Reverse Osmosis studies
(Westchester County, NY, USA)
My reading indicates that on balance RO (I'm interested in under sink) systems have more detriments (e.g. too much mineral filtration) than advantages (filtration of Lead, VOCs,...)
Can you please share where in the US and in the world the bulk of your cited studies or the major reported studies (if not the same) were conducted?
In my research, most of the studies have been on demineralised water rather than RO water specifically. But, as you know, RO water is demineralised (as is distilled water) so the studies apply. The bulk of studies seem to be from Russia, Germany, Japan and the U.S.
The World Health Organization's report on Health Risks from Drinking Demineralised Water cites many of these studies.
Other studies are listed in this report Demineralization of Drinking Water: Is It Prudent? from the National Institutes of Health.
Even though R.O. does filter many contaminants, it does not filter everything. In addition, the types of contaminants you listed, such as lead, VOCs, etc. are also filtered by high-quality multi-stage filtration systems.
Depending on the type of filtration system people want—such as counter top, under sink, or whole house—there are many options. In general, counter top and under sink filtration systems have the highest degree of filtration (as opposed to faucet mounted or whole house).
Just as an example, the Crystal Quest drinking water filtration multi-stage media are certified to NSF/ANSI 42 and 53 for the reduction of chlorine, chloramine, lead, cysts, mercury and VOCs. They filter over 60 known contaminants and are used in both their counter top and under sink systems.
Further reading . . .
Undersink Water Filters - Reviews and Recommendations