Copyright 2006 1

Determination of Sewage Contamination on Personal Belongings or Equipment Following Flooding or Waste System Malfunctions

POPO--109109American Industrial Hygiene Conference and Exposition

May 13-16, 2006

Chicago, Illinois

David Regelbrugge, CIH, CSPGary N. Crawford, CIHFelice Holcomb, MSPHJeff RuhlPH: 847-692-4700E-Mail: dcr@boelter-yates.com

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Introduction

• “Bacterial monitoring is messy”– Physically messy especially in the case of

sewage back-ups/flooding– Monitoring results do not always support

original hypothesis

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Background

• Sewage contamination due to:– Natural disasters

• Flooding• Hurricanes

– Malfunctions • Pipe breaks• Back-ups in basements

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Background

• When back-ups occur – Occupants may be exposed to raw sewage– Building materials become contaminated with

sewage

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Background

• Sewage can carry a number of pathogenic organisms– Viruses

• Rotovirus, Hepatitis-A, Norwalk Virus, etc.– Parasites

• Giardia, cryptosporidium, round worms, etc.– Bacteria

• Samonella, tetanus, E-coli

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BackgroundBackground

• Institute of Inspection, Cleaning and Restoration Certification (IICRC) Standard and Reference Guide for Professional Water Damage Restoration S-500.– Classifies sewage incidents as a Category 3-

Black Water event• Black Water contains potential pathogens

– e.g., sewage and/or water from seaways, rivers, streams, etc.

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Background

• IICRC S-500 – Recommends that all items that had direct

contact with black water be decontaminated or disposed of (disposal up to the discretion of the remediators)

• Consistent with other recommendations and guidelines developed by the EPA, ACGIH, etc.

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Background

• IICRC S-500 – No guidance as to how to determine if the

areas or remaining items were decontaminated adequately.

– Suggests that an indoor environmental consultant, environmental health specialist or IH