Study of the genotoxicity of organic extracts from wastewater-irrigated vegetables using in vitro and in vivo biological tests.

The purpose of this study was to explore genotoxicity due to organic pollutants in wastewater-irrigated vegetables using biological and chemical analyses. Chinese cabbages from wastewater-irrigated farmland were taken as the research object. For the in vitro test, DNA damage was characterized in rat hepatocytes exposed to organic extracts from the cabbages using the comet assay. For the in vivo tests, mice were exposed to organic extracts from the cabbages. DNA damage was assessed in mouse peripheral blood lymphocytes (PBLs), and chromosome damage was assessed in bone marrow cells using the comet assay and micronucleus test, respectively. For the chemical analysis, gas chromatography-mass spectrometry (GC/MS) was used to analyze the organic compounds in the organic vegetable extracts. The in vitro test results showed that the comet tail lengths of the DNA in rat hepatocytes were significantly increased in the group dosed with 0.36 g/ml (P < 0.05), and the comet tailing rates of the hepatocytes were significantly increased in the groups dosed with 0.24 and 0.36 g/ml (P < 0.05). The in vivo test results indicated that the comet tail lengths of the DNA in mouse PBLs were increased in the low- and high-dose groups and that the comet tailing rate of the PBLs was increased in the high-dose group (P < 0.05). The chemical analysis results showed that the total organic content in the organic vegetable extracts from the wastewater-irrigated area (1.355 mg/kg) was significantly higher than the content in the cabbage samples from the clean-water-irrigated area (0.089 mg/kg). This finding indicated that wastewater irrigation can cause organic pollution with genetic toxicity in vegetables. This study also showed that in vivo and in vitro biological tests can reflect the joint toxicity of organic pollutants, and the test results were in accordance with the chemical analysis of the organic pollutant compositions.