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841.
Jan H. Christensen Giorgio Tomasi Maria de Fatima Guadalupe Meniconi 《Environmental pollution (Barking, Essex : 1987)》2010,158(10):3290-7840
A novel multivariate method based on principal component analysis of pre-processed sections of chromatograms is used to characterize the complex PAH pollution patterns in sediments from Guanabara Bay, Brazil. Five distinct sources of 3- to 6-ring PAHs could be revealed. The harbour is the most contaminated site in the bay, its plume stretches in a South West to North East direction and the chemical profile indicates mainly pyrogenic sources mixed with a fraction of high-molecular-weight petrogenic PAHs. Rio São João de Meriti is the second largest source of PAHs, and introduces mainly a fraction of low-molecular-weight petrogenic PAHs from the western region of Rio de Janeiro. The sites close to the ruptured pipeline at the Duque de Caxias Refinery show a distinctive pollution pattern indicating a heavy petroleum fraction. The method also led to the identification of new potential indicator ratios also involving coeluting peaks (e.g., triphenylene and chrysene). 相似文献
842.
Numerical investigation concerning the impact of CO2 geologic storage on regional groundwater flow 总被引:1,自引:0,他引:1
Hajime Yamamoto Keni Zhang Kenzi Karasaki Atsunao Marui Hitoshi Uehara Noriaki Nishikawa 《International Journal of Greenhouse Gas Control》2009,3(5):586-599
Large-scale storage of carbon dioxide in saline aquifers may cause considerable pressure perturbation and brine migration in deep rock formations, which may have a significant influence on the regional groundwater system. With the help of parallel computing techniques, we conducted a comprehensive, large-scale numerical simulation of CO2 geologic storage that predicts not only CO2 migration, but also its impact on regional groundwater flow. As a case study, a hypothetical industrial-scale CO2 injection in Tokyo Bay, which is surrounded by the most heavily industrialized area in Japan, was considered, and the impact of CO2 injection on near-surface aquifers was investigated, assuming relatively high seal-layer permeability (higher than 10 microdarcy). A regional hydrogeological model with an area of about 60 km × 70 km around Tokyo Bay was discretized into about 10 million gridblocks. To solve the high-resolution model efficiently, we used a parallelized multiphase flow simulator TOUGH2-MP/ECO2N on a world-class high performance supercomputer in Japan, the Earth Simulator. In this simulation, CO2 was injected into a storage aquifer at about 1 km depth under Tokyo Bay from 10 wells, at a total rate of 10 million tons/year for 100 years. Through the model, we can examine regional groundwater pressure buildup and groundwater migration to the land surface. The results suggest that even if containment of CO2 plume is ensured, pressure buildup on the order of a few bars can occur in the shallow confined aquifers over extensive regions, including urban inlands. 相似文献
843.
Su Mei Liu Xiao Na Li Jing Zhang Hao Wei Jing Ling Ren Gui Ling Zhang 《Water, Air, & Soil Pollution: Focus》2007,7(6):625-643
Three cruises were carried out in Jiaozhou Bay (JZB) in the neap tide in October 2002 (fall) and in both neap and spring tides
in May 2003 (spring) to understand the relative importance of external nutrient inputs versus physical transport and internal
biogeochemical processes. Nutrients (, , , , silicic acid, total dissolved nitrogen (TDN) and phosphorus (TDP), dissolved organic nitrogen (DON) and phosphorus (DOP))
were measured. The concentrations of nutrients were higher in the northern part than in the southern part. High concentrations
of and DON in JZB demonstrated the anthropogenic input. Ambient nutrient ratios indicated that the potential limiting nutrients
for phytoplankton growth were silicon, and then phosphorus. Nutrients showed an obvious tidal effect with low values at flood
tide and high values at ebb tide. Nutrient elements were transported into JZB in the north and output in the south (i.e.,
into the Yellow Sea), which varied with season, tidal cycle and investigation sites. Water exchange between JZB and the Yellow
Sea exports , and DON out of JZB, while it inputs , silicic acid and DOP into JZB. Nutrient budgets demonstrate that riverine input and wastewater discharge are major sources
of nutrients, while residual flow is of minor importance in JZB ecosystem. JZB is a sink for the nutrient elements we studied
except for DON. Stoichiometric calculations demonstrate that JZB is a net autotrophic system. 相似文献
844.
Goal, Scope and Background Marine cage aquaculture produces a large amount of waste that is released directly into the environment. To effectively manage
the mariculture environment, it is important to determine the carrying capacity of an aquaculture area. In many Asian countries
trash fish is dominantly used in marine cage aquaculture, which contains more water than pellet feed. The traditional nutrient
loading analysis is for pellet feed not for trash fish feed. So, a more critical analysis is necessary in trash fish feed
culturing areas.
Methods Corresponding to FCR (feed conversion rate), dry feed conversion rate (DFCR) was used to analyze the nutrient loadings from
marine cage aquaculture where trash fish is used. Based on the hydrodynamic model and the mass transport model in Xiangshan
Harbor, the relationship between the water quality and the waste discharged from cage aquaculture has been determined. The
environmental carrying capacity of the aquaculture sea area was calculated by applying the models noted above.
