The Effects Cannabis Cultivation have on the …...The Global Cannabis Cultivation Research...
Transcript of The Effects Cannabis Cultivation have on the …...The Global Cannabis Cultivation Research...
Picture taken from (Field, 2018)
THE EFFECTS CANNABIS
CULTIVATION HAVE ON
THE ENVIRONMENT
ABSTRACTThe growth of the marijuana industry has impacted the economy, the environment and public health in the United States. Although laws legalizing the use, production and distribution of marijuana have progress, they have done so with little regard to the industries impacts on the environment. This paper explores research published addressing the adverse effect that cannabis cultivation can have on environmental health. The paper also provides alternative options to traditional cultivation to assist in encouraging sustainable and safe cultivation practices, while focusing on how we can improve the cannabis industry in California.
Azalia RiveraENVS 190Dr. Foran
1
Contents
Introduction ..............................................................................................................................................2
Discussion ................................................................................................................................................4
Cannabis biology and origin ................................................................................................................4
Disconnect between State and Federal Government. ...........................................................................6
Challenges in research .........................................................................................................................8
Pesticide and Plant Growth Regulators (PGR) use and regulation ...................................................10
Indoor cultivation ...............................................................................................................................14
Outdoor cultivation.............................................................................................................................15
Waste management .............................................................................................................................18
Conclusion:.............................................................................................................................................22
Figures and Tables..................................................................................................................................23
Works Cited............................................................................................................................................28
2
Introduction
The marijuana industry in the United States has expanded significantly as states begin to
legalize its production, use and distribution. In 2015, 15 states had legalized the medical use and
distribution of marijuana (Carah et al, 2015), supporting a $2.4 billion industry (Butsic and
Brenner, 2016). As of 2018, 29 states have legalized the medical use and distribution of cannabis
and 9 states including California, have legalized the recreational use and sale of cannabis
(Gorrie, 2018). McVey, 2018 estimated that by 2022 the marijuana industry could reach $75
billion (Figure 1). The passing of Proposition 64: the Control, Regulate and Tax Adult Use of
Medical Marijuana Act (AUMA) in 2016 made the distribution and cultivation of marijuana
legal for both medicinal and recreational purposes in California. As of 2017 the National
Institute on Drug Abuse found that 45.2% of US persons ages 12 or older reported using
marijuana throughout their lifetime (Table 1) (National Institute on Drug abuse, 2019).
AUMA has dramatically increased the demand thus increasing the horticulture of
cannabis without much regard to its effects on the environment. Bezdek et al, 2017 reports
cannabis production is accountable for 3-6% of the United States electricity consumption and 5-
10% of Californians energy use. Indoor cannabis production alone can consume 6 times more
energy than the average commercial business (Bezdek et al, 2017). Cannabis cultivation can
involve activities that negatively affect land management practices and further degrade the
environment including habitat fragmentation, illegal water diversions, and contaminating water
supplies (Short-Giannotti, 2017).
Increasingly, evidence has illustrated the environmental effects of cannabis cultivation,
particularly the use of pesticides and nutrient additives to ensure the production of a large
healthy crop yield quickly. Lack of regulation on pesticide use during cannabis development has
3
resulted in records indicating that the toxicity of pesticides used can vary from causing organ
damage to being skin irritant (Cuypers et al, 2017). The effects pesticides have on an individual
can depend on how it is ingested. Inhalation has been reported as having the most adverse effects
on the body because when inhaled pesticides are absorbed directly into the bloodstream. Cuypers
et al, 2017 found evidence that supports the theory that cannabis crops still have traces of
pesticides used during the growing period once harvested putting consumers at risk of inhaling
pesticide residues. Sullivan et al, 2013 found that nearly 65.9% of glass pipes and water pipes
with and without filters tested positive for pesticide residues. Without regulations on pesticide
use during developmental stages, cannabis consumers are at risk for hidden toxicological threats.
Indoor cultivation typically has high energy demands (Table 2). Indoor cultivation
requires a temperature of 75 Degrees and high levels of Carbon dioxide (CO2) to promote ideal
outdoor conditions to simulate optimal productivity (Bezdek, 2017). Marijuana farmers will
increase the CO2 available in grow rooms because cannabis is a carbon sink and large amounts
of CO2 help it thrive. This can be done by burning propane or natural gas within the grow room
which requires additional ventilation (Mills, 2012). Although this information is focused more on
small scale indoor growing operations, it should still be taken into consideration because there is
a large population of growers still partaking in small scale farming. A web survey conducted by
The Global Cannabis Cultivation Research Consortium on primarily small scale growers in 11
countries reported that respondents from the US, UK, Canada and Finland were more likely to
grow indoors than outdoors (Potter et al, 2015). The survey also reported that 75% of individuals
grew their own cannabis because it was cheaper than going out and buying it (Potter et al, 2015).
Despite the lack of energy use outdoor cultivation can be detrimental to our
environment’s health because of its impacts on land and land management. The offset of
4
California's rainy season and marijuana’s main growing season has created a need for cultivators
to locate farms in watersheds where water is readily available through the dry season. The use of
pesticides and excessive nutrient runoff in outdoor growing sites pollute and further degraded
natural ecosystems. Northern California is popular for outdoor cannabis cultivation because of its
secluded forest, especially prior to the legalization of cannabis production. This is problematic,
specifically in secluded natural landscapes like the “The Emerald Triangle” which has become
increasingly at risk for habitat fragmentation and deforestation (Wang, 2017). Many of these
sites are located within sensitive habitats which further stresses endemic and endangered
dependent on those landscapes (Butsic, 2016). Farm location can create other problems like soil
erosion, introducing sediments and nutrients into streams and causing landslides (Wang, 2017).
