Plant Growth Is Found to Be Particularly Vigorous in a Rural

Multiple Choice

Plant growth is found to be particularly vigorous in a rural area of Australia, until the opening of a bauxite mine for Al production. After the opening of the mine, the growth rate of plants declines in a manner proportional to the plants' proximity to the mine. Rainfall is good, the soil is neutral and there is no change in pathogen levels or soil nutrient content. Why might plant growth be limited around the mine?

A) The mine is leeching nutrients from the surrounding soil via its tailings dam.
B) Mine construction has disturbed a reservoir of previously bound toxins in the soil.
C) The activities of the mine have increased Al³⁺ levels in the soil, which is toxic to root growth and development.
D) Dust and run-off from the mine has increased the Al content of surrounding soils. The Al has bound to phosphorous causing it to become immobile and unavailable to plants.
E) Dust and run-off from the mine has increased the Al content of surrounding soils. The Al has bound to nitrogen causing it to become immobile and unavailable to plants.