LEWISTON — As third-graders in Marc Lavoie’s classroom wrote papers Friday about waste and the environment, the teacher asked how long it takes for a plastic bottle to decompose in a lake, the ocean or the Androscoggin River.

“Three hundred thousand years!” the Montello Elementary School students answered in unison.

“How long for Styrofoam?”

“Forever!” the students shouted.

The teacher began a sentence that his students finished: “Way back in 1997 …” he said.

“ … Mr. Lavoie was very, very bad!” they said, all smiles.

The students were reacting to a recent environmental lesson and to the plastic bottle containing a message that Lavoie tossed in the river in 1997. The bottle and message were recently retrieved in Topsham.

Some history.

In October 1997, Lavoie took his third-graders on a field trip near Bates Mill to learn about the community. “We decided to throw in one bottle to see how far the bottle would go,” Lavoie said.

Inside the bottle was a message:

“To whoever finds this bottle. Hi, we are third graders of Montello School in Lewiston, Maine. We are on a field trip crossing the Grand Trunk walking bridge over the Androscoggin River. We would really like it if you could write back to us. Could you tell us about yourself? Could you also tell us where and when you found our bottle? Thank you, Mr. Lavoie’s third grade students.”

Lavoie assumed the bottle would be found within a few weeks.

Wendell Cressey found it last month, while looking for fiddleheads.

“I could see the clear bottle in the bushes with tape around the top,” Cressey said Friday. “The message was a bit tough to force out of the bottle. It had been laminated and broke apart.”

Last week, Cressey returned the bottle and delivered his own letter to the school. He told them the date he found the bottle, that he lives in Freeport, is 25 years old and owns a wholesale floral supply company, which was why he was out looking for fiddleheads.

He returned the bottle because he wanted kids to know people care about them, he said. “And I think it’s pretty neat.”

Lavoie’s current third-graders recently went on a field trip to Thorncrag Nature Sanctuary. Nature educator Susan Hayward taught students how long it takes for waste to break down in the environment.

When Lavoie told his class about the message in the bottle, they recalled what Hayward had told them about how harmful litter is to the environment. “They called me on it,” Lavoie said.

Third-grader Chris Newton, 9, said his cousin, Michael Smart, was one of the 1997 third-graders in Lavoie’s class. “I asked him, ‘What did you do in 1997?’ He said, ‘I don’t remember.’”

Newton told his cousin how the bottle had been found and returned. Then his cousin remembered.

Holding the old juice bottle in his hand, Newton said the story “is pretty cool.” It demonstrates how plastic doesn’t break down, he said, adding that he has learned: “Don’t litter, because it ruins our environment.”

Jacob Caldwell, who turns 9 today, said that when Lavoie told the class about the message in a bottle being found, it sounded like something out of a movie, “like how pirates throw the bottle into the ocean.” He was surprised how sturdy the bottle was after 12-plus years. The lesson is, he said, “not to litter and don’t throw stuff into the ocean (or river), unless it’s an emergency.”

Savannah Jones, 9, said it was “amazing” that someone found the bottle “that’s been traveling all these years.” In her home, her father takes their bottles to a bottle place where they are recycled, she said.

As for Lavoie being “very, very bad” as his students teased Friday, the message in the bottle dropped in the river did have an environmental message.

It stated: “P.S., please recycle the bottle.”

bwashuk@sunjournal.com