细化搜索
结果 1671-1680 的 5,098
Integrated toxicity evaluation of metals in sediments of Jiaozhou Bay (China): Based on biomarkers responses in clam Ruditapes philippinarum exposed to sediment extracts
2018
Lin, Yufei | Liu, Qunqun | Meng, Fanping | Lin, Yichen | Du, Yongxiang
To evaluate the integrated toxicity of metals in sediments of Jiaozhou Bay, we exposed clam (Ruditapes philippinarum) to sediments extracts obtained using of sediment extraction with deionised water adjusted to pH 4 which simulated the weak acidity in the digestive juice of clams and tested the selected biomarkers responses in clams for exposure over 15 days. At the same time, the contents of metals in sediments were assessed with method of the mean sediment quality guideline quotient (SQG-Q). The integrated biomarker response version 2 (IBRv2) was used to assess the integrated toxicity induced by metals in sediment extracts based on biomarkers response in clams: the results demonstrated that site S7 located in the mouth of Nanxin'an River show higher IBRv2 values compared to the other sites. The IBRv2 values exhibited the good consistency with SQG-Q values.
显示更多 [+] 显示较少 [-]Spatial distribution of sewage pollution on a Hawaiian coral reef
2018
Abaya, Leilani M. | Wiegner, Tracy N. | Beets, James P. | Colbert, Steven L. | Carlson, Kaile'a M. | Kramer, K Lindsey
While sewage pollution is contributing to the global decline of coral reefs, its offshore extent and direct reef impacts from water column mixing and benthic seeps are poorly documented. We addressed this knowledge gap on a Hawaiian coral reef using sewage indicator and benthic cover measurements, macroalgal bioassays, and a pollution scoring tool. Fecal indicator bacteria (FIB) and nutrient concentrations were spatially variable in surface and benthic waters, with shoreline values being highest. Shoreline macroalgae δ15N and %N indicated high nitrogen loads containing sewage, while offshore surface and benthic values suggested lower nitrogen loads from environmental sources. Coral cover was negatively correlated with FIB, macroalgal δ15N, and nutrient concentrations. Benthic salinity and temperature measurements detected daily tidal groundwater pulses which may explain these associations. While pollution scores revealed that sewage was largely concentrated along the shoreline, results showed some reached the reef and may be contributing to its declining condition.
显示更多 [+] 显示较少 [-]Metal detoxification in the marine teleost fish Sparus aurata L. and Dicentrarchus labrax L
2018
Morcillo, Patricia | Esteban, María A. | Cuesta Arranz, Alberto
Transcription of ATP-binding cassette (ABC) transporters has been evaluated in cell lines and primary cultures from gilthead seabream and European sea bass teleost fish exposed to methylmercury (MeHg), arsenic, cadmium or lead. The mRNA expression levels showed abcb1, abcc2 and abcc5 constitutive gene expression in all seabream tissues analyzed; however, we were unable to detect any constitutive transcription of abcb1 in many of the sea bass tissues. Furthermore, ABC mRNA expression levels were all affected by metal exposure, especially in the case of fish cell lines and erythrocytes, and greatly depended on cell type and fish species. Thus, while ABC transcription was up-regulated in the seabream cell line it was down-regulated in the sea bass cell line, while the opposite occurred in the primary cultures. All these data point to the importance of ABC transporters in metal detoxification and in the differential regulation in seabream and sea bass cells.
显示更多 [+] 显示较少 [-]Water quality near Estonian harbours in the Baltic Sea as observed from entire MERIS full resolution archive
2018
Sipelgas, Liis | Uiboupin, Rivo | Arikas, Age | Siitam, Laura
Variations and trends in water quality parameters (total suspended matter and coloured dissolved organic matter) were examined in five harbours in the eastern Baltic Sea using satellite imagery collected from 2002 to 2011 by the Medium Resolution Imaging Spectrometer (MERIS) at full spatial resolution (300×300m). In the eastern Gulf of Finland harbours (Sillamäe, Kunda) the TSM monthly variations were related to monthly mean wind speed. In Tallinn harbour, which operates >6000 vessels annually, evidence of anthropogenic impacts was identified through inter-annual TSM variations. The vessel traffic footprint was ascertained from the significant correlation (R=0.66; p=0.035) between the number of annual vessel visits and mean annual TSM concentration. In the harbour of Pärnu, located close to the river mouth, inter-annual water quality variations in terms of the CDOM concentrations were affected by the mean annual river discharge levels of the Pärnu River.
