Runoff from mines often contains a high concentration of dissolved chemicals such as cadmium, mercury, arsenic and lead that can reach local streams. These streams then drain into larger bodies of water such as seas and lakes. The dissolved chemicals can damage the environment and degrade the water quality as well as remain locked up in bottom sediments for many years.

Question

How could a scientist best monitor a stream near a new mine to determine if there are negative impacts to the local ecosystem?
A.
The scientist could test the amount of water in the stream monthly.
B.
The scientist could test the oxygen level of the water monthly.
C.
The scientist could test the salt content of the water monthly.
D.
The scientist could test the water for heavy metals monthly.

Answer 1

D. The scientist could test the water for heavy metals monthly.

Testing for heavy metals would be the most appropriate way to monitor a stream near a new mine for potential negative impacts on the local ecosystem. This option directly addresses the concern of runoff from mines containing harmful dissolved chemicals such as cadmium, mercury, arsenic, and lead, which can have significant adverse effects on both the water quality and the ecosystem. While the other tests may provide useful information about the water quality, they do not specifically target the contaminants of concern associated with mining activities.