvious, namely, the shear force hinders the aggregation of NPs in natural waters, instead of promoting aggregation. Remarkably, a negative value of the dis-heteroaggregation rate based on the combined von Smoluchowski–Stokes equation can reflect the hindering effect on the aggregation process. The results of this study will provide scientific and accurate guidance for the parameter selection in the existing prediction model and contribute to a prediction of the fate and transport of NPs in the environment.
Mostrar más [+] Menos [-]Urbanization and regional air pollution across South Asian developing countries – A nationwide land use regression for ambient PM2.5 assessment in Pakistan Texto completo
2020
Shi, Yuan | Vēlāyutan̲, T. A. | Ho, Hung Chak | Omar, Abid
Rapid economic growth, urban sprawl, and unplanned industrialization has increased socioeconomic statuses but also decreased air quality in South Asian developing countries. Therefore, severe increase in air pollution has been a threat of local population, regarding health statuses, livability and quality of life. It is necessary to estimate fine-scale spatiotemporal distribution of ambient PM₂.₅ in a national context so that the environmental planners and government officials can use it for environmental protocol development and policy-making. In this study, a spatiotemporal land use regression (LUR) model is developed to refine global air quality data to the national-scale ambient PM₂.₅ exposure in a high-density country in South Asia – Pakistan. Combining with transport network, patterns of land use, local meteorological conditions, geographic characteristics, landscape characteristics, and satellite-derived data, our resultant model explains 54.5% of the variation in ambient PM₂.₅ concentration level. Furthermore, tree coverage and road transport are identified to be two influential factors of the national-scale spatial variation of PM₂.₅ in Pakistan, which implied that urbanization might be the major cause of air pollution across the country. In conclusion, our resultant LUR model as well as the spatial map of ambient PM₂.₅ concentration level can be used as a supporting tool for national health risk management and environmental planning, and could also contribute to the air quality management and pollution reduction actions of Pakistan.
Mostrar más [+] Menos [-]Oxidative stress parameters, DNA damage and expression of HSP70 and MT in midgut of Trachyderma hispida (Forskål, 1775) (Coleoptera: Tenebrionidae) from a textile industry area Texto completo
2020
The textile mill industry is one of the major sources of pollution and contributors of metal contaminants to the environment. At the same time, the industry is important for global economy. Pollution caused by the textile industry is characteristic due to a unique set of potentially toxic substances. Darkling beetles (Coleoptera, Tenebrionidae), which live in all biogeographical regions, are especially common in soil quality and soil degradation studies. Our study was designed to assess long-term effects of textile industry (which generates specific pollution) on soil organisms, namely Trachyderma hispida. We especially wanted to find out what changes allow the species to survive and adapt to these specific conditions. Energy-dispersive X-ray spectroscopy of soil and midgut tissues of T. hispida sampled from a polluted site in the Edku textile industrial area in Egypt revealed a high accumulation of chemical elements, compared to a reference site. The concentration of elements in soil was well correlated with their concentration in the midgut of insects. Activity of superoxide dismutase, catalase, ascorbate peroxidase and glutathione S-transferase were negatively correlated with concentration of elements in soil and in the midgut. Meanwhile, malondialdehyde concentration in the midgut revealed an opposite tendency. DNA damage and expression of stress proteins, (HSP70 and metallothionein - MT) were elevated in insects from the polluted site. The activity of textile industry in the area of Edku undoubtedly causes an increase of soil pollution and, in consequence, causes a number of changes in the bodies of organisms living in these areas, including T. hispidus. Therefore, it is necessary to find a solution which limits the emission of waste from the textile industry, as well as to design modern strategies of processing, storing and utilizing it.
