my.marijuana.com/pipestudy.php3
Marijuana Water Pipe and Vaporizer Study Dale Gieringer, PhD Contrary to popular impression, waterpipes don't necessarily protect smok ers from harmful tars in marijuana smoke, according to a new study spons ored by MAPS and California NORML (National Organization for the Reform of Marijuana Laws). The reason is that waterpipes filter out more psycho active THC than they do other tars, thereby requiring users to smoke mor e to reach their desired effect. The study does not rule out the possibi lity that waterpipes could have other benefits, such as filtering out ga ses, but it suggests that other methods, such as the use of high potency marijuana, vaporizers, or oral ingestion are needed to avoid harmful to xins in marijuana smoke. Seven Devices Tested The study, which was supported by the Drug Policy Foundation and private donors, was conducted at a research lab with expertise in the analysis o f various chemical properties of tobacco and marijuana. Researchers test ed the smoke from seven different sources: a regular rolled joint, a joi nt with a cigarette filter, three different waterpipes, and two vaporize rs, designed to heat marijuana to a temperature where psychoactive vapor s form without producing smoke. The waterpipes included a standard bong (Picture #1), a small portable device with a folding pipestem (Picture # 6), and a battery-operated model with a motorized paddle to thoroughly m ix the smoke in the water (Picture #3). The first vaporizer (Picture #5) , commercially produced in Canada, consisted of a battery-powered metal hot plate inside a jar to trap the marijuana vapor. The second (Picture #4) was a homemade, hybrid apparatus, in which vapors were produced by a hot air gun and then drawn through a beaker of water, thereby combining vaporization with water filtration. The smoke was produced from standar d NIDA-supplied marijuana drawn through a smoking machine adjusted to mi mic the puff length of marijuana smokers. Focus: Cannabinoid/Tar Ratio The study focused on two key components of the smoke: total solid par ticulates, or tars, which are noxious waste by-products of burning leaf like those from tobacco; and cannabinoids, the chemicals distinctive to marijuana, including its major psychoactive ingredient, delta-9-tetr ahydrocannabinol (THC), and its two commonest chemical relatives, cannab inol (CBN) and cannabidiol (CBD), which are only weakly psychoactive but may have medical benefits. Like tobacco, marijuana tars are rich in carcinogenic compounds known as polycyclic aromatic hydrocarbons, which are a prime culprit in smoking-r elated cancers. A n obvious way to protect smokers' health is therefore to minimize the co ntent of smoke tars relative to cannabinoids. One way to do this is to increase the THC potency of the marijuana. Assum ing smokers adjust their smoke intake to the cannabinoid dosage, the hig her the concentration of cannabinoids, the lower the amount of tars they are likely to consume. Another strategy is to try to reduce the tars in the smoke with some kind of filtering device. Obviously, this is beneficial only to the extent t hat THC isn't also reduced, thereby inducing users to smoke more to comp ensate. A major aim of the study was to determine the efficacy of variou s smoking devices at reducing the concentration of tars relative to cann abinoids. The performance of each device was accordingly rated in terms of the cannabinoid-to-tar ratio in its smokestream. Joints and Waterpipes Surprisingly, the unfiltered joint outperformed all devices except the va porizers, with a ratio of about 1 part cannabinoids to 13 parts tar. Thi s disturbingly poor ratio may be explained by the low potency of the NID A-supplied marijuana used in the study, which was around 23%. Disappointingly, waterpipes performed uniformly worse than the unfiltered joint. The least bad waterpipe, the bong, produced 30% more tar per can nabinoids than the unfiltered joint. Ironically, the pipe with the elect ric mixer scored by far the worst of any device. This suggests that wate r filtration is actually counterproductive, apparently because water ten ds to absorb THC more readily than noxious tars. Like the waterpipes, th e cigarette filter also performed worse than the unfiltered joint, by ab out 30%. Researchers speculate this is because cannabinoids are exceptio nally sticky and adhere to other solids. Hence, any filtration system th at picks up particulates is likely also to screen out cannabinoids. Vaporizers The vaporizer results appeared more promising, but confusing. The two vap orizers were the only devices to outscore unfiltered joints in terms of raw cannabinoid/tar ratio. The electric hotplate vaporizer did best, wit h a performance ratio about 25% higher than the unfiltered joint. The ho t air gun was just marginally superior, but might have done better had i t not been for its water filtration component. However, the situation was complicated by the fact that the cannabinoids produced by the electric hotplate vaporizer were unusually high in CBN, leaving 30% less THC as a percentage of the total cannabinoids than with the other smoking devices. Since CBN is not psychoactive like THC, recr eational users might be expected to consume more smoke to make up for th e deficit. For this reason, it seem ed advisable to recompute the performance efficiencies of the vaporizers in terms of THC, rather than all cannabinoids. When this was done, the electric hotplate vaporizer turned out to have a lower THC/tar ratio tha n the unfiltered joint, while the hot air gun was still marginally highe r The reason for the excess CBN from the hotplate vaporizer remains unexpla ined. Because CBN is produced from THC by chemical oxidation, it has bee n suggested that the device somehow exposed the sample to too much oxyge n However, there is no evidence that this was the case. As for the seco nd, hybrid vaporizer, it seems likely that its performance could have be en improved by deleting its water component. The results clearly indicat e that more developmental work needs to be done on vaporizers. Theoretic ally, an ideal vaporizer could minimize production of tars by holding th e temperature just above 155 C, the point at which THC vaporizes, which is well below the temperature where carcinogenic hydrocarbons are though t to be produced. In practice, both vaporizers produced over ten times m ore tars than cannabinoids, indicating that there is plenty of room for improvement. In the late 1970s, a vaporizer known as the Tilt appeared on the market. According to the manufacturer, laboratory tests showed that it released 80% more THC and 79% less tar than a regular pipe, a performance ratio a lmost ten times better than any observed in this study. It is to be hope d that these impressive results can be replicated in the future. Unfortu nately, the Tilt was withdrawn from the market in the early 1980s due to the passage of anti-paraphernalia laws. As for waterpipes, the prospects for improvement appear more dubious. It has been suggested that the performance of waterpipes could be improved by using liquids other than water or by changing the temperature of the liquid. However, it seems doubtful whether such tactics would circumvent the basic problem of separating the tars from the sticky cannabinoids. The study results are obviously discomforting to waterpipe enthusiasts, m any of whom prefer the cooler, milder smoke they produce, and have natur ally assumed it is also more healthful. Unfortunately, however, the stud y indicates that waterpipes may actually be counterproductive in increas ing consumption of carcinogenic tars. Nonetheless, it is still premature to judge that waterpipes are actually unhealthful, since they may filter out other, non-solid smoke toxins occ urring in the gas phase of the smoke, which was not analyzed in the stud y Noxious gases known to occur in marijuana smoke include hydrogen cyan ide, which incapacitates the lung's defensive cilia; volatile phenols, w hich contribute to the harshness of the taste; and carbon monoxide, a known risk factor in heart disease. Previ ous studies indicate that water filtration may...
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