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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Arsenic acid (AA) is an inorganic compound of arsenic (As). AA being an inorganic chemical, biodegradation is not applicable. However, biotransformation mediated by organisms influenced the environmental fate of As.


Modes of biotransformation involve redox transformation between arsenite and arsenate, reduction and methylation of As, biosynthesis of organoarsenic compounds. The biomethylation and bioreduction are considered the most important pathways. Such biotransformation of As species occurs in the soil, in sediments, in plants and animals, and in zones of biological activity in the oceans.

Under aerobic conditions, the mixed microbial cultures of lake sediments were able to reduce arsenate (the predominant from of As in water) to arsenite and a variety of methylated arsenicals, and also to oxidise arsenite to arsenate.

Under anaerobic conditions, however, only reduction occurs.