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Результаты 2141-2150 из 7,292
Organophosphate esters and synthetic musks in the sediments of the Yangtze River Estuary and adjacent East China Sea: Occurrence, distribution, and potential ecological risks Полный текст
2022
Ji, Bingjing | Liu, Yi | Wu, Yang | Liang, Yi | Gao, Shutao | Zeng, Xiangying | Yao, Peng | Yu, Zhiqiang
Occurrence, distribution, and potential ecological risks of ten organophosphate esters (OPEs) and nine synthetic musks (SMs) were investigated in sediments from the Yangtze River Estuary (YRE) and adjacent East China Sea (ECS). The total concentrations of OPEs in the surface sediments ranged from 0.977 to 19.0 ng/g dry weight (dw) with tris(2-chloro-propyl) phosphate being the dominant component. Total concentrations of SMs ranged from 0.176 to 7.25 ng/g dw, with 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene as the dominant SMs. Higher sedimentary concentrations of ΣOPEs and ΣSMs were found in the river mouths of the YRE, inter face of Hangzhou Bay, and mud area of the ECS; the results suggested that terrestrial discharge might be the main source of OPEs and SMs in the studied region. Risk assessment revealed that low ecological risks were posed by OPEs, and limited to low ecological risks were posed by SMs.
Показать больше [+] Меньше [-]Development of automated marine floating plastic detection system using Sentinel-2 imagery and machine learning models Полный текст
2022
Sannigrahi, Srikanta | Basu, Bidroha | Basu, Arunima Sarkar | Pilla, Francesco
The increasing level of marine plastic pollution poses severe threats to the marine ecosystem and biodiversity. Open remote sensing data and advanced machine learning (ML) algorithms could be a cost-effective solution for identifying large plastic patches across the scale. The potential application of such resources in detecting and discriminating marine floating plastics (MFP) are not fully explored. Therefore, the present study attempted to explore the full functionality of open Sentinel satellite data and ML models for detecting and classifying the MFP in Mytilene (Greece), Limassol (Cyprus), Skala Loutron, Greece, Calabria (Italy), and Beirut (Lebanon). Two ML models, i.e. Support Vector Machine (SVM) and Random Forest (RF), were utilized to perform the classification analysis. In-situ plastic location data was collected from the control experiments conducted in Mytilene, Greece (in 2018 and 2019), Skala Loutron, Greece (2021), and Limassol, Cyprus (2018), and the same was considered for training the models. The accuracy and performances of the trained models were further tested on unseen new data collected from Calabria, Italy and Beirut, Lebanon. Both remote sensing bands and spectral indices were used for developing the ML models. A spectral signature profile for marine plastic was created for discriminating the floating plastic from other marine debris. A newly developed index, kernel Normalized Difference Vegetation Index (kNDVI), was incorporated into the modelling to examine its contribution to model performances. Both SVM and RF were performed well in five models and test case combinations. Among the two ML models, the highest performance was measured for the RF. The inclusion of kNDVI was found effective and increased the model performances, reflected by high balanced accuracy measured for model 2 (~89% to ~100% for SVM and ~92% to ~98% for RF). An automated floating plastic detection system was developed and tested in Calabria and Beirut using the best-performed model. The trained model had detected the floating plastic for both sites with ~80%–90%% accuracy. Among the six predictors, the Floating Debris Index (FDI) was the most important variable for detecting marine floating plastic. These findings collectively suggest that high-resolution remote sensing imagery and the automated ML models can be an effective alternative for the cost-effective detection of MFP. Future research will be directed toward collecting quality training data to develop robust automated models and prepare a spectral library for different plastic objects for discriminating plastic from other marine floating debris and advancing the marine plastic pollution research by taking full advantage of open-source data and technologies.
Показать больше [+] Меньше [-]Occupational exposure to mercury from cinnabar enriched sand in workers of Grado Beach, Gulf of Trieste (North-eastern Italy, upper Adriatic Sea) Полный текст
2022
Cegolon, Luca | Mastrangelo, Giuseppe | Covelli, Stefano | Petranich, Elisa | Pavoni, Elena | Larese Filon, Francesca
Health and safety of occupations entailing extensive skin contact with cinnabar-enriched sand in beaches of Friuli-Venezia Giulia (FVG) Region (North-eastern Italy) have been questioned for possible skin absorption of mercury (Hg). One hundred mg hair was collected from the occipital scalp of 50 male workers of Grado beach and 121 males from FVG general population. Factors associated with hair Hg content were investigated by multivariable logistic (considering Hg levels >1 vs ≤1 mg/kg) and log-transformed linear regression. The median hair concentration of Hg in male beach workers was 0.70 (IQR = 0.42; 1.34) mg/kg, lower than FVG general population's [1.29 (IQR = 0.87–2.06) mg/kg (p < 0.001)]. In both regression models the hair Hg increased with fish consumption, both among beach workers of Grado and FVG general population. The mean Hg levels in beach workers of Grado fell within an acceptable range, not requiring restrictions of their occupational activities.
