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Результаты 1821-1830 из 4,936
Trace elements in microplastics in Cartagena: A hotspot for plastic pollution at the Caribbean Полный текст
2019
Acosta-Coley, Isabel | Mendez-Cuadro, Dario | Rodriguez-Cavallo, Erika | Rosa, Jesús de la | Olivero-Verbel, Jesus
Microplastics are new pollutants considered a source of concern for the oceans worldwide. This research reports the concentrations of trace metals on microplastics collected on beaches from Cartagena, an industrialized city in the Caribbean. Mercury (Hg) was quantified using a Hg analyzer and forty-seven trace elements were assessed by ICP/MS. Most abundant microplastics in beaches were those with the lower degree of surface degradation features (SDF), categorized as white-new polyethylene pellets, followed by secondary microplastics (SM). Greater Hg levels were found in SM, white-degraded (WDP) and black pellets. Trace elements concentrations were linked to the degree of SDF registered in examined pellets, with larger concentrations in WDP. Compared to white-new pellets, Ba, Cr, Rb, Sr, Ce, Zr, Ni, Pb were the most accumulated elements in WDP, as their surface enhance the sorption processes. Microplastic pollution represents a toxicological hazard because its ability to accumulate and transport toxic elements.
Показать больше [+] Меньше [-]Occurrence, seasonal variation and risk evaluation of selected endocrine disrupting compounds and their transformation products in Jiulong river and estuary, China Полный текст
2019
Ashfaq, Muhammad | Sun, Qian | Ma, Cong | Rashid, Azhar | Li, Yan | Mulla, Sikandar I. | Yu, Chang-Ping
In the present study, 13 endocrine disrupting compounds (EDCs) and their transformation products (TPs) were monitored in Jiulong River and its estuary, China in different seasons. The analytes included antimicrobials [triclosan (TCS) and triclocarbon (TCC)]; estrogens [estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2)]; alkylphenol ethoxylates [4-n-nonylphenol (NP) and 4-n-octylphenol (OP)] and the TPs [methyl triclosan (MeTCS), carbanilide (NCC), dichlorocarbanilide, 4-hydroxy estrone (4-OH E1) and 4-hydroxy estradiol (4-OH E2)]. A significant seasonal variation was observed for most EDCs. Approximately, 79% of the total E2 residues were detected in the normal season in comparison with the wet season to indicate recalcitrant behavior of E2 during the normal season. Risk assessment revealed that E2 was most potent among the EDCs to cause highest risk to both vertebrate and invertebrate aquatic species, whereas, E1, EE2, MeTCS and TCS also showed relatively high risk for some surface water aquatic species.
Показать больше [+] Меньше [-]Description of buoyant fibers adhering to Argonauta nouryi (Cephalopoda: Argonautidae) collected from the stomach contents of three top predators in the Mexican South Pacific Полный текст
2019
del Carmen Alejo-Plata, María | Herrera-Galindo, Eduardo | Cruz-González, Diana Guadalupe
Argonauta nouryi Lorois, 1852 is an octopod that inhabits the holopelagic zone, the objective of this study was to describe the occurrence of buoyant fibers adhering to the body and mantle cavity of A. nouryi females found in the stomach contents from Euthynnus lineatus (skipjack), Coryphaena hippurus (dolphinfish), and Istiophorus platypterus (sailfish). Stomach contents from 224 individuals were examined. All female evaluated presented fibers adhering to the mantle cavity; 92.6% of the fibers measured 0.25 to 5 mm in length and hyaline was the dominant color (72%). The amount of fibers in the fish stomach contents with A. nouryi was significantly greater than in stomachs without; this suggests that the fibers might be introduced via A. nouryi. Findings of this work could be related to the discharge of solid materials in the water column.
