The international program on plant bioassays and the report of the follow-up study after the hands-on workshop in China.

Among the seven plant bioassays reviewed by the US Environmental Protection Agency (EPA) Gene-Tox program in 1980, the Allium/Vicia root tip chromosome aberration assay and the Tradescantia stamen hair mutation and micronucleus assays were adopted by the International Program on Plant Bioassays (IPPB) for monitoring or testing environmental pollutants. These assays are highly sensitive and capable of detecting mutagens, clastogens and carcinogens from the environment. They are effective in situ monitors. These bioassays were validated and their protocols were standardized through a program under the International Program on Chemical Safety (IPPB), the precursor of the IPPB program which currently is in operation under the auspices of the United Nations Environment Program (UNEP). Six different categories of environmental studies, ranging from wastewater, surface or ground water, soil samples, ambient air, pesticides, and radiation, were carried out and are reported in this special issue. The mission of the IPPB/UNEP is to use these bioassays to monitor or test environmental mutagens and clastogens in the air, water, and soil to safeguard the quality of these essential elements in life and to use these simple and clear indicators of pollution damage as the tool for environmental education for the general public. The published reports of the monitoring and testing results will establish the database for environmental conditions in a number of locations around the world. An international monitoring network for the detection of genotoxicity of environmental pollutants is being established under the auspices of UNEP to protect the global environment. Copyright 1999 Elsevier Science B.V.