Revelation 8:10 And the third angel sounded, and there fell a great star from heaven, burning as it were a lamp, and it fell upon the third part of the rivers, …and upon the fountains of waters;
11 And the name of the star is called Wormwood: and the third part of the waters became wormwood; and many men died of the waters, because they were made bitter.
Now the third trumpet is thought to be another meteor or an enormous nuclear explosion falling on the fresh water supply turning it poisonous causing a plague to strike and kill all who drink the water. It is believed to be a nuclear explosion because of the one at the Chernobyl nuclear plant in Russia. The word Chernobyl means Wormwood and that is what the water turns to. Remember there is still time for people to be save but because of the destruction taking place people are turning from God instead of to Him.