细化搜索
结果 1711-1720 的 4,938
Fecal indicator bacteria levels at beaches in the Florida Keys after Hurricane Irma 全文
2019
Roca, Matthew A. | Brown, R Stephen | Solo-Gabriele, Helena M.
Hurricanes cause infrastructure failures which can lead to contamination of impacted areas. The objective of the current study was to evaluate whether Hurricane Irma contributed towards sewage contamination of coastal beaches. Through this study we evaluated indicators of fecal pollution (fecal indicator bacteria [FIB], enterococci and fecal coliform) and physico-chemical parameters (salinity, pH, turbidity, and temperature) in coastal waters of the Florida Keys shortly after the hurricane. To augment available county sampling data, two sets of sampling efforts were conducted; one focused on collecting samples spatially throughout the Keys to assess whether areas closer to hurricane landfall were more highly impacted. The second was to collect temporally intensive samples at one location during falling tide to evaluate the hypothesis of groundwater contamination. Samples were analyzed for FIB using a new method called timed appearance of culture signal (TACS), which was subsequently calibrated using traditional membrane filter and chromogenic substrate methods. Results showed that coastal beach waters were characterized by elevated but sporadic levels of fecal indicator bacteria up to two months after the hurricane. Spikes were not correlated with physico-chemical characteristics of the water. Our temporally intensive sampling effort did not support the hypothesis that groundwater was a source of elevated FIB. Competing factors could have played a role in the sporadic nature of the FIB levels after the hurricane. We suggest that beach erosion may have flushed out sediments at beaches closer to the hurricane landfall location thereby improving water quality during dry conditions. We also suggest that during wet conditions a source of FIB could include runoff from debris staging areas. Preemptive beach closures immediately after the hurricane were justified due to the sporadic nature of FIB contamination.
显示更多 [+] 显示较少 [-]Response planning for accidental oil spills in Persian Gulf: A decision support system (DSS) based on consequence modeling 全文
2019
Amir-Heidari, Payam | Raie, Mohammad
Different causes lead to accidental oil spills from fixed and mobile sources in the marine environment. Therefore, it is essential to have a systematic plan for mitigating oil spill consequences. In this research, a general DSS is proposed for passive and active response planning in Persian Gulf, before and after a spill. The DSS is based on NOAA's advanced oil spill model (GNOME), which is now linked with credible met-ocean datasets of CMEMS and ECMWF. The developed open-source tool converts the results of the Lagrangian oil spill model to quantitative parameters such as mean concentration and time of impact of oil. Using them, two new parameters, emergency response priority number (ERPN) and risk index (RI), are defined and used for response planning. The tool was tested in both deterministic and probabilistic modes, and found to be useful for evaluation of emergency response drills and risk-based prioritization of coastal areas.
显示更多 [+] 显示较少 [-]Occurrence of polycyclic aromatic hydrocarbons (PAHs) in coral reef fish from the South China Sea 全文
2019
Li, Yali | Wang, Chenglong | Zou, Xinqing | Feng, Ziyue | Yao, Yulong | Wang, Teng | Zhang, Chuchu
Little data are available on the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in coral reef fish from the South China Sea (SCS). In this study, we collected 21 coral reef fish species from the Xisha and Nansha Islands in the SCS to investigate the occurrence of 16 US-EPA PAHs. The total PAH concentrations (ΣPAH) in the collected fish ranged from 12.79 to 409.28 ng/g dry weight (dw, Xisha Islands) and from 32.71 to 139.09 ng/g dw (Nansha Islands), respectively. The ΣPAH concentration of Scarus niger collected from the Xisha Islands (237.13 ng/g dw) was about twofold higher than that of Scarus niger collected from the Nansha Islands (139.09 ng/g dw). The dominant compounds were found to be 2-ring and 3-ring PAHs. Based on qualitative and quantitative analyses, the main PAH sources were found to be coal and biomass combustion (50.43%), petroleum sources (25.86%), and vehicular emissions (16.10%).
