KB - There is a common misconception that for the most part all marijuana smells the same, but those of us who actually smoke can tell the differences between strains. There are some similarities of course, yet there is definitely a distinction between them.
Dr. Whitehurst - As a scientist I am aware of how often the "common sense" of people who have a great deal of personal knowledge about something is so often dismissed by scientists as unfounded. If scientists have not studied something then at times they have a tendency to dismiss folk knowledge. One of the issues that fits this is the odor of marijuana.
I have had the occasion to smell what was presented to me as marijuana on quite a number of occasions, first as a law enforcement officer and then as an analytical chemist. I can not say that marijuana has a particular singular odor. I know that law enforcement officers "smell" marijuana but what is the basis for that? Folks who have grown and/or possessed marijuana may also believe that marijuana (whatever that means) has a particular odor. As a chemist I ask for the foundation of that belief.
I browse the marijuana sales sites on the net and see that the product is sold based upon its appearance, effect and odor. So different varieties must have different odors. Is that sales talk or is that real knowledge among people who deal with marijuana every day.
When I talk with Mahmud El-Sohly, who raises marijuana for the government, he tells me that the odor is characteristic. What does that mean? What are we detecting? He has daily access to the plants that he is raising. But of what variety are those? Has he actually conducted experiments in detection of volatile organic compounds from cannabis sativa of different varieties? What are the compounds that we are detecting and how does our olfactory sense function to detect those odors. Are these questions answered by scientific research?
The law enforcement officer who "smells" marijuana can never be examined because there is nothing in the way of evidence for him to bring forward except his demand that he be believed, his badge, his gun, his uniform and his given authority. He escapes the protections built into our Constitution by simply declaring himself to be correct and giving defendants in courts of law nothing to review. That may be fine for folks who just want to be left alone (unless they are themselves charged with crime) but it does not answer the scientific question of whether that officer can in fact smell marijuana and identify the smell of marijuana to the exclusion of all other smells.
To go further with this question one might refer to the journal article Topics in Heterocyclic Chemistry, 2007 10: 1-42 in which we find that there are 120 terpenoid type compounds which give rise to the odor of marijuana.
Imagine these then in a graph depicting on the "x" axis the compounds 1 through 120 and on the "y" axis the amount of material present. The envelope formed by a line drawn through the xy coordinates then might be considered as the odor envelope formed by an examination of the quantitative amount of each compound that is present in one particular variety of marijuana and possibly in one plant of marijuana. Do we know that that envelope does not dramatically change with environmental impact? We do know that the THC content changes dramatically with weather, soil, and light conditions. So what about the odor compounds? Has anyone actually conducted that research? I have not seen it. If it does not exist and the folks who know (the individuals who come into contact with marijuana on a daily basis) believe that the marijuana varieties have different odors then who can deny that knowledge?
We might resort to personal attack, calling these users and producers childish names or casting doubt about their genetic lineage, however that does not answer the question posed. We might ask whether we can trust a man in a uniform with a badge, a gun and a law enforcement demeanor over trusting an individual who smokes marijuana daily, raises the plants and is among them on a regular basis, wearing blue jeans, a T-shirt, long hair and having a cannabis demeanor (whatever that is)? Though distracting the answers to that question do not tell us whether marijuana actually has different odors.
The difficulty with raising any of these questions is that marijuana is illegal and we can not conduct experiments and report our results without exposing ourselves to incarceration. We can not provide our knowledge to courts of law without providing the pedigree for that knowledge and therefore risking incarceration. The government refuses to allow us to determine the truth here, whatever that truth is. So we can not control the variables; we can not conduct experiments; we can not determine the truth; we can not present a defense in court. (So much for drug use being a victimless crime). And do we have law enforcement officers who are not scientists making "scientific" statements in courts of law and denying citizens the right to defend themselves by making the material they have been accused of having inaccessible for scientific review and study.
This caused the family a lot of grief having to be subjugated to intense scrutiny, and embarrassment for the drug task force which was unable to determine the difference in odor perception between a marijuana plant and a skunk.
Since not all varieties of marijuana do not smell the same, how does a scientist use marijuana odor perception to address that issue?
Dr. Whitehurst - The only studies that address this issue have been conducted by Dr. Richard Doty. His paper is available on the web and can be found by simply Googling his name. He directs the paper toward the smell detection of marijuana basis for probable cause to search and or arrest.
KB - Considering that law enforcement consistently uses marijuana odor perception techniques to determine if someone is possessing cannabis, such as sticking their face up to a cars window to smell inside a vehicle, should this technique be scrutinized when it comes to determining probable cause to search a persons vehicle, or home?
Dr. Whitehurst - Again, Dr. Richard Doty's paper will surprise you. Be sure to access it on the web.
KB - I found the link to Dr. Richard Doty's report "Law and Human Behavior, Vol. 28, No. 2, April 2004"
Dr. Richard Doty "Marijuana Odor Study"
KB - So now lets say the police think they smell marijuana, so they call in the drug sniffing dogs to validate their suspicions. Since they already believe the person has marijuana, due to their own sense of smell, and possible influence of their handlers the dogs are alerted to the presence of marijuana, should a search be invalidated if a dog's handler is misleading their dogs by their own sense of odor perception?
Dr. Whitehurst - What is it that the dog is smelling? If an officer works with and around controlled substances every day does he contaminate a place that he is searching with residues from other searches. Imagine that the dog handler has just been to another marijuana growing site or found a cache of marijuana and processed it. The residues will be all over him and possibly his dog. When they come to the new "crime scene" do they, in touching items put the residues on the items they touch without even knowing it?
KB - I recently found this article.
University of Minnesota. "New DNA 'Fingerprinting' Technique Separates Hemp From Marijuana." Science Daily 23 March 2006.
Considering they have the technology to change the DNA of a marijuana plant to look completely different than it normally does, and the ability to take THC in or out of it's DNA structure to possibly design strains of cannabis for industrial purposes, Do you think someone could possibly restructure the DNA of cannabis to look like a completely different species of plant?
If so, would a new strain of marijuana still be under the same general guidelines of prohibition enforcement if it was to be combined with say a dandelion?
Dr. Whitehurst - What happens when we see transgenic mutations in which common weed plants are mutated to produce THC?. This happening will result in the end of prohibition of marijuana.