خيارات البحث
النتائج 2321 - 2330 من 7,250
Metal-associated human health risk assessment due to consumption of pelagic and benthic ichthyofaunal resources from the highly contaminated Cuddalore coast in Southern India
2022
Vinothkannan, Anbazhagan | Rajaram, Rajendran | Charles, Partheeban Emmanuel | Ganeshkumar, Arumugam
We present seasonal variation of four metals (Cd, Cu, Pb, and Zn) in nine pelagic and three benthic fish species from the highly polluted Cuddalore coast in Tamil Nadu, India. Metals were assessed using atomic absorption spectrometry and detected in all fish species, in at least one season, except Iniistius cyanifrons where cadmium was not detected throughout. In both benthic and pelagic fish, order of metal concentration was Zn > Cu > Pb > Cd. Multivariate statistical analysis revealed that metals may have originated from both natural and anthropogenic sources. Health risk assessment revealed that consumption of fish from Cuddalore coast does not pose health risk for now; however, hazard index values (pelagic = 0.97; benthic = 0.90) are in borderline. Even a slight increase in metal concentration in fish can prove hazardous for human consumption. Sooner or later, eating fish from Cuddalore coast may pose a considerable health risk to humans if metal pollution is not held at Bay.
اظهر المزيد [+] اقل [-]Bioaccumulation patterns of trace elements by native (M. galloprovincialis) and invasive (X. securis) mussels in coastal systems (Vigo Ria, NW Iberian Peninsula)
2022
Rodríguez-Velarte, P. | Babarro, J.M.F. | Cobelo-García, A.
A number of trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Nb, Mo, Ag, Cd, Pb, U and the rare earth elements – REE) were analyzed in the dissolved phase, suspended particulate matter and in different organs (gills, hepatopancreas, and the rest of soft tissue) in mussels of the native Mytilus galloprovincialis and invasive Xenostrobus securis species in the Vigo Ria (NW Iberian Peninsula) in order to assess potential differences in their bioaccumulation patterns. Results obtained do not show significant differences in the bioaccumulation of trace elements by M. galloprovincialis and X. securis, except for Zn and Ag. In the case of Zn, a 4-fold enrichment in M. galloprovincialis compared to X. securis was found. The most important differences between species were observed for Ag, with approximately 40-fold higher concentrations in X. securis. Such elevated Ag bioaccumulation by X. securis can be useful for Ag biomonitoring using these invasive species in this area.
اظهر المزيد [+] اقل [-]An assessment of floating marine debris within the breakwaters of the University of the South Pacific, Marine Studies Campus at Laucala Bay
2022
Paris, Andrew | Kwaoga, Alex | Hewavitharane, Chinthaka
Contributions of Pacific Islands countries to marine plastic debris are disproportionate to the effects on people's connections to the ocean. Plastic waste management initiatives face challenges in containing waste and consequently plastics plague coastal environments. The Seabin, a floating trash skimmer, presents a novel and replicable approach to collecting and cataloguing marine plastics. The objectives of the study were to conduct an audit of marine plastic debris within the breakwaters of the University of the South Pacific, Marine Campus at Laucala Bay while simultaneously gauging the effectiveness of the Seabin and providing recommendations to enhance its utility. Inorganic debris was comprised entirely of plastics while the majority of debris collected was organic. This study provides the first assessment of floating marine plastic debris in an inshore environment of a Pacific Island country. Plastic debris assessments have the potential to inform policy and pivot management efforts to mitigate plastic waste pollution.
اظهر المزيد [+] اقل [-]Operationalizing the Exposome Using Passive Silicone Samplers
2022
Fuentes, Zoe Coates | Schwartz, Yuri Levin | Robuck, Anna R. | Walker, Douglas I.
