冬小麦旱灾风险评价的指标体系构建及应用——基于2009年北方春旱野外实地考察的认识

2009年2月初,我国北方冬麦区遭受了数十年未遇的严重干旱。基于野外实地考察,判断本次干旱对冬小麦造成的实际影响比气象统计与遥感监测结果要轻,同时因纬度、地貌类型、微地貌和田间管理水平的不同而呈现出明显的区域差异。在此基础上,提出应在已有的旱灾致灾指标（气象干旱）基础上,综合考虑地带性、地貌、水库等孕灾环境指标和田间管理水平等灾害适应指标来构建冬小麦旱灾风险的综合评价指标体系。并以北方冬麦区为例,选取SPI、地貌类型、DEM和水库缓冲区等指标得到的旱灾综合风险等级与实际旱情存在较高的吻合性。研究可为高风险区的冬小麦旱灾风险防范提供理论依据和案例支撑。     

中国雨日变化趋势的分形研究

利用1951-2002年中国752个台站的雨日资料,运用分形理论和R/S分析法,研究并预测了中国五大降水区年雨日的气候变化趋势.研究表明:中国五大降水区未来的年雨日变化趋势与过去50a的变化有着很好的自相似性.为了更深入研究雨日的未来的变化,设计了两项Hurst指数试验,用两项试验结果与年雨日年际变化趋势的对应关系来推断未来的变化趋势及其转折与突变.结果表明:中国五大降水区年雨日有着一致的减少趋势,但其变化呈现显著的地域分异特征.依照五大降水区的气候倾向率,西北区、西南区、青藏高原区、东部北方区、东部南方区未来平均每10a雨日减少分别为4.1d,11.4d,3.7d,6.8d和5.9d,其中西南区年雨日减少最多.期间,中国五大降水区虽有气候变化的转折,但不存在雨日气候变化的突变点.     

Distribution of polybrominated diphenyl ethers in breast milk from North China: Implication of exposure pathways

The breast milk concentrations of polybrominated diphenyl ethers (PBDEs; sum of eight congeners: BDE-28, 47, 99, 100, 153, 154, 183 and 209) were determined (by high resolution gas chromatographic high resolution mass spectrometry) in samples from primiparous women collected in 2006 in Tianjin, China. Dietary and lifestyle habits of the participants were obtained by questionnaires. The median total PBDE concentration (including BDE-28, 47, 99, 100, 153, 154, 183) was 2500 pg g⁻¹ lipid weight, ranging from 1700 to 4500 pg g⁻¹ lipid weight. These levels were in the same range as those from Europe and Japan but much lower than those from North America. The congener profile in China was also different from other countries. The contribution of BDE-28 was around 15%, much higher than any other country, implying that a different Penta-BDE formulation might be used in the Chinese market. The lower ratio of the sum of BDE-47, 99, and 100 to the sum of BDE-153 and 154 suggested that Octa-products were in more demand in China. A significant correlation was found between a woman’s PBDE concentration and the time she used electronic appliances (h/d). This implies that electronics are a potential source of PBDEs to people. Inhalation or ingestion of particulate matter (such as dust) may also be an important exposure pathway. There was no significant correlation between the PBDE concentration and the consumption of meat, fish, and milk. Further research is needed to determine the specific contribution of each exposure route and their health effects.     

Levels and congener profiles of PCDD/Fs, PCBs and PBDEs in seafood from China

A nationwide investigation into polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in market seafood was conducted for the first time in this study. Total PCDD/F concentrations in fatty fish ranged from 0.13 to 8.64 pg g⁻¹ wet weight (mean 2.05 pg g⁻¹ wet weight), total PCB concentrations ranged from 38.9 to 3514 pg g⁻¹ wet weight (mean 1133 pg g⁻¹ wet weight), and total PBDE concentrations ranged from 42.8 to 913 pg g⁻¹ wet weight (mean 322 pg g⁻¹ wet weight). Corresponding mean toxicity equivalent (TEQ) values for total PCDD/F and dioxin-like PCB were 0.25 pg g⁻¹ wet weight (WHO 98-TEQ) and 0.32 pg g⁻¹ wet weight (WHO 98-TEQ), respectively. OCDD, PCB-138 and PBDE-47 were the dominant compounds according to their respective congeners. WHO 98-TEQ _{PCDD/PCDF/PCB} for fatty fish and shell fish were 0.60 and 0.070 pg g⁻¹ wet weight, respectively, lower than the standard set by the European Commission. The contamination levels and profiles were compared with those documented in previous publications.     

Biomagnification of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls in a highly contaminated freshwater food web from South China

To evaluate the biomagnification extent of polybrominated diphenyls ethers (PBDEs) and polychlorinated biphenyls (PCBs) in a highly contaminated freshwater food web from South China, trophic magnification factors (TMFs) for 18 PBDE congeners and 53 PCB congeners were calculated. The TMF values ranged 0.26-4.47 for PBDEs and 0.75-5.10 for PCBs. Forty-five of 53 PCBs and BDEs 47, 100 and 154 had TMFs greater than one, suggesting their biomagnification in the present food web. The TMFs for PBDEs were generally smaller than those for PCBs with the same degree of halogenation, indicating a lower biomagnification potential for PBDEs compared to PCBs. For PCBs, it followed a parabolic relationship between TMFs and log K_OW (octanol-water partition coefficient). However, this relationship was not significant for PBDEs, possibly due to the more complex behaviors of PBDEs in the food web (e.g., metabolism), compared to that of PCBs.     

