There are plenty of chemicals that don't degrade or degrade extremely slowly (e.g., PCBs, radioactive chemicals), and which can influence a species or ecosystem

There are plenty of chemicals that don't degrade or degrade extremely slowly (e.g., PCBs, radioactive chemicals), and which can influence a species or ecosystem over many generations. Introducing genes definitely pose risks, but I they aren't fundamentally different from any other dangerous chemicals. We have tools and frameworks to evaluate this risk.