I have read the NORML MAPS study and it appears to be the only study to have been done on the efficiency of various smoking devices. As such, I would not be wanting to claim that the results of that one study are the gospel truth. It is very possible that the study was flawed in some way and produced questionable results and conclusions. In any case, it is never wise to use results from only one experiment to formulate solid theories. As it stands right now there has not been close to enough research performed to conclusively determine what smoking device is the safest or most efficient nor to rank them in any meaningful order (the study itself admits as much). Argue as much as you want, but I think no one will truly know the answer until research is carried out on a broader scale and the results can be analyzed and interpreted in a much more significant manner. The NORML MAPS study itself says that more work must be done and they only tested for (1) solid particulates, and (2) THC, CBN, CBD, when a lot more chemicals do exist in smoke. What is needed is a full analysis done with a chromatograph used to analyze the smoke so that its full composition can be known.

quoting from the study ...

"Nonetheless, it is still premature to judge that waterpipes are actually unhealthful, since they may filter out other, non-solid smoke toxins occurring in the gas phase of the smoke, which was not analyzed in the study. Noxious gases known to occur in marijuana smoke include hydrogen cyanide, which incapacitates the lung's defensive cilia; volatile phenols, which contribute to the harshness of the taste; aldehydes, which promote cancer; and carbon monoxide, a known risk factor in heart disease. Previous studies indicate that water filtration may be quite effective in absorbing some of these [Nicholas Cozzi, Effects of Water Filtration on Marijuana Smoke: A Literature Review, MAPS Newsletter, Vol. IV #2, 1993]. If so, waterpipes might still turn out to have net health benefits."


So let's hope they make it easier for anyone wanting to experiment with marijuana so we can get some hard definitive truths ...


One last thing ... the reason that bong water does contain THC is because the THC itself becomes attached to water soluble tars and solids which do get filtered out by the bong water. THC in its pure form is not water soluble, but when it exists as part of a marjuana plant and is smoked it exhibits some water solubility due to its adherence to the tars.