Distribution of 1,4-dioxane and N, N-dimethylformamide in river water from Niigata, Japan

1,4-Dioxane (dioxane) and N,N-dimethylformamide (DMF) are polar organic compounds mainly used as solvents miscible with water as well as several organic solvents. Dioxane had been used as a stabilizer of 1,1,1-trichloroethane which was prohibited manufacturing in 1996 by the Montreal Protocol. The IARC has classified dioxane as a possible human carcinogen; US EPA showed a value of 30 mu g/L as a concentration of drinking water at a 1/100000 risk level. Dioxane is found in many industrial waste streams and by-products (Draper et al. 2000). For example, it can be formed as a by-product by dimmerization of ethylene oxide during forming polyethoxylated alcohols which may be used to synthesize sulfate surface activate agents for cosmetic products (Black et al. 2001). Dioxane is low-biodegradable (Abe 1999) and has been detected in landfill leachates (Lesage et al. 1990; Yasuhara et al. 1992; Yasuhara 1995; Yasuhara et al. 1997), effluent from sewerage systems (Abe 1999), sea water, river water, ground water (Abe 1999; Draper et al. 2000; Kadokami et al. 1993; Kawata et al. 2001) and rain water (Kadokami et al. 1993). DMF, which is considered to be a potent liver toxin, is used as solvent for manufacturing synthetic leatherette and polymer as well as for toxicological studies (Yan et al. 2002). DMF was detected in sea water, river water, ground water and rain water (Kadokami et al. 1993; Okamoto et al. 1992; Ibaraki et al. 1999; Kawata et al. 2001) as well as leachate from wastes landfill (Yasuhara 1992).