What’s in your weed? Amongst the cannabis community this question usually revolves around the
positives – THC, CBD and other cannabinoid percentages, flavonoids, terpenes
– but very rarely do we consider the bad stuff – like cannabis contamination.
Cannabis users often live inside a bubble that is surrounded by a protective coating of positivity
about the plant and the culture around it. Perhaps it’s a self defense mechanism prompted by years
of being demonized by society but it does sometimes blind us to the more unpleasant realities.
The extraordinary changes to everyday lives brought by the Coronavirus crisis has made us all
reconsider routines, habits and behaviours that we had never questioned before. This period has
also brought a new focus on personal health and lifestyle habits that may affect it. Many cannabis
users are looking for healthier ways to consume and also starting to take a closer look at the
healthiness of their supply.
The problem with buying from the street is you really have no idea where your cannabis comes from
and what is in it. By the nature of the business, street dealers have an eye on their profits, not on
your health. Do not be under any illusion – that weed you bought from a street dealer was not
grown organically in sterile conditions by a grower in a white lab coat and gloves!
Cannabis Contamination – Under the Microscope
One of the great ‘pluses’ of cannabis is the fact that it is ‘natural’, but the whole process of growing,
harvesting, drying and storing plant matter increases the risk of contamination. Even under the
umbrella of ‘legal’ cannabis cultivation and sale through dispensaries, large scale production brings
risk from contamination by pesticides and heavy metals (the cannabis plant is a recognized
hyperaccumulator, which will absorb heavy metals in soil).
So what else might be in your cannabis? Dead insects are far more common than you may think (do
street weed cultivators dispose of the whole crop when they find they have a spider mite
infestation?) and fungus is another infection component which is regularly highlighted in street deal
tests – particularly Aspergillus mold, which can cause serious issues to anyone with a compromised
The Coronavirus episode has taught us all the benefits of thoroughly washing hands but cannabis
sample testing has highlighted the frequent existence of faecal related bacteria such as E.coli and
salmonella are also common and in 1981 salmonella contaminated cannabis affected 81 people
across states in the USA.
Contaminated Cannabis – A case study
A 2019 study by the Complutense University in Madrid highlighted the worst suspicions of hash fans
when it conducted tests on 90 samples bought from the streets of the Spanish capital for cannabis
contamination - putting a new emphasis on the phrase ‘smoking good shit’.
Worst offenders were the hash pellets (or ‘acorns’) that are a common deal in Spain. They often
come heavily wrapped in plastic film accompanied by a dense odor that transcends the aromatic
hashy smell. If hash smokers had their suspicions, then this study confirmed them; of the samples
93% contained E.coli bacteria and 40% smelt of faeces. There is a good reason those acorns are the
size of a piece of candy and what goes in the mouth of a hash smuggler has to come out the other
Can You Avoid Contaminated Cannabis?
The problem with cannabis is that, despite legalization in many parts of the world, its roots still come
from the underground and the black market. This is why much of the debate post-legalization is
about the kind of regulation and consumer safeguarding that is the norm in any other product
Until there is a universal safety standard that is adhered to – which, realistically, would require a
universal legalization of cannabis cultivation (strangely that time could be coming closer as we face
the economic shock of the Coronavirus lockdown) – the only effective solution is to be in control of
your own supply and what goes into it.
Unfortunately home growing is still illegal in most countries and until this situation changes,
cannabis contamination will continue to be a negative aspect of using the plant that users –
especially those using for medical reasons - need to consider.