显示更多 [+] 显示较少 [-]Environmental triggers of a Microcystis (Cyanophyceae) bloom in an artificial lagoon of Hangzhou Bay, China
2018
Tang, Chunyu | Sun, Bin | Yu, Kefeng | Shi, Jinting | Liu, Mengmeng | Jiang, Ting | Huo, Yuanzi | He, Peimin
The relationship between Microcystis abundance and environmental variables was studied during a Microcystis bloom in the summer months of 2016 in an artificial lagoon of Hangzhou Bay, China. It was determined that Microcystis abundance increased from 0.16 × 104 cell/L to 5.8 × 107 cell/L within 17 days from 28 July to 14 August, contributing to 96.84–99.56% of the total phytoplankton abundance. Then, Microcystis gradually disappeared 57 days afterwards. The results showed that the growth of Microcystis, including the stage of recovery, outbreak, subsidence and disappearance, was significantly correlated with water temperature, salinity, soluble reactive phosphorus (PO4-P), dissolved inorganic nutrients (DIN), silicate (SiO4-Si), the ratio of DIN/SiO4-Si and zooplankton abundance, and the key environmental triggers which promoted the outbreak of Microcystis were water temperature, PO4-P concentration and zooplankton abundance in this artificial lagoon.
显示更多 [+] 显示较少 [-]Sources and scavenging of plutonium in the East China Sea
2018
Wu, Junwen
The 240Pu/239Pu atom ratio and 239+240Pu activity of seawater in the East China Sea (ECS) was measured in order to examine the Pu sources and elaborate Pu scavenging process. High 240Pu/239Pu atom ratios (0.187–0.243, average = 0.221 ± 0.017) in the surface water and water column were observed during 2011, implying of non-global fallout Pu sources. The distribution of 240Pu/239Pu atom ratio in the ECS was in agreement with the introduction pathway of the Kuroshio, showing a decreasing trend away from the outer shelf. An even higher 240Pu/239Pu atom ratios (0.243–0.263, average = 0.253 ± 0.007) were observed in the Kuroshio, indicating the non-global fallout Pu signal from the Pacific Proving Grounds (PPG). Using a two end-member mixing model, the Pu source from the PPG contribution was calculated to be 36 ± 9% in the ECS seawater. The 239+240Pu activities of surface seawater were in the range of 2.00–2.95 mBq m−3 in the ECS. The spatial distribution of 239+240Pu activity in the surface seawater showed an increasing trend from the outer shelf to the nearshore. Moreover, 239+240Pu inventory of water column at the station DH23 in the ECS was calculated to be ~0.29 Bq m−2, which was 1–3 orders of magnitude lower than the estimates of sediment cores in the ECS shelf (9–407 Bq m−2). Such differences were determined by the high degree Pu scavenging efficiency in the ECS and high Pu input carried by terrestrial sediments from the Yangtze River. Finally, both 240Pu/239Pu atom ratios and 239+240Pu activities were identical before and after the Fukushima nuclear accident (FNA), suggesting that the impact of the FNA on the ECS was negligible.
显示更多 [+] 显示较少 [-]Impact of seasonality on the nutrient concentrations in Gautami-Godavari Estuarine Mangrove Complex, Andhra Pradesh, India
2018
Rao, Karuna | Priya, Namrata | Ramanathan, AL.
