Ashleigh, 16, was also concerned about the impact of microbeads from face washes on the world's oceans, and runoff from farms into New Zealand's waterways.
"With all the farming in New Zealand, it's something I think will get worse."
The Te Puke High School student said she was looking forward to meeting new people who were also interested in the environment.
There were 60 students selected for the forum from New Zealand and the Pacific Islands.
It will be fully funded, and run by the trust with assistance from the Ministry for the Environment.
The week will include a range of activities including a visit to the Goat Island marine reserve and two days with the Navy learning about leadership and teamwork.
The students would also learn about iwi sustainability initiatives and the effect of microplastics on the environment.
"It's amazing to see how they develop in one week and this is just the beginning of their journey with us," said Shelley Campbell, chief executive of the Sir Peter Blake Trust.
"They arrive with a passion for the environment and leave with skills, knowledge and confidence."
Ashleigh said she was interested in protecting the environment after the Rena disaster when she was in primary school.
"When I was younger, we did some stuff to help with the Rena oil spill."
She applied for the forum after a teacher suggested it, but did not think she would be accepted.
Alana McConkey, a Year 12 student at Trident High School in Whakatane, has taken part in a number of conservation projects including native bird surveys.
Alana said she was looking forward to meeting new people at the forum and developing her leadership skills.
Bradley Wiggins, a Year 12 student at Rotorua Boys' High School, said one of his major concerns was the effects of microplastics on the ocean environment.
The forum will run from April 18-24.
