Now that I have a few minutes… Although I appreciate your interest (and attempt to engage on my level), your argument, quite frankly, falls short. Setting aside, for just a moment, the fact that SODIS (Solar Water Disinfection) has been around since at least the mid-eighties (I believe), and that the CDC, the NCBI, the WHO and other international organizations are all very well aware of the use of PET (polyethylene terephthalate) plastic bottles for SODIS use, and of course the BILLIONS of people all over the world who have benefited from precisely that, “Mooniac” has an opposing opinion, shall we?

Firstly, while you are very emphatic about “… no association with milk implied…”, you’re also very nonspecific, but presuming you’re talking about the figure at the top of the page you cited (at https://tinyurl.com/rg8zwwp), I can only guess you didn’t actually READ the very article you cited starting with the title, which is, “Protective Influence of Several Packaging Materials on Light Oxidation of Milk”, 2005, from the Journal of DAIRY Science (which you would have easily found if only you had clicked the “view publication” button. HELPFUL HINT: You may want research that is on point to support your arguments!

Alternatively, you may want to re-start your research with a ‘quick’ look at an article called “Solar Disinfection of Viruses in Polyethylene Terephthalate Bottles”, 2015, from a journal called Applied and Environmental Microbiology (at https://aem.asm.org/content/82/1/279#sec-2), which I found with just a quick check. An even MORE on point article called “A Pilot Study of Solar Water Disinfection in the Wilderness Setting”, 2014, from a journal called Wilderness & Environmental Medicine (at https://www.wemjournal.org/article/S1080-6032(14)00076-3/pdf) may also be of interest, if your interest is sincere.

On the other hand, you may simply want to read (or RE-read) my earlier post on SODIS in which I wrote, “Pathogenic microorganisms are vulnerable to two effects of sunlight: radiation in the spectrum of UV-A light (wavelength 320-400nm) and heat (increased water temperature). A synergy of these two effects occurs, as their combined effect is much greater than the sum of the single effects. This means the mortality of the microorganisms increases when they are exposed to both temperature and UV-A light at the same time.”

You apparently disagreed stating, “… PET strongly absorbs light below 300nm…”, clearly this is a NON-issue since, as I stated, UV-A has a wavelength of 320-400nm! (not that you mentioned which TYPE of UV light you were referring to, perhaps UV-B?) I will say this, the ability of SODIS to kill viruses is less certain than bacteria, but that’s nothing new if you read my initial post since I made it clear viruses are harder to kill than bacteria. On the other hand, HERE, in North America (specifically the U.S. as in other first-world countries), we don’t really have viral issues with our water. In fact, and to restate, our backcountry “wild water” is actually fairly clean! Sure, there is the POSSIBILITY of giardia or crypto’, but except for relatively few people, they present essentially non-issues making SODIS a very valid and viable solution as an emergency water treatment option, particularly in emergency/survival situations. Questions?