TRADESCANTIA-MICRONUCLEUS BIOASSAY

Four coded chemicals, azidoglycerol (AG), N-methyl-N-nitrosourea (MNU) , sodium azide (NaN3), and maleic hydrazide (MH), were tested with the Tradescantia micronucleus (Trad-MCN) bioassay by five independent lab oratories from five different countries. The purpose of this internati onal collaborative study was to evaluate four plant bioassays, of whic h the Trad-MCN assay was one, for their sensitivity, efficiency and re liability. The study was carried out under the sponsorship of the Inte rnational Programme on Chemical Safety. All laboratories adhered to a standard Trad-MCN protocol which suggested that three replicate tests be conducted with each chemical. The results reported by all laborator ies, although not equal, showed good agreement among the laboratories. In fact, all five laboratories obtained positive results with MH and MNU, while four of the five laboratories achieved positive results wit h NaN3. AG was tested in only three laboratories. Two reported negativ e results, while one reported positive results but only at a single hi gh dose. The data from this study suggest that under normal conditions , the Trad-MCN bioassay is an efficient and reliable short-term bioass ay for clastogens. It is suitable for the rapid screening of chemicals , and also is specially qualified for in situ monitoring of ambient po llutants.