Japanese Field Voles (Microtus montebelli, a type of field mouse) living on a large-scale illegal dump site located on the border of Aomori and Iwate Prefectures in northern Japan were found to have a high rate of chromosome abnormalities, as reported by Prof. Yoshitaka Obara (Department of Biofunctional Science, Faculty of Agriculture and Life Science, Hirosaki University) at a July 5, 2004 meeting of a committee set up by Aomori Prefecture to review issues related to the illegal dump.

This site has been illegally used to dump industrial waste for more than a decade, and has become one of Japan's largest dump sites, covering 27 hectares. The volume of waste now totals about 820,000 cubic meters, such a large amount that it has changed the topography of the site. Because it contains a large volume of hazardous wastes such as medical waste and drums containing organic solvents, it is feared that soil, groundwater and rivers in and around the site may have been contaminated.

From spring to autumn in 2003, Prof. Obara caught 30 voles at the dump site and 15 voles at a site over two kilometers away in order to study their chromosomes. The results showed that two of the 30 voles at the dump site had 31 chromosomes as opposed to 30 (15 pairs) in normal voles. The incidence of other types of abnormalities, such as chromosome gaps and breaks, was also three times higher among the voles from the dump compared to those caught away from the site.

Field voles, underground-dwelling rodents, were chosen as the subject of the study because they eat mainly plant roots and stalks, and sometimes soil-dwelling insects, and thus can potentially be seriously affected by groundwater contaminated by industrial waste. Prof. Obara says that genetic effects on voles can be an indicator in considering possible effects of environmental pollution on humans, since both are mammals. He also says that he will now focus on how the voles' chromosome abnormalities are inherited.



Posted: 2004/11/02 02:32:22 PM
Japanese version

TAG Chemicals , Ecosystem , Material reduction , University/Research institute