Determination and QSPR analysis of log Kow and log Koc for fluorine containing benzene derivatives

Octanol‐water partition coefficients (Kow) and soil organic carbon sorption coefficients (Koc) were determined for 14 fluorinated benzene derivatives. Quantitative structure‐property relationships were developed using molecular connectivity indices and quantum chemical parameters to analyze the most significant factors influencing these physico‐chemical properties of the compounds. The substitution by F in benzene derivatives has greater influence on Koc than on Kow.     

Uncertainty analysis of a pharmacokinetic modeling for inorganic arsenic

This paper presents an uncertainty and sensitivity analysis of a pharmacokinetic modeling of inorganic arsenic deposition in rodents for a short‐term exposure. Efforts to develop the pharmacokinetic model are directed towards predicting the kinetic behavior of inorganic arsenic in the body, including tissue and blood concentrations, and especially, the urinary excretion of arsenic and its methylated metabolites. However, the use of the model raises an important question when fixed values of model parameters are used: how is the uncertainty in the model prediction based on the collective uncertainties in the model inputs? This study focuses on an “epistemic”; uncertainty in order to handle this problem. In this case, the uncertainty refers to an input that has a single value which cannot be known with precision due to a lack of knowledge about items or its measurement. The combination of the pharmacokinetic model and the uncertainty analysis would help understand the uncertainties in risk assessment associated with inorganic arsenic.     

Urban planning and sustainable development under transitional economy: a case study of Guangzhou

There are always conflicts between the need for conservation and economic growth in the developing countries. Planning plays a primary role in balancing these conflicts. This is particularly obvious in Chinese cities since China adopted its open door policy in 1978. Foreign investment has been a major driving force for rapid growth of the Chinese economy. Planners in China have been facing the dilemma of protecting the natural environment on the one hand while, on the other hand, supporting the overall national goal of attracting foreign investment to maintain continuous economic growth. The planning system in China, which has been largely based on a planned economy, soon found itself handicapped in safeguarding the environment from rapid industrialization and urbanization fostered by market forces. This paper takes Guangzhou as an example to study challenges to the planning system in Chinese cities in the past two decades of rapid economic growth and urbanization. By means of a case study on an industrial development within a protected orchard area in Guangzhou, this study illustrates the conflict between the need for rural conservation and the pressure for economic development in the Chinese cities. In particular, it analyzes the pressures on the present urban planning system in China in terms of the following categories: the emergence of private investors in urban development; the goal of pursuing a high economic growth rate; the implications of a transitional economy for urban planning; and the weakness of the present urban planning system. It concludes that the role of urban planning in China should change from simply providing guidelines on board land-use strategy, to a combination of a strategic plan with specific development control laws at the operational level. Finally, some recommendations are suggested as to how to improve the planning system in China.     

A GIS-based moving window analysis of landscape pattern in the Beijing metropolitan area,China

Quantifying landscape pattern and its change is essential for monitoring and assessment of ecological consequences of urbanization. Using the GIS-based land-use data for 2002, we combined moving window analysis along an urban-rural gradient and around the urban centre with landscape metrics to quantify the spatial pattern of urbanization in Beijing. The results of moving window analysis along the urban-rural gradient indicated that, for class-level metrics, the spatial pattern of urbanization could be quantified using landscape metrics, different land-use types exhibited distinctive spatial signatures, and, for landscape-level metrics, the increase in urbanization in the metropolitan Beijing region has resulted in dramatic increases in patch density (PD), edge density (ED), and patch and landscape shape complexity, and sharp decreases in the largest and mean patch size (MPS), agriculture land-use type, and landscape connectivity. The results of moving window analysis around the urban centre showed that the direction of urbanization could be quantified using the class-level metrics, and landscape-level metrics indicated similar results to gradient analysis. In general, moving window analysis showed that the increasingly urbanized landscape became compositionally more diverse, geometrically more complex, and ecologically more fragmented.     

