How are test results for radon in water expressed?

Test results for radon in water are expressed in picocuries of radon per liter of water (pCi/L). This unit is widely recognized and used in measuring radioactivity, particularly for radon, which is a radioactive gas. Picocuries represent a very small amount of radioactive decay, making them suitable for the low concentrations typically found in drinking water.

Using this unit allows for clear communication of radon levels in a way that aligns with health and safety standards. Regulatory agencies, such as the Environmental Protection Agency (EPA), utilize this unit to set guidelines and recommendations regarding radon in water, which underscores its significance in environmental health assessments.

Other units such as grams per liter, micromoles per liter, and parts per million, while useful in different contexts, are not appropriate for expressing radon concentration because they do not account for the radioactive nature of radon and the specific measurements that reflect its hazards in the context of water safety.