显示更多 [+] 显示较少 [-]Micro(nano)plastics: Unignorable vectors for organisms 全文
2019
Shen, Maocai | Zhu, Yuan | Zhang, Yaxin | Zeng, Guangming | Wen, Xiaofeng | I-Huan, | Ye, Shujing | Ren, Xiaoya | Song, Biao
Micro(nano)plastics, as emerging contaminants, have attracted worldwide attention. Nowadays, the environmental distribution, sources, and analysis methods and technologies of micro(nano)plastics have been well studied and recognized. Nevertheless, the role of micro(nano)plastic particles as vectors for attaching organisms is not fully understood. In this paper, the role of micro(nano)plastics as vectors, and their potential effects on the ecology are introduced. Micro(nano)plastics could 1) accelerate the diffusion of organisms in the environment, which may result in biological invasion; 2) increase the gene exchange between attached biofilm communities, causing the transfer of pathogenic and antibiotic resistance genes; 3) enhance the rate of energy, material and information flow in the environment. Accordingly, the role of microplastics as vectors for organisms should be further evaluated in the future research.
显示更多 [+] 显示较少 [-]Geochemical imprints of occurrence, vertical distribution and sources of aliphatic hydrocarbons, aliphatic ketones, hopanes and steranes in sediment cores from ten Iranian Coral Islands, Persian Gulf 全文
2019
Jafarabadi, Ali Ranjbar | Dashtbozorg, Mehdi | Bakhtiari, Alireza Riyahi | Maisano, Maria | Cappello, Tiziana
The levels, vertical distribution and sources of hydrocarbons and petroleum biomarkers were estimated for the first time in sediment cores (0–40 cm) from ten coral Islands of the Persian Gulf, Iran. Discrepant hydrocarbons, including linear n-alkanes (n-C₁₁ to n-C₄₀) and isoprenoids (AHs), aliphatic ketones (AKs), hopanes and steranes were measured in all core samples, showing mean concentrations ranging from 209 to 5388 μg g⁻¹dw (∑₃₀AH), 2–244 μg g⁻¹-dw (∑₁₃AK), 189–3713 ng g⁻¹dw (∑₃₁hopane) and 42–3864 ng g⁻¹dw (∑₁₅sterane), respectively. All sediment cores were found to be petroleum polluted, with ∑₃₀AH > ∑₃₁hopane > ∑₁₅sterane > ∑₁₃AK, with higher levels recorded at 10–20 cm, mainly at industrial sites. Various diagnostic indices revealed that hydrocarbons derived mainly from anthropogenic inputs, with significant contribution of biogenic origin at sites less polluted. Moreover, total organic carbon (0.24–23.45 mg g⁻¹-dw), terrestrial and marine organic matter had an overwhelming effect on hydrocarbons deposition in sediment cores. Overall, findings provide relevant information for monitoring and preventing petroleum pollution in the sensitive ecosystems of the Persian Gulf.
显示更多 [+] 显示较少 [-]Microplastics in Tampa Bay, Florida: Abundance and variability in estuarine waters and sediments 全文
2019
McEachern, Kinsley | Alegria, Henry | Kalagher, Amelia L. | Hansen, Cypress | Morrison, Samantha | Hastings, David
This study provides the first measurement of microplastic abundance and distribution in surface waters and sediments in Tampa Bay, FL. Microplastic concentrations in discrete water samples ranged from 0.25 to 7.0 particles/L with an average of 0.94 (±0.52) particles/L. Samples taken with a 330 μm plankton net had 1.2–18.1 particles/m³ with an average of 4.5 (±2.3) particles/m³. Discrete samples were 200 times higher than net samples, suggesting substantial losses or undersampling with the net. For both discrete and plankton tow samples, there were no significant differences in concentrations between stations or regions. Intense rainfall events in the summer always preceded samples with substantially higher counts. Most (>75%) microplastics were fibers. Using an average value of 1 particle/L, Tampa Bay contains ~4 billion microplastic particles. Surface sediments had an average of 280 (±290) particles/kg, ranging from 30 to 790 particles/kg. Highest concentrations of microplastics were found in sediments close to industrial sources; lowest values in Middle and Lower Tampa Bay are consistent with shorter residence times.
显示更多 [+] 显示较少 [-]The residency, movement patterns and habitat association of several demersal fish species to the Orange County Sanitation District wastewater outfall 全文
2019
Burns, Echelle S. | Armstrong, Jeff | Tang, Danny | Sakamoto, Ken | Lowe, Christopher G.