The exposome, which is defined as the cumulative effect of environmental exposures and corresponding biological responses, aims to provide a comprehensive measure for evaluating non-genetic causes of disease. Operationalization of the exposome for environmental health and precision medicine has been limited by the lack of a universal approach for characterizing complex exposures, particularly as they vary temporally and geographically. To overcome these challenges, passive sampling devices (PSDs) provide a key measurement strategy for deep exposome phenotyping, which aims to provide comprehensive chemical assessment using untargeted high-resolution mass spectrometry for exposome-wide association studies. To highlight the advantages of silicone PSDs, we review their use in population studies and evaluate the broad range of applications and chemical classes characterized using these samplers. We assess key aspects of incorporating PSDs within observational studies, including the need to preclean samplers prior to use to remove impurities that interfere with compound detection, analytical considerations, and cost. We close with strategies on how to incorporate measures of the external exposome using PSDs, and their advantages for reducing variability in exposure measures and providing a more thorough accounting of the exposome. Continued development and application of silicone PSDs will facilitate greater understanding of how environmental exposures drive disease risk, while providing a feasible strategy for incorporating untargeted, high-resolution characterization of the external exposome in human studies.
اظهر المزيد [+] اقل [-]Quantitative assessment of microplastic in sandy beaches of Gujarat state, India
2022
Rabari, Vasantkumar | Patel, Krupal | Patel, Heris | Trivedi, Jigneshkumar
The present study was carried out to quantify microplastic prevalence among 20 sandy beaches on the Gujarat coast. Beaches were categorised into three different classes, viz. low-impacted sites, moderately impacted sites, and highly impacted sites based on anthropogenic pressure. Microplastic (MP) (≤ 5 mm) contamination on the beaches varied with an average of 1.4 MPs/kg to 26 MPs/kg sediment. Sutrapada site-1 and Porbandar showed the highest and lowest mean abundance of microplastics, respectively, among 20 selected beaches. Out of the total assessed microplastics, threads were the maximum (89.98%), followed by the films (4.75%), fragments (3.36%) and foam (1.89%). In terms of colour and size, different microplastics were recorded in this study. The chemical composition of microplastics was identified by ATR-FTIR as polypropylene (47.5%), polyethylene (26%), and polystyrene (25%). Tourism and fishing activities are the possible sources of higher microplastic contamination at highly impacted sites.
اظهر المزيد [+] اقل [-]Microplastic distribution within core sediments of beach and its responses to anthropogenic activities
2022
Pervez, Rashid | Wang, Yonghong
Nowadays, people have known more about the distribution features on the surface of beaches. However, the understanding on the microplastics (Mps) distribution in the vertical direction on beaches is still lacking. This study analysed the vertical distribution of Mps from five beaches, with one long core [Shilaoren Beach (C1), 8 m] and four short cores [Aoshan Beach (C2); Liuqinghewan Beach (C3); Bathing Beach No. 3 (C4); and Golden Beach (C5); approximately 70 cm]. An increasing trend of Mps from bottom to top layers were observed with an average of 16.6 ± 4.8 Mps/25 g d.w. in C1. Conversely, a fluctuating trend was found in C2–C5, with an average Mps abundance on the 70 cm depth to be 6.7, 7.1, 11.1 and 7.0 Mps/25 g d.w., respectively. These Mps were mainly comprised of fibres (>98%) and few were fragments. Mps were not uniformly distributed within all cores, and this variation was due to changes in Mps sources, hydrodynamics and sedimentation process in the beach environment. Although the vertical accumulation of Mps is not as stable as the other sedimentary environments, it still presents the increasing trend in the 8-m core from the bottom to the top, which is consistent with the plastic production history in China since 1950. Therefore, the 8-m core has been deposited on the beach in the recent 70 years. Thus, this study provides a valuable example for tracing the sedimentation history on the beach, which can help in understanding the sediment deposit and transport processes with time on beaches.
اظهر المزيد [+] اقل [-]Ingestion of polyethylene microspheres occur only in presence of prey in the jellyfish Aurelia aurita
2022
Romero-Kutzner, Vanesa | Tarí, Javier | Herrera, Alicia | Martínez, Ico | Bondyale-Juez, Daniel | Gómez, May
Microplastic ingestion was studied in A. aurita, a bloom-forming, circumglobal medusa. Here, we determined whether factors such as the concentration of polyethylene microspheres (75–90 μm) or the absence/presence of prey affect the ingestion, duration of microspheres in the gastrovascular cavity (time of presence), and retention time. The presence of polyethylene microspheres' was determined by exposing medusae during 480 min to three different treatments (5000, 10,000, 20,000 particles L⁻¹), and was checked every 10 min to ascertain whether they had incorporated any. Preliminary results show that microsphere ingestion occurred only in the presence of prey (⁓294 Artemia nauplii L⁻¹). The time of presence of microbeads in A. aurita increased (103, 177, and 227 min), with increasing microplastic concentration, and the microbeads were egested within 150 min. This study initiates the understanding of the potential implications that arise of the encounter between jellyfish and microplastic agglomerates, and with perspectives for future research.
