居民饮食方式改变对自然界中氮含量影响的定量研究

A Quantitative Study on Changes in Diet Style of Residents to Influence the Nitrogen Content in Nature

为定量研究居民饮食方式变化对自然界中氮含量的影响，对上海市崇明县及市区居民进行了日常活动调查，计算人均每日从食物中摄入及排泄物中可能被排入自然界的氮量。研究表明：在崇明和上海市区，人均每日分别摄入11．04、18．83g氮；分别有84％，8％的人类排泄物回归土地，16％、92％被排入河流；崇明年人均排泄物中，约3．39kg氮被用来施肥，0．64kg排放到河流中，在上海市区则分别为0．55、6．32kg。调查受访者10a前的饮食情况及对未来饮食的期望时发现，居民饮食结构的主要改变之一是蛋白质摄入量的增加，直接导致排泄物中氮元素的增加。

To quantitatively study the influence of changes in residents＇ diet style on the nitrogen content in nature, a survey of residents＇ daily activities in Chongming County and Shanghai urban areas was carried out. Daily nitrogen intake from food per capita and potential nitrogen load from human excreta on the environment were calculated. The research showed that the daily per capita nitrogen intakes in Chongming County and Shanghai urban areas were 11.04 gm and 18.83 gm, respectively. In Chongming and Shanghai urban areas, 84% and 8% of human excreta went to lands whilst the rest were discharged into waterways, respectively. Regarding the annual potential nitrogen load from human excreta in Chongming, approximately 3.39 kg per capita were returned to farmland whilst 0.64 kg was directly discharged into waterways. Correspondingly, those two figures in Shanghai urban areas were 0.55 kg and 6.32 kg, respectively. In addition, the investigation of respondents＇ diets a decade ago and expected in future has found that the main changes in diet structure of residents was the increasing intake of protein so as to directly cause an increase in nitrogen load from their excreta.