I'm taking part in the Marine Conservation Society's Plastic Challenge by running the Exeter Marathon. Plastic bags, cutlery and food wrappers have a lifespan of just minutes but often end up in our rivers and seas. Every year 11 million tonnes of plastic are dumped in the worlds oceans, causing devastating harm to wildlife, polluting our water with chemicals and breaking down into microplastics that enter into our food chain.We all have a part to play in cutting back on single-use plastic and changing our throwaway culture. When you refuse to reuse, it's the ocean you abuse.