Cd contamination status and cost-benefits analysis in agriculture soils of Yangtze River basin.

Soil is a fundamental carrier to support for human living and development and has been polluted seriously by heavy metals. This fact highlights the urgency to realize soil heavy metal pollution prevention through soil heavy metals contamination status assessment and root cause analysis. The previous research tends to focus status assessment and source identification without consideration of economic aspect. This study realized the systematic analysis from status assessment, sources identification and economic-environmental cost-benefits analysis in the Yangtze River basin. Through the spatial difference comparison among the provinces of upper, middle and lower in the Yangtze River basin, it revealed that anthropogenic influence is the main reason caused the current Cd contamination in Yangtze River basin. An interesting finding is that the human caused Cd concentration contribution amount is nearly the same between upstream and downstream which is all about 0.1 mg/kg, while they have quite different economic scale. It indicated that due to the difference of the scale and structure of local economy, and the level of cleaner production and pollution treatment, some regions could own high economic-benefits and low environmental cost, which it is opposite in other regions. The geographic location and natural resources is the root cause to form the environmental cost-economic benefits difference among regions. The convenient traffic promoted downstream to develop large amount and high quality of economy. The natural mineral resources promoted midstream to develop resources based economy. The poor condition of traffic and natural resources has restricted the development of Qinghai province, and made it has the highest Cd pollution intensity. The results would provide effective economic management measures for better soil quality and sustainable development goals achievement.

Spatial explicit management for the water sustainability of coupled human and natural systems.

Linking water to research on coupled human and natural systems (CHANS) has attracted wide interest as a means of supporting human-natural sustainability. However, most current research does not focus on water environmental properties; instead, it is at the stage of holistic status assessment and measures adjustment from the point of view of the whole study region without revealing the dynamic interaction between human activities and natural processes. This paper establishes an integrated model that combines a System Dynamics model, a Cell Automaton model and a Multiagent Systems model and exploits the potential of the combined model to reveal regions' human-water interaction status during the process of urban evolution, identify the main pollution sources and spatial units, and provide the explicit space-time measurements needed to enhance local human-natural sustainability. The successful application of the integrated model in the case study of Changzhou City, China reveals the following. (1) As the city's development has progressed, the water environment status in some spatial units is still unsatisfactory and may even become more serious, especially in the urban areas of the Urban District and Liyang County. The concentration of Chemical Oxygen Demand (COD) in monitoring section 157 of the Urban District has increased from 36.90 mg/l to 40.84 mg/l. The main source of this increase is the increase in secondary industry. (2) With the application of the spatially explicit measures of the sewage treatment ratio improvement and new sewage plant construction, the water quality in the urban area has significantly improved and now satisfies the water quality standards. The measure of livestock manure utilization enhancement is adopted to improve the spatial units in which livestock is the main pollution source and achieve the goal of water quality improvement. The model can be used to support the sustainable status assessment of human-water interaction and to identify effective measures that can be used to realize human-water sustainability along with social-economic development.

Validation of the hypothesis on carrying capacity limits using the water environment carrying capacity.

The concept of "carrying capacity" has been widely used in various disciplines in reference to human-environment sustainability. No unified cognition exists regarding carrying capacity limits for humans. As a typical type of carrying capacity, the water environment carrying capacity (WECC) has been researched for human-water environment sustainability. However, most recent research has focused on the assessment of the water environment carrying capacity of a certain region or river basin. The detailed resilience potential of human-water environment systems that could improve the local water environment carrying capacity has not been systematically exploited. The key concerns of the existence of water environment carrying capacity limits and the exact value have not been addressed. This study first distinguished the characteristics of related concepts, such as carrying capacity, planetary boundaries, resilience, limitations, thresholds and tipping points. An analytical framework was then established to exploit the resilience potential from the four dimensions of "scale, structure, pattern and network". The economy scale with full use of the resilience potential is 11,511,880 M yuan under the current technology and development status, which is nearly 37 times that of the current scale of the economy. The analytical framework confirms that the limit on the water environment carrying capacity is a dynamic value, which could be changed from the four dimensions. The socioeconomic scale that the local water environment can support would be nearly unlimited in some extreme ideal situation. The results would provide some enlightenment on the carrying capacity and other similar marked concepts of theoretical research and provide support for human-environment sustainability.

An approach of habitat degradation assessment for characterization on coastal habitat conservation tendency.

Coastal zones are population and economy highly intensity regions all over the world, and coastal habitat supports the sustainable development of human society. The accurate assessment of coastal habitat degradation is the essential prerequisite for coastal zone protection. In this study, an integrated framework of coastal habitat degradation assessment including landuse classification, habitat classifying and zoning, evaluation criterion of coastal habitat degradation and coastal habitat degradation index has been established for better regional coastal habitat assessment. Through establishment of detailed three-class landuse classification, the fine landscape change is revealed, the evaluation criterion of coastal habitat degradation through internal comparison based on the results of habitat classifying and zoning could indicate the levels of habitat degradation and distinguish the intensity of human disturbances in different habitat subareas under the same habitat classification. Finally, the results of coastal habitat degradation assessment could be achieved through coastal habitat degradation index (CHI). A case study of the framework is carried out in the Circum-Bohai-Sea-Coast, China, and the main results show the following: (1) The accuracy of all land use classes are above 90%, which indicates a satisfactory accuracy for the classification map. (2) The Circum-Bohai-Sea-Coast is divided into 3 kinds of habitats and 5 subareas. (3) In the five subareas of the Circum-Bohai-Sea-Coast, the levels of coastal habitat degradation own significant difference. The whole Circum-Bohai-Sea-Coast generally is in a worse state according to area weighting of each habitat subarea. This assessment framework of coastal habitat degradation would characterize the landuse change trend, realize better coastal habitat degradation assessment, reveal the habitat conservation tendency and distinguish intensity of human disturbances. Furthermore, it would support for accurate coastal zone protection measures for the specific coastal area.