An environmental scientist investigated the impact of an active copper mine on the surrounding terrestrial ecosystem. They measured the concentration of soluble copper ions in soil samples at five different distances from the boundary of the mine tailings.
Table 1
| Distance from boundary (m) | Copper ion concentration (mg/kg) |
|---|---|
| 15 | 680 |
| 50 | 340 |
| 100 | 115 |
| 250 | 42 |
| 500 | 8 |
Describe the trend in copper ion concentration as the distance from the boundary of the mine tailings increases from 15 m to 500 m.