Mostrar más [+] Menos [-]Integrated farming system producing zero emissions and sustainable livelihood for small-scale cattle farms: Case study in the Mekong Delta, Vietnam Texto completo
2020
This study proposes an integrated cattle breeding and cultivation system that provides zero emission and sustainable livelihood for the community in rural areas. The proposed integrated farming system improves agricultural productivity and environmental and sanitation conditions, minimizes the amount of waste, and increases the family income up to 41.55%. Several waste types can be recycled and transformed into valuable products, such as energy for cooking, organic fertilizer for crops, and cattle feed for breeding. Wastewater effluent from the biogas tank can be treated by biochar and results show that it then meets the standards for irrigation purposes. Also, the waste flow from cattle breeding supplies enough nutrients to cultivate plants, and the plants grown supply are adequate food for the 30 cows living on the farm. This research shows that the use of an integrated farming system could achieve zero-emission goal. Thereby, it provides a sustainable livelihood for cattle breeding family farms. The proposed integrated cattle breeding and cultivation system improves agricultural productivity, environmental and increases the farmer income up to 41.55%.
Mostrar más [+] Menos [-]Influence of microplastics on nutrients and metal concentrations in river sediments Texto completo
2020
He, Beibei | Duodu, Godfred O. | Rintoul, Llew | Ayoko, G. A. (Godwin A.) | Goonetilleke, Ashantha
Microplastics pose threats to aquatic environments because they serve as hard-substrate for microbial community colonization and biofilm formation due to their long-life span and hydrophobic surface which can impact on aquatic ecosystems. However, the association between microplastics and other pollutants, particularly nutrients and metals in river sediments are largely unknown. In this study, microplastics abundance and hazard scores which are the risks arising from chemical compounds used for plastics manufacture, and the correlations between microplastics and the concentrations of total carbon (TC), total nitrogen (TN), total phosphorus (TP) and metals commonly present in the urban environment such as Al, As, Cr, Co, Cu, Fe, Mg, Mn, Ni, Cd, Se, Sr, Zn, Pb, in Brisbane River sediments were investigated. The study confirmed that the risk associated with microplastics is based on their monomer composition rather than the quantities present. Sediments having relatively higher abundance of microplastics with a relatively lower hazard score result in higher nutrient concentrations. The concentrations of metals in river sediments are more dependent on their original sources rather than the concentration of microplastics. Nevertheless, leachate from plastics should be considered in risk assessment in relation to the association between metals and plastics in aquatic environments.
Mostrar más [+] Menos [-]Occurrence and risk assessment of psychoactive substances in tap water from China Texto completo
2020
Wang, Zeyuan | Gao, Siyue | Dai, Qingying | Zhao, Meirong | Yang, Fangxing
Psychoactive substances are becoming a new concern in aquatic environment along with the increase in use of these substances. In this study, 23 psychoactive substances were investigated in the tap water collected in 63 sites in China. Eighteen out of 23 psychoactive substances were detected at the range of < method detection limits (MDLs) to 24.9 ng L-1. It was found that diazepam and temazepam were the major psychoactive substances in the tap water with the median concentration of 1.0 and 0.06 ng L⁻¹, respectively. The high exposure dose for each psychoactive substance was calculated from 0.6 to 855 pg kg⁻¹ bw d⁻¹ and showed an order of men ≥ boys ≥ girls ≥ women. Risk assessment revealed there was little risk of psychoactive substances on human health at current residual levels.
Mostrar más [+] Menos [-]Biotransformation and tissue bioaccumulation of 8:2 fluorotelomer alcohol in broiler by oral exposure Texto completo
2020
Chen, Dongmei | Zhao, Ying | Xu, Wei | Pan, Yuanhu | Wei, Qu | Xie, Shuyu
In order to examine whether 8:2 FTOH exposure would lead to a contamination risk of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in broiler derived food, the biotransformation, and tissue distribution and accumulation of 8:2 FTOH following oral exposure in male broilers were investigated. The main metabolites of 8:2 FTOH in plasma and six tissues (muscle, liver, kidney, fat, heart, and lungs) identified by LC-Q-TOF were 2-perfluorooctyl ethanoic acid (8:2 FTCA), 8:2 fluorotelomer unsaturated carboxylic acid (8:2 FTUCA), 3-perfluoroheptyl propanoic acid (7:3 FTCA), perfluoropentanoic acid (PFPeA), perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluorononanoic acid (PFNA), 8:2 FTOH glucuronide conjugate, and 8:2 FTOH sulfate conjugate. The tissue distribution and bioaccumulation of 8:2 FTOH and its unconjugated metabolites were determinated by LC-MS/MS. 8:2 FTOH was quickly depleted in plasma and all six tested tissues, while PFOA, PFNA, and 7:3 FTCA showed strong accumulation in blood and all six examined tissues and were eliminated more slowly than the other metabolites. The tissues with the highest accumulation levels for 8:2 FTOH and its metabolites were heart, kidneys and liver, and the tissue with the lowest accumulation levels was muscle. The elimination half-lifes of PFNA in kidney and 7:3 FTCA in lung were longer compared to those of other metabolites in all six determined tissues. Thus, PFNA and 7:3 FTCA can be selected as potential biomonitoring markers after 8:2 FTOH exposure. This study has improved our understanding of 8:2 FTOH biotransformation and tissue bioaccumulation in broilers, which will help us monitor human exposure risk via food derived from broilers polluted by 8:2 FTOH.
Mostrar más [+] Menos [-]Insights into chemical composition, abatement mechanisms and regional transport of atmospheric pollutants in the Yangtze River Delta region, China during the COVID-19 outbreak control period Texto completo
2020
Jia, Haohao | Huo, Juntao | Fu, Qingyan | Duan, Yusen | Lin, Yanfen | Jin, Xiaodan | Hu, Xue | Cheng Jinping,
To investigate chemical characteristics, abatement mechanisms and regional transport of atmospheric pollutants during the COVID-19 outbreak control period in the Yangtze River Delta (YRD) region, China, the measurements of air pollutants including fine particulate matter (PM₂.₅) and volatile organic compounds (VOCs) on non-control period (NCP, 24 December 2019–23 January 2020) and control period (CP, 24 January–23 February 2020) were analyzed at the urban Pudong Supersite (PD) and the regional Dianshan Lake Supersite (DSL). Due to the stricter outbreak control, the levels of PM₂.₅ and VOCs, and the occurrence frequencies of haze-fog episodes decreased substantially from NCP to CP, with average reduction rates of 31.6%, 38.9% and 35.1% at PD, and 34.5%, 50.7% and 37.9% at DSL, respectively. The major source for PM₂.₅ was secondary sulfate & nitrate in both periods, and the emission control of primary sources such as coal burning and vehicle exhaust decreased the levels of precursors gas sulfur dioxide and nitrogen oxide, which highly contributed to the abatement of PM₂.₅ from NCP to CP. The higher levels of ozone at both PD and DSL on CP might be due to the weak nitrogen monoxide titration, low relative humidity and high visibility compared with NCP. Vehicle exhaust and fugitive emission from petrochemical industry were the major contributors of ambient VOCs and their decreasing activities mainly accounted for VOCs abatement. Moreover, the high frequency of haze-fog events was closely impacted by medium-scale regional transport within Anhui and Jiangsu provinces. Therefore, the decreasing regional transported air pollutants coincided with the emission control of local sources to cause the abatement of haze-fog events in YRD region on CP. This study could improve the understanding of the change of atmospheric pollutants during the outbreak control period, and provide scientific base for haze-fog pollution control in YRD region, China.
Mostrar más [+] Menos [-]Ecofriendly laccases treatment to challenge micropollutants issue in municipal wastewaters Texto completo
2020
In this study, a multidisciplinary approach investigated the enzymatic degradation of micropollutants in real, not modified, municipal wastewaters of a plant located in Italy. Stir Bar Sorptive Extraction combined to Gas Chromatography-Mass Spectrometric detection (SBSE-GC-MS) was applied to profile targeted pollutants in wastewaters collected after the primary sedimentation (W1) and the final effluent (W2). Fifteen compounds were detected at ng/L - μg/L, including pesticides, personal care products (PCPs) and drugs. The most abundant micropollutants were bis(2-ethylhexyl) phthalate, diethyl phthalate and ketoprofen. Laccases of Trametes pubescens MUT 2400 were very active against all the target micropollutants: except few cases, their concentration was reduced more than 60%. Chemical analysis and environmental risk do not always come together. To verify whether the treated wastewaters can represent a stressor for the aquatic ecosystem, toxicity was also evaluated. Raphidocelis subcapitata and Lepidium sativum tests showed a clear ecotoxicity reduction, even though they did not evenly respond. Two in vitro tests (E-screen test and MELN assay) were used to evaluate the estrogenic activity. Treatments already operating in the plant (e.g. activated sludge) partially reduced the estradiol equivalent concentration, and it was almost negligible after the laccases treatment. The results of this study suggest that laccases of T. pubescens are promising biocatalysts for the micropollutants transformation in wastewaters and surface waters.
Mostrar más [+] Menos [-]Plastic debris accumulation in the seabed derived from coastal fish farming Texto completo
2020
Plastic debris accumulation in the seabed derived from coastal fish farming Texto completo
2020
In this study, we assessed plastic accumulation in marine sediments due to finfish aquaculture using floating net-pens. We studied plastic concentrations around three fish farms located at the Mediterranean coastline of Spain. The macroplastic categories and abundances were determined by video monitoring, detecting the majority of elements (78%), including ropes, nets and fibres, a basket trap and a cable tie, close to the facilities, which were not exclusively linked to fish farming but also to fishing activities. Concentrations of microplastics (<5 mm) ranged from 0 to 213 particles/kg dry weight sediment with higher values in sites directly under the influence of the fish farms. Most particles (27.8%) were within the size fraction from 1.1 to 2.0 mm and fibre was the most common shape with 62.2%. The Infrared spectroscopy analysis showed that PE and PP were the predominant types of polymers analysed. In addition, changes in the enthalpy of melting (ΔHₘ (J/g)) and the degree of crystallinity indicate degradation of the microplastics analysed. This study shows that, in the studied fish farms, levels of microplastic pollution can be one order of magnitude lower compared to other areas suffering other anthropogenic pressures from the same or similar regions. Nevertheless, more research effort is needed to get concluding results.
Mostrar más [+] Menos [-]Plastic debris accumulation in the seabed derived from coastal fish farming Texto completo
2020
Krüger, Lotte | Casado-Coy, Nuria | Valle-Pérez, Carlos | Ramos, Marina | Sanchez-Jerez, Pablo | Gago, Jesús | Carretero, Olga | Beltrán Sanahuja, Ana | Sanz-Lázaro, Carlos | Universidad de Alicante. Departamento de Ciencias del Mar y Biología Aplicada | Universidad de Alicante. Departamento de Química Analítica, Nutrición y Bromatología | Universidad de Alicante. Departamento de Ecología | Universidad de Alicante. Instituto Multidisciplinar para el Estudio del Medio "Ramón Margalef" | Biología Marina | Análisis de Polímeros y Nanomateriales | Análisis de Alimentos, Química Culinaria y Nutrición (AAQCN) | Bioquímica Aplicada/Applied Biochemistry (AppBiochem)
In this study, we assessed plastic accumulation in marine sediments due to finfish aquaculture using floating net-pens. We studied plastic concentrations around three fish farms located at the Mediterranean coastline of Spain. The macroplastic categories and abundances were determined by video monitoring, detecting the majority of elements (78%), including ropes, nets and fibres, a basket trap and a cable tie, close to the facilities, which were not exclusively linked to fish farming but also to fishing activities. Concentrations of microplastics (<5 mm) ranged from 0 to 213 particles/kg dry weight sediment with higher values in sites directly under the influence of the fish farms. Most particles (27.8%) were within the size fraction from 1.1 to 2.0 mm and fibre was the most common shape with 62.2%. The Infrared spectroscopy analysis showed that PE and PP were the predominant types of polymers analysed. In addition, changes in the enthalpy of melting (ΔHm (J/g)) and the degree of crystallinity indicate degradation of the microplastics analysed. This study shows that, in the studied fish farms, levels of microplastic pollution can be one order of magnitude lower compared to other areas suffering other anthropogenic pressures from the same or similar regions. Nevertheless, more research effort is needed to get concluding results. | This work has been funded by the project GRE14-19 from the University of Alicante from Spain, and the project GV/2015/001 from the “Conselleria de Educación, Cultura y Deporte” of the government of the Valencia region from Spain and the project CGL2015-70136-R from the Spanish National Agency for Research (MINECO / FEDER). LK was funded by the German Agency DAAD RISEWorldwide (Ref. num.: ES-BI-2977). C. S. was funded by the University of Alicante from Spain (Ref. UATALENTO 17-11).
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