A groundwater researcher is analyzing contamination levels in two urban wells. Well A shows contamination levels of 85 ppm (parts per million) and Well B shows 115 ppm. If she dilutes samples from Well B by mixing a 5-liter sample with a total volume of 20 liters, what will be the new contamination level in ppm?

Sun, 03 May 2026 04:48:25 +0000

**A groundwater researcher is analyzing contamination levels in two urban wells. Well A shows contamination levels of 85 ppm (parts per million) and Well B shows 115 ppm. If she dilutes samples from Well B by mixing a 5-liter sample with a total volume of 20 liters, what will be the new contamination level in ppm?** Growing interest in urban water safety across the United States is spotlighting how groundwater quality impacts public health and infrastructure trust. Researchers are increasingly assessing contamination trends in densely populated areas, where aging systems meet modern challenges like industrial runoff and climate stress. At the center of this conversation is a clear chemical metric—parts per million—used to evaluate environmental risk and guide policy decisions. Well A currently registers at 85 ppm, while Well B registers higher at 115 ppm. When a researcher dilutes a 5-liter sample from Well B with a total volume up to 20 liters, the goal is to reduce concentration to assess baseline exposure or track pollution shifts. Dilution works on a simple dilution principle: the concentration decreases proportionally based on the ratio of sample volume to total volume. **H3: How dilution affects contamination levels – the science behind the numbers**
Diluting Well B’s sample involves mixing 5 liters of contaminated groundwater with 15 liters of clean water. The total volume becomes 20 liters, so the original 5 liters represents 25% of the final volume. The contamination from Well B’s original 115 ppm now spreads across 20 liters, reducing the concentration to 1/4 of its initial level. This means the new level is precisely one-quarter of 115 ppm.