I think that you are confusing or intertwining a society that establishes government for the preservation of liberty and the concept of anarchy sir.
To use your example of pouring toxic chemicals down the drain, it is not an infringement of individual liberty for a community to prohibit such activity by law and prescribe consequences for breaking that law. In doing such a thing one would be causing harm to others via his or her actions and thereby infringing on the rights and liberty of others.
The exercise of liberty does not include the right to cause harm to others.
I am not confusing these, at all. Much of the unbridled liberty that you lament as leaving is simply going away due to our growth as a nation.. You can eat any amount you want if you live out in the wild west not surrounded by neighbors. Once the city grows up around you and you join an insurance pool (health ins.), your diet does adversely affect my premiums. Years ago you could shoot a gun in your backyard, but now it endangers my kids. But, you cry, no one should be able to limit your right to smoke, shoot, eat, drive, etc. Of course not... if only you are affected by that etc. But, the larger we get, the closer we get and more personal liberty will get constrained. So, the infringement that you see declining is partially by necessity, so that you don’t “...cause harm to others.”