Good question. It's about unknown unknowns, right? But we could map out where those may be. I guess chemical toxicity, drugs with long half-lives that affect

Good question. It's about unknown unknowns, right? But we could map out where those may be. I guess chemical toxicity, drugs with long half-lives that affect soil organisms, and antibiotics that promote resistance. (yeah yeah they are all chemicals.) For the chemical toxicity, it's chemicals that are harmful to plants but allowed for human consumption, or chemicals in sufficient quantity to disrupt soil balance. Doesn't seem like a real concern? With metabolic disruption to soil organisms, yes, there may be real danger there. That smells like previous environmental mistakes. Antibiotics, yeah, some danger. Livestock is exposed, and resistance-conferring genes might jump directly to human pathogens. It's worth studying. There are requirements for both sewage processing and fertilising soil, so the value of a solution would be high.