What is the benefits of toxic link..?

Toxic back links are the non organic links, it's most harm the search engine rankings for your website so it will not give benefits.

Through active national campaigning and building public opinion, Toxics Link (TL) has been able to bring awareness on the environmental impact of such technologies, extended producer responsibility, the benefits of community-based waste management, as well as the impacts on traditional and informal sector recycling ...

Toxic Links is a technique of black hat SEO. It is very harmful to a website. So, I would suggest you to did not use this technique.