And does that matter? Is there a measurable impact on the environment? Not just detecting it as present; that seems certain. But then what? Does it have an affect?
Plastic is organic. As it breaks down, it does so in an endless variety of organic molecules. These being similar to biological molecules, they readily interact with all sorts of biological systems. Those systems have all seen a few billion years of optimisation, making it unlikely for any random interference to be beneficial.