MONITORING OF MUTAGENICITY IN AQUATIC BIOTA AS A TECHNIQUE FOR THE ENVIRONMENTAL ASSESSMENT

在濑户内海沿岸选定的5个地点收获贻贝，用丙酮-乙腈提取其可食用部分。提取液经蓝粘胶（BR）处理后，用高效液相色谱法测定鼠伤寒沙门菌YG1024的致突变性和苯并(a)芘（BaP）的致突变性。49个贻贝组中有8个组的BaP含量大于1.0 ng/g， 29个组中有17个呈阳性，回复物的数量超过溶剂对照的3倍。在个体组中，BaP水平与致突变性呈正相关。在收集贻贝的同一地点，蓝色人造丝在海水中悬挂24小时。用甲醇氨浓缩洗脱液，测定其致突变性和BaP含量。1g等量BR的洗脱液中BaP含量为0.05 ~ 19.5 ng， 29个样品中有17个呈阳性。再次观察到BaP的数量与诱变性呈正相关。为了确定致突变性的归因成分，我们利用高效液相色谱（HPLC）对贻贝样品提取物和BR洗脱液进行了分离，并测定了各组分的致突变性。在贻贝中，极性部分的诱变性高于含BaP的部分。进一步在水族箱中对日本Corbicula japonica Yamato-shijimi进行了0.058 ~ 0.224 ng/ml的BaP暴露实验。在12和24小时后，在极性部分再次观察到诱变性升高，但双壳类动物的BaP积累水平仅为水族馆的11-38倍。上述结果表明，监测生物群样本中的诱变性将为水生环境中的致癌物质提供一种潜在的方法。

Mussels were harvested at 5 selected sites along the coast of Seto Inland Sea and their edible parts were extracted with acetone-acetonitrile. The extract was then subjected to blue rayon (BR) treatment and the sample thus prepared was analyzed for mutagenicity with Salmonella typhimurium YG1024 and for benzo(a)pyrene (BaP) with HPLC-Fl. Eight out of 49 mussel groups contained BaP more than 1.0 ng/g and 17 out of 29 group showed positive results, the number of revertants exceeded 3 times more than that of solvent control. A positive correlation was observed between the level of BaP and the mutagenicity in individual groups. Blue rayon was hunged for 24 hr in the sea water at the same sites where mussels were collected. The eluate with methanoammonia was condensed and also assayed mutagenicity and BaP content. The eluate from 1g equivalent BR contained 0.05 to 19.5 ng of BaP and 17 out of 29 samples showed positive results. Again a positive correlation was observed between the amount of BaP and the mutagenicity. In order to identify the attributable components to the mutagenicity, we fractionated sample extract from mussel and the eluate from BR through C18 column with HPLC and assayed mutagenicity in each fraction. In case of mussel, elevated mutagenicity was observed in the polar fraction than that contained BaP. Further Yamato-shijimi, Corbicula japonica, was experimentally exposed to BaP at 0.058-0.224 ng/ml in an aquarium. After 12 and 24 hr, an elevated mutagenicity was again observed in the polar fraction, however the bivalve accumulated merely 11-38 times higher level of BaP than that in the aquarium. The above results suggest that a monitoring of mutagenicity in biota samples will provide a potential approach to carcinogenic substances in the aquatic environment.