Sang Nan, Li Guangke, Xin Xiaoyun
Department of Environmental Science, College of Environment and Resource, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China.
Ecotoxicol Environ Saf. 2006 Mar;63(3):469-73. doi: 10.1016/j.ecoenv.2005.02.009.
With increasing use of municipal solid waste landfills for solid waste disposal, municipal landfill leachate has become a serious concern for aquatic environments. Therefore, it is important to study its toxic effects on plants, animals, and humans. In the present study, the genotoxicity of leachate was investigated with the Hordeum vulgare root-tip cytogenetic bioassay, using Chemical oxygen demand (COD(Cr)) as a measure of leachate concentration. Leachate decreased the mitotic index (MI) in a concentration-dependent and a time-dependent manner. Compared with the negative control, reductions of MI of 37%, 56%, and 70% were detected for the highest leachate concentration (COD(Cr) 800 mg/L) in root tips treated for 24, 48, and 72 h, respectively. Leachate caused significant increases of micronucleus (MCN) frequencies in a concentration-dependent and a time-dependent manner. Among the exposure groups, COD(Cr) 40 mg/L leachate induced MCN formation after 24, 48, and 72 h of exposure, and the frequencies of MCN significantly increased with increasing concentrations of leachate from COD(Cr) 40 to 640 mg/L. In addition, pycnotic cells (PNC) occurred in root tips at all leachate concentrations tested after 24, 48, and 72 h of exposure, and PNC frequencies had a positive relation with the treatment concentration and the exposure time. The results also indicate that the concentration required to produce cytogenetic damage was lower in cells that had a longer exposure time. The results confirm that components of leachate may be genotoxic in plant cells and imply that long exposure to leachate at low concentrations in the aquatic environment may pose a potential genotoxic risk to organisms. The results suggest that the H. vulgare cytogenetic bioassay is efficient, simple, and reproducible in genotoxicity studies of leachate, and that there appears to be a correlation between the genotoxicity in a plant system and the COD(Cr) of leachate.
随着城市固体废弃物填埋场越来越多地用于固体废弃物处理，城市垃圾渗滤液已成为水生环境的一个严重问题。因此，研究其对植物、动物和人类的毒性作用具有重要意义。在本研究中，采用大麦根尖细胞遗传学生物测定法，以化学需氧量（COD(Cr)）作为渗滤液浓度的指标，研究了渗滤液的遗传毒性。渗滤液以浓度和时间依赖性方式降低有丝分裂指数（MI）。与阴性对照相比，在分别处理24、48和72小时的根尖中，最高渗滤液浓度（COD(Cr) 800 mg/L）时MI分别降低了37%、56%和70%。渗滤液以浓度和时间依赖性方式导致微核（MCN）频率显著增加。在暴露组中，COD(Cr) 40 mg/L渗滤液在暴露24、48和72小时后诱导MCN形成，并且随着渗滤液浓度从COD(Cr) 40 mg/L增加到640 mg/L，MCN频率显著增加。此外，在暴露24、48和72小时后，在所有测试的渗滤液浓度下，根尖中均出现了固缩细胞（PNC），并且PNC频率与处理浓度和暴露时间呈正相关。结果还表明，产生细胞遗传学损伤所需的浓度在暴露时间较长的细胞中较低。结果证实渗滤液的成分可能对植物细胞具有遗传毒性，并暗示在水生环境中长时间低浓度暴露于渗滤液可能对生物体构成潜在的遗传毒性风险。结果表明，大麦细胞遗传学生物测定法在渗滤液遗传毒性研究中高效、简单且可重复，并且植物系统中的遗传毒性与渗滤液的COD(Cr)之间似乎存在相关性。
