During its parade, one of Portela's floats depicted the destruction of the River Doce in 2015 and the dam was used to hold waste at an iron ore mine near the city of Mariana.
Portela is Rio's most successful samba school but it had not won the world-famous parade for 33 years.
A panel of judges gave it top marks in most categories, including costumes, rhythm and the quality of the samba song composed for this year's carnival.
Every February, Brazil hosts one of the biggest, and most colorful parties in the world.
Thousands of people gathered together on the streets in cities of Brazil to participate in Carnival — a five-day celebration leading up to Lent.
(Pics : Metro.us / Los Angeles Times / Daily Mail)