Horizontal distribution of main hydroxyanthraquinones in soil

Six hydroxyanthraquinones (chrysophanol, chrysotalunin, microcarpin, physci on, 7,7'-biphyscion, and hinakurin) present in the samples of 26 surface so ils were quantitatively analyzed, and the contents of HAQs in soil types we re compared. The soil samples had been collected from 19 Umbric Andosols an d seven Distric Cambisols, and the Andosols were further subdivided into th ose with allophanic soil materials (exchange acidity (y(1))<5 mL 100 g(-1)) and non-allophanic soil materials (y(1)greater than or equal to 5 mt 100 g (-1)). The following results were obtained. (1) It was determined quantitat ively for the first time that chrysotalunin was the major hydroxyanthraquin one in many soils. (2) The amounts of major dimeric hydroxyanthraquinones ( chrysotalunin, 7,7'-biphyscion, and microcarpin) in non-allophanic soil mat erials were significantly larger than those in allophanic soil materials. A s the contents of chrysotalunin in Andosols were positively correlated with y(1), which was reported to be positively correlated with aluminum toxicit y and exchangeable aluminum in soil, it is suggested that toxic aluminum ma y be involved in the production of soil hydroxyanthraquinones.