اظهر المزيد [+] اقل [-]Marine bacteria-based polyvinyl chloride (PVC) degradation by-products: Toxicity analysis on Vigna radiata and edible seaweed Ulva lactuca
2022
Khandare, Shrikant D. | Chaudhary, Doongar R. | Jha, Bhavanath
Biodegradation of polyvinyl chloride (PVC) by marine bacteria is a sustainable approach that leads to the production of different by-products but their toxicity needs to be evaluated. In the present study, polyvinyl chloride degradation products (PVCDP) produced by three marine bacterial isolates (T-1.3, BP-4.3 and S-237) in the culture supernatant were evaluated for toxicity on the germination of Vigna radiata and growth of Ulva lactuca. A total of 24 compounds comprising of benzene, fatty acid, ether, ester and plastic stabilizer (tris (2, 4-di-tert-butylphenyl) phosphate) were identified by GC–MS using diethyl ether solvent extraction from the supernatant. The per cent germination rate of the seed treated with PVCDP showed no significant effect but germination index and elongation inhibition rate were influenced significantly by PVCDP treatments. In seaweed (U. lactuca), PVCDP showed improvement in the daily growth rate. After ten days of treatment with PVCDP, pigment contents were improved in seaweed and PVCDP (2%) of isolate T-1.3 recorded the highest chlorophyll-a and chlorophyll-b.
اظهر المزيد [+] اقل [-]The deposition of atmospheric microplastics in Jakarta-Indonesia: The coastal urban area
2022
Purwiyanto, Anna Ida Sunaryo | Prartono, Tri | Riani, Etty | Naulita, Yuli | Cordova, Muhammad Reza | Koropitan, Alan Frendy
The air pollution in Jakarta has been recorded regularly; meanwhile, the information of atmospheric microplastics is still unknown. This study examines the characteristics (shape, size, and polymer) and deposition rate of atmospheric microplastics in Jakarta. The sample was obtained by putting a rain gauge for 12 months. All microplastic samples were analyzed for polymer using FT-IR. The lowest to the highest percentage of atmospheric microplastic based on shape were foam<fragment<fiber, meanwhile based on size were of 500–1000 μm < 300–500 μm. The detected polymers included polyester, polystyrene, polybutadiene, and polyethylene. The microplastics deposition rate ranged from 3 to 40 particles m⁻²d⁻¹, with an average of 15 particles m⁻²d⁻¹. The rainy season's deposition rate (23.422 particles m⁻²d⁻¹) was higher than the dry season (5.745 particles m⁻²d⁻¹). Our study proves that the atmospheric microplastic exists in Jakarta's air and needs to be considered to monitor by the government regularly.
اظهر المزيد [+] اقل [-]Application of diffusive gradients in thin films to determine rare earth elements in surface sediments of Daya Bay, China: Occurrence, distribution and ecotoxicological risks
2022
Gu, Yang-Guang | Huang, Hong-Hui | Gong, Xiu-Yu | Liao, Xiu-Li | Dai, Ming | Yang, Yu-Feng
Known as burgeoning contaminants, the bioavailability of rare earth elements (REEs) can be determined using diffusive gradients in thin films (DGT). As Daya Bay (South China) has been under serious anthropogenic influences, the present study examined the distribution of REEs in surface sediments and their possible ecological risks in the bay. The range of DGT-labile concentrations of REEs (∑REEs) was from 5.67 μg/L to 8.41 μg/L, with an average of 7.34 μg/L. Results of assessment of single REE toxicity revealed that the risk quotient (RQ) values of Y, Ce and Yb were >1, indicating that their potential negative impacts on the nearby environment. However, analysis of the integral toxicity of REE mixtures through assessment of probabilistic ecotoxicological risks showed that there was a negligibly low probability of toxicity of PRE surface sediments to aquatic organisms in the study area.
اظهر المزيد [+] اقل [-]