Guo Yu Qiu

Distribution, Fraction, and Ecological Assessment of Heavy Metals in Sediment Plant System in Mangrove Forest, South China Sea

Overlying water, sediment, rhizosphere sediment and mangrove seedlings in the Futian mangrove forest were analyzed for heavy metals. The results showed that mangrove plant acidified sediment and increased organic matter contents. Except for chromium (Cr), nickel (Ni) and copper (Cu) in Aegiceras corniculatum sediment, heavy metals in all sediments were higher than in overlying water, rhizosphere sediment and mangrove root. Heavy metals in Avicennia marina sediments were higher than other sediments. The lower heavy metal biological concentration factors (BCFs) and translocation factors (TFs) indicated that mangrove plant adopted exclusion strategy. The geo-accumulation index, potential ecological risk index and risk assessment code (RAC) demonstrated that heavy metals have posed a considerable ecological risk, especially for cadmium (Cd). Heavy metals (Cr, Ni, Cu and Cd) mainly existed in the reducible fractions. These findings provide actual heavy metal accumulations in sediment-plant ecosystems in mangrove forest, being important in designing the long-term management and conservation policies for managers of mangrove forest.

Water and Energy Nexus in China: Current Situation and Future Perspectivein Energy Industry, Water Industry and Agriculture

Water is needed to generate energy. Energy is required to deliver, clean, and evaporate water. There are extensive linkages between water and energy. Meanwhile, both resources may limit the other, especially in the context of urbanization and industrialization as well as climate change. Due to the large population and fast-growing economy, China is one of the most water and energy shortage countries in the world. Relations between water and energy are particularly strained. Unfortunately, up to now, little attention has been paid to the tension relation between water and energy in China. Studying water and energy nexus can provide more information than investigating them separately because of their concomitant relationship. In this paper, we reviewed the recent situations on these issues in China, mainly focused on the following topics: 1) energy consumption in water industry; 2) water consumption and energy nexus in energy industry and urban; 3) water and energy nexus in agriculture; and 4) Energy consumption by evapotranspiration and its cooling effect on reducing urban temperature. Extensive data are analyzed and reported in this study, which will be useful for policy making by taking account of climate change, urbanization, and population growth.

Influence of introduced Sonneratia apetala on nutrients and heavy metals in intertidal sediments, South China

To investigate the influence of Sonneratia apetala on nutrients and heavy metals in intertidal sediments, sediment cores of S. apetala marsh and mudflat in Shenzhen Bay, China were analyzed. The results showed that S. apetala improved sediment nutrient properties due to increased total carbon (TC), total nitrogen (TN), and total sulfur (TS). The levels of heavy metals were higher in S. apetala site than in mudflat, including chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). In S. apetala site, TC, TN, and TS were not positively correlated with Cr, Ni, As, Cd, and Pb, indicating their less important roles in trapping heavy metals. There were positive correlations among Ni, Cu, Zn, and Cd in both sites, suggesting similar anthropogenic source. Levels of As were higher than the probable effect level at both sites, indicating their toxicological importance. The geo-accumulation index and potential ecological risk index revealed higher metal contaminations in S. apetala site, especially for Cd, Hg, and As. Multivariate analysis implied that S. apetala alter the biogeochemical cycle of Cd and Cr to a certain extent. These findings indicate that S. apetala may improve soil nutrient properties and facilitate heavy metal accumulation in intertidal sediments.

Interactive Effects of Salt and Drought Stresses on Seed Germination of Ammopiptanthus mongolicus in Northwest China

A study quantifying the role of the interactive effects of salt and drought stresses, generally co-occurred in deserts, on seed germination in Ammopiptanthus mongolicus was conducted in a constant temperature incubator. The experiment consisted of seven levels of salinity stress (0, 0.3, 0.6, 0.9, 1.2, 1.5 and 1.8% NaCl) as well as six drought stress levels (0, -0.2, -0.4, -0.8, -1.6 and-2.0 MPa PEG). Accordant to our expectations, the interactive effects of salinity and drought stresses were additive on seed germination percentages, germination rate, and germination energy; significant decreases were seen in all of them in response to increases in salt and/or drought stresses. Furthermore, regression coefficients of salinity (β1) were higher than drought (β2), indicating that salinity was the first factor, and drought was secondary for salt and drought mixed stresses.

Effects of conversion of mangroves into gei wai ponds on accumulation, speciation and risk of heavy metals in intertidal sediments

Mangroves are often converted into gei wai ponds for aquaculture, but how such conversion affects the accumulation and behavior of heavy metals in sediments is not clear. The present study aims to quantify the concentration and speciation of heavy metals in sediments in different habitats, including gei wai pond, mangrove marsh dominated by Avicennia marina and bare mudflat, in a mangrove nature reserve in South China. The results showed that gei wai pond acidified the sediment and reduced its electronic conductivity and total organic carbon (TOC) when compared to A. marina marsh and mudflat. The concentrations of Cd, Cu, Zn and Pb at all sediment depths in gei wai pond were lower than the other habitats, indicating gei wai pond reduced the fertility and the ability to retain heavy metals in sediment. Gei wai pond sediment also had a lower heavy metal pollution problem according to multiple evaluation methods, including potential ecological risk coefficient, potential ecological risk index, geo-accumulation index, mean PEL quotients, pollution load index, mean ERM quotients and total toxic unit. Heavy metal speciation analysis showed that gei wai pond increased the transfer of the immobilized fraction of Cd and Cr to the mobilized one. According to the acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) analysis, the conversion of mangroves into gei wai pond reduced values of ([SEM] − [AVS])/foc, and the role of TOC in alleviating heavy metal toxicity in sediment. This study demonstrated the conversion of mangrove marsh into gei wai pond not only reduced the ecological purification capacity on heavy metal contamination, but also enhanced the transfer of heavy metals from gei wai pond sediment to nearby habitats.

The Measurement of Environmental Performance and Economic Performance Based on Catastrophe Theory: Case Studies of Thermal Power Industry and Steel Industry in China

We employed catastrophe theory and entropy method to measure and compare the environmental performance and economic performance of 40 listed companies from the thermal power and steel industries in China, to explore their relationship. The results showed that the environmental performance of the steel industry was less than that of the thermal power industry, but their economic performance was similar. This means that steel industry has had lower resource use efficiency and more pollutant emission, and has a larger potential to saving resources, energy and environment pollution. Both the correlation analysis and regression analysis indicated that there existed a significant positive relationship between the environmental performance and economic performance of the steel industry and thermal power industry in China. This means that it is very possible to gain win-win situation of these two performances, if the listed companies tend to make advanced production and environment protection activities come into a benevolent cycle, by means of technology upgrading and transformation.

Spartina alterniflora: Potential Bio-Energy Source for Biofuel Production in China

Spartina alterniflora can be widely used for fodder, sewage treatment and as a substantial source of bioactive material. As an invader, it strongly disturbs the structure and function of native ecosystem in China. However, it is also a promising bio-energy source. We analyzed the potential of S. alterniflora as a bio-energy source, including the superiority at both temporal and spatial scales, advantages in high photosynthetic efficiency and high productivity. Meanwhile, its exploitation for biofuel production was introduced.