Which characteristic makes hexavalent chromium a concern in wastewater treatment?

Hexavalent chromium is considered a significant concern in wastewater treatment primarily due to its toxicity to the environment. This form of chromium is known to cause various health problems, including respiratory issues, skin irritation, and is classified as a carcinogen. When released into the environment, hexavalent chromium poses risks not only to human health but also to aquatic life and ecosystems.

The ability of hexavalent chromium to persist in water systems and its potential to bioaccumulate in living organisms further exacerbate its harmful effects. In wastewater treatment processes, it is crucial to monitor and manage concentrations of hexavalent chromium to prevent environmental contamination and health risks.

While hexavalent chromium is indeed water-soluble, its natural occurrence in some geological formations and the fact that it is not easily biodegradable play less critical roles in understanding its major environmental concerns compared to its high toxicity. Thus, the primary focus in wastewater treatment is on its hazardous nature and the necessary precautions needed to mitigate its impact on health and the ecosystem.