Remediation of Former Marijuana Grow · PDF fileRemediation of Former Marijuana Grow Operations Jennifer Mustard, M.Sc., RPBio Peter Hansen, P.Eng. Gordon Wedman, ROH, CIH Pacific

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

0

2000

4000

6000

8000

10000

12000

14000

Total

spor

es/m

3History Unknown (n=68)History Known (n=80)Outside Ambient (n=74)

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

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Basidospores Ascospores Cladosporium Asp/Pen Stachy OtherSpore Type

Spor

es/m

3

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

*

*

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