If the water contains 30,000 pCi/L of radon, how much of the indoor measurement may come from that water?

To determine how much of the indoor radon measurement may come from the water containing 30,000 pCi/L of radon, it's important to understand the typical mechanism by which radon in water contributes to indoor air concentrations.

Radon gas can be released from water during various household activities such as showering, washing dishes, or cooking, leading to potential exposure in the air. The contribution of radon from water to indoor air is generally modeled by using a specific transfer coefficient. This coefficient varies for different activities, but a commonly used figure indicates that approximately 0.1% of the radon concentration in water can become airborne.

In this case, if the water has a radon concentration of 30,000 pCi/L, applying the transfer coefficient of 0.1% results in the calculation of 30,000 pCi/L × 0.001 = 30 pCi/L. This value would be the theoretical maximum concentration of radon in the air that could derive from that specific concentration in the water.

Therefore, the correct choice reflects this standard approximation of radon transfer from water to indoor air, which highlights the importance of understanding the conversion between the two mediums in radon measurement and exposure considerations.