Arsenic compounds found in edible algae can vary in their stability depending on the specific compound and the environmental conditions. In general, arsenic in algae is present in different chemical forms, including inorganic arsenic (iAs), such as arsenite (As(III)) and arsenate (As(V)), and organic arsenic (oAs), such as arsenosugars and arsenolipids.

Inorganic arsenic compounds, such as As(III) and As(V), are generally more stable than organic arsenic compounds. Arsenite (As(III)) is more toxic and less stable than arsenate (As(V)). In the presence of oxygen, As(III) can be easily oxidized to As(V). Arsenate (As(V)) is more stable and can form strong bonds with other elements, making it less mobile and less likely to be taken up by organisms.

Organic arsenic compounds, such as arsenosugars and arsenolipids, are less stable than inorganic arsenic compounds and can be more easily degraded by microorganisms and environmental processes. Arsenosugars and arsenolipids can undergo various transformations in the environment, such as methylation and demethylation, which can affect their stability and toxicity.

The stability of arsenic compounds in edible algae can also be influenced by environmental factors such as pH, temperature, light, and the presence of other ions or compounds. For example, the stability of arsenite (As(III)) decreases with increasing pH, while the stability of arsenate (As(V)) increases. The presence of other ions, such as iron and phosphate, can also affect the stability and mobility of arsenic in algae.

Overall, while inorganic arsenic compounds in algae are generally more stable than organic arsenic compounds, the stability of both forms can be influenced by various environmental factors. Therefore, it is important to consider the specific conditions and environmental factors when assessing the stability and potential risks associated with arsenic compounds in edible algae.