Substance flow analysis of nickel for risk assessment of nickel and nickel compounds in Japan

Abstract

Nickel compounds have been suspected of causing cancer in humans through inhalation exposure, therefore nickel compounds were specified as priority chemicals of hazardous air pollutants together with volatile organic compounds in 1997 in Japan. Thus, in this study, substance flow of nickel was analyzed from production, shipment and disposal, and the amount of domestic supply, gross additions to stock and waste generation were estimated from 1970 to 2015 in order to conduct risk assessment of nickel and nickel compounds. Additionally, sensitivity analysis was conducted in order to identify the effect to the substance flow of nickel associated with variation of uncertain parameters. As a result, the amount of domestic waste generation was estimated 200 thousand tons per year in 2015 as much as the amount of domestic supply. However, the amount of recovery would be increased as the improvement of rate of recovery, and the amount of incineration and landfill in 2015 would be half as much as those in 2002. Therefore, the emission of nickel into the air will decrease 4 tons per year in 2015. Furthermore, the amount of incineration was largely varied by the factors of the way of municipal waste treatment and future trend of domestic supply of other products. Thus, it was interpreted that the amount of incineration of other products should be estimated in consideration of interval analysis.