This report will evaluate the effects traditional cannabis cultivation methods, specifically
indoor and outdoor cultivation, has on the environment. The report will also identify alternatives
to traditional cultivation methods by focusing on aquaponics as an alternative method of
cannabis cultivation. Although aquaponic systems are similar to hydroponic systems, they differ
in that aquaponic systems use fish and fish waste as a natural fertilizer for the plants in the
system eliminating the dependence on chemical additives. When aquaponics is implemented
correctly, it is a closed system that requires little added water or nutrients making it an ideal
alternative for cannabis cultivation.
Discussion
Cannabis biology and origin
There is debate amongst scientist as to how to differentiate the variants of cannabis.
Initially, using the geographic origins and the reproductive parts of plants, Swede Carl Linnaeus
5
concluded that there was one species, Cannabis sativa with five variants (Laursen, 2015). As
time progressed, using chemistry and morphology, Cannabis indica was distinguished as a new
species of Cannabis by Jean-Baptiste Lamarck (Laursen, 2015). Later, Ernest Small found that
Cannabis in fact has only one species, Cannabis sativa with multiple variants (Laursen, 2015)
which has backing in the botany community. However, more recent evidence suggest that there
are in fact two species with multiple variants of each species. Yet, the debate continues with new
technology being developed to assist in better differentiating types of marijuana. The
differentiation of Cannabis as either ‘Hemp’ or ‘Marijuana’ by government officials is vital
during enforcement of drug laws in relation to cannabis. Marijuana has been defined by law
officials as the intoxicating variant of cannabis, whereas hemp has been defined as the non-
intoxicating version (Cherney & Small, 2016). Although the minimum level of 1%
Tetrahydrocannabinol (THC) is required to have an intoxication effect (Cherney & Small, 2016),
governments have deemed cannabis plants with less than 0.3% THC as hemp and those with
more as marijuana (Laursen, 2015). For the terms of this paper no species will be identified, and
all variants of the plant will be referred to as cannabis, marijuana or hemp to prevent confusion.
In the Jepson Manual only one strain of Cannabis is mentioned, Cannabis sativa: Hemp,
Marijuana which is considered to be the non-drug form of the cannabis plant by law
enforcement. Cannabis is described as an erect annual with unbranched hairs, the inner bark is
fibrous, and the plant is dioecious meaning a plant either produces male or female reproductive
parts but not both (Patterson et al, 2012). The female flowers have psychoactive resin
(Tetrahydrocannabinol) which is what gives the plant its intoxicating effects when consumed
(Patterson et al, 2012). Most of the known lineages seem to be capable of producing viable
offspring from hybrids (Laursen, 2015). In the marijuana sector, individuals differentiate
6
marijuana by strains named by breeders (Laursen, 2015). Cannabis can be used as a medicine,
the stems fibers can be used for rope, fabric, paper, etc (Patterson et al, 2012). It is believed to be
native to Asia but has been cultivated in the U.S. for centuries and is found commonly in
disturbed areas (Patterson et al, 2012).
Marijuana is a water dependent crop that thrives in moist soils (Bauer et al, 2015).
Reports suggest that an individual cannabis plant requires between 3.8 to 56.6 Liters of Water
Per Day (LPD) but averaging at 18.9-22.7 LPD (Bauer et al, 2015). Withholding water during
early developmental stages could stunt floral formations (female inflorescences and intercalated
bracts) which is the part of the plant that is typically harvested for profit. The optimal growing
season for marijuana is between May and September. This conflicts with northern California’s
wet season where approximately 95% of the precipitation occurs between October and April
(Bauer et al, 2015). Yet, nearly 75% of the marijuana consumed in the United States is produced
in California (Carah, 2015) The lack of precipitation has driven many growers to choose land
with year round water services to secure irrigation through hot and dry summers for cultivation
sites (Bauer et al, 2015).
Disconnect between State and Federal Government.
The classification of marijuana by the federal government as a schedule one drug makes
the use and production of marijuana illegal federally under the United States Controlled
Substance Act (CSA) (Bezdek et al, 2017). This creates a complex legal status for marijuana
when production is legal at state level yet still subject to federal drug laws. The legal status of
cannabis has forced growers to establish farms in secluded areas like the “Emerald Triangle”
which includes Humboldt, Trinity and Mendocino County (Butsic and Brenner, 2016). The
Emerald Triangle is dominated by dense forest, steep rugged terrain and consist of remote
7
sparsely populated area making it ideal for growers that want to remain discrete (Bauer et al
2015). The complexity of the legal status of marijuana has established a distrust between growers
and law enforcement (Bauer et al 2015).
Initially Humboldt and Mendocino County had some of the most lax regulations on the
marijuana production. The state Senate Bill 420, The Medical Marijuana Program Act (MMPA),
granted each county in CA the power to interpret and implement regulations on marijuana use,
possession and agriculture for medicinal purposes, clarifying Proposition 215 which exempts
permitted patients using medical marijuana from criminal laws (Senate Bill No. 420, 2003;
Ballotpedia, 2019). In Humboldt county, qualified patients and their caregivers were allowed to
grow any number of plants within a 100 square foot plot (Short-Gianotti et al, 2016). After
discovering the impacts that both indoor and outdoor grow sites have on the environment,
Humboldt and Mendocino County placed restrictive guidelines on marijuana production.
