The Genotoxicity Of Pollutant Mixtures, Soils, Sediments And Incinerator Ashes By V.faba Micronucleus Assay

The environment is a multimedia complex system influenced by many factors. Pollutants enter and reside in the environment as complex mixtures, and jointly have impacts on ecosystems and human health with a series of migration and transformation. Chemical analysis often cannot easily indicate the potential environmental risks, but bio-monitoring can reflect the risks in a more direct way. In the present paper, by V. faba micronucleus (MN) assay, we made assessments of the genotoxicity of pollutant mixtures, soils in Guangzhou, solid waste incinerator ashes from Macao and sediments from the Pearl River, and explored the possible correlation between the genotoxicity and the chemical compositions. The main results are:The formation of MN in the root cells of V. faba was observed, and reduction of somatic cell division was found in the root cells of V. faba under the stress of chemicals. The cell division index (CDI) was suggested as one of the supplemental criteria in the V.faba MN assay. Other aspects of the MN assay, like the background MN value, chromosome aberration (CA) and the cell cycle, were also discussed.The genotoxicity of mixtures of Di-(2-ethylhexyl) phthalate (DEHP) and Potassium dichromate (Cr (VI)) was studied. The results showed that DEHP and Cr (VI) individually induced the increasing MN in the root cells of V. faba at the tested dosages, and there were significant difference between the tested and negative groups. DEHP could decrease the genotoxicity of Cr (VI) on the V.faba in general, except for a few case that the genotoxicity of Cr (VI) was enhanced by DEHP at some dosage combinations, implying that their joint action could not simply termed as synergetic or antagonistic. We also found that, for the chemicals at certain dose ranges, the CDI and the biomass increase with the decreasing of MN and CA.Heavy metals in the leaching solutions of bottom ashes from municipal solid Incinerator in Macao were in higher concentrations when the water pH was lower, andPb was exceptionally high in the leaching solutions. All the leaching solutions induced the increasing of MN in the root cells of V. faba. Na2EDTA could decrease the genotoxicity of the solutions on V.faba, and might be used for remediation.Soils sampled from vegetable fields and sediments from the Pearl River all showed significant genotoxicity to V. faba, and their contents of polycyclic aromatic hydrocarbons (PAHs), phthalic acid esters (PAEs) and heavy metals were also relatively high. There were good correlation between their genotoxicity to V. faba and their relevant contents of PAHs and heavy metals. Many tested soils and sediments have pollutant levels below relevant guideline levels from chemical analysis, but show significant genotoxicity compared to background soils from the endpoint of V. faba MN, indicating that bio-monitoring like MN assay might reflect the potential ecological and health risks in a more sensitive and integrative way than merely chemical analysis. The MN assay by V. faba is a useful technique for assessing the potential risks of pollutants to ecosystems and health in the total environments.