Applied Mechanics and Materials Vols. 295-298

Abstract: In processing food wastes, odorous gases are generated, which significantly affect the workers and occupants in the plant. This study applies gas chromatography-mass spectrometry and chemical methods to analyze qualitatively and quantitatively the characteristics of odorous gases in the workshop, in order to find the composition and pollution level of odorous gases emitted from municipal food waste. The research results showed that the common compositions in the food waste gases were dimethylacetamide, naphthalene, methylnaphthalene, phenol and limonene, which the tested probability is 100%. Based on the comparison of odor concentration and threshold at four sampling sites, it can be concluded that ethyl thioether, trimethylamine, ethylbenzene and citric acid were major gases that belonged the standard threshold. Both odor intensity and activity of trimethylamine and ethyl thioetherwere highest, which odor intensity were 70.58 and 1.79, as well as odor activity were 2.25 and 1.79, separately. Therefore, the compounds attributed to the odor gases in food waste weretrimethylamine and ethyl thioether.

Abstract: In the process of source apportionment for particulate matter by mass balance model, the colinearity between various source profiles leads to the different analyzing results. For this reason, carbon isotopic apportionment based on the difference in carbon isotopic composition of particulate from different sources was put forward in this study. On the basis of chemical mass balance model, carbon isotope mass balance model is built to discriminate the sources including soil dust, coal dust and vehicle exhaust dust. This improved method has been used in the source apportionment of particulate in Taiyuan, and the results showed that the contributions of vehicle exhaust dust, coal dust and soil dust to air particulate in Taiyuan are 45%,13% and 18% respectively in heating season, while 23%,21% and16% in non-heating season. Therefore, the control of ash fly from burning coal is a long-term and arduous task.

Abstract: This paper reviewed oil spill incidents in Zhejiang coastal waters and characteristics of these incidents were analysed from geographical and seasonal distributions. Both operational and accidental oil spill incidents were examined, and key factors on ship accidents were identified. It was found that traffic density may be an important contributor to the oil spill incidents as key majority of accidents happened in busy waterways of important ports, especially Ningbo-Zhoushan area. The most significant oil spill risks were associated with navigational hazards of collision and grounding. The findings could be very useful for developing oil spill risk control and pollutants recovery measures.

Abstract: The water quality monitoring revealed that the water quality in Poyang Lake is increasely degenerating in the past several years and the deterioration reasons were analyzed. The increasingly serious water pollution indicated that there were inherent drawbacks in current environmental management system of China. Therefore, the typical models of water pollution prevention and control in developed countries and China were researched. The explorations of water pollution prevention and control based on ecosystem management for Poyang Lake were reviewed, especially the practice of Mountain-River-Lake (MRL) Program in Poyang Lake Basin. At last, the challenges of water pollution prevention and control in Poyang Lake Basin was put forword such as law and policy, organization structure, participation mechanism. The researches indicated that the multiplicity and complexity of nature, humanities, society and economy in Poyang Lake determined its importance and necessity to implement ecosystem-based water environment management. In the future construction of water pollution prevention model based on integrated ecosystem management is an inevitable trend for Poyang Lake basin.

Abstract: Jiaozuo is located on the Quaternary Alluvial Fan area of submountain, lithology of which is gravel, sandy loam and loam.The pollution of Cr₆ ⁺, Nitrate, Sulfate, Hardness, TDS and F are serious in the shallow groundwater of the study area. Water quality and safety was seriously affected by pollution entering into groundwater. The Chromium of shallow groundwater is from a power plant in Jiaozuo gray field, where fly ash contained a lot of heavy metal chromium. the main reason why shallow groundwater is polluted by nitrate, sulfate, hardness, TDS and F is that mining and industrial sewage is used for irrigating farmland.