Показать больше [+] Меньше [-]Microplastic pollution at the intersection of the Aegean and Mediterranean Seas: A study of the Datça Peninsula (Turkey) Полный текст
2019
Yabanlı, Murat | Yozukmaz, Aykut | Şener, İdris | Ölmez, Özge Tokul
This study aims to reveal microplastic pollution. It is the first to be conducted in the South Aegean Region and one of the limited numbers of such studies in Turkey. To this aim, in September 2018 microplastic particles (MP's) pollution was evaluated on the sandy beaches along the coastline of the Datça Peninsula (Southern Aegean coast of Turkey) located at the intersection of the Aegean and Mediterranean Seas. MP's were analyzed using standard operating procedure along with some experimental techniques. Prior to the identification process, microplastics ranging from 1 to 5 mm were exposed to an experimental pre-treatment and efficient polymer scanning. The results showed that fragments (72%) were the dominant category from all the beaches exposed to dominant winds and surface currents and that MP contamination in the Datça Peninsula was higher than that reported in the literature from similar locations around the world (1154.4 ± 700.3 particles kg⁻¹ dw). More specifically the highest contamination was found in Aktur Beach (2073.3 ± 648.6 particles kg⁻¹ dw) which could be considered as a hotspot for the whole region in terms of MP pollution. As a result of the study, as sampling stations are remote from major cities and industrial zones, maritime activities increase during summer season and tar has been observed on particles during analyses, it can be asserted that the pollution may be caused by marine resources.
Показать больше [+] Меньше [-]Taking control of persistent solid waste pollution Полный текст
2019
Coe, James M. | Antonelis, George “Bud” | Moy, Kirsten
The complexity and scale of the sources, types and environmental impacts of persistent solid waste pollution (PSWP) continue to overwhelm the capabilities of government and private efforts to control it. Global cumulative production of virgin plastics is expected to quadruple by 2050 with a concomitant doubling of plastic waste. All nations must take significant steps to realize eventual mitigation of PSWP. These will include adopting a long-term PSWP elimination policy, creating an overarching authority to lead and coordinate a comprehensive national solid waste management program, and creating an International Convention for the Prevention of PSWP to enable global solutions for this global pollution. Initiating these changes will necessitate major, coordinated efforts on the part of environmental organizations, their supporting foundations and concerned citizens.
Показать больше [+] Меньше [-]137Cs and 40K concentration ratios (CRs) in annual and perennial plants in the Caspian coast Полный текст
2019
Abbasi, Akbar | Mirekhtiary, Fatemeh
This research attempted to investigate the plant/soil concentration ratios (CRs) of ¹³⁷Cs and ⁴⁰K in plants that grow on the Anzali Lagoon of the Caspian coast, Iran. The activity concentrations of ¹³⁷Cs and ⁴⁰K were measured in soil samples, annual plants (Echinochloa crus-galli, Digitaria sanguinalis, and Trifolium repens), and perennial plants (Phragmites australis, and Cynodon dactylon). The relationship of activity concentration with soil particle density, and pH of soil samples, CR, and ¹³⁷Cs/⁴⁰K discrimination factor (DF) were determined. The activity concentration of ¹³⁷Cs in the soil, annual plants, and perennial plants ranged between 12- and 124 (Bq/kg dry weight), 2- and 17 (Bq/kg dw), and 2 - and 14 (Bq/kg dw), respectively. The geometric mean (GM) values of DF in annual and perennial plants were 0.57 and 0.55, respectively. The CR for ¹³⁷Cs and ⁴⁰K varied as a non-linear relation in annual plants and perennial plants. This study showed that the CRs for ¹³⁷Cs in annual plants were higher than the CRs for perennial plants.
Показать больше [+] Меньше [-]Microplastic in the sediments of a highly eutrophic tropical estuary Полный текст
2019
Alves, Vivianne E.N. | Figueiredo, Gisela M.
