Swedish Nitrogen Flows : A national budget of anthropogenically induced reactive nitrogen

Sammanfattning: Nitrogen is a fundamental element in all forms of life and a crucial component of our agricultural productivity and global food security. However, excess nitrogen caused by human activity poses a serious threat to the environment and human health. Understanding human influences on the nitrogen cycle are therefore essential for sustainable management of the nutrient. The flows of anthropogenically influenced and created reactive nitrogen in Sweden are examined in this study. Human-induced sources and mechanisms associated with nitrogen are quantified and illustrated in several charts constructed with material flow analysis (MFA) methodology. Swedish society is divided into sectors of agriculture, industry, consumption, and waste management and the quantified nitrogen flows interacting with each system are used to highlight areas of interest. Results show considerable impacts stemming mainly from the food system, starting with agricultural use of mineral and organic fertilizer. Emissions of ammonia to air from animal husbandry and leakage of nitrogen to waterways are the biggest losses in the agricultural sector. The driving force behind the large agricultural losses is first and foremost the consumption pattern of households. Emissions of nitrogen oxides from traffic and industrial processes also make up a large part of the total nitrogen load. The recovery rate of nutrients that ultimately end up in the waste sector is relatively low and most of the nitrogen is denitrified in wastewater treatment plants.