Urbanization in China Based on International Comparison： A Discussion with Two Prevalent Views

Two prevalent views are reviewed on China＇s urbanization firstly. Then, this article highlights the characteristics and pattern of urbanization in the world based on the quadrants map, using data of 118 countries or areas. The results indicate that the process of urbanization in the world excluding the data of China has slowed down gradually. A further exploration examines China＇s urbanization process and economic development over time, which reveals that both urbanization level and the level of economic development belong to the low-grade coordination pattern. The low level of urbanization is closely connected with the low level of economic development. Actually, China＇s urbanization gap appeared during 1985-1995, but it has been eliminating this urbanization gap since 1995 as a result of rapid urbanization growing. The complicated realities revealed in this analysis challenge the existing two prevalent views.     

China＇s Land Carrying Capacity Based on Man-grain Relationships

With population growth and increasing pressure on land resources, land carrying capacity （LCC） and food safety have been attracting great attention worldwide. From the point of man-grain relationship and by establishing LCC and land carrying capacity index （LCCI） models, this article firstly analyzes the spatial-temporal dynamics of LCC of China from 1949 to 2005 at county, provincial and national levels. Choosing 2005 as a representative year, this article then evaluates the LCC of 264 pastoral regions （semipastoral regions）, 663 urban regions and 592 poverty stricken regions of the country. The results show that： （1） from 1949 to 2005, with the increase of grain production, the LCC of China has been improved conspicuously, but due to the rapid population growth, the production can only maintain a low level grain consumption; （2） over the past 25 years （1980-2005）, the number of population overloading provinces decreased from 23 to 15 and the mangrain relationship has been improved gradually, but there were more overloading provinces than surplus provinces in China; （3） at county level, there were 1572 overloading counties in 1980 accounting for 68.26% of the total counties of the country and where were 649 million people lived, while in 1990, 2000 and 2005, the number of overloading counties were 1066, 1133 and 1087 respectively, which shows that the man-grain relationship has been improved obviously during the past 25 years; as for spatial distribution, the surplus counties were mainly concentrated in agriculture developed regions, such as Northeast Plain, North China Plain, middle and lower Reaches of the Yangtze River Plain, and overloading counties were mainly located in regions with poor natural environment and low grain production capacity, such as Northwest China, Tibetan Plateau and Loess Plateau and economically developed urban regions, such as Beijing, Tianjin and Shanghai; （4） animal husbandry improved greatly the LCC of pastoral and semi-pastoral regions, while urban regions were overloading for increasing population pressure and more than half of poverty stricken regions were overloading due to critical natural environment and poor economic conditions.     

Small-scale mining in China: Assessing recent advances in the policy and regulatory framework

This paper explores the background of a proposed revision to the Mineral Resources Law of China, why and how the law was amended in the past, its salient features and objectives. Of equal importance is an analysis of how this national law, with its attendant regulations and policies, formed the basis for the growth and continued development of China's small-scale mining industry. The Xiaoqingling Gold Mountain case study is shown to justify the necessity and feasibility for formalizing and consolidating small-scale mines in China, and to some extent, the success of the nation-wide ASM resource consolidation policy at a local level.     

An eco-environmental water demand based model for optimising water resources using hybrid genetic simulated annealing algorithms. Part II. Model application and results

The present optimisation model described in Part I of this work is applied to optimise water resources in the Haihe river basin, an important basin in north China that covers 31.82 million km². Results show that this optimisation model with the HGSAA solution is feasible and effective in the long-term optimisation of water resource use. It is shown that the combined forecasting method can improve the forecast precision. The results obtained indicate that the mean relative errors of BP and polynomial models are 2.3% and 4.9%, respectively, while that of the combined forecasting method is 1.93% in a case study on the Tumahe River for 2010. The combined forecasting method performs better because it incorporates various forecasting methods. The optimisation results show that both domestic and eco-environmental water demands can satisfy the requirements of the forecasting procedure, and the harmonious indices all exceeded 0.7. The Luanhe River is the most water-scarce sub-basin in the Haihe river basin.     

China's water scarcity

China has been facing increasingly severe water scarcity, especially in the northern part of the country. China's water scarcity is characterized by insufficient local water resources as well as reduced water quality due to increasing pollution, both of which have caused serious impacts on society and the environment. Three factors contribute to China's water scarcity: uneven spatial distribution of water resources; rapid economic development and urbanization with a large and growing population; and poor water resource management. While it is nearly impossible to adjust the first two factors, improving water resource management represents a cost-effective option that can alleviate China's vulnerability to the issue. Improving water resource management is a long-term task requiring a holistic approach with constant effort. Water right institutions, market-based approaches, and capacity building should be the government's top priority to address the water scarcity issue.