3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX): toxicological properties and risk assessment in drinking water.
MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone), one of the byproducts formed during the chlorine disinfection process of drinking water, shows strong mutagenic activity for Salmonella strains in the Ames test. In several countries, the contribution of MX to the total mutagenicity of drinking water is estimated to range from 7% to 67%. To assess the risk of MX for human health, we summarized the toxicological properties of MX and estimated the tolerable daily intake (TDI) or tolerable concentration in drinking water. MX is genotoxic in cultured mammalian cells and causes in vivo DNA damage in several tissues. MX is carcinogenic for rodents in addition to possessing skin and gastric promotion activities. From these toxicological profiles of MX, we estimated the virtual safety dose (VSD) for genotoxic action as 5 ng/kg/d and the TDI for non-genotoxic action of MX as 40 ng/kg/d. We assumed a tolerable MX concentration of 150 ng/L in drinking water. Because of the uncertainty about human genotoxicity, however, and the lack of information on reproductive or developmental toxicity, the estimated tolerable dose level may be provisional.
Hirose
A
A
Division of Risk Assessment, National Institute of Health Sciences, Tokyo, Japan. hirose@nihs.go.jp
Nishikawa
A
A
Kinae
N
N
Hasegawa
R
R
D004249:DNA Damage; D005663:Furans / Q000633:toxicity*; D006801:Humans; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D018570:Risk Assessment; D012475:Salmonella / Q000187:drug effects / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D014881:Water Supply
D005663:Furans; D009153:Mutagens; D014874:Water Pollutants, Chemical