title: Annual changes of vitamin B1, biotin and vitamin B12 in water in Lake Biwa.
abstract: Annual changes in the concentrations of B1, biotin and B12 were investigated at the designated stations in the north basin (main basin) and south basin of lake Biwa. Sampling was carried out twice a week in spring and monthly in the other seasons throughout one year in the south basin, and in the same way for three years in the main basin from April of 1978 to December of 1980. The concentrations of B1, biotin and B12 in water of the main basin over three years ranged from 106.6 to 4.1 ng/liter, from 4.17 to 0.14 ng/liter and from 5.78 to 0.19 ng/liter, respectively. On the other hand, those in the south basin ranged from 268.7 to 9.7 ng/liter, from 11.50 to 0.12 ng/liter and from 6.06 to 0.20 ng/liter, respectively. The concentrations of these vitamins in the south basin of the lake were twice as high as those in the main basin. The concentrations of these three kinds of vitamins in water remarkably changed seasonally in both the north and south basins of the lake throughout the investigation period and were generally high in September and October at every station in the main basin, except for B1 and biotin in the south basin of the lake.
mesh_terms: D001710:Biotin / Q000032:analysis*; D005618:Fresh Water / Q000032:analysis*; D007564:Japan; D012621:Seasons; D013831:Thiamine / Q000032:analysis*; D013997:Time Factors; D014805:Vitamin B 12 / Q000032:analysis*; D014867:Water / Q000032:analysis*
chemical_list: D014867:Water; D001710:Biotin; D014805:Vitamin B 12; D013831:Thiamine