To check this idea, we kept a close eye on groundwater levels and water quality for a long time at three nearby wells. What we found was interesting: each well reacted differently to changes. Well T1, where nitrate levels were between 12 and 26 mg N/L, showed a really quick, distinct response to heavy rain. This suggests the ground around T1 is super permeable, letting rainwater quickly reach the aquifer.

But wells T2 and T3, which were only 0.6 and 1.9 km from T1, had much lower nitrate concentrations, from 4.5 to 8.0 mg N/L. They also responded slowly to heavy rain. This tells us that the highly permeable ground near well T1 is probably why it had more serious nitrate contamination than T2 and T3.

This study really shows why it’s so important to monitor groundwater levels and quality carefully, over time, especially when it rains. It helps us understand exactly what’s going on with nitrate contamination. (C) 2018 Elsevier B.V. All rights reserved.