In situ evaluations of biological effects of chemicals from industrial waste sites provide an assessment of potential health hazards to humans under the complexities of natural environment. For such studies, plants, being cost effective and suitable for multimedia exposure, are ideal for preliminary investigations for hazard identification. Several native plant species have been used as biomonitors for providing an integrated response to the bioavailability of chemical toxicants in the real-world environment.
We have utilized the Tradescantia micronucleus (Trad-MCN) assay for evaluating genetic hazards at a chemical waste site contaminated with agricultural insecticides scheduled for cleanup under the Superfund program. The chemical analysis of soil samples from the site indicates presence of lindane, beta BHC, and heptachlor in the subsurface samples. Tradescantia plants were planted at five locations to evaluate the mutagenic effects of the total environment, i.e., soil, water, and air. In addition, stem cuttings were also placed at these locations to sample the genetic impact of vapor phase organics in the atmosphere. Surface and subsurface samples were obtained from these locations for chemical and biological analysis in the laboratory. Concurrent laboratory and field controls were maintained in Durham, NC.
Results of Tradescantia exposures at the site showed significantly higher frequencies of micronuclei from contaminated plots before remediation, but no genetic activity was detected after the remedial action. Plants exposed to soil samples in the laboratory yielded nonsignificant results except for one subsurface sample before remediation and two surface samples after remediation. From comparison of plants exposed in the laboratory and under natural conditions, we concluded that genetically effective levels of volatile organics were present at the site before remediation. This study demonstrates the utility of simple bioassays for detecting environmental hazards at chemical waste sites.