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Resultados 2711-2720 de 8,010
A rapid assessment of litter magnitudes and impacts along the Torre Guaceto marine protected area (Brindisi, Italy) Texto completo
2021
Rizzo, Angela | Rangel-Buitrago, Nelson | Impedovo, Angelita | Mastronuzzi, Giuseppe | Scardino, Giovanni | Scicchitano, Giovanni
This study focuses on assessing litter magnitudes along the Torre Guaceto Marine Protected Area (Brindisi, Italy). Collected litter was grouped into twenty different types and classified into four litter typologies according to the Guidance on Monitoring of Marine Litter in European Seas. All data were analyzed using an index-based approach that allowed the classification of a coastal stretch in terms of cleanliness, and presence of plastics as well hazardous items. The average litter abundance in the study area was 0.5 items/m², being plastics the most common litter item. Hazardous litter items were found along the study area, reaching 21.3% of the total collected items. The application of environmental indices allowed to define the study area with a “moderate cleanliness” and a “moderate” presence of hazardous litter items. Sampled litter typologies and related magnitudes suggest a combination of sources that mainly include direct activities on the nearby coastal zones and river basins (dumping).
Mostrar más [+] Menos [-]Spatial and seasonal variations of endocrine disrupting compounds in water and sediment samples of Markman Canal and Swartkops River Estuary, South Africa and their ecological risk assessment Texto completo
2021
Ohoro, Chinemerem Ruth | Adeniji, Abiodun Olagoke | Okoh, Anthony Ifeanyi | Okoh, Omobola Oluranti
The presence of pharmaceuticals in surface water and sediment has sparked up a global concern, as they could cause harm to human health. In this study, we investigated five pharmaceuticals (caffeine, carbamazepine, sulfamethoxazole, testosterone, and trimethoprim) in surface water and sediment samples from Swartkops River Estuary and Markman Stormwater Canal, in the Eastern Cape Province, South Africa. Ultra-Performance Liquid Chromatography (UPLC) systems coupled with a hyphenated quadrupole-time-of-flight mass spectrometry (QTOF-MS) was used for the analysis. Of the five pharmaceuticals investigated, three were detected in sediment samples at concentrations ranging from BDL – 23.86 μg/kg (dw). Caffeine and sulfamethoxazole were below the detection limit. The finding of this current study suggests that Markman and Motherwell's stormwater canals were potential contributors to pollution in Swartkops River Estuary. Ecotoxicity risk assessment indicated that trimethoprim and carbamazepine could constitute potential risk to aquatic organisms in Markman Canal and Swartkops Estuary, suggesting the need for proper control measure to prevent the pollution from toxicants in aquatic resources.
Mostrar más [+] Menos [-]Benthic foraminifera geochemistry as a monitoring tool for heavy metal and phosphorus pollution — A post fish-farm removal case study Texto completo
2021
Oron, Shai | Sadekov, Aleksey | Katz, Timor | Goodman-Tchernov, Beverly
Measuring environmental contaminants in coastal areas is critical for monitoring and managing their impacts. Commonly used techniques involve repetitive field sampling, which provides a single moment in time during each effort. In this study, we examine the potential for using foraminifera in monitoring and risk assessment as recorders of bioavailable pollutants. Geochemical analysis of benthic foraminifera (Operculina ammonoides) shells sampled annually at a previous fish farm location showed extremely high levels of copper (Cu), zinc (Zn), and phosphorus (P) during the three years following the fish cages removal, with a general reduction afterwards. Levels of Cu/Ca were still more than 4-fold higher than background levels 10 years after the removal of the fish cages. Based on our finds, it is concluded that the geochemical analysis of recent benthic foraminifera shells can serve as a powerful monitoring tool of bioavailable contaminants in seawater. Additionally, the results highlight the need for heavy metal monitoring near marine aquaculture facilities and suggest that long-term effects extend spatially and temporally far beyond the original point source. Finally, we observed variations in micro-distribution of elements within the top 1–2 μm of the shells, where Cu/Ca, Zn/Ca and P/Ca are consistently higher in the chamber wall than in the septa. This observation is relevant for studies conducting single chamber analyses.