Abstract: Based on the farmland soils along the Bijiang River, a main tributary of the international Lantsang-Mekong River flowing through the Jinding Lead-Zinc Deposit, this dissertation makes analyses on the pollution characteristics of spatial variation in farmland soils by adopting the soil sampling and testing analysis and applying single-factor pollution index (SPI) evaluation and Nemerow composite pollution index (NCPI) evaluation. The results indicate that: (1) In accordance with Environmental Quality Standard for Soils (II), the content of Cd contained in the farmland soils has severely exceeded the standard in a large scale, followed by Pb and Zn. However, the content of As is maintained within the specified standard; (2)The SPI values of soils are in the following sequence: Cd＞Zn＞Pb＞As. The pollution level caused by the heavy metal “Cd” to the farmland soils is extremely heavy in a wide range, and a majority of the farmlands are heavily polluted by Zn. The farmlands with moderate pollution by Pb are centered at Plot 2 in the deposit, and only a few farmland soils are moderately polluted by As at Plot 2 in the deposit;(3) Based on the NCPI, the results indicate that the NCPI of the farmland soils has reached to the degree of heavy pollution; (4) It is indicated based on the RPI evaluation that the RPI values of As, Cd, Pb and Zn contained in the farmland soils have exceeded the standard in the following sequence: Pb＞Zn＞Cd＞As, which illustrates that during the development of Jinding Lead-Zinc Deposit in Lanping County, the heavy metals imposing the most profound influence on the soil pollution are Pb and Zn. The heavy metal pollution in the farmland soils from the upper reaches to the lower reaches of the Bijiang River is not only caused by the development of Jinding Lead-Zinc Deposit in Lanping County, but is also associated with its high soil background value;(5) There is a remarkable spatial variation of heavy metal pollution in farmland soils from the upper reaches to the lower reaches of the Bijiang River. Both the SPI and the NCPI values of heavy metals in the soils within the deposit at the upper reaches of the Bijiang River are the lowest; the pollution index of the soils closest to the deposit are the highest, and the pollution index of the soils with a certain distance from the deposit drops swiftly; the pollution index of Plot 4 rises to a certain degree at the middle reaches, and gradually ascends near the Yunlong County seat at Plot 5, however, with a comparatively small growth rates.

Abstract: This paper took the SongSan wastewater irrigation district of Liaoning Province, Anshan city as object of study. Base on the survey on the sewage irrigation situation, heavy metal concentration in rice grain and drinking water were measured through single pollution index evaluation and comprehensive pollution index evaluation (Nemerow index method). It could be served as the basis for environmental management and relevant laws and regulations. Experimental results showed that drinking water were not polluted by heavy mental. Sewage irrigation had a comparatively small impact on drinking water. According to the heavy mental determination results of grain crop seeds, it can conclude that the Cu and Pb content were above the national food quality standard. The pollution is serious, however, the content of Zn and Cd were below or close to the national food quality standard, which is in danger of exceeding the standard. Determined by comprehensive pollution index, it showed that the rice in the whole sewage irrigation is serious polluted by heavy mental. The heavy metal pollution presented the characteristics of extensive area-source pollution. Pollution intensity was strengthened and more difficult to be managed.

Abstract: How to assist decision making efficiently using information technologies such as GIS and water environment models has become a hot issue in the field of emergency study. Starting from the actual need of water pollution accident emergency handling, this paper uses scenario analysis, organically couples GIS, water environment accident models and decision making methods, and establishes an intelligent decision making system for emergent water pollution events. Then, with the actual data from Beijiang River cadmium pollution event entered into this system, it analyses and compares the change of pollution situations in different scenarios, and verifies the effects of the study. Finally, it provides a technical summary and prospect.

Abstract: A series of stream water, soil and fruits samples in the orchards were collected from Lianhuashan tungsten area in Guangdong Province. The concentrations of As, Cd, Pb, Zn, Cu and Ni in the samples were determined. This study targeted at the impacts of Lianhuashan wasteland on the orchards at the downstream. The results showed that the stream water was severely polluted by heavy metals, especially As and Cd, with low pH value and high electric conductivity (EC). Compared to the background orchards, the soils in the orchards at the downstream were polluted by As and Cd. The fruits in the orchards surrounding the polluted stream were seriously polluted by As and Cd. Acid waste water derived from the tailings of Lianhuashan tungsten mine entered the streams and resulted in elevated concentrations of heavy metals, lower pH values and higher EC in the stream water. The polluted streams caused soils and fruits pollution by As and Cd in the surrounding orchards.

Abstract: The contamination levels and distribution of heavy metals in surface water of the Taizi River were investigated. Samples of water were collected from upstream to downstream locations, and also from the main tributaries of the Taizi River. All samples were analyzed for arsenic, mercury, and chromium (Ⅵ). Results indicated that the metal levels of upriver sites were lower than downriver sites. The total concentrations of Cr6+ and As in dry season was higher than that in flood season. While heavy metal Hg represents the highest concentration in flood season. Compared with the permissible levels of surface water environmental quality standards (GB3838-2002), the levels of Cr6+ and As attained the first and second level, but Hg attained the fifth level. This indicated that most sites of the Taizi River have a high risk of Hg pollution in flood period.