Genotoxicity of airborne particles from the urban area in Sapporo : Evaluation of the particulate samples collected over 22 year by bioassays

为了研究大气颗粒物的遗传毒性，分析了从1974年开始的24年间在日本北海道最北方大城市札幌采集的大气颗粒物样品。主要研究结果如下：1.用艾姆斯试验测定致癌物质和致突变性，在24年的观察期内，多环芳烃（PAHs）的浓度明显下降，而硝基芳烃的浓度没有明显变化。TA 98和TA 100菌株的致突变活性仅略有降低。这些结果表明，多环芳烃的浓度不是一个合适的指标，肺癌的大气风险和进一步的人类健康的风险并没有显着降低在观察期内在空气颗粒物的致突变性.小鼠淋巴瘤细胞致突变性试验使用L5178 Y细胞（一种小鼠淋巴瘤细胞系）进行的致突变性试验有效地检测了突变。 关于我们 NS和染色体畸变。间接致突变活性（+S9）在此期间明显下降，而直接致突变活性（-S9）则没有下降.用体外微核试验测定致突变性用中国仓鼠肺成纤维细胞体外微核试验测定空气颗粒物的致突变性。在观察期内，+S9试验系统的诱导微核发生率相当稳定。对于-S9检测系统，发生率在20世纪80年代初升高，其他年份波动较小。代谢缺陷型试验菌株的选育通过基因敲除，建立了硝基还原酶活性完全和部分被抑制的艾姆斯试验菌株YG 7128和YG 7132。还建立了O-乙酰转移酶缺陷型菌株YG 7126和YG 7130。这些菌株有效地检测硝基芳烃，它表明，硝基芳烃的贡献是相当大的总致突变活性的空气颗粒物样品。少

To investigate genotoxicity of airborne particles, the airborne particulate samples collected in Sapporo, the most northern large city in Hokkaido, Japan, during the period of 24 years from 1974 were analyzed. The results obtained are followings :1. Concentrations of carcinogenic substances and mutagenicity assayed by Ames test.Concentrations of polycyclic aromatic hydrocarbons (PAHs) markedly decreased during the observation period of 24 years, while concentrations of nitroarenes did not. Mutagenic activities assayed by TA98 and TA100 strains did only slightly decrease. These results indicates that concentrations of PAHs is not an appropriate indicator for the atmospheric risk of lung cancer and further the risk to human health did not significantly decrease over the observation period in terms of mutagenicity in airborne particles.2. Mutanenicity assayed by mouse lymphoma cells.Mutagenicity assay using the L5178Y cell, a cell line of mouse lymphoma cells, efficiently detected mutatio … More ns and chromosomal aberration induced by the airborne particulate samples. The indirect mutagenic activities (+S9) clearly decreased over the period, while direct mutagenic activities (-S9) did not.3. Mutagenicity assayed by in vitro micronucleus test.It was shown that mutagenicity of airborne particles is possibly assayed by in vitro micronucleus test using Chinese hamster lung fibroblast cells. The incidences of induced micronucleus were rather stable for +S9 test system over the observation period. For the -S9 test system, the incidences were elevated in early 1980s with small fluctuations for other years.4. Development of new test strains with metabolic deficits.By gene disruption, new test strains for Ames assay, YG7128 and YG7132 with completely and partially inhibited nitroreductase activities, were established. YG7126 and YG7130, O-acetyltransferase deficient strains, were also established. These strains effectively detect nitroarenes and it was shown that contribution by nitroarenes was considerable among the total mutagenic activities in the airborne particulate samples. Less