Mostrar más [+] Menos [-]Characterization of common phytoplankton on the Louisiana shelf Texto completo
2021
Parsons, Michael L. | Brandt, Ashley L. | Turner, R Eugene | Morrison, Wendy L. | Ralabais, Nancy N.
Phytoplankton and accompanying environmental data (temperature, salinity, secchi depth, stratification, and inorganic nutrients) were analyzed from 672 surface water samples (0 to 1.5 m depth) collected from 95 stations located on the Louisiana shelf between April 1990 and August 2011. Phytoplankton were identified to the lowest practical taxonomic unit from glutaraldehyde-preserved samples using epifluorescent microscopy and reported as cells L⁻¹. Twenty-six phytoplankton taxa (primarily diatoms) that were > 8 μm in size, identified to genus-level resolution and ranked in the top 20 in at least one of three separate categories (average abundance; frequency of occurrence; and bloom frequency) were used in subsequent analyses. Temperature, stratification, and secchi depth constituted the environmental variable combination best related to the phytoplankton community composition patterns across the 672 samples (r = 0.288; p < 0.01) according to BEST analysis (PRIMER 7). The environmental optima of the 26 taxa were calculated using the weighted-averaging algorithm in the C2 program and then used to group the taxa into common phytoplankton clusters (i.e., niches) using PRIMER 7 CLUSTER. The phytoplankton clustered into three groups: Group A (summer assemblage), Group B (winter assemblage), and Group C (spring bloom assemblage). The results demonstrate that the composition of the phytoplankton community is most related to seasonality and physical variables, whereas nutrients appear to play a larger role in driving overall phytoplankton biomass. This study provides a platform to examine phytoplankton responses to future environmental perturbations in the region.
Mostrar más [+] Menos [-]Pollutant transport and residence time of a shallow and narrow coastal lagoon estimated using a numerical model Texto completo
2021
Zainol, Zuraini | Mohd Fadzil Akhir, | Zainol, Zuraidah
Setiu Wetland is rapidly developing into an aquaculture and agriculture hub, causing concern about its water quality condition. To address this issue, it is imperative to acquire knowledge of the spatial and temporal distributions of pollutants. Consequently, this study applied combinations of hydrodynamic and particle tracking models to identify the transport behaviour of pollutants and calculate the residence time in Setiu Lagoon. The particle tracking results indicated that the residence time in Setiu Lagoon was highly influenced by the release location, where particles released closer to the river mouth exhibited shorter residence times than those released further upstream. Despite this fact, the pulse of river discharges successfully reduced the residence time in the order of two to twelve times shorter. Under different tidal phases, the residence time during the neap tide was longer regardless of heavy rainfalls, implying the domination of tidal flow in the water renewal within the lagoon.
Mostrar más [+] Menos [-]Bayesian submerged oil tracking with SOSim: Inference from field reconnaissance data and fate-transport model output Texto completo
2021
Ji, Chao | Englehardt, James D. | Beegle-Krause, C.J.
When spilled oil collects at depth, questions as to where and when to dispatch response equipment become daunting, because such oil may be invisible by air, and underwater sensing technology is limited in coverage and by underwater visibility. Further, trajectory modeling based on previously recorded flow field data may show mixed results. In this work, the Bayesian model, SOSim, is modified to locate and forecast the movement of submerged oil, with confidence bound, by inferring model parameters based on any available field concentration data and the output of one or more deterministic trajectory models. Novel aspects include specification of a prior likelihood function, and generation of results in 3-D from data in the 2-D density space of the isopycnal layer containing oil. The model is demonstrated versus data collected following the Deepwater Horizon spill. This new inferential modeling approach appears complimentary to deterministic methods when field concentration data are available.
Mostrar más [+] Menos [-]Spatial and temporal assessment of oil spills in the Mediterranean Sea Texto completo
2021
Polinov, Semion | Bookman, Revital | Levin, Noam
Ship-generated oil pollution is a significant threat to the Mediterranean Sea. We present a geostatistical analysis of oil spills using three databases for the Mediterranean Sea: REMPEC (1977–2000) with 385 spills (17/year), ITOPF (1970–2018) with 167 spills (3.5/year) and EMSA (2015–2017) with 2066 detections (688/year). It was found that 88% of spills reported by REMPEC occurred near coastline areas, while 65% of the spills detected by EMSA occurred within a range of 22–100 km from the coastline. At the Exclusive Economic Zone (EEZ) level, EMSA oil spills densities were positively correlated with shipping and port activity. We conclude that there is a need to develop an open-access database of oil spills that will be based on both reports and remote sensing acquisition methods. Such a database will facilitate more efficient enforcement of international conventions in offshore areas and will increase the likelihood of effective response.
