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Description of key information

Phototransformation in soil follows similar degradation processes as in water.

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Additional information

The publication on photocatalytic degradation of Indigo [Vautier et al. (2001)] cited under phototransformation in water also covers respective reactions of solid Indigo.

The following degradation products of solid Indigo were identified.

Table21. Degradation products of solid Indigo

No.

Identity

1.              

Oxalic acid

2.              

2-Nitrobenzoic acid

3.              

Nitrobenzene

4.              

Malic acid

5.              

Fumaric acid

6.              

Dihydroxyfumaric acid

7.              

Glycolic acid

8.              

Acetic acid

Degradation of matrix bound Indigo was investigated by Sousa et al. (2008) and Poulin (2007) (see IUCLID 5.2.4). As main photo-induced degradation products of Indigo, isatin, anthranilic acid and isatoic acid anhydride were identified. It was found that this degradation process takes also place in the dark albeit at a slower rate.

From these results it can be estimated that phototransformation in soil will follow similar degradation processes as in water.