抄録
1 . Biological water quality of streams on campus was measured by observing aquatic invertebrates during 1994-1996. Results were compared with those in spring and autumn and with those at Sandankyo in 1996.
2 . The number of species observed on campus in the spring were 28-35 and in the autumn was 19-32. At Sandankyo the numbers were 35 in the spring and 33 in the autumn.
3 . Insects represented 75-83% of the species on campus and 91-94% of the species at Sandankyo. The dominant species on campus were Amphipoda, Diptera, Ephemeroptera and at Sandankyo were Ephemeroptera and Tricoptera.
Because the numbers arc small, the red Chironomidae, which are pollution resistant, are of little problem at both sites.
4 . The pollution index of the water samples was measured by the Beck-Tsuda biotic index method. The indices on campus were 25-34 in the spring, 16-37 in the autumn and at Sandankyo were 39 in the spring and 34 in the autumn. The cleanest water quality was in the mid-and upper streams on campus and in the streams at Sandankyo.
