title: [Studies on mutagenicity of humic acid samples collected from arsenosis-affected areas in China].
abstract: OBJECTIVE
  To explore whether there is mutagenicity of humic acid samples collected from arsenosis affected areas in China.
  
  
  METHODS
  Ames' test was used for natural humic acid samples extracted from the coal containing high arsenic in Guizhou Province, and the well water in the areas with blackfoot disease in Taiwan and with arsenosis in Inner Mongolia of China.
  
  
  RESULTS
  Coefficients of revertant mutation were 1.02-0.82 net revertant per microgram (rev/microgram) of humic acid extracted from the coal containing high arsenic in Guizhou without rat liver homogenate (-S9), and 1.53-1.12 rev/microgram of that with rat liver homogenate (+S9), with an obvious dose-response relationship.
  
  
  CONCLUSIONS
  Humic acid extracted from the coal containing high arsenic produced in Guizhou could cause stronger direct mutation in Salmonella typhimurium TA98 (frameshift mutation) and that extracted from the well water in the areas with blackfoot disease in Taiwan could cause weaker direct mutation in Salmonella typhimurium (-S9), but that extracted from the well water with arsenosis in Inner Mongolia could not cause mutation. Mutagenicity of commercial humic acid, purchased from Aldrich Co. in the United States, arsenic and iron was also studied, and no mutagenicity was found for them independently, but arsenic combined with humic acid, at certain concentrations, could cause weak mutation in TA98 (-S9), with or without iron. No mutagenicity in TA100 (+/- S9, base pair substitution mutation) was found in all the samples mentioned above.
mesh_terms: D000818:Animals; D001151:Arsenic / Q000633:toxicity*; D002681:China; D004347:Drug Interactions; D006812:Humic Substances / Q000633:toxicity*; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D051381:Rats