contaminadas

In a sentence

• Las aguas del río están contaminadas por la industria.

  The waters of the river are contaminated by the industry.

  Here, 'contaminadas' is used as an adjective referring to the state of the water being polluted by external factors.

• Algunas áreas urbanas están contaminadas debido a la falta de políticas adecuadas.

  Some urban areas are contaminated due to the lack of adequate policies.

  In this sentence, 'contaminadas' again functions as an adjective, describing areas affected by pollution or other degrading influences.

• Los alimentos contaminados pueden causar serias enfermedades.

  Contaminated food can cause serious illnesses.

  Here, 'contaminados' refers to the food that has been tainted or made unsafe, illustrating its usage to describe a condition of being impure or unhealthy.