Remediation of Former Marijuana Grow

OperationsJennifer Mustard, M.Sc., RPBio

Peter Hansen, P.Eng.Gordon Wedman, ROH, CIH

Pacific Environmental, North Vancouver, BC604-980-3577

www.pacificenvironmentalbc.com

OverviewBackground

The Problem: Grow-opsHow Consultants/Hygienist Become InvolvedCombating Grow-ops with Environmental Inspections

Does an initial inspection by a hygienist improve the success of remediation in former marijuana grow operations?

Fungal SamplingChemical Sampling

Conclusions

The Problem: Grow-opsSingle family homes, town home complexes, apartments and warehouses are often used for the illegal cultivation of marijuanaThere are an estimated 15,000 to 28,000 illegal grow-ops in British ColumbiaAltered to produce residential greenhouses

High humidityExcess water use and additional water linesStructural, mechanical, electrical modifications

http://www.winnipeg.ca/police/drug_awareness/growopphotos.stm

Environmental ConcernsFungal ContaminationResidual Pesticide ContaminationResidual Fertilizer ContaminationIncreased Levels of CO2 and CO

How Hygienists Become Involved

Concerned New HomeownerFacilitate the Sale of a PropertyFinancing PurposesRequired by Municipal By-laws

Combating Grow-ops: Municipal Bylaws

Grow Operation is Busted?Utilities Disconnected – gas, hydro, waterOccupancy Permit RemovedCost Recovery – emergency services, inspection fees, utility connectionBuilding Safety Standards – electrical, structural, water, mechanical systems

Environmental/Health & Safety Inspections –may require cleaning and inspection by certified individuals (CIH or ROH)

Environmental Inspection: Ideal

ProcessAn initial inspection conducted by a certified inspector prior to the start of remediationScope of work preparedRemediation conducted by a certified restoration company (scope of work followed)Final inspection and clearance samplingAcceptable results = completion of certificate and occupancy is granted

Environmental Inspection: Typical

ProcessAn initial inspection conducted following completion or partial remediation (renovation)Work is typically conducted by a general contractor or cleaning companyMay or may not be remaining fungal contaminationFollowing removal of all visible fungal contamination clearance sampling is doneOften unacceptable results due primarily to improper cleaning and/or enclosure

Post Remediation Verification

Visual inspectionSpore trap sampling for residual fungal spores (2-6 samples/house)Pesticide swab samplingFertilizer swab sampling for nitrogen

Does an initial site visit by a hygienist improve

the success of remediation in former

marijuana grow operations?

Methods – Fungal Contamination

Spore trap data from 68 homes was usedSampling was only conducted when fungal contamination was not visibleTwo categories: 1.History Unknown: spore trap sampling was

conducted during the initial site visit2.History Known: initial site visit to prepare a

scope of work, spore trap sampling conducted on a subsequent visit

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Figure 1. Total Fungal Spore Concentrations Identifiedin Former Marijuana Grow Operations

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Basidospores Ascospores Cladosporium Asp/Pen Stachy OtherSpore Type

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History Unknown (n=68)History Known (n=80)Outside Ambient (n=74)

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Figure 2. Fungal Spore Concentrations by Spore Type Identified in Former Marijuana Grow Operations

Pesticide/Fertilizer Sampling: Method

Gauze moistened with either isopropyl alcohol or distilled water used to swab an area of 1ft2Typically 4-6 areas were swabbed and combined for a composite analysisAnalysis

Pesticides: 186 different compoundsFertilizer: percent nitrogen

18.60FungicidieChlorothanlonil0.73Permethrin(trans)0.62Broad-Spectrum Synthetic Pyrethroid InsecticidePermethrin(cis)0.70Synthetic Pyrethroid InsecticideTetramethin0.33Synthetic Pyrethroid InsecticideCypermethin0.05Synthetic Pyrethroid InsecticideFenvalerate6.63Broad-Spectrum Organophosphate InsecticideChlorpyrifos0.75Wide-spectrum Organophosphate InsecticideMalathion0.03Chlordane(trans)0.02InsecticideChlordane(cis)1.00Organochorine Miticide, Manufactured from DDTDicofol

Concentration (ug/ft2)DescriptionPesticide

Pesticide ResultsOf 40 samples collected, pesticides were detected in 5

Fertilizer Results

Average Concentration: 0.033%Blank Concentration: <0.01 to 0.02%Range: 0.01% to 0.08%Generally no significant concentrations identified

Conclusions

Total Fungal Spores – no significant difference between outside ambient and inside regardless of historyAspergillus/Penicillum and Other Spores –Significantly elevated concentrations from sites where the history was unknownNo other significant differences Results indicate that a hygienists involvement improves the effectiveness of remediation, but more work is still required

Conclusions 2

Pesticides – very little contamination detected, mostly InsecticidesFertilizers – no significant concentrationsA hygienists involvement may also improve the remediation of chemical contamination, but more data is required

Improving Grow-op Remediation

By-laws should require an initial inspection by a hygienistRequiring qualified remediation contractors would likely improve the clean-upNeed more enforcement, if they are not busted, they do not get properly cleaned-up

Questions?

www.pacificenvironmentalbc.com