Mostrar más [+] Menos [-]Toxicity effect of Diuron on gill tissue structure and the tissue residue of blood cockles (Tegillarca granosa) Texto completo
2021
Mohamat-Yusuff, Ferdaus | Ibrahim, Dhilshad Shereen Mohamed | Mukhtar, Aqilah | Joni, Amirul Azuan Mad | Kusin, Faradiella Mohd | Mohamed, Khairul Nizam | Zulkeflee, Zufarzaana | Asha'ari, Zulfa Hanan | Zulkifli, Syaizwan Zahmir | Ismail, Ahmad | Arshad, Aziz
This study aimed to identify the toxicity effect of Diuron on Tegillarca granosa by determining accumulation in the soft tissues and alteration on the gill tissue structure. Wild stocks T. granosa were grouped to identify the initial Diuron concentration and 48-h exposure in different concentrations (0, 1, 2, 3, and 4 mg·L⁻¹). The Diuron in tissue was extracted using an established procedure and identified using High-Performance Liquid Chromatography (HPLC). Gills were analysed for histopathological study; tissue structure was classified and scored using a developed scoring system. Diuron concentration in the soft tissue of exposed T. granosa was in the range 1.27–8.09 mg·kg⁻¹, w/w and not proportionately increase along with the exposure concentration. The mean index values of the gill histopathology ranged from 5.25–7.67 and classified as moderate to severe. Gills characteristics and T. granosa protective behaviour potentially limit Diuron accumulation in the soft tissue.
Mostrar más [+] Menos [-]Occurrence and partition of organochlorine pesticides (OCPs) in water, sediment, and organisms from the eastern sea area of Shandong Peninsula, Yellow Sea, China Texto completo
2021
Li, Huaxin | Jiang Weiwei, | Pan, Yulong | Li, Fujuan | Wang, Chunhui | Tian, Hua
To evaluate the occurrence and partition of organochlorine pesticides (OCPs), hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs), water, sediment, and organisms were sampled from the eastern sea area of Shandong Peninsula (Yellow Sea, China) across all four seasons in 2016. There were three OCP hotspots in the sediment, mainly caused by the transportation of lindane and dicofol from adjacent Swan Lake and Guhe River. Waterborne OCP levels were highest in winter and lowest in spring, without vertical variability, suggesting that the Yellow Sea Cold Water Mass was governing the spatio-temporal distribution of OCPs in seawater. There was substantial accumulation of HCHs and DDTs in organisms via sediment, as indicated by the relatively low fraction of sedimental fugacity, high bio-sediment accumulation factor, and a positive linear correlation between logΣHCHs and trophic level. This is the first study that has focused on the accumulation of OCPs in entire sediment-seawater-organism system involving multi-phyla of species.
Mostrar más [+] Menos [-]Polycyclic aromatic hydrocarbons in marine mammals: A review and synthesis Texto completo
2021
Lourenço, Rafael André | Taniguchi, Satie | da Silva, Josilene | Gallotta, Fabiana Dias Costa | Bícego, Márcia Caruso
Most marine mammal species and populations are listed as endangered, threatened, or depleted under the Endangered Species Act and the Marine Mammal Protection Act. Organic contaminants such as polycyclic aromatic hydrocarbons from anthropogenic activities are part of the threat to marine mammals. The evaluation of the potential bioaccumulation of these compounds by marine mammals is a tool for adoption of policies to reduce polycyclic aromatic hydrocarbons discharges to the marine environment, where important players such as the oil and gas industries, maritime transport and sewage companies operate. This review seeks to present a bibliographic survey covering all published peer reviewed works of the contents of polycyclic aromatic hydrocarbons in biological tissues of marine mammals. It intended to compare the sampling protocols, procedures for preservation of the tissues, and the analytical method applied to quantify the polycyclic aromatic hydrocarbons, no to criticize any of them but to review the data and discuss how they can be compared.
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