2018 Volume 31 Issue 1 Pages 28-33
Humans have been increasingly altering the global nitrogen (N) cycle through consumption of food, energy, fibre and other non-food products. This alteration negatively affects human and ecosystem health. An N footprint is an indicator to quantify direct and indirect N loads to the environment induced by resource consumption. Despite their importance to the anthropogenic N loads, especially on urbanized areas, non-food products are not yet incorporated into the existing N footprint model for consumers’ decision-making (N-Calculator) that considers only food and energy. In order to understand the effect of waste reduction on N loads, household solid waste in Kawasaki City in Japan during 1985–2014 was assessed using N content for each type of waste. The direct N loads of household solid waste had reduced from 1.28 kg N/capita in 1990 and 1.27 kg N/capita in 2003 to 0.70 kg N/capita in 2014. This reduction was primarily due to decrease of food and paper waste through residents’ actions in cooperation with municipal guidance. Considering increased proportions of fabric waste, a further target for reduction is suggested to be clothing and apparels. These findings provide a first step for incorporating non-food goods into the N-Calculator accounting.
