This subject is of special interest to me, as my most likely scenario is urban and involves, at most, a small GHB. In the past, I've relied on The Survival Straw. From the scant literature and comments on various sites, that seemed most versatile re bacteria, viruses and chemicals. But, I was never entirely sanguine with my choice. The claims were big and the evidence small. More recently, I've switched to the Seychelles Advanced Water Straw. Better literature and smaller claims on capacity. If the situation allows, I also use a Katadyn bottle filter with the virus cartridge or the Seychelles advanced Water bottle Filter. . I think the Berkey sports bottle is in the same category. With the Seychelles bottle and the Berkey bottle, you can use the filters separately with a bit of tubing. On all three bottles, you can also use the bottle alone and keep the filter in a ziplock in your kit. Sadly, I have little practical experience with the units and I'm not a scientist. In any event, I hope this helps or at least points you in the right direction. Please share NY new data you may find.