1.   The chemical pollution poses a threat to the population at large.

2.   Pollution poses a threat to fish.

3.   It had previously been thought that pollution posed the greatest threat to inshore marine mammals.

4.   The Clinton administration said Wednesday that it would start focusing all environmental protection standards on the risks that pollution poses to the health of children.

5.   Topping the list of villains mentioned earlier, air pollution these days poses the menacing threat.