IV. Discussion
A higher pH value promotes the precipitation of metals, which subsequently settles to the sediments [21] in fact when the pH values of soils ranged from 5.0 to 7.0, the mean values of extractable metals are approximately the same [22] Since there is no significant difference across stations and the pH are neutral, pH is not a factor in the bioavailability of metals in the case of Butuanon River