Empirical analysis on the influence of the Shaanxi fruit industry on regional food security

As part of its development policy to relieve rural poverty in west China, the Chinese government has introduced measures such as agricultural tax exemptions, agricultural subsidies, and scientific, technological and restructuring improvements to agriculture. Following these actions, farmers’ incomes have increased greatly and the economy in poor areas of west China has seen rapid improvements. However, agricultural restructuring, infrastructure construction and ecological restoration projects have reduced the area of land under arable farming, restricting opportunities for increasing total grain yield. Regional food security is therefore threatened and an imbalance between economic development and food security is created. Shaanxi is a representative province in west China where agricultural restructuring has resulted in large areas of arable land being converted into orchards that produce higher economic returns. This study randomly surveyed 1430 farm households in three counties in the apple-producing region of Shaanxi Province (Luochuan, Changwu and Baishui). The standard of living and household income of farmers in the fruit production areas were higher than in grain-producing areas, thus discouraging grain production. Land under agriculture in the counties studied comprised 59% orchards and 39% arable, with 2% under other uses. Per capita, 204.3 kg of grain was produced, 51% of that required for self-sufficiency. Other staple foods produced amounted to only 13.9% of that needed for self-sufficiency. As a result, nearly half of the grain needed by the community was purchased from outside, resulting in very poor regional food security. Clearly, fruit production in this region seriously affects regional food security. Coordination of relationships between rural economic development and regional food security is key for sustainable development of the regional agriculture and economy of west China.     

Polychlorinated dibenzo p-dioxins and dibenzofurans emissions in a primary copper smelter in China

Metallurgical production is the largest polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) emission source in China. However, PCDD/F monitoring and research are rarely conducted on primary metallurgical production. In this study, a demonstration primary copper smelter in China was selected to investigate PCDD/F characteristics and control. Samples were collected from major PCDD/F release points in the smelter process (fly ashes and waste water sludge). Specific analysis of PCDD/F congeners was carried out using a high resolution gas chromatography/high resolution mass spectrometry method. The results showed that PCDD/Fs might be unintentionally produced in the primary copper smelter processes, with sample concentrations of 180–6110 pg/g dry wt; highly chlorinated PCDD/F homologues were predominant. The toxicity of all the samples was calculated to be 120 pg WHO TEQ/g, fly ashes from the refining process furnaces air pollution control device and sludge were hazardous waste with higher PCDD/F toxicity. Both precursor formation and de novo synthesis were found to contribute to PCDD/F formation in the smelter process. PCDD/F characteristics and formation were compared with reported secondary copper smelters. Life-cycle control of PCDD/F was proposed for retrofitting of this smelter and for similar plants in China's primary copper production sector, including control at the PCDD/F formation, removal and disposal stages.     

δ13C and fatty acid composition of mesopelagic fishes in the South China Sea and their influence factors

Study of the ecology of mesopelagic fishes is central for assessing the active biological pump in the ocean, especially in the mesopelagic layers. The use of δ¹³C and fatty acid analysis can help to analysis the ecology of mesopelagic fishes. Here, we analysed the fatty acid composition of mesopelagic fishes from the continental northern slope of the South China Sea (NSSCS) and compared with nearshore SCS fishes and mesopelagic fishes collected from the Southern Ocean. The mesopelagic fishes had unusually high lipids, which resulted in Δδ¹³C values exceeding 1‰, more than the enrichment factor in the food web. The mesopelagic fishes had higher C18:1n-9/C18:1n-7 and C20:1n-9/ C18:1n-7 ratios compared with other fishes in the SCS, which confirmed that plankton were their main dietary source. The mesopelagic fishes from SCS and Southern Ocean had different ratios of C20:5n-3/C22:6n-3 (EPA/DHA), suggesting geographical locations and diet sources had obvious influence on their fatty acid composition. The SCS mesopelagic fishes had higher C20:4n-6/C22:6n-3 (ARA/DHA) and C20:4n-6/C20:5n-3 (ARA/EPA) ratios than mesopelagic fishes in the Southern Ocean, indicating the influence of physical factors on fatty acid composition. Thus, future studies of the fatty acids in mesopelagic fishes should consider both dietary sources and physical environments.     