Humboldt County’s Ordinance 2328 (2004) required marijuana growers to comply with
state regulations on activities that affect waterways while encouraging growers to practice
environmental stewardship as well as limiting the amount of plants that can be grown in on a plot
(Short-Gionnati et al, 2016). This was later revised by Humboldt County’s Ordinance 2525
(2014) which restricted growers to a plant canopy of 100 square feet on plots less than one acre
and a 200 square foot plant canopy on plots between one and five acres (Short-Gionnati et al,
2016). Mendocino county implemented a permit program, Mendocino county code 9.3 (2010),
which limits the amount of plants that can be cultivated on a plot to 25 cannabis plants per grow
site despite the number of qualified growers using the area (Short-Gionnati et al, 2016). The
county code requires qualified growers to pay permitting fees, participate in 4 annual
inspections, install security measures and requires growers to comply with state environmental
8
regulations (Short-Gionnati, 2016). Although the permit program proved to be successful, the
involvement of the federal government led Mendocino County to revise the permit program
(Short-Giannotti et al, 2016). Federal official’s used court orders to have access to counties
inspection and registration records to assist with locating and raiding grow sites (Short-Giannotti
et al, 2016). Mendocino County later revised permit programs to eliminate inspection and
registration requirements, but still requires limits on the amount of plants that can be grown at a
cultivation site. In 2014, a spending bill was released prohibiting the US Justice Department
from spending money to enforce the federal ban on marijuana in states that have legalized the
use of medical marijuana in hopes of mending distrust between growers and law-enforcement
(Halper, 2014).
The diversion of water from most of Northern California’s watersheds must be registered
with the State Resources Control Water Board (SWRCB), whether it is for domestic or
agricultural purposes, and are restricted to standards set by the California Department of Fish and
Wildlife to protect natural ecosystems (Bauer et al, 2015). Despite the requirement for marijuana
farmers to comply with California’s environmental regulations, especially those pertaining to the
state’s water laws, numerous growers have been recorded as not reporting their water diversions
in the Northern California basin (Bauer et al, 2015). The lack of reported water diversions limits
the SWRCBs ability to regulate water use in these watersheds. This combined with the common
distrust established between growers and law enforcement allows for the assumption that the
majority of cannabis farmers do not want to risk identifying themselves by registering water
diversions.
Challenges in research
9
The complex legal status of marijuana has made research difficult by limiting who can
and does participate in research and what data is collected (Short Giannotti et al, 2016). In
interviews conducted with researchers focusing on the environmental impacts of cannabis
horticulture, Short-Giannotti et al, 2016 found that as of 2008 agency staff were aware of the
environmental impacts cultivation has but were unable to address it because of lack of legislative
direction. Social and economic aspects also come into play when addressing the lack of research.
Academic research has a lack of funding because universities have deemed marijuana as non-
academic and as having nothing to do with natural resource and ecological management
practices (Short Giannotti et al, 2016). It has also proven difficult to find research assistants that
lack bias or political motives (Short Giannotti et al, 2016). Safety concerns also limit the
undertaking and quality of field research. Marijuana grow sights are typically secured by armed
guards and have hidden traps to deter anyone from discovering the cultivation site. Researchers
will avoid collecting data in areas that present any evidence of being cultivation site, unless they
are accompanied by law-enforcement officers (Short-Giannotti et al, 2016).
Reliance on law-enforcement has constricted study designs by only including sites that
have been discovered and raided by law enforcement, thus excluding most legal marijuana
production from research (Short-Giannotti et al, 2016). This creates a biased in research studies
because research sites center around those that are prioritized by law enforcement. Which puts
research at a disadvantage because law-enforcement does not accommodate to the time sensitive
needs that most test require. For example, researchers testing water quality for traces of
pesticides must collect samples after the first rain event of the year to gather accurate data on a
sites runoff (Short-Giannotti et al, 2016). Lack of diversity on site selection due to dependence
on law enforcement officials has encouraged researches to use aerial imagery to identify grow
10
sites. However, Bauer et al, 2015 found that aerial imagery is most effective on large scale
cultivation plots in forest clearings greater than 10 meters squared because forest canopy cover
and shadows can hide individual plants or small sites. To avoid detection, growers plant cannabis
on wide spacing in small canopy forest canopy openings (Bauer et al, 2015). Which indicates
than even in cases where cultivation sites are identified, many sites are looked over because of
lack of visibility.
Pesticide and Plant Growth Regulators (PGR) use and regulation
Pesticide and chemical use during the cultivation of marijuana is a complex and
controversial topic between the marijuana industry and those concerned about environmental and
public health. As research increases it has become apparent that regulations are necessary to
address the impacts on the health of consumers and organisms that are dependent on nearby
habitats (Subritzky et al, 2017). When regulations are being implemented, the needs of the
cannabis industry should be met to ensure the production of a quality product. When left
unchecked, growers will continue to disregard the risks on the health of consumers and the
environment (Subritzky et al, 2017). If regulators can limit the pesticide and chemical use
acceptable during marijuana production, California can limit the amount of chemicals and
pesticides that this ecosystems are exposed to.
Subritzky et al, 2017 defines a pesticide as “any substance or mixture of substances
intended for preventing, destroying or controlling any pest or unwanted organism causing harm
during or otherwise interfering with the production, processing, storage, transport or marketing
of a crop. This includes substances intended for use as growth-regulator, defoliants, or desiccants
and any substance applied to crops, either before or after harvest to protect the commodity from
deterioration during storage and transport.” Plant growth regulators (PGR) are chemicals used to
11
produce ideal plants that are more uniform with high levels of THC (Subritzky et al, 2017).
PGRs are becoming more popular amongst those growing for medicinal purposes, however
harvested plants tend to have traces of PRGs (Subritzky et al, 2017). PRGs when consumed can
cause infertility, cancer and liver damage (Subritzky et al, 2017).
Regulations on pesticide use during cultivation have been lax despite its legal status.
Regulators are becoming more concerned of the health effects that pesticides and PGRs can have
on consumers. As mentioned in the introduction, inhalation of a pesticide by smoke is one of the
most toxic ways to ingest a pesticide (Cuypers et al, 2017), yet smoking is one of the most
common ways marijuana is ingested (Pacula et al, 2015). Beyond public health, the use of
pesticides can contaminate entire ecosystems stressing and risking organisms in nearby habitats.
