A B S T R A C TUrbanization is accompanied by the intense transformation and conflicts among different land use types that produce a series of economic, social, and environmental impacts. Ascertaining the quantity and pattern optimization of urban ecological land is critical to solving urban environmental problems and realizing urban sustainable development. Using the Chinese city of Changzhou, an important and typical city in the Yangtze River delta, as the case study, we applied the minimum cumulative resistance model (MCRM) to calculate the amount of ecological land that meets the demand of socioeconomic development and ecological protection considerating the source of ecological land and constructed land, ecosystem services, and the resistance plane. Results showed that the suitable ecological land area is about 1006.9 km 2 , which is 53.8% of the total urban area of Changzhou, and is mainly distributed in Wujin and Xinbei districts. Considering the ecological land space and functional changes of the study area and comparing the current land use status with the model simulation results, we propose three land use types. For urban ecological land, positive protection measures and prohibiting economic development initiatives are necessary. For ecotones between urban developed land and ecological land, protection should be given priority and economic development activities should be rigidly controlled. For constructed land, measurements and policies should be taken to promote reasonable development and improve land intensity.

Urban parks improve quality of life by providing an array of cultural and natural ecosystem services, such as maintaining biodiversity, reducing air pollution, and benefiting residents' physical and mental states. Although government invests a large amount of capital into park management, parks are still underused in many cases. In this study, the association and relative importance of socio-demographic, environmental, and individual factors were investigated with regards to their impact on citizens' park visitation. Data was collected through cross-sectional door-to-door questionnaires and online databases, and was analyzed using a hierarchical regression model. Results showed that physical exercise (27.4% of collected reports) and rest and relaxation (26.7%) were the two most widespread reasons for park use. When asked about constraints of park visitation, time limitations were reported as being the most constraining factor. However, our quantitative analysis found no significant correlation. Socio-demographic, environmental, and individual variables explained 1%, 20% and 26% (adjusted R 2 ) of the total variance in frequency of park visitation between participants, respectively. A citizen's neighborhood greenspace, housing price, and distance from the nearest park were negatively correlated with park use. Among individual factors, a participant's reported affinity for park visits, time spent in their residential greenspace, and number of children under seven were positively correlated with park visitation, with a decreasingbcoefficient. This research highlights the predominant contribution of attitude over accessibility factors when it comes to park visitation. Furthermore, the data indicates that accessibility factors function differently for frequent, infrequent, and moderate park users and provision with parks within 1000 m of their home is recommended. The findings have implications for park management and future research.

Although the nephrotoxicity of microcystin and aflatoxin has been observed in animal and clinical cases, few population data are available. We conducted a cross-sectional study in Southwest China to investigate the association of renal function indicators (RFIs, including BUN, SCr, and eGFR) with exposure to microcystin and aflatoxin in 5493 members of the general population. Microcystin-LR levels in water and aquatic products and aflatoxin B1 levels in daily foods were measured by ELISA, and individual estimated daily intake (EDI) was assessed on the basis of the measurement and questionnaire. We found that participants with abnormal RFIs had a much higher mean level of microcystin-LR EDI than those with normal RFIs and that there was a significant increasing trend for abnormal rates and odds ratios of RFIs with increasing microcystin-LR EDI quartiles (p for trend = 0.000). Compared with the lowest quartile of microcystin-LR exposure, those in the highest quartile had significantly higher risks of abnormal BUN (OR = 1.80, 95% CI = 1.34-2.42), SCr (OR = 4.58, 95% CI = 2.92-7.21), and eGFR (OR = 4.41, 95% CI = 2.55-7.63), respectively, but no higher risk was found in subjects with higher AFB1 exposure. After adjustment for confounding factors, risk associations with microcystin-LR persisted. Consequently, our results suggest that microcystin, rather than aflatoxin, might be one important risk of renal-function impairment.