The lake is formed by the flow of the Desaguadero River at its mouth into Lake Poopó, over the extensive sedimentation known as "Santo Tomás" from the small hermitage found there that was completely inundated.

This was described by local media and experts as an environmental catastrophe caused by several factors, including climate change and the use of water for mining.

[2] In 2021, a large part of the lake is covered by trash.

Much of it is plastic from nearby Oruro where residents dump their refuse.

The lake is polluted by heavy metals such as cadmium, zinc, and arsenic.