In 2000, the California Fish and Wildlife Services reported that 70% of the animals they had
tested returned with traces of Anticoagulant rodenticides (Thompson et al, 2014). Anticoagulant
rodenticide, a type of pesticide that was created to deter rodents from crops, exposure can lead to
wildlife population declines as well as act as an inhibitor for anti-predator, pathogen and parasite
defenses (Thompson et al, 2013). Pesticide contamination often occurs near agricultural fields,
urban or suburban areas (Thompson et al, 2013). However, there has been an increase in the
amount of cases where organisms native to undeveloped landscapes are being affected by
rodenticide poisoning (Thompson et al, 2013). In many of these cases the only anthropogenic
exposure that these landscapes have was pinpointed to illegal marijuana cultivation sites
(Thompson et al, 2013).
Gabriel et al, 2012 found that 83% of Pacific Fishers (Pekania pennanti) sampled and
submitted by the US Forest Service Kings River Fisher Project and the UC Berkeley Sierra
Nevada Adaptive Management Project tested positive for at least one anticoagulant rodenticide
12
compound. Fishers are considered to be a species of conservation concern in the western US
because populations are small and highly fragmented (Thompson et al, 2013). The status of
Fishers makes them vulnerable to disease and spontaneous events like wildfires and natural
disasters. Fishers have been under state and federal protection by the US Forest Service, the
United States Federal Endangered Species Act and California and Oregon Endangered Species
Act (Thompson et al, 2013). Though they have been in protection for nearly 40 years, the Fisher
populations have not expanded or recolonized much of their historical habitat (Thompson et al,
2013).
Researchers at the UC Berkeley Sierra Nevada Adaptive Management Project Fisher
research team discovered a Fisher in 2009 whose death was linked to anticoagulant rodenticide
exposure. The discovery of this deceased Fisher was concerning because as mentioned earlier,
anticoagulant rodenticides are commonly used in conjunction with anthropogenic developments.
A Fishers habit in the Sierra Nevada’s consist of mountainous terrain between 1000 and 2400
meters which do not come into contact with anthropogenic exposure (Thompson et al, 2013).
However, upon discussing with law enforcement it was discovered that the area has had reports
of illegal marijuana farms (Thompson et al, 2013). After conducting test along the west slope of
the southern Sierra Nevada, the High Sierra Nevada and Bass Lake Ranger Districts of the Sierra
National Forest (California), Thompson et al, 2013 found a positive correlation between the
number of cannabis cultivation sites that a Fisher comes into contact with and rates of Fisher
mortality.
Though organisms can be exposed to pesticides in numerous ways by agricultural and
urban use, regulations have been implemented to prevent exposure in large amounts and avoid
sensitive habitats. The lack of pesticide regulations on cannabis cultivation specifically has
13
enabled growers to use whatever pesticide is readily available despite toxicity levels. Cuypers et
al, 2017 focuses on illegal marijuana farms raided in Belgium. Although the information was
collected in another country, the paper presents information on how cultivators are using
pesticides on their marijuana plants. Cannabis growers are spraying plants directly with any
available pesticide instead of mixing environmentally friendly pesticides in irrigation water.
(Cuypers et al, 2017). Most growers use pesticides during different developmental stages to
protect crop yield (Cuypers et al, 2017). As plants reach maturity, they attract additional pest
which establishes a need for pest management (Cuypers et al, 2017). Pesticide use during later
developmental stages creates a toxicological threat to consumers (Cuypers et al, 2017). The use
of pesticides on cannabis plants is not regulated by the US Food and Drug Administration and
the Environmental Protection Agency due to the federal prohibition of cannabis, which creates a
public health concern (EPA, 2017; US Food and Drug Administration, 2018).
Growers will ‘flush’ plants in an attempt to rid any traces of pesticides, yet no studies
have been conducted which affirm that this method is able to remove pesticide residues. The
process of flushing requires the grower to halt all pesticide use for two weeks and only rely on
pure water, typically right before harvest to purge plants of pesticide and chemical traces
(Subritzky et al, 2017). Despite assumed positive intentions, flushing has proven to be more
problematic than a resolution when addressing the toxicant issue. In many cases, flushing will
merely reduce pesticide residue to levels so low that they initially receive a non-detect status
(Subritzky et al, 2017). Cannabis concentrates tend to intensify the dangers of pesticide residue
even when they are not detected in lab test (Subritzky et al, 2017). When a second test is
conducted on the final product, especially in the case of THC and Cannabinol (CBD)
concentrates, lab test can come back positive because residuals tend to increase during the
14
extraction process (Subritzky et al, 2017). This established a distrust between manufactures,
cultivators and testing laboratories, especially when manufactures have products recalled
because cultivators reported to manufacturers that the labs results on the product came back as
non-detect (Subritzky et al, 2017).
Despite the federal prohibition, Colorado was the first state in the United States to take
measures towards testing marijuana products for pesticide residue before distribution (Subritzky
et al, 2017). Colorado government offers a separate license which allows testing labs to analyze
plant matter for traces of pesticides and other chemicals that can cause harm and threaten public
health (Subritzky et al, 2017). Colorado wanted the process of regulating pesticides to be
collaborative amongst all stakeholders and to no surprise the biggest push back came from the
cannabis industry (Subritzky et al, 2017). As a huge stakeholder, the cannabis industries input
was highly valued due to experience in the field. There is a concern of biased in these reports
because as with any crop, marijuana farmers are concerned with pest management. One of the
central concerns within the marijuana industry about pesticide regulations stemmed from the fear
of losing plants to pest because the loss is not covered under insurance. The cannabis industry
felt as if limitations on pesticide use would make crops more vulnerable to failure. Manufactures
and cultivators feel as if testing is not as conductive as it is perceived to be because of the lack of
clarity when determining if a product has potentially harmful residual levels. The cost of testing
is another factor that has made regulations difficult. The Humboldt county ordinance draft 2010
reported testing as being unaffordable with test cost averaging between $300-$500 with
additional cost per pound of marijuana and type of test run (Carah et al, 2015).
