Aerobic photodegradation of X(N) chelates of (ethylenedinitrilo)tetraacetic acid (EDTA): implications for natural waters.

The behavior of several metal chelates [X(N)] of 1-14C-(ethylenedinitrilo) tetraacetic acid [EDTA] under irradiation from a wide spectrum Xenon arc lamp has been studied. In static tests at pH 4.5, chelates of Mn(II), Fe(II) and Co(II) photodegraded to give 14CO2 and CH2O. Chelates of Na(I), Mg(II), Ca(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) did not exhibit any significant photodegradation as measured by 14CO2 evolution. It is concluded that the photodegradation of Fe(III)-EDTA by sunlight will prevent EDTA build up in natural waters.