15TH INTERNATIONAL SYMPOSIUM ON TOXICITY ASSESSMENT Toxicity test using medaka (Oryzias latipes) early fry and concentrated sample water as an index of aquatic habitat condition H. Yamashita & R. Haribowo & M. Sekine & N. Oda & A. Kanno & Y. Shimono & W. Shitao & T. Higuchi & T. Imai & K. Yamamoto Received: 8 December 2011 / Accepted: 29 March 2012 # Springer-Verlag 2012 Abstract The aim of the present study was to show a relation- ship between toxicity of 100-fold concentrated water and aquat- ic habitat conditions. Environmental waters are 100-fold concentrated with solid-phase extraction. Medaka early fry was exposed in these waters for 48 h. The number of death and disorder was counted at 1, 2, 3, 6, 12, 24, and 48 h; toxicity was expressed using inverse median effect time and median lethal time (ET 50 -1 , LT 50 -1 ). Average score per taxon (ASPT) for benthic animals and Index of Biotic Integrity (IBI) for fish were applied as indices of aquatic habitat conditions. The results of toxicity test were compared using ASPT and IBI. The differ- ent levels of toxicity were detected in the seawater of Japan. At the Husino River area, toxicity cannot be detected. In rivers, high toxicity appeared at urban districts without sewerage. By Spearman coefficient, the relationship between toxicity and high biochemical oxygen demand (BOD) were obtained. BOD household wastewater contains hydrophobic toxic matters; oth- erwise, seawater in industrial area does not show clear relation- ship between toxicity and chemical oxygen demand. Gas chromatography to mass spectrometry simultaneous analysis database may give an answer for the source of toxicity, but further test is required. Ratio of clear stream benthic animal sharply decreased over 0.25 of LT 50 -1 or 0.5 of ET 50 -1 . Tolerant fish becomes dominant over 0.3 of LT 50 -1 or 0.5– 1.0 of ET 50 -1 . By Pearson product–moment correlation coef- ficient, correlation coefficient between toxicity and ASPT was obtained at -0.773 (ET 50 -1 ) and -0.742 (LT 50 -1 ) at 1 % level of significance with a high negative correlation. Toxicity (LT 50 -1 ) has strong correlation with the ratio of tolerant spe- cies. By Pearson product–moment correlation coefficient, cor- relation coefficient between toxicity and IBI obtained were -0.155 (ET 50 -1 ) and -0.190 (LT 50 -1 ) at 1 % level of signifi- cance and has a low or no correlation between toxicity and IBI. Even with low toxic environmental waters, toxicity test using 100-fold concentrated and medaka early fly could detect acute toxicity. The detected toxicity seemed to limit the inhabiting aquatic species in the water body. Keywords Toxicity . Aquatic habitat condition . ASPT . IBI Introduction For more than a century in the USA, federal law has been applied to protect water resources. The most important lan- guage in that law is its powerful objective “to restore and maintain chemical, physical, and biological integrity of the Nation’ s waters.” More recently, Australia and New Zealand’ s water quality guidelines (ANZEEC 1992), Australia’ s 2004 National Water Initiative, Japan’ s River Law (Tamai 2000), and the European Water Framework Directive (European Com- mission 2000) have also been focusing their attention on the biology of waters. As the focus on biology spreads to various new regions, demands for more effective biological monitoring (sampling the biota of a place) and biological assessment (using Responsible editor: Philippe Garrigues H. Yamashita (*) : R. Haribowo : M. Sekine : A. Kanno : T. Higuchi : T. Imai : K. Yamamoto Graduate School of Science and Engineering, Yamaguchi University, Tokiwadai, Ube, Yamaguchi, Japan e-mail: k060fj@civil.yamaguchi-u.ac.jp N. Oda Tosoh Corporation, Syuunan, Yamaguchi, Japan Y. Shimono : W. Shitao Yamaguchi Prefectural Institute of Public Health and Environment, Yamaguchi, Japan Environ Sci Pollut Res (2012) 19:2581–2594 DOI 10.1007/s11356-012-0906-0