Indoor cultivation
15
Indoor cultivation techniques tend to consume large quantities of energy, in California
indoor cultivation production consumes 9% of household electricity (Bezdek, 2017). Most
indoor cultivation operations use lighting that is equivalent to that of hospitals, with an average
energy intensity of 2283 kWh/kg in the United States (Mills, 2012). The high energy
consumption required by indoor grows stem from a growers need to mimic outdoor conditions
(Mills, 2012). Illegal grow houses seeking discretion will use air-cleaning, noise and odor
suppression machines as well as separate electric/gas/diesel generators that tend to be inefficient
(Mills, 2012). In California cannabis production is responsible for 3% all of energy use (Mills,
2012) and Colorado found that approximately 1,200 legal growers used as much power as 35,000
households (Nestor, 2017). Indoor cultivation is assigned the blame for the high energy usage
associated with cannabis production because outdoor cultivation typically has little energy
requirements. The increase of individuals producing marijuana has led to an increase of resource
demand thus creating the need of new policies, taxes, and fees being implemented in areas where
legal marijuana cultivation has been established.
Outdoor cultivation
Outdoor cultivation encompasses grow sites located outdoors as well as those in
greenhouses that do not require excessive energy use and rely primarily on natural elements like
sunlight to encourage plant growth. Instead of requiring energy intensive practices, outdoor
cultivation risks land management by degrading the environment via land clearing, illegal water
diversions, polluted water runoff, etc. Outdoor cultivation presents a popular alternative amongst
cannabis growers. Decorte, 2010 reported that 53.3% growers in Belgium preferred to grow
outdoors. In the United States, Kotch et al, 2016 estimates that approximately half of the grow
sites identified by the DEA were located outdoors. 44% of marijuana plants discovered and
16
eradicated by the federal government were located in national forest in California, Oregon and
Washington (Kotch et al, 2016).
Land clearing for cannabis horticulture is responsible for fragmenting forest into smaller
more isolated patches (Wang et al, 2017). Wang et al, 2017 found a significant change in
Humboldt County landscape resulting in an increase of fragmented small forest patches with
more exposed edges and reduced core areas over a 13 year period. This change can be accredited
to cannabis cultivation because the only other stressor present is timber harvest. Timber harvest
typically creates isolated smaller fragments of forest as well, but the forest patches have regular
patterns whereas land clearing for cannabis cultivation does not (Wang et al, 2017). Generally
land clearing for cannabis cultivation generates proportionally greater losses of core area and
increases forest edge and shape complexity (Wang et al, 2017).
Forest fragmentation in national parks can put biodiversity hotspots at risk of failure.
Fragmentation, isolation and shape of forest patches can change the density and persistence of
organism populations inhabiting the patches (Magrach, 2011). The irregular distribution of
cultivation sites has generated more isolated patches of forest. When searching for an ideal
cultivation site the majority of cultivators will choose an area based primarily on physical
accessibility and access to nearby roads and water sources (Bouchard et al, 2011). The ideal
location for a grow site is relatively close to both water for irrigation and a nearby by
road. Bouchard et al, 2011 reported that 75% of grow sites discovered were located within 175
meters of a road, deeming road access as a driving factor for location. Approximately 25%
growers stayed within 92 meters of a water source, however the mean distance from a water
source was 380 meters (Bouchard et al, 2011). As for physical accessibility most growers stayed
within an elevation of 200 meters, however 25% growers were located at elevations above 350
17
meters (Bouchard et al, 2011). Location of sites prioritizing accessibility, water and road access
explains the irregular distribution and strong spatial clustering of marijuana grow sites (Short-
Giannotti et al, 2016). As cannabis cultivation continues to gain popularity, the spatial
distribution of sites need to be taken into consideration during mitigation to minimize the
impacts on natural ecosystems. It can be assumed that this pattern of small grow sites
fragmenting forest will continue because currently in California outdoor cannabis cultivation is
limited to 0.4 ha per site (Wang et al, 2017).
Beyond habitat fragmentation, outdoor marijuana cultivation has been reported as being
responsible for illegal water diversions and altering watersheds. Marijuana plants are a water
intensive crop requiring approximately 18.9-22.7 LPD of water which explains why outdoor
cannabis cultivators prefer locations in sensitive watersheds (Figure 2) (Bauer et al, 2015; Wang
et al, 2017; Bouchard et al, 2011). Bauer et al, 2015 depicts the effects that cannabis cultivation
have on 4 watersheds in Northwestern California, it’s primary findings suggest that most
marijuana grow sites are not distributed well thus stressing streams where water is being
diverted. Bauer et al, 2015 estimated that within the study site, watersheds had an average of
between 23,000- 32,000 marijuana plants requiring a total of 523,144 - 724,016 LPD of water.
Even though water use estimates have large ranges making most regulators hesitant on
implementing legislation targeting water use, one cannot be ignore the effects water diversions
have on watersheds. Bauer et al, 2015 found that water diversions in 3 out of 4 sites could be
responsible for completely dewatering streams. Even in cases where streams are not dewatered,
decrease in flow alters the chemistry in streams by increasing temperature, changing pH and
alkalinity (Bauer et al, 2016). Changes in water chemistry and flow often result in an increase in
amphibian and anadromous fish mortalities (Bauer et al, 2016). In the 4 watersheds studied,
18
summer flows tend to be so low that they can barely support the SWRCB guidelines on water
diversion without the cannabis industries additional water diversions (Bauer et al, 2015).
