摘要:城市食物源氮消费产生的环境排放是全国氮污染的重要源头，城市食物氮足迹评估可反映维持城市人口基本食物需求的活性氮排放以及对周边环境的潜在影响。以典型移民城市深圳市为例，基于改进N-Calculator模型的基础上，估算了2010-2015年间因城市人口流动导致的城市食物氮足迹变化，并分析其时空异质性及其与城市化间的关系。结果表明：深圳市不同类型城市居民食物氮足迹不一致，其中常住户籍居民人均食物氮足迹从14.63 kg N a^-1增加至15.17 kg N a^-1，高于非户籍居民食物氮足迹13.09 kg N a^-1，其主要体现在瓜果、肉类、水产品等食物消费上。总体上，深圳城市食物氮足迹呈增长趋势，5年增幅11.50%，增幅最大为常住户籍居民食物氮足迹，但目前深圳非户籍居民的食物消费主导着城市食物氮足迹。深圳城市内部区域食物氮足迹呈高度空间异质性与聚集性，各区域增长量差异明显，街道尺度城市食物氮足迹增长热点主要分布在城市的西部沿海区域，部分热点区域单位增长量数量级比肩区级尺度单位的增长量，城市区域食物氮足迹与人口城市化的关联性不明显，但与经济城市化存在一定的关联性。当前城市移民落户趋势及居民高氮饮食倾向不利于城市氮足迹的削减，减少食物生产上游活性氮流失为深圳市贯彻粤港澳大湾区协同可持续发展的关键。



Abstract:The anthropogenic release of reactive nitrogen (Nr, consists of all nitrogen species except N₂) from urban food consumption contributes to national nitrogen-related pollution. The emergence of food nitrogen footprint indicator, which quantifies the amount of reactive nitrogen release to the environment by food production and consumption, can address the potential environmental impacts on urban surroundings to feed the increasing population of a city with rapid urbanization. In this study, a modified N-Calculator model was developed to calculate the food nitrogen footprint of Shenzhen City from 2010 to 2015, the typical immigrant city with higher degree of urbanization in China. The related spatio-temporal variations in regional food nitrogen footprints within the city and their relationships with urbanization were then analyzed. The results showed as follows: (1) the food nitrogen footprints caused by different types of urban residents per capita presented variations. The trend in average food nitrogen footprints of urban permanent resident presented growing from 14.63-15.17 kg N per capita, which exceeded 13.09 kg N per capita of urban non-registered resident during study period, mainly due to the differences in daily consumption of meat, fruit and aquatic products. These data revealed the gradually strengthening of the gap between permanent and impermanent urban residents' food nitrogen footprints. (2) The entire food nitrogen footprint of Shenzhen City increased by 11.50% in 5 years, which was driven by growth of food nitrogen footprints produced by urban permanent residents, while urban non-registered residents' food consumption was the main contributor to current urban food nitrogen footprint. The variations in regional food nitrogen footprints within Shenzhen City presented spatial heterogeneity and aggregation, and the growths of those generated from the internal administrative districts and subdistricts were significantly different. The hotspots of food nitrogen footprints growing in the scale of subdistrict mainly located in the western coastal regions in Shenzhen City, the growths of their footprints were partially exceeded the magnitude of those created by some administrative districts. (3) The study found that there were no obvious relationships between the increases in urban food nitrogen footprints and population urbanization within the city, but to some extent correlations between smaller-scaled footprints and economic urbanization were witnessed. Current trends in immigrant population settlement and the personal preference for high nitrogen diet post barriers to further reductions in urban food nitrogen footprints, and the alleviation in the upstream reactive nitrogen loss from food production is the key measure for Shenzhen City to contribute to the sustainable development of Guangdong-Hong Kong-Macao Greater Bay Area.





PDF全文下载地址:

https://www.ecologica.cn/stxb/article/pdf/stxb201906161269