Wastewater outfall pipes are structures that may attract marine fishes, yet previous studies that address the risks of exposure to wastewater effluent rarely account for the movements of the species studied. This study used acoustic telemetry to quantify the movement patterns and habitat association of demersal species (Citharichthys sordidus, Pleuronichthys verticalis, Parophrys vetulus, Sebastes miniatus) at two sites (near a wastewater outfall and at a reference site) in southern California over one year. Residencies to both sites were low for pleuronectiform fishes (C. sordidus, P. verticalis, P. vetulus, less than 10% of the study duration was spent in either site), which indicates that tissue samples from these species likely reflect the accumulation of contaminants across individuals’ ranges, not just the outfall site. Alternatively, S. miniatus showed higher degrees of residency to the outfall site (nearly 40% of the study duration) and may be the most susceptible to wastewater effluent effects.
显示更多 [+] 显示较少 [-]Deepwater ocean outfalls: A sustainable solution for sewage discharge for mega-coastal cities (Sydney, Australia): A synthesis 全文
2019
Besley, C.H. | Birch, G.F.
In 1990–91 three deepwater ocean outfalls replaced three cliff-face outfalls discharging approximately 940 ML/day, or 80% of sewage generated by the City of Sydney (Australia) (population 3.3 million). Operation of these outfalls was assessed for the first two years and performed well, mitigating most of the environmental problems previously experienced from shoreline discharge. However, a concern remained for the unknown long-term effects on the marine environment. The current series of articles examine over 20 years of monitoring, for possible accumulative effects. Oceanographic modelling provided an understanding of particle settling, dispersion and distribution of discharged wastewater and monitoring assessed potential impact of offshore discharges on beach bathing water quality, sediment chemistry and benthic infauna. These four articles demonstrate that properly designed ocean outfalls are a viable, sustainable solution to sewage disposal for mega-coastal cities, however, continued monitoring is required to assess possible long-term environmental degradation.
显示更多 [+] 显示较少 [-]Ingestion of plastic marine litter by sea turtles in southern Brazil: abundance, characteristics and potential selectivity 全文
2019
Rizzi, Milena | Rodrigues, Fábio L. | Medeiros, Luciana | Ortega, Ileana | Rodrigues, Lucas | Monteiro, Danielle S. | Kessler, Felipe | Proietti, Maíra C.
The ingestion of plastic marine litter (PML) by sea turtles is widespread and concerning, and the five species that occur in the southwestern Atlantic – green, loggerhead, olive ridley, leatherback and hawksbill – are vulnerable to this pollution. Here, we quantified and characterized PML ingested by these species in southern Brazil, and observed PML ingestion in 49 of 86 sampled individuals (~57.0%). Green turtles presented the highest rates and variety of ingested plastics, and such ingestion has been high at least since 1997. Omnivorous turtles presented higher PML ingestion than carnivorous ones. Loggerheads displayed a negative correlation between body size and number of ingested items. Green turtles ingested mostly flexible transparent and flexible/hard white plastics; loggerheads ate mainly flexible, hard and foam fragments, in white and black/brown colors. These results help us better understand PML ingestion by sea turtles, highlighting the seriousness of this threat and providing information for prevention and mitigation strategies.
显示更多 [+] 显示较少 [-]Beachgoer participation in prevention of marine litter: Using design for behavior change 全文
2019
Much marine litter comes from land-based sources, with a significant amount coming from activities on bathing beaches. Thus, the overall focus of this exploratory research is to identify elements important for the design of beach infrastructure (i.e., trash cans (TCs)) to reduce littering behaviors. We base our investigation on principles of a relatively new approach, called Design for Sustainable Behavior. In doing so, we consider design for two user groups: bathing beachgoers and beach managers. We examined these users' perceptions of beach TCs through the use of an on-line survey of beachgoers, in-depth interviews with Israeli beach managers, a survey of international Blue Flag beach managers and a design ‘ideation’ workshop. Most importantly, we found that there is interest on the part of beach managers and other stakeholders in applying design principles to improve TCs. The findings of this study have implications for further interdisciplinary – and multidisciplinary – research on this topic.
显示更多 [+] 显示较少 [-]