Lack of accountability has enabled cultivators to use surface water at the expense of these
sensitive watersheds. Bauer et al, 2015 found that even in situations where growers have on-site
water supplies, direct surface water diversions continue until the source is depleted. Only when
the water in streams is dried up will the water that was stored earlier be used. The complexity of
the legal status of marijuana cultivation contributes to most cultivators’ absence of
environmental stewardship. Pesticides used at outdoor marijuana grow sites tend to find a way
into ecosystems, entering food chains and threatening organisms in nearby ecosystems (Carah et
al, 2015). The inadequacy of incentives and impracticability of being environmentally conscious
because of costs and risks at these grow sites has led to large amounts of litter and poaching
being reported at grow sites (Short-Giannotti et al, 2016).
Waste management
Organic waste produced by the cannabis industry has been estimated at several million
pounds in the United States (Gorrie, 2018). Organic waste typically includes failed plants,
leaves, buds, seeds and stem and root balls along with growing mediums that are no longer
viable (Gorrie, 2018). The legal status of marijuana makes waste management difficult for
marijuana cultivators whether or not they are growing within the parameters that the state allows
(Gorrie, 2018). To insure discretion most growers are hesitant to risk discovery using traditional
waste management methods seeing that obtaining a warrant is not necessary for law-enforcement
to search garbage (Gorrie, 2018). To implement these regulations states hold cultivators
responsible for keeping track of organic waste, some jurisdictions go as far as requiring each
plant to have an ID and tracking tag and for senior managers to accompany waste to any external
19
disposal site (Gorrie, 2018). Although waste typically has little to no potency regulators still
require evidence of all waste activity and marijuana waste must store in a secure area with
limited access and constant surveillance (Gorrie, 2018). This prevents black market growers
from stealing waste products to support their farms.
Gorrie, 2018 describes a few general options for waste management within the cannabis
industry. Compost is often the most sought out method of disposal, however regulations on
cannabis organic waste make it difficult for growers to use compost as a disposal method. States
like Oregon limit on site compost to 100 tons annually, preventing pollution or odor issues
(Gorrie, 2018). If waste is combined with equal parts of another organic or inorganic matter
making the product unrecognizable (50/50 ratio), it can be sent to a landfill or composting
facility (Gorrie, 2018).This can pose a problem in areas with small composting facilities that
need to dispose of large quantities of marijuana waste since smaller facilities tend to lack the
non-cannabis products to meet the required 50/50 ratio (Gorrie, 2018). The Bokashi process uses
waste to create a liquid fertilizer, however is difficult to create these fertilizers as the amount of
activator required in this process is difficult to estimate (Gorrie, 2018). The Micron Wastes
system turns cannabis waste into a liquid residue that enables sewer disposal but requires
cleaning to render the product non-potable and disposable (Gorrie, 2018).
Alternatives and mitigation
A major barrier in building a sustainable cannabis industry stems from lack of knowledge
as to how to implement sustainable practices within the cannabis industry. Chouvy et al, 2018
describes modern cannabis cultivation techniques adopted in Morocco that mimic techniques
used in other agricultural practices. These methods include cultivation of high yielding varieties,
seedlings planted on raised nursery beds typically in greenhouses, single row planting using drill
20
and transplanting methods, drip irrigation, mulching with hay, drying plants in indoor dust free
facilities, individual harvesting techniques and excessive fertilizer use (Chouvy et al, 2018). The
legalization of recreational use of marijuana in California has increased demand making large
scale industrialization similar to that established in Morocco a realistic possibility for California's
future. Both large and small scale agricultural practices can stress the surrounding environment.
To minimize impacts that the cannabis industry has on the environment education opportunities,
incentives and legal repercussions should be implemented. Subritzky et al, 2017 suggest that
jurisdictions consider using tobacco as a reference when drafting regulations on the use of
pesticides during marijuana cultivation since tobacco and marijuana share similar attributes.
Investments in funding and expanding testing labs to improve the current testing laboratories
already established should be prioritized. Developing guidelines of practices that cultivators
should follow to encourage safer cultivation practices.
While regulators may have difficulty enforcing legal repercussions in relation to
marijuana production due to the complex legal status of cannabis use and production, reward
based programs established within states where cannabis is legal can directly address the
issue. Denver has begun to take steps towards encouraging a sustainable future within the
cannabis industry. To encourage cannabis retail businesses to strive for suitability the Denver's
Department of Environmental Health has opened their Certifiably Green Denver retail
certification to cannabis dispensaries, recognizing sound environmental resources and business
management practices (Andrle, 2017). The first cannabis facility to receive the city of Denver’s
Certifiably Green certification, L’Eagle led by co-owner Amy Andrle, is actively breaking
barriers in the cannabis industries sustainability movement (Ruby-Cisneros, 2018). L’Eagle is a
zero waste facility, located in a warehouse in downtown Denver which combines a retail
21
business and cultivation facility (Ruby-Cisneros, 2018). L’Eagle is focused on conserving
energy, water and resource management. L’Eagle is a prime example of how to produce a quality
product while minimizing effects on the environment as well as public health. Even pest
management practices have been modified to minimize negative impacts. L’Eagle uses Organic
Materials Review Institute rated pesticides derived from all natural ingredients (Ruby-Cisneros,
2018). L’Eagle’s storage of water intended for irrigation use overnight is considered to be one its
most effective conservation practices (Ruby-Cisneros, 2018). Cannabis cultivation typically
requires an average water temperature of 70 Degrees Fahrenheit for irrigation (Ruby-Cisneros,
2018). Storing cold water overnight assists in limiting energy usage required to heat up irrigation
water by bringing the water to room temperature before the next day (Ruby-Cisneros, 2018). The
Cannabis Sustainability Work Group lead by the Denver's department of Environmental Health
promotes non-regulator sustainable strategies by developing educational resources including a
best management proactive manual, and sponsorship of the organic cannabis associations’ annual
cannabis sustainability symposium.