Results Nitrogen and phosphorus are the water quality parameters considered in this study. The simulated results show that the maximum
nitrogen and phosphorus concentrations were 0.216 mg/L and 0.039 mg/L, respectively. In most of the sea area, the nutrient
concentrations were higher than the water quality standard. The calculated environmental carrying capacity of nitrogen and
phosphorus in Xiangshan Harbor were 1,107.37 t/yr and 134.35 t/yr, respectively. The waste generated from cage culturing in
2000 has already exceeded the environmental carrying capacity.
Discussion Unconsumed feed has been identified as the most important origin of all pollutants in cage culturing systems. It suggests
the importance of increasing the feed utilization and improving the feed composition on the basis of nutrient requirement.
For the sustainable development of the aquaculture industry, it is an effective management measure to keep the stocking density
and pollution loadings below the environmental carrying capacity.
Conclusions The DFCR-based nutrient loadings analysis indicates, in trash fish feed culturing areas, that it is more critical and has
been proved to be a valuable loading calculation method. The modeling approach for Xiangshan Harbor presented in this paper
is a cost-effective method for assessing the environmental impact and determining the capacity. Carrying capacity information
can give scientific suggestions for the sustainable management of aquaculture environments.
Recommendations and Perspectives It has been proved that numerical models were convenient tools to predict the environmental carrying capacity. The development
of models coupled with dynamic and aquaculture ecology is a requirement of further research. Such models can also be useful
in monitoring the ecological impacts caused by mariculture activities.
ESS-Submission Editor: Hailong Wang (hailong.wang@ensisjv.com) 相似文献
845.
为了探究浮游细菌和蓝藻暴发之间的关系,利用实时荧光定量PCR和高通量测序技术,对夏季蓝藻暴发期间太湖竺山湾表层水和底泥中浮游细菌群落结构和多样性进行研究。结果表明,从门水平来看,水样和底泥中平均相对丰度最高的为变形菌门,放线菌门次之,此外蓝藻门也有一定的比例,可为水华暴发提供预警指示;从属水平来看,水样中的优势细菌主要为GpXI和GpIIa,底泥中为Gp6和GpIIa。 相似文献
846.
湄洲湾海域底质重金属环境背景值研究 总被引:7,自引:0,他引:7
根据湄洲湾区域自然环境特点 ,用背景区调查法 ,选择远离污染源的洁净海区进行表层底质重金属调查 ,并进行数据技术处理和影响因素分析。提出湄洲湾海域底质重金属环境背景值 相似文献
847.
河口海湾位于陆海交错带,受径潮流作用的双重影响,具有物质输运格局复杂、生态环境变化梯度大等特点。生态环境监测点位布设与优化是科学、客观评估河口海湾生态环境状况的前提。采用空间平衡抽样法开展监测点位增设和优化方案研究,将2020年5月上海市海洋环境趋势性监测布设的142个监测点位,增设至200个,并进一步优化至170个,对优化前后的点位数据进行显著性检验、方差分析和空间自相关分析。结果显示:2组数据之间无显著性差异,并且优化后点位的方差和空间自相关值更小,说明空间平衡抽样法适用于河口海湾生态环境监测点位布设和优化,点位布设和优化结果可客观反映河口海湾的生态环境状况。随后,采用泰森多边形法确定了优化所得的170个离散点位的海域代表面积,克服现有空间插值法的缺陷,为河口海湾生态环境总体状况评价提供技术参考。 相似文献
848.
2012年5月钦州湾近岸海域水质监测结果表明,钦州湾近岸水温、盐度、pH、溶解氧等基本环境参数均有利于亚热带海洋生物的生长繁殖;溶解无机氮(DIN)和活性硅酸盐(SiO2-3-Si)均显示过剩,但溶解无机磷(DIP)具有低磷特征,高的氮磷比值使PO3-4-P可能成为浮游植物生长的潜在限制因子,且COD部分站位出现超标现象。污染指数(A)和单因子污染指数(Pi)结果显示,近期整个钦州湾近岸水域污染程度达到2级,属于开始受到污染,水质受到化学耗氧有机物不同程度的污染,超标率达到30%。富营养状态指数结果表明,钦州湾近岸海域总体尚未达到富营养化,但局部区域已出现富营养化状况。COD对富营养化的贡献率平均值及范围为72.46%(67.36%~83.96%),COD已成为影响钦州湾近岸海域富营养化的重要因素。 相似文献
849.
2015年10月和11月调查了海州湾潮间带A、B 2个断面的大型底栖动物,共发现大型底栖动物29种,其中A断面发现19种,B断面23种;潮间带大型底栖动物的总平均丰度为1 790 m~(-2),总平均生物量185.11 g/m~2。A、B 2断面的丰度生物量差异较大,主要是由于2个断面底质类型不同造成的。潮间带Shannon-Wiener多样性指数平均值为2.90,波动为2.44~3.45,其沉积物环境存在轻度有机质污染。 相似文献