Carson’s basic premise—that man-made activities were destroying the environment—was correct. Thanks to Rachel Carson, we are now far more attentive to our impact on the planet. Unfortunately, Carson also gave birth to the notion of zero tolerance—the assumption that any substance found harmful at any concentration or dosage should be banned absolutely. If large quantities of DDT (like those used in agriculture) were potentially harmful, then even small quantities (like those used to prevent mosquitoes from biting) should be avoided.
You're ignoring established science regarding the buildup of toxic chemicals in the environment and thise animals higher up the food chain, called biomagnification. For example, it is widely advised that people - especially pregnant women and children - not eat too much of certain fish, such as swordfish. Why? Because swordfish are apex predators that prey on smaller fish, many of whom are contaminated with anthropogenic environmental mercury. Due to health concerns, it's recommended that people eat medium sized fish (such as tuna) only a couple times a week and large fish (such as swordfish). Just because something is a small dose when you're initially using it doesn't mean it will stay small and not dangerous, it doesn't mean that it will not accumulate and become harmful.
