Hi there, yes plastic is a huge problem in the sea. There are things called microplastics which sea animals can eat, which can kill them. Some of the larger plastics can also kill sea animals as well. But, there are some projects that are helping to clean the sea. One project is called Seabin and there are some sea bins in Ireland, there is 1 in Howth, 2 in Dun Laoghaire, 1 in Dingle and 1 in Bangor.