* Simple and direct: The prolonged exposure to the chemical had a deleterious effect on the environment.
* With emphasis on negative consequences: Smoking cigarettes has a deleterious impact on lung health, often leading to serious respiratory problems.
* In a more formal context: The study concluded that excessive screen time in children has a deleterious effect on their cognitive development.
* With a contrasting element: While the new policy aimed to improve efficiency, it had a deleterious impact on employee morale.
"Deleterious" is a strong word that emphasizes harmful or damaging effects. It's often used in formal writing or when discussing serious issues.