Abstract
When incinerated ashes contact with water, leaching of chemical toxic factors such as high alkaline pH, salts and heavy metals may occur. We have assessed the safety of incinerated ash-leachates using rice plants regarding the reduction of photosynthetic activity in its leaves as a toxic indicator after 1-day of giving the test solution (ash-leachate and hydroponic solution) for its roots. Consequently, toxic ash-leachates tended to be high alkaline pH (almost 11 in their test solution), and to contain high concentration of Ca, Cu and Pb. Thus we investigated the tendencies by adding 0-3 compounds among CaCl2 (30 mM), CuCl2 (130 µM) and PbCl2 (45 µM) in hydroponic solution at pH5.5 and pH11. Photosynthetic activity in rice leaves and the accumulation of chemical elements in its plants were examined for the discussion of toxic factor(s) in Ca+Cu+Pb treatment at each pH condition.
(Supported by the leading project of the MEXT)
