Abstrakt

Safety assessment of wastewater drained from landfill using medaka (Oryzias latipes) in aquarium system

Makiko Doi, Kazuhiko Fukatsu

There are more than 10,000 different chemical substances in the environment, andmany of themexist as a complexmixture of unknown substances in leachate from landfill, which can carry the chemicals into waterways. Assessing the risk that these potentially harmful chemicals pose to humans andwildlife is difficult. The aimof this study is to establish the use of aquarium-cultured medaka fish (Oryzia latipes) as a practical system for monitoring the safe of the treated water of leachate from landfill sites. Leachate that has been treated by desalination or activated-carbon filtration is thought to be of sufficient quality to support breeding populations of medaka, with no adverse reproductive consequences.We bred medaka in an aquarium containing water that had been treated by the leachatetreating equipment at a model landfill plant.We recorded and analyzed the survival rate, sex ratio, and reproduction stability (fecundity, fertility, hatchability, and deformity) in experimental and control aquarium-cultured medaka populations.Medaka grewand reproduced normally in the treated water. Based on our results, we proposed the establishment of a practical assay that uses aquarium-cultured medaka ecosystems and surrounding areas.