You should be pretty well practiced to also recognise that the impacts can be on the land, air water or health.

It is impossible to balance the dangers to land versus dangers to health.

However you are expected to recognise the differences and make a judgment that you can justify.

The significance could be at a;

• local,
• regional,
• national, or
• international level.

A smell like animal glue may be significant at a local level, but irrelevant internationally.

Yet something like carbon dioxide we thought harmless for years has now a significant impact on the global environment.

You have to determine which is significant.

They both may be!

Check ISO and significance of impact