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Yang M.,CAS Wuhan Institute of Hydrobiology | Yang M.,University of Chinese Academy of Sciences | Yang M.,Chongqing Academy of Environmental science | Bi Y.,CAS Wuhan Institute of Hydrobiology | And 4 more authors.
Chinese Journal of Oceanology and Limnology | Year: 2011

We describe the phytoplankton dynamics and structure in Xiangxi Bay, Three Gorges Reservoir. Samples were collected monthly in the surface waters between August 2007 and July 2008. We identified 10 principle functional groups. C-strategists and S/R-strategists with a wide range of tolerance dominated the phytoplankton assemblage. Seasonal variation was related to water column stability because of changes in hydraulic operation in October, January, and May. Functional group C (Asterionella formosa) and P (Aulacoseria granulata) dominated in August and September, whereas group Lo (Peridiniopsis niei) was the most abundant between February and April, forming a dinoflagellate bloom. Group B (Stephanodiscus hantzschii), X2 (Komma acudata), and Y (Cryptomonas erosa) were present throughout most of the year but were most abundant in late spring. A cyanobacterial bloom occurred from June to July, during which group M (Microcystis aeruginosa, M. wesenbergii) and H1 (Anabaena flos-aquae) were dominant. Green algae, characterized by group G (Eudorina sp., Pandorina sp., Pyramidomonas sp.) and J (Pediastrum spp., Coelastrum spp., Scenedesums spp.), were abundant after the bloom degraded. This sequence was corroborated by canonical correspondence analysis (CCA). The summary sequence of functional groups resulting from CCA was: C/P → Lo → H1/M/J/G. The dynamics of the phytoplankton community may be explained by the stability of water column, irradiance, water temperature, and nutrient structure. © 2011 Chinese Society for Oceanology and Limnology, Science Press and Springer-Verlag Berlin Heidelberg. Source


Cai Q.,Chongqing Vocational Institute of Engineering | Zhang D.-J.,Chongqing University | Ding J.-J.,Chongqing Academy of Environmental science
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2014

Complete autotrophic nitrogen removal over nitrite (CANON) process was successfully startedup with a low volumetric exchange ratio (30%) under alternative limited-oxygen/anaerobic mode in SBR, and the total nitrogen removal rate as well as the total nitrogen removal efficiency reached (312±15)mg/(L·d) and (71.2±4.3)%, respectively. The startup of CANON SBR experienced nitrification-leading phase, partitial-nitritation-leading phase and CANON phase in general. Granular biomass and floccular biomass were both found in SBR. The volume of granular biomass (radius≥300μm) and floccular biomass (radius<300μm) made up 39% and 61% of total sludge volume, respectively. The long-term N2H4 addition recovered and enhanced their autotrophic nitrogen removal capacity, with the total nitrogen removal rate increased to (480±34)mg/(L·d). The proportion of granular biomass increased to 51% of total sludge volume. ©, 2014, Chinese Society for Environmental Sciences. All right reserved. Source


Deng H.,Chongqing University | Chen G.,Chongqing Academy of Environmental science
Chinese Journal of Geochemistry | Year: 2014

Chromium pollution were investigated by sampling the abandoned chromium contaminated sites in Chongqing. Its health risk was assessed following the procedures made by USEPA. The results showed that the most seriously polluted land was found at the former production area (G4) with average Cr(VI) concentration of 3369.2 mg°kg−1 on the surface soil. The assessment indicated that there was high risk of non-carcinogens for children. The assessed risk of the first layer of office area (G1) for children, chromium slag transition (G2), drainage pipeline chromium slag transition (G3) and production area (G4) for both children and adults were not acceptable (>1.00×10−6). It was strongly suggested that the accessible measures of remediation should be taken for a portion of contaminated sites before the reuse of abandoned lands. © 2014, Science Press, Institute of Geochemistry, CAS and Springer-Verlag Berlin Heidelberg. Source


Tang W.,CAS Research Center for Eco Environmental Sciences | Ao L.,Chongqing Academy of Environmental science | Zhang H.,CAS Research Center for Eco Environmental Sciences | Shan B.,CAS Research Center for Eco Environmental Sciences
Environmental Earth Sciences | Year: 2014

The enrichment characteristics and risk of heavy metals were studied in the sediments of Liucha River in Chao Lake Valley, where agricultural intensification has developed rapidly since the 1980s. The results revealed that Cd, Pb and Zn showed the lowest levels in the upper reaches and peak values in the lower reaches, increasing from 0.064, 7.75 and 59.75 mg/kg to 0.176, 12.33 and 96.82 mg/kg on average, respectively. Enrichment factor (EF) analysis showed that the EF values of Cd, Pb and Zn (maximum 4.76, 2.51 and 2.74, respectively) all increased from the upper reaches to the lower reaches (>1.5), while correlation analysis and cluster analysis showed that they primarily originated from the extensive use of phosphate fertilizer. In addition, the comprehensive potential ecological risk due to Cd, Cr, Cu, Ni, Pb and Zn in the sediments showed low degree, but Cd showed moderate and high risk at some sites. Therefore, heavy metal pollution due to agricultural intensification in the agricultural regions of Chao Lake Valley should be given great attention during management of the water environment. © 2013 Springer-Verlag Berlin Heidelberg. Source


Zhang H.,CAS Research Center for Eco Environmental Sciences | Shan B.,CAS Research Center for Eco Environmental Sciences | Ao L.,Chongqing Academy of Environmental science | Tang W.,CAS Research Center for Eco Environmental Sciences | Wen S.,CAS Research Center for Eco Environmental Sciences
Environmental Earth Sciences | Year: 2014

A complete record derived from a core dated both by 210Pb and 137Cs chronologies from Lake Ngoring at the headwater areas of the Yellow River provides new insight into the changing atmospheric deposition of trace metals including Cd, Cr, Cu, Ni, Pb, and Zn. This study showed that there was an inflection in the early 1960s, before which both fluxes and contents of Cd, Ni, Pb, and Zn remained relatively steady or slowly increased, and thereafter continued increases both in fluxes and contents were found. Taking Pb as an example, the flux increased from 0.13 (before 1960) to 0.25 mg m-2 a-1 (averaged 1963-2006). According to atmospheric flux calculations using Al as a reference element, atmospheric fluxes of trace metals generally showed a rapid increase and peaked in recent years, closely following the historical economic development of the neighboring region, mainly for Qinghai and Gansu provinces. The atmospheric inventory for Zn was the highest, reaching 1.068 g m-2, while the lowest was for Cd, at only 0.079 gm-2. The percentage proportions of atmospheric deposition for Cd, Ni, and Zn were 37, 12, and 8.7 %, respectively. Hence, the atmospheric contribution to the trace metal content via long range transport is not negligible when considering input of materials to lake ecosystems. © 2013 Springer-Verlag Berlin Heidelberg. Source

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