Due to the acceleration of industrialization and urbanization in recent decades, the majority of coastal rivers and estuaries in China have been moderately or severely contaminated by a variety of pollutants. We investigated the spatial and seasonal variations of water nutrients (permanganate index, chemical oxygen demand, biochemical oxygen demand, ammonium, nitrate, total nitrogen, and total phosphorus) and heavy metals (Hg, Pb, Cu, Zn, Se, As, Cd, Cr, Fe, and Mn) in 27 subtropical rivers draining into the South China Sea. Our results indicated that the average concentrations of all water quality parameters except ammonium, total nitrogen, and total phosphorus satisfied the requirements for grade III of the surface water quality standard of China. The concentrations of both nutrients and heavy metals showed a strong spatial variation. Cluster analysis classified the 27 rivers into three spatial clusters corresponding to low, moderate, and high pollution levels. In terms of seasonal variation, the values of chemical oxygen demand and biochemical oxygen demand in wet seasons were significantly lower than those in dry seasons. Multivariate statistical analyses demonstrated that river nutrients might mainly originate from domestic, industrial, and agricultural wastewaters, while heavy metals likely came from industrial activities and natural weathering processes. The findings of this study suggest that for reducing the pollution of subtropical rivers draining into the South China Sea, further efforts should be made to control nitrogen and phosphorus export from catchments.

Aging and urbanization significantly impact the physical and mental well-being of the elderly population. Empirical investigations have highlighted the contribution of the built environment to promoting elderly health. However, there is a need for further exploration of the factors within the built environment that impact the subjective well-being (SWB) of the elderly. To address this, this study selected 50 communities in Guangzhou, where 1403 elderly people were surveyed. Employing the random forest, we have identified contributing factors of the built environment affecting the SWB of the elderly. Meanwhile, we used a prediction model constructed by random forest to predict the SWB level of the elderly. The results indicated that accessibility to parks (positive emotions (PA): 0.822, positive experiences (PE): 0.235), hospitals (PA: 0.680, PE: 0.546), and supermarkets (PA: 0.237, PE: 0.617) significantly contributed to PA and PE. On the other hand, factors such as population density had a significant contribution to negative emotions (NA: 0.431) and negative experiences (NE: 0.194). Based on the prediction results, the spatial distribution of SWB among the elderly can be derived. Overall, our study can provide planning and improvement strategies for built environments that promote SWB among the elderly.

Urban regeneration has become one of the most effective ways to develop urban areas that have declined. Compared with other types of urban regeneration, community micro-regeneration is characterised by scattered stakeholders. Existing studies on public participation in community micro-regeneration mainly focus on revealing the interaction between different stakeholders with less attention to the main users’ social profiles in their participation process. This paper explores residents’ social profiles influencing their participation in community micro-regeneration projects in China. An evaluation framework for residents’ participation in community micro-regeneration projects is designed through literature research, the Delphi technique, and an analytic hierarchy process (AHP) based on the case study of Yongtai community, Guangzhou. Relative residents’ social profiles with the data from the questionnaire and literature research are further verified by stepwise linear regression. The results show that residents’ participation is still in the stage of tokenism with high-level passive information receipt but low-level enthusiasm for interactive activities. The older (i.e., 65-years of age and above) and middle-income groups (i.e., between 3000 and 14,999 CNY/Month) are positively associated with their participation in the Yongtai community micro-regeneration project. These findings can provide references for managers to distribute social resources.

Cultivated land quality (CLQ) is associated with national food security, benign economic development, social harmony, and stability. The scientific evaluation of CLQ provides the basis for achieving the “trinity” protection of cultivated land quantity, and quality, as well as ecology. However, the current research on CLQ evaluation has some limitations, mainly the poor consideration of evaluation indicators, time-consuming and labor-intensive data acquisition, and low precision of evaluation at the regional scale. Therefore, this study introduced multisource data to evaluate CLQ and proposed a new method for CLQ evaluation (natural grade evaluation, utilization grade evaluation, and economic grade evaluation), combining multisource data and the recurrent neural network (RNN) algorithm. Initially, optimal indicators were determined by correlation analysis and generalized linear regression coefficient methods based on factors related to CLQ acquired from multisource data. Then, CLQ evaluation models were constructed with the RNN algorithm on the basis of the aforementioned optimal indicators. Finally, the models were adopted to map CLQ. The present study was carried out in Guangzhou City, Guangdong Province, China. According to the results: (1) CLQ showed close relationship to pH, effective soil layer thickness (EST), chemical fertilizer application rate (CHFE), organic matter content (OMC), annual accumulated temperature (TEMA), 5–15 cm soil depth soil cation exchange capacity (CEC515), 0–5 cm soil depth soil cation exchange capacity (CEC05), 5–15 cm soil depth soil organic carbon content (SOC515), 0–5 cm soil depth soil organic carbon content (SOC05), field slope (FS), groundwater level (GWL), and terrain slope (TS). (2) All modeling accuracies (${\mathrm{R}}^2$) were greater than 0.80 for the CLQ evaluation models constructed based on the RNN algorithm. The area and spatial distribution of each grade of CLQ evaluation were consistent with the actual situation. The best and the worst quality cultivated land occupied a small area, and the area without a gap with the actual CLQ was as high as 76%, indicating that the model results were reliable. The study shows the suitability of the method for evaluating CLQ at the regional scale, offering a scientific foundation for the rational utilization and management of cultivated land resources, as well as a reference for evaluating CLQ in the future.

Amidst global sustainability challenges across domains such as energy, water, and transportation, China’s urbanisation process presents unique socio-economic dynamics, particularly following the Reform and Opening Up policy. The existing literature has not fully captured the complex interplay between urban growth and sustainability challenges in China, nor has it adequately explored the phased nature of urbanisation informed by evolving policies. This paper provides a comprehensive review of China’s urban transition, emphasising its evolution since the Reform and Opening Up policy. Through systematic analysis, it delineates the multifaceted nature of urbanisation, reflecting on policy impacts and socio-economic shifts. Findings indicate transformative urban growth characterised by new challenges in environmental sustainability, social equity, and urban–rural integration. The research unveils the transition to a human-centric urban development model, highlighting policy shifts towards sustainable practices. The results suggest a nuanced urban–rural convergence, advocating for participatory governance and balanced growth. The unique contribution of this study lies in its empirical and theoretical examination of China’s urbanisation within a global context, offering a critical perspective on policy formulation and sustainable urban development.

Driven by manufacturing supply reform and regional industrial transformation and upgrading, village industrial parks are key areas for deepening urban renewal. The complex relationship between various property rights actors is a key factor limiting the sustainable development of village industrial parks, and thus attracts considerable research. However, existing research is limited to individual cases and lacks systematic approaches to provide effective guidance for the renovation of village industrial parks. In addition, the paper summarises the participation pathways and characteristics of 12 typical cases of village industrial parks in the PRD. This is particularly true for rural industrial parks. The study identifies five scenarios based on the renewal of village collective ownership (government warehousing, land lease to developers, land lease to operating companies, land lease to enterprises, independent management); five situations based on the renewal of market enterprises’ rights of use (regular leasing, government support, abolition on expiry, introduction of enterprises, autonomous management); and four situations based on the renewal of government management rights (land expropriation, unified lease management, policy stimulation, supervision and management). The results are valuable for the research of urban regeneration and sustainable development in the context of government ownership.