Given the implications of microplastics contamination in aquatic ecosystems and information scarcity about microplastic abundances in estuarine sediments, this study aimed to quantify and describe the microplastics in the sublittoral sediments from Guanabara Bay. Sediment samples were collected at four sites and three months, microplastics were separated and classified according to type, color, size, and polymer composition. High abundances of microplastic (160 to 1000 items kg⁻¹ or 4367 to 25,794 items m⁻²) occurred independent of area or period, indicating microplastics are widely spread in Guanabara Bay. The dominant microplastic in the sediment was the translucent polyester microfiber of <1 mm size; which is a secondary microplastic, possibly coming from washing machines wastes. The extremely high availability of microplastics in Guanabara Bay, compared to the majority of studies around the world, suggests high risk of contamination to benthic organisms and demersal fish, as they may be ingesting microplastics.
Показать больше [+] Меньше [-]Variability of organic nitrogen and its role in regulating phytoplankton in the eastern Arabian Sea Полный текст
2019
Shetye, Suhas S. | Kurian, Siby | Nāyaka, Hemā Puṇḍalīka | Gauns, Mangesh | Chndrasekhararao, A.V. | Kumar, Ashwini | Naik, Bhagyashri
The relative importance of organic nitrogen (ON) and inorganic nitrogen (IN) as nitrogen sources for the phytoplankton communities were studied through a seasonal time series of nitrogen species in the eastern Arabian Sea. Seasonal data on nitrogen species showed that ON dominates the system throughout the year and account for >90% of the total nitrogen (TN) during north east monsoon (NEM). The average ON concentration in the study region was 11.5 μM during NEM as compared to 7.2 μM during south west monsoon (SWM). The contribution of picoplankton to the total phytoplankton pool (fpico) increased from 19% during SWM to 36% in NEM. Along with cyanobacteria, the diatoms Thalassionema nitzchoides and Thalassiosira sp. and among the dinoflagellates Pronoctiluca sp. were found to proliferate in ON rich waters. We suggest atmospheric deposition, riverine-input, resuspension of bottom sediment and ground water intrusion as the possible sources of ON in the study region.
Показать больше [+] Меньше [-]Arsenic in Drinking Water : Is 10 μg/L a Safe Limit?
2019
Ahmad, Arslan | Bhattacharya, Prosun
Arsenic (As) is a naturally occurring element in the Earth’s crust. Both anthropogenic and natural processes can release As into sources for drinking water supply. A substantial epidemiological evidence is available to support that the chronic exposure to high concentrations in drinking water (> 10 μg/L) is associated with several detrimental effects on human health including skin lesions [1] and cancer of the lung [2], bladder [3], kidney [4], and liver [4]. Furthermore, dermatological, developmental, neurological [5], respiratory [6], cardiovascular [7], immunological [8], and endocrine effects [9] as a result of chronic exposure to high As concentrations have been reported. However, there remains considerable uncertainty on the chronic risks due to As exposure at low concentrations (< 10 μg/L) and the shape of the dose-response relationship [10, 11]. It is therefore crucial to question whether the 10 μg/L limit ensures protection of human health from the adverse health effects of As.
Показать больше [+] Меньше [-]When the levee breaks: Effects of flood on offshore water contamination and benthic community in the Mediterranean (Ionian Sea) Полный текст
2019
Mistri, Michele | Pitacco, Valentina | Granata, Tommaso | Moruzzi, Letizia | Munari, Cristina
In the last few years extreme weather events, including changes to storm frequency and intensity, have increased across all continents. In this note we assessed, for the first time in the Mediterranean Sea, the impact of a violent storm and consequent flood on offshore water contamination and benthic community along the Calabrian coast (Ionian Sea). Three sites (at 500, 1000, and 2000 m off the coast) were sampled along three parallel transects in 2013, 2014 (before), and 2015 (after the flood). After the flood, metals (especially Al, CrVI, Ni, Cu, Zn) in the water column increased in concentration. The flood affected the structure of the benthic community, causing a decrease of diversity, the dominance of few opportunistic species, and the decrease of M-AMBI values.
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