Agricultural methods like large scale outdoor and hydroponic horticulture can have
detrimental impacts on the environment because the excessive use of fertilizer and chemical
additives. Though hydroponics can conserve water, hydroponic growers tend to be dependent on
chemical nutrients to support crop yield (Suhl, 2016). Lenton et al, 2018 reported that
hydroponic growers are 12 times more likely to use chemicals to support crop yield than natural
growers. Chemicals used during developmental stages of marijuana cultivation tend to remain
present after harvest and have adverse effects on public health (Subritzky, et al 2017, Cuypers,
2017, Lenton et al, 2018). Large scale outdoor cultivation tend to require excessive fertilizer use
to accommodate for poor soil quality and encourage a healthier crop yield (Short-Gianotti et al,
22
2016). In 2003, Morocco's large scale outdoor cannabis agricultural sites reported using
approximately 600 tons of synthetic fertilizers (Chouvy et al, 2018). The United States Forest
Service reported that approximately 1 pound of fertilizer is used for every six marijuana plants
produced in outdoor cultivation (USFS, 2009). Excessive fertilizer use can pollute surface water
and contribute to eutrophication increasing the occurrence of algal blooms in nearby watersheds
(Short-Gianotti et al, 2016).
Implementing aquaponics in cannabis cultivation can decrease reliance on chemical
nutrient additives and excessive fertilizer use unlike hydroponics and large scale outdoor
cultivation. Green Relief, a licensed marijuana cultivation facility located in Hamilton, Ontario is
the planets first cannabis provider using aquaponics as a sustainable cultivation technique (Green
Relief, 2019). Aquaponics is the combination of hydroponic agricultural systems and aquaculture
creating a sustainable soil-less form of agriculture. Aquaponic systems provide nutrients to
plants via recycled water from fish tanks. Fish excrete feces in the water creating waste
byproduct and organic matter which is then filtered through the plant roots. Plants uptake fish
waste and organic waste as fertilizers, supporting plant growth and cleaning the water so that it
can be cycled back to the fish tanks (Suhl, 2016). The only way water can escape from the
system is through evaporation and evapotranspiration which assists in water conservation (Suhl,
2016). Green relief reports that while using aquaponics they are able to produce 10 times the
average crop yield while using 90 % less water than conventional cultivation techniques (Green
Relief, 2019).
Conclusion:
It is clear that the expansion of the marijuana industry if not managed properly will
continue to have adverse effects on the environment. As legislation and research develop it has
23
become apparent that presently cannabis cultivation is damaging ecosystems and increasing
energy demands. California has taken the lead in the nation’s sustainability and environmental
stewardship movement but has yet to implement regulations that specifically target cannabis
cultivation. This stems from a lack of support from organizations that are under control the
federal government. Within the last five years there has been legislation passed (assembly bill
243, 266 and state bill 64) which requires the development of land use ordinances, permits for
water diversions, and enforcing of seed-consumer tracking amongst cannabis growers (Butsic,
2016). However, most outdoor farms in Northern California are located in secluded areas that
require access to private road making it difficult to implement these laws. The lack of enforced
legislation combined with the increase of marijuana cultivation due to legalization of recreational
cannabis use will allow growers to expand farms in fragile areas.
There is a lack of knowledge and research on how to implement safe and sustainable
practices in cannabis cultivation. Only recently was the effects that pesticide residue introduced
to human body through cannabis consumption recognized. Lifting the federal prohibition on
cannabis can make it easier implement regulations preventing the distribution of cannabis
products with pesticide residue levels that pose a health risk. By redirecting the sales tax imposed
on marijuana to fund research projects that explore cultivation alternatives and education
programs focused on implementing sustainable agricultural practices, California can minimize
the effects cannabis cultivation has on the environment. While the cannabis industry is still
establishing itself measures need to be taken to ensure that it is moving towards a green future.
Figures and Tables
24
Table 1Drug Time
PeriodAges 12 or
OlderAges 12 to
17Ages 18 to
25Ages 26 or
Older
Marijuana/ Hashish
Lifetime 45.20 15.30 52.70 47.50
Past Year 15.00 12.40 34.90 12.20
Past Month 9.60 6.50 22.10 7.90
(Table 1: National Survey on Drug Use and Health: Trends in Prevalence of Marijuana/ Hashish for Ages 12 or Older, Ages 12 to 17, Ages 18 to 25, and Ages 26 or Older; 2017 (in percent).) (National Institute on Drug abuse, 2019).
26
(Table 2: Depicts the standard energy model for small scale indoor cultivation sites) (Mills, 2012)
27
Figure 2
(Figure 2: Map of Humboldt County, California depicting the number of cannabis plants in each watershed.) (Wang et al, 2017)
28
Works Cited
Andrle, A. (2017). Making the Cannabis Industry green(er). The Denver post
Ballotpedia. (2019). California Proposition 215, the Medical Marijuana Initiative (1996).
Bauer, S., Olson, J., Cockrill, A., Hatten, M., Miller, L., Tauzer, M. & Leppig, G. (2015). Impacts of
surface water diversions for marijuana cultivation on aquatic habitat in four northwestern
California watersheds. PLoS ONE, 10(3), E0120016.
Bezdek, R., Harshfield, M. Tegart,S., and Vyas,U. (1994) "Surprising Energy Requirements of the
Cannabis Industry: Part 1: Implications for Utilities, Regulators." Public Utilities Fortnightly
155.3 pp 44-49.
Butsic, V., & Brenner, J. "Cannabis (Cannabis Sativa or C. Indica) Agriculture and the Environment: A
Systematic, Spatially-explicit Survey and Potential Impacts." Environmental Research Letters
11.4 (2016): 10.
