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[en] Unequivocal evidence is presented for the removal of uranium in two major estuarine systems of the north-eastern United States: the Delaware and Chesapeake Bays. In both the estuaries, during all seasons but mostly in summer, dissolved uranium shows distinctly non-conservative behaviour at salinities ≤ 5. At salinities above 5, there are no deviations from the ideal dilution line. In these two estuaries as much as 22% of dissolved uranium is removed at low salinities, around salinity 2. This pronounced removal of uranium observed at low salinities has been investigated in terms of other chemical properties measured in the Delaware Estuary. In the zone of uranium removal, dissolved oxygen is significantly depleted and pH goes through a minimum down to 6.8. In the same low salinity regime, total alkalinity shows negative deviation from the linear dilution line and phosphate is removed. Humic acids, dissolved iron and manganese are also rapidly removed during estuarine mixing in this low salinity region. Thus, it appears that removal of uranium is most likely related to those properties of alkalinity and acid-base system of the upper estuary that may destabilize the uranium-carbonate complex. Under these conditions, uranium may associate strongly with phosphates or humic substances and be removed onto particulate phases and deposited within upper estuarine sediments. (author)
[en] The deformation law of building in Dayawan Nuclear power station is obtained from the building deformation observation and the deformation monitoring data processing and analysis which is from the site monitoring and data collection of building deformation. The results show that the nuclear power station is sate, its horizontal displacement and settlement amount agree to the deformation law and are normal building deformation
[en] San Francisco Bay (California, USA) and its local watersheds present an interesting case study in estuarine mercury (Hg) contamination. This review focuses on the most promising avenues for attempting to reduce methylmercury (MeHg) contamination in Bay Area aquatic food webs and identifying the scientific information that is most urgently needed to support these efforts. Concern for human exposure to MeHg in the region has led to advisories for consumption of sport fish. Striped bass from the Bay have the highest average Hg concentration measured for this species in USA estuaries, and this degree of contamination has been constant for the past 40 years. Similarly, largemouth bass in some Bay Area reservoirs have some of the highest Hg concentrations observed in the entire US. Bay Area wildlife, particularly birds, face potential impacts to reproduction based on Hg concentrations in the tissues of several Bay species. Source control of Hg is one of the primary possible approaches for reducing MeHg accumulation in Bay Area aquatic food webs. Recent findings (particularly Hg isotope measurements) indicate that the decades-long residence time of particle-associated Hg in the Bay is sufficient to allow significant conversion of even the insoluble forms of Hg into MeHg. Past inputs have been thoroughly mixed throughout this shallow and dynamic estuary. The large pool of Hg already present in the ecosystem dominates the fraction converted to MeHg and accumulating in the food web. Consequently, decreasing external Hg inputs can be expected to reduce MeHg in the food web, but it will likely take many decades to centuries before those reductions are achieved. Extensive efforts to reduce loads from the largest Hg mining source (the historic New Almaden mining district) are underway. Hg is spread widely across the urban landscape, but there are a number of key sources, source areas, and pathways that provide opportunities to capture larger quantities of Hg and reduce loads from urban runoff. Atmospheric deposition is a lower priority for source control in the Bay Area due to a combination of a lack of major local sources. Internal net production of MeHg is the dominant source of MeHg that enters the food web. Controlling internal net production is the second primary management approach, and has the potential to reduce food web MeHg in some habitats more effectively and within a much shorter time-frame. Controlling net MeHg production and accumulation in the food web of upstream reservoirs and ponds is very promising due to the many features of these ecosystems that can be manipulated. The most feasible control options in tidal marshes relate to the design of flow patterns and subhabitats in restoration projects. Options for controlling MeHg production in open Bay habitat are limited due primarily to the highly dispersed distribution of Hg throughout the ecosystem. Other changes in these habitats may also have a large influence on food web MeHg, including temperature changes due to global warming, sea level rise, food web alterations due to introduced species and other causes, and changes in sediment supply. Other options for reducing or mitigating exposure and risk include controlling bioaccumulation, cleanup of contaminated sites, and reducing other factors (e.g., habitat availability) that limit at-risk wildlife populations.
[en] Probed into the concept and developing phases of safety couture in the management of nuclear power station, especially analyzed the background and the road of cultivating nuclear safety culture in GNPS, highlighted the core concept of GNPS nuclear safety culture, presented GNPS safety culture indicators, summarized the major measures taken by GNPS, depicted the propagandizing process of transparency in GNPS, and systematically appraised the effect of GNPS in implementing nuclear safety culture. (authors)
[en] Existing literature illustrates inconsistent responses of seagrasses to oil exposure, both in the field and in the laboratory. Here, we add a new study that combined morphometric, demographic and photophysiology assessments to determine the potential oiling impacts to eelgrass (Zostera marina) from the 2007 Cosco Busan event in San Francisco Bay. Shoot densities, reproductive status, and rhizome elongation of Z. marina were examined at sites with pre-spill data, and eelgrass photosynthetic efficiency was measured post-spill. Shoot densities and percent elongation of rhizome internodes formed after the oil spill varied but with no consistent relationship to adjacent shoreline cleanup assessment team (SCAT) oiling categories. Similarly, differences in seagrass photosynthetic efficiency were not consistent with SCAT oiling categories. While thresholds for negative impacts on seagrass in general remain to be defined, conclusive oiling indicators for degree and duration of exposure would be important considerations and need examination under controlled study. - Highlights: • A review of papers spanning 54 years describing the effect of oiling on seagrass revealed inconsistent findings. • Eelgrass was evaluated following the Cosco Busan oil spill in San Franciso Bay approximately three weeks after the event. • No relationship was found between oil exposure and eelgrass rhizome growth, shoot density or electron transport rate. • Controlled studies of oil exposure and seagrass responses are needed to define exposure limits for each seagrass species.
[en] In the original publication of this article , some reference lines are missing in Fig. 5a and Fig. 6b(6). This correction shows the correct figures. The publisher apologizes to the readers and authors for the inconvenience.
[en] The goal of this work is to examine the effects of the “expanded” or “high-latitude” substorms at mid-latitudes. These substorms are generated at auroral latitudes and propagate up to geomagnetic latitudes above ∼70° GMLat. They are usually observed during reccurent high-speed streams (HSS) from coronal holes. To identify the substorm activity, data from the networks IMAGE, SuperMAG and INTERMAGNET, and data from the all-sky cameras in Lovozero were used. To verify the interplanetary and geomagnetic conditions, data from the CDAWeb OMNI and from the WDC for geomagnetism at Kyoto were taken. We analyzed one substorm event on 20 February 2017 at ∼18:40 UT, it developed during HSS, in non-storm conditions. Some features of mid-latitude positive bays (MPB) at the European and Asian stations, and in particular at the Scandinavian meridian have been studied: the bay sign conversion from negative to positive values, the longitudinal and latitudinal extent of the MPB. The central meridian of the substorm was determined.