Abstract
Organic rubber additives in automobile tire listed up as PRTR chemicals are potential hazards to give adverse effects on the environment. Therefore, it is important to evaluate the behavior of these chemicals in the environment. The purpose of this study was to clarify their fate and concentration in the environment and evaluate their risks to human health and environmental organisms.
The result of exposure tests verified that unstable bond of the organic rubber additives could be split during exposure, though the chemical structures were maintained in the tire rubber.
N-Cyclohexylbenzothiazole-2-sulphenamide (CBS) and N-(1,3-Dimethylbutyl)-N′-phenyl-1,4-phenylenediamine (DMPPD) contained in tire rubbers in high concentrations were found in the atmospheric particles, water and sediment. CBS and DMPPD concentrations were high in the sediment at the outlet spots of wastewater from overhead road. It has been clarified that the tire dust burdens environment with the load of organic rubber additives in automobile tire.
Risk assessment for the aquatic environment which was based on margin of exposure (MOE) and product of uncertainty factors (UFs) indicated that no adverse effects on environmental organisms in the river water were anticipated by the organic rubber additives and their degradation products for the moment, though the MOE value for DMPPD was less than UFs in the wastewater samples from overhead load.
Risk assessment for human health which was based on MOE and UFs indicated that there was no human risk by the organic rubber additives and their degradation products for the moment.
