Occurrence of polymer additives 1,3-diphenylguanidine (DPG), N-(1,3-dimethylbutyl)-N'-phenyl-1,4-benzenediamine (6PPD), and chlorinated byproducts in drinking water: contribution from plumbing polymer materials

Abstract

While the occurrence of polymer additives in the environment has gained much attention in recent years, particularly through the emission of tire wear particles (TWPs), evidence of the occurrence of such chemicals in drinking water systems is limited. Even less information is available regarding potential chlorination/chloramination transformation byproducts. In this study, we report the occurrence of N-(1,3-dimethylbutyl)-N′-phenyl-1,4-benzenediamine (6PPD), 1,3-diphenylguanidine (DPG), and three chlorinated byproducts (1,3-bis(2-chlorophenyl)guanidine (CC15), 1-(4-chlorophenyl)-3-(2,4-dichlorophenyl)guanidine (CC05), and 1-(2,4-dichlorophenyl)-3-phenylguanidine) (CC11)) in drinking water samples (n = 20). DPG showed detection frequency of 100%; median 4.3 ng/L (min = 0.25 ng/L; max = 32.6 ng/L), and a chlorinated by product of DPG (CC15) was also detected in 100% of samples; median 1.7 ng/L (min = 0.29 ng/L; max = 11.2 ng/L). CC11 was also found in 10% of samples and was previously reported as potentially genotoxic. While most studies have focused on the tire rubber related origin of DPG and 6PPD in the environment, results show a potential major contribution of other polymer materials used in household devices such as tap water aerators, particularly O-rings and seals. Leaching potential of such materials was demonstrated, and contact with free chlorine and monochloramine induced the formation of different halogenated transformation byproducts.