Monitoring of environmental pollution caused by the heavy oil spill accident at the Japan sea and evaluation of toxicities of polluted environmental samples

1997年1月2日，俄罗斯“纳霍德卡”号油轮在日本海航行时发生了船体破裂事故，大量重油泄漏到日本海，从岛根县到山形县的海岸线受到了污染。因此，我们进行了广泛的科学研究，以评估石油或化学品污染在环境中持续的位置和时间，以及泄漏对生物系统的影响。本研究得到以下结果：1)对石川县石油污染地区的调查显示，即使在事故发生2年后，仍有几个地区仍存在严重的石油污染，而污染地区的数量却在逐年减少。2)许多被石油污染的海岸位于陡峭而难以接近的地区，表面覆盖着岩石或巨石/鹅卵石/卵石/砾石。人们一直认为，没有做出很大的努力来去除到达的油，对这些区域的自然清洁效果很小。3)采出油中3 ~ 6环的多环芳烃（PAHs）浓度没有明显下降，约为纳霍德卡装载油的一半。4)事故发生1年后采出油的间接诱变性约为事故发生后立即采出油的80%，与采出油中的多环芳烃浓度相对应。5)包括纳霍德卡油在内的重油被发现具有抗雌激素活性，这种活性部分是由于多环芳烃。

A Russian tanker Nakhodka met a hull-broken accident in sailing in the Sea of Japan on January 2, 1997, releasing a huge quantity of heavy oil into the Sea of Japan and the spilled oil polluted the coastline from the Shimane Prefecture through the Yamagata Prefecture. So, we conducted extensive scientific studies to assess where and how long the pollution by the oil or chemicals persist in the environment and the impact of the spill on biological systems. The following results were obtained in the present study: 1) The survey of oil-polluted area in Ishikawa Prefecture revealed that several area have been still heavily polluted with oil even at 2 years post-accident while number of polluted area has decreased in the course of years. 2) Many of the coasts polluted with oil located at the area steep and hard to get near and had surfaces covered with rocks or boulder / cobble / pebble / gravel. It has been considered that much effort to remove the reached oil was not made and natural cleaning effect with those areas was small. 3) As for polycyclic aromatic hydrocarbons (PAHs) in reached oils, concentrations of PAHs with 3-to 6-rings did not decrease significantly and were approximately half those of the oil loaded in the Nakhodka. 4) Indirect mutagenicities of reached oils sampled at 1 year post accident were approximately 80% of those sampled immediately after the accident and found to correspond to the PAH concentrations in reached oils. 5) Heavy oils including the Nakhodka-loaded oil were found to show antiestrogenicity and this activity was due in part to PAHs.