Carah, J., Howard, J., Thompson, S., Short-Giannotti, A., Bauer, S., Carlson, S., . . . Power, M. (2015).
High Time for Conservation: Adding the Environment to the Debate on Marijuana
Liberalization. BioScience, 65(8), 822-829.
Cherney, J.H. & Small, E. (2016). Industrial Hemp in North America; Production, Politics and Potential.
Agronomy, 6(4), 58.
Chouvy, P. & Macfarlane, J. (2018) "Agricultural Innovations in Morocco’s Cannabis Industry."
International Journal of Drug Policy 58. Pp 85-91.
Cuypers, E., Vanhove, W., Gotink, J., Bonneure, A., Van Damme, P., & Tytgat, J. (2017). The use of
pesticides in Belgian illicit indoor cannabis plantations. Forensic Science International, 277, 59-
65.
29
Decorte, T. (2010). Small scale domestic cannabis cultivation: An anonymous Web survey among 659
cannabis cultivators in Belgium. Contemporary Drug Problems, 37(2), 341-370,189.
Field, H. (2018). Scoring Guides Used by Arkansas Medical Marijuana Commission Member to Rate
Pot Growers Varied.
Green Relief. (2019). Blending sustainability with science to produce pure, effective medical cannabis.
Gabriel, M. W., Woods, L. W., Poppenga, R., Sweitzer, R. A., Thompson, C., Matthews, S. M., ... &
Wengert, G. M. (2012). Anticoagulant rodenticides on our public and community lands: spatial
distribution of exposure and poisoning of a rare forest carnivore. PloS one, 7(7), e40163.
Gorrie, Peter. "Recycling Cannabis Organics." BioCycle59.6 (2018): 17-19.
Halper, E. (2014). Congress Quietly Ends Federal Government’s Ban on Medical Marijuana. Los
Angeles Times.
Koch, F. H., Prestemon J. P., Donovan, G. H., Hinkley, E. A., & Chase, J. M..(2016). Predicting
cannabis cultivation on national forests using a rational choice framework. Ecological
Economics, 129(C), 161-171.
Laursen, L. (2015) "The Cultivation of Weed." Nature 525.7570 S4, 85.
Lenton, S., Frank, V. A., Barratt, M. J., Potter, G. P., & Decorte, T. (2018). Growing practices and the
use of potentially harmful chemical additives among a sample of small-scale cannabis growers in
three countries. Drug and Alcohol Dependence, 192, 250-256.
Magrach, A., Larrinaga, A. R., & Santamaría, L. (2011). Changes in patch features may exacerbate or
compensate for the effect of habitat loss on forest bird populations. PLoS One, 6(6), e21596.
McVey, E. (2018). Chart: How many billions will the US marijuana industry hit by 2022?
Mills, E. (2012). The carbon footprint of indoor Cannabis production. Energy Policy, 46(C), 58-67.
National Institute on Drug Abuse. (2019). Marijuana.
30
Nestor, M. (2017). How legalized Cannabis cultivation can boost the waste Industry Revenue, Support
the Economy and Protect the Environment. Waste360 (Online).
Patterson, R., Rosatti, T. J., & Wilken, D. H. (2012). The Jepson manual: Vascular plants of California.
Berkeley, CA: University of California Press.
Pacula, R. L., Jacobson, M., & Maksabedian, E. J. (2016). In the weeds: a baseline view of cannabis use
among legalizing states and their neighbours. Addiction, 111(6), 973-980.
Potter, G. R., Barratt M. J. , Malm, A., Bouchard, M., Blok, T., Christensen, A. . . . Wouters.M. (2015).
Global patterns of domestic cannabis cultivation: Sample characteristics and patterns of growing
across eleven countries. International Journal of Drug Policy, 26(3), 226-237.
Ruby-Cisneros, K. (2018). Promoting the Sustainable Growth of Cannabis. Journal of Environmental
Health, 80(7), 56.
Senate Bill No. 420. (2003). SB-420 Medical marijuana.
Short-Giannotti, Harrower, Baird, & Sepaniak. (2017). The quasi-legal challenge: Assessing and
governing the environmental impacts of cannabis cultivation in the North Coastal Basin of
California. Land Use Policy, 61, 126-134.
Subritzky, T., Pettigrew, S., & Lenton, S. "Into the Void: Regulating Pesticide Use in Colorado’s
Commercial Cannabis Markets." International Journal of Drug Policy 42 (2017): 86-96. Web.
Suhl, J., Dannehl, D., Kloas, W., Baganz, D., Jobs, S., Scheibe, G., & Schmidt, U. (2016). Advanced
aquaponics: Evaluation of intensive tomato production in aquaponics vs. conventional
hydroponics. Agricultural Water Management, 178, 335-344.
Sullivan, N., Elzinga, S., & Raber, J. C. (2013). Determination of pesticide residues in cannabis smoke.
Journal of toxicology, 2013.
31
Thompson, C., Sweitzer, R., Gabriel, M., Purecell, K., Barrett, R., & Poppenga, R. (2013). Impacts of
Rodenticide and Insecticide Toxicants from Marijuana Cultivation Sites on Fisher Survival Rates
in the Sierra National Forest, California. Conservation Letters, 7(2), 91-102
United States Environmental Protection Agency (EPA) (2017). Pesticide use on marijuana.
US Food and Drug Administration (2018). FDA and marijuana.
United States forest Service (USFS). (2019). Forest focus: National Forest in California- Episode 5
Marijuana: Cultivation and Eradication on California's National Forests; Podcast and Transcript.
Wang, I., Brenner, J., & Butsic,V. (2017) "Cannabis, an Emerging Agricultural Crop, Leads to
Deforestation and Fragmentation." Frontiers in Ecology and the Environment 15.9 pp 495-501.