Spatiotemporal variations of dissolved nutrients were studied along Gautami-Godavari mangrove ecosystem to delineate their sources and fate. Average values of nitrate (NO3−), dissolved silica (DSi) and phosphate (PO43−) is 2.09 mg/l, 12.7 mg/l and 0.16 mg/l in wet season and 0.47 mg/l, 6.96 mg/l and 0.29 mg/l in dry season respectively. In wet season river discharge has significant influence on NO3− and DSi. In dry season, NO3− and PO43− are controlled by groundwater discharge, benthic exchange and various in situ processes owing to sediment redox condition. Mixing model shows net addition of phosphate in Coringa mangroves (95%) and Lower estuary (13%) and net removal of nitrate (24.79%) in Coringa mangrove and in estuary (58.9%). Thus present mangrove acts as net source for phosphate and net sink for nitrate and DSi. Nutrient ratio shows seasonal switching between potential Phosphorus and Nitrogen limitation in wet and dry season respectively.
显示更多 [+] 显示较少 [-]Artificial polymer materials debris characteristics along the Moroccan Mediterranean coast
2018
Maziane, F. | Nachite, D. | Anfuso, G.
A monitoring program was carried out in autumn 2015 along the Mediterranean coast of Morocco, at sites including urban, village and remote/rural beaches. Artificial Polymer Materials (APM) represented 70.64% of all collected items and included plastic (16 categories), foamed plastic (3) and other APM materials (2). Plastic items represented the dominant debris with 5356 items, i.e. 94.53% of all APM debris, foamed plastics presented 191 items (i.e. 3.37%) and other APM summed 119 items, i.e. 2.1% of all APM. Urban areas presented 49.63% of all APM recollected items with cigarette butts representing 32% of total APM items. Village areas presented 40.43% of total APM recollected items with cigarette butts representing 14.1%. Remote and rural beaches recorded 9.94% of total APM items and no cigarette butts were observed. Despite the efforts of local administrations, which introduced litter bins and enforced mechanical and manual cleaning operations, debris were essentially related to beachgoers.
显示更多 [+] 显示较少 [-]Innovative Approaches for Noise Management in Smart Cities: a Review
2018
Asdrubali, Francesco | D’Alessandro, Francesco
According to the European Commission, “a Smart City is a city seeking to address public issues via ICT-based solutions on the basis of a multi-stakeholder, municipally based partnership”. The smart city concept “encompasses a more interactive and responsive city administration and safer public spaces”. The new paradigm of smart city, which is closely correlated to Internet of Things, requires a new approach also for environmental noise assessment and monitoring, in order to establish noise management strategies that should be more dynamic, widespread and closer to citizens’ wellbeing. In the last decade, new technologies and methodologies have been developed in order to supply smart cities with smart noise solutions. This paper presents three examples which are considered by the authors among the most interesting and promising ones, i.e. dynamic noise mapping, smart sensors (and in particular, the use of smartphones in environmental noise assessment) and soundscape approach.
显示更多 [+] 显示较少 [-]Monitoring of Polycyclic Aromatic Hydrocarbons (PAHs) in Scottish Deepwater environments
2018
Webster, L. | Russell, M. | Shepherd, N. | Packer, G. | Dalgarno, E.J. | Neat, F.
Polycyclic aromatic hydrocarbons (PAHs) were measured in environmental samples (sponges, fish and sediment) collected in 2014 and 2016 from the Faroe-Shetland Channel and Rosemary Bank Seamount. These data could be used to provide a baseline against which any changes can be assessed in the event of an oil spill and contribute to any environmental impact assessment. Concentrations in all samples were low, often below the detection limits, and were typical of reference sites. Sponges can be used as an alternative indicator species to mussels for monitoring PAHs in the marine environment as they can accumulate PAHs from both the dissolved and particulate phase. PAH concentrations in marine sponges from Scottish waters have not previously been reported. Concentrations were low, but contained a higher proportion of heavier 4- to 6-ring PAHs compared to the fish samples.
显示更多 [+] 显示较少 [-]