Probably the molecule does break up with a certain half life, either due to sun, or other animals metabolising it, etc. Then that 2.2 kg brick needs to be replaced once every two half-lives.
Also 1 ppq is the lower bound. I think 1 ppt is quite reasonable for many methods though, so that can multiply the limit by 1000x.
All the factors above can increase the threshold amount of opoids, but here are some factors that can decrease it substantially:
There are people who dump unused drugs in, so that needs no attenuation factor.
Also, mussels are filter feeders, and oxycodone might accumulate in them substantially more (like 1000x+) than the background.
Finally, where they collected the mussels is probably correlated with sewage drains due to ease of human access, so the effective "volume of distribution" can be way less than the 110 km^3.
All that is to say, the real statistics are in the overdose calls for opoids. The headline is still an interesting cocktail-party line, but probably should be taken as a statement just by itself.
Probably the molecule does break up with a certain half life, either due to sun, or other animals metabolising it, etc. Then that 2.2 kg brick needs to be replaced once every two half-lives.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2991390/ Gives really hand-wavy half-life of many drugs in the environment as about 500 days, so the brick needs to be replaced every 1000 days.
Also 1 ppq is the lower bound. I think 1 ppt is quite reasonable for many methods though, so that can multiply the limit by 1000x.
All the factors above can increase the threshold amount of opoids, but here are some factors that can decrease it substantially:
There are people who dump unused drugs in, so that needs no attenuation factor.
Also, mussels are filter feeders, and oxycodone might accumulate in them substantially more (like 1000x+) than the background.
Finally, where they collected the mussels is probably correlated with sewage drains due to ease of human access, so the effective "volume of distribution" can be way less than the 110 km^3.
All that is to say, the real statistics are in the overdose calls for opoids. The headline is still an interesting cocktail-party line, but probably should be taken as a statement just by itself.