电气石和沸石对土壤-小麦幼苗系统中重金属行为的影响

为探明电气石对重金属污染土壤的修复能力,本文采用盆栽方法研究了电气石对小麦幼苗的生长及对重金属积累的影响,并与常用改良剂沸石进行修复效果的比较.结果表明,添加电气石和沸石均能有效提高小麦幼苗的株高、干重和叶绿素含量,其中干重最大能提高1.56倍;电气石和沸石处理均能有效降低小麦幼苗对Cd、Cu、Pb、Zn的积累,总体体现为电气石修复效果优于沸石,添加电气石组Cd、Cu、Pb、Zn最大分别降低37.93%、41.45%、16.35%和20.65%.因此,新型材料电气石可用于重金属污染土壤的修复.     

北京地区典型二噁英(PCDDs)及多氯联苯(PCBs)的长距离传输潜力——基于TaPL3模型的应用研究

以典型二噁英(PCDDs)和多氯联苯(PCBs)为研究对象,利用TaPL3模型模拟计算了稳态假设下北京地区4种PCDDs和7种PCBs通过大气和水体的长距离迁移潜力(LRTP)和总持久性(Pov),比较了不同氯取代数的特征迁移距离(CTD)和Pov的大小,分析讨论了二者之间的关系,并以PCB180为例对关键参数进行了灵敏度分析.结果表明,4种PCDDs和7种PCBs在北京地区通过大气的CTDair范围分别为714—874 km和1771—8517 km,Povair范围分别为1422—5169 d和1210—35687 d;通过水体的CTDwater范围分别为1232—1385km和643—4222 km,Povwater范围分别为4900—5618 d和1831—35922 d.对于PCDDs,CTD和Pov基本上随着氯取代数目的增加而增大;对于PCBs,Pov的变化规律与PCDDs类似,而通过大气和通过水体的CTD的变化规律不同.CTD和Pov没有表现出直接的关系.与国内外同类研究相比,北京地区的结果和国外接近,但高于兰州地区通过大气的CTDair,低于通过水体的CTDwater.     

大气高CO2浓度对油菜氮素同化累积与植株生长的影响

为了指导高CO2浓度条件下甘蓝型油菜Brassica napus L.合理施氮、创建油菜高产高效以及进一步探明油菜氮代谢的调节机制提供理论依据,本研究采用微区试验,研究2个油菜品种（沪油15-33号和742-2）在2个CO2浓度水平（自然CO2摩尔分数400μmol·mol-1和高CO2摩尔分数（800±20）μmol·mol-1）和2个氮素水平（施氮与不施氮）条件下,氮素同化酶（NR和GS）活性和可溶性蛋白含量的变化,以及油菜地上部干物质量和氮素累积量的响应。试验结果表明,高CO2浓度会提高NR和GS活性;在氮素处理的影响方面,NR活性的变化与油菜的品种和生育时期不同有关：在高CO2浓度条件下,品种A在各时期的施氮处理的酶活性高于不施氮处理;品种B只在抽薹期的施氮处理低于不施氮处理,其他时期则升高;对于GS酶活性,在自然CO2浓度条件下施氮会提高GS酶活性,高CO2浓度条件下施氮则降低其活性（苗期除外）。CO2浓度升高会降低叶片中可溶性蛋白含量（盛花期除外）;在正常CO2浓度下,增施氮肥会提高叶片中可溶性蛋白含量,而在高CO2浓度下,增施氮肥会降低叶片中可溶性蛋白含量。CO2浓度升高和增施氮肥都会提高油菜地上部干物质量与氮素累积量,油菜干物质量与氮素累积量总体上与上述测定指标呈极显著相关。