Показать больше [+] Меньше [-]An examination of seed germination and seedling growth of Zostera marina for planting-time selection in Rongcheng Bay, Shandong Peninsula, China Полный текст
2022
Deng, Xiao-Fan | Zhang, Yan-Hao | Liu, Jie | Yu, Bing | Li, Hong-Chen | Zhang, Pei-Dong
This study firstly quantified the responses of seeds of Zostera marina to different planting times (22 September, 5 October, 23 October, 7 November and 20 November in 2015) through a field seed-planting experiment over a two year period. The suitable seed planting time required by the seeds of Z. marina was evaluated. The seedling establishment rate of Z. marina subjected to different planting times ranged from 7% to 55%, with the higher values attained on the treatments of 22 September and 5 October. New plant patches from seed were fully developed and well maintained on the planting time of 22 September, 5 October and 23 October after 2 years following planting. The shoot density under the three treatments ranged from 62 shoots per replicate to 72 shoots per replicate with an average of 67 shoots per replicate in September 2017. According to the propagation assessment and growth analysis, we found that the planting time from mid-September to mid-October may be the optimal time to plant seeds of Z. marina in our experimental site. Our results demonstrate that seed planting time has an important effect on the effectiveness of eelgrass restoration and provide data that could prove helpful in the development of successful eelgrass restoration.
Показать больше [+] Меньше [-]Isotopic signatures, hydrochemical and multivariate statistical analysis of seawater intrusion in the coastal aquifers of Chennai and Tiruvallur District, Tamil Nadu, India Полный текст
2022
Balasubramanian, Muthusamy | Sridhar, Sithu Govindasamy Dinakaran | Ayyamperumal, Ramamoorthy | Karuppannan, Shankar | Gopalakrishnan, Gnanachandrasamy | Chakraborty, Monica | Huang, Xiaozhong
In coastal aquifers, seawater intrusion is a significant groundwater issue. The research paper contributes to the understanding of the consequences of seawater intrusion in the Chennai coastal aquifer from Foreshore Estate to Thirunilai along the coastline. 110 groundwater samples were collected and analyzed for physicochemical parameters such as pH, (EC), (TDS), (TH), major anions (Cl⁻, NO₃⁻, HCO₃²⁻, and SO₄²⁻), and cations (Ca²⁺, Mg²⁺, Na⁺, and K⁺) during the pre-monsoon (June 2014) and post-monsoon (January 2015) seasons. Stable isotopic analyses of ¹⁸O were performed on 24 groundwater samples collected from various locations throughout the research region based on EC, TDS, Na, and Cl⁻ concentrations for both seasons. The stable isotopic composition of ¹⁸O and Deuterium in groundwater samples was determined for the study region. According to the Correlation matrix and Factor analysis, the main contributors to groundwater salinity as a result of seawater intrusion into the coastal aquifer are EC, TDS, Na⁺, and Cl⁻. GMWL exhibits a similar pattern, and the samples have been classified into various molar ratio diagrams to identify seawater intrusions for better evaluation. The result revealed that seasonal, geogenic, and anthropogenic factors always make a significant contribution to the heterogeneous chemistry of groundwater.
Показать больше [+] Меньше [-]Microplastics in an anadromous national fish, Hilsa shad Tenualosa ilisha from the Bay of Bengal, Bangladesh Полный текст
2022
Siddique, Mohammad Abdul Momin | Uddin, Azad | Rahman, Shahriar Md Arifur | Rahman, Mahfuzur | Islam, Md Sahedul | Kibria, Golam
Hilsa shad is one of the most important fisheries, contributing about 12.9% of the country's (Bangladesh) total fish production. There was no previous study on microplastic contamination of this important commercial fish. This study aims to identify, classify, and quantify microplastics (MPs) ingested by the national fish of Bangladesh, Hilsa shad, Tenualosa ilisha. A total of 287 MPs were recovered from the gastrointestinal tracts. All the fishes analyzed were contaminated with MPs. The mean (±SD) of the number of MPs was 19.13 ± 10.77 particles/fish, ranging from 7 to 51 particles/fish. Significant correlation was not found between the fish body length and MP abundance (rs = 0.287, p = 0.299), and between the fish body weight and MPs abundance (rs = 0.261, p = 0.347). The most dominant color was transparent (30%), followed by gray and black, contributing to 26% and 23%, respectively. The maximum number of MPs accounted for in the 300–1500 μm size class where fiber was the most dominant (50%) shape of observed MPs. These results provide a baseline of MP contamination in seafood from Bangladesh that should be useful for future monitoring efforts. The present study is the first research on MP contamination of Hilsa shad.
Показать больше [+] Меньше [-]Research Progress on Volatile Organic Compounds Emissions from Coal-fired Power Plants Полный текст
2022
Xu, Jingxin | Zhu, Fahua | Ge, Xinlei | Li, Haiwei | Zhao, Xiuyong | Tian, Wenxin | Zhang, Xi | Bai, Yuan | An, Fengxia | Wang, Sheng
Known as the high-priority air pollutants in the atmosphere, volatile organic compounds (VOCs) are a dominated precursor of secondary organic aerosols (SOAs), leading to complex PM₂.₅ and O₃ pollution and severe risks to human health. Considering upward concentrations of VOCs emitted from a great number of coal-fired power plants in China, considerable contributions of this primary source to current air pollution remain to be addressed. Previous studies have underestimated the concentration level of VOCs emissions from actual coal-fired power plants, largely because of incomplete monitored species, inconsistent results of emission characteristics and unclear effectiveness of VOCs removal by current flue gas purification units. Herein, recent progress on the field measurement techniques, pollution characteristics of VOCs (i.e., concentrations, chemical speciation and transformation) and impacts of flue gas purifying technologies on the VOCs control in coal-fired power plants were reviewed. In addition, key research perspectives in the future are proposed to formulate the technical standards for precise monitoring of VOCs from coal-fired power plants. The optimal combustion conditions under low-load operation conditions are to be determined. The ideal synergistic control strategies of VOCs emissions are anticipated to work out. As such, this review will provide some new insights into the development and formulation of VOCs control technologies in coal-fired power plants for the air quality improvement in China.
Показать больше [+] Меньше [-]Occurrence of alkylphenols and alkylphenol ethoxylates in North Sea sediment samples collected across oil and gas fields Полный текст
2022
McLaren, Diana E.K. | Rawlins, Andrew J.
Alkylphenol ethoxylates (APEs) have been used in several offshore oil and gas production applications including as emulsifiers in drilling mud formulations, which may have resulted in their disposal to sea. Despite concern over the endocrine disrupting potential of their alkylphenol (AP) degradation products, information on the presence of AP/APEs in marine sediments in the vicinity of oil and gas production facilities is scarce. This paper presents the occurrence of AP/APEs in marine sediment in North Sea oil and gas fields. The concentrations of octylphenol, nonylphenol and their ethoxylates near offshore installations were broadly comparable to, or higher than those of coastal and estuarine point source discharges. When compared to environmental assessment criteria, the NPCA Class V threshold values for octylphenol and nonylphenol were exceeded within 100 m and 500 m of infrastructure respectively, with higher concentrations of AP/APEs reported in fields that came online prior to 1986.
Показать больше [+] Меньше [-]Non-destructive biomarkers can reveal effects of the association of microplastics and pharmaceuticals or personal care products Полный текст
2022
da Silva, Letícia Fernanda | Nobre, Caio Rodrigues | Moreno, Beatriz Barbosa | Pereira, Camilo Dias Seabra | de Souza Abessa, Denis Moledo | Choueri, Rodrigo Brasil | Gusso-Choueri, Paloma Kachel | Cesar, Augusto
Methods to assess the effects of contaminants on marine organisms typically involve euthanasia to obtain samples, but less invasive techniques may be more appropriate for working with threatened species. In this study, were assessed the biological responses of crabs exposed to microplastics and contaminants of emerging concern. Biochemical and cellular effects (lipid peroxidation, DNA damage, cholinesterase activity, and lysosomal membrane stability) in hemolymph were analyzed in a kinetic study, at 3 and 7 days, in U. cordatus exposed to microplastics spiked with Triclosan (TCS) or 17α-Ethynylestradiol (EE2). The results showed that the contaminants were produced toxic effects in the crabs exposed either to the microplastics alone (oxidative stress, genotoxicity, and neurotoxicity), or to microplastics with TCS or EE2 adsorbed (neurotoxic and cytotoxic). The present study showed the responsiveness of non-lethal analyzes to understanding the biological effects of combined exposure to microplastics and chemical pollution.
Показать больше [+] Меньше [-]Scenery evaluation as a tool for the determination of visual pollution in coastal environments: The Rabigh coastline, Kingdom of Saudi Arabia as a study case Полный текст
2022
Alharbi, Omar A. | Rangel-Buitrago, Nelson
Visual pollution is the visible deterioration and negative aesthetic quality of the landscape. Erosion, marine wrack, litter, sewage, and beach driving are affecting the coastal scenery and are generating a visual pollution problem on the Rabigh coastal area, Kingdom of Saudi Arabia. This work provides the scenic evaluation of 31 coastal sites using the Coastal Scenery Evaluation System (CSES) to determine the current state of this situation and give management inputs. The CSES assesses values from a checklist of 18 physical and 8 human parameters and allows the calculation of a scenic evaluation index (D Value), which classifies coastal sites into five classes: Class I, usually natural areas of top scenic characteristics, to Class V, poor scenic natural areas with a higher impact of human interventions. Along the study area, three sites (9.7 %) appeared in Class II; five (16.1 %) in Class III; 15 (48.4 %) in Class IV, and eight sites (25.8 %) in Class V. Class I sites were not found in the study area. Assessment presented in this work provides a complete overview of the Rabigh coastal scenery and serves as a baseline for implementing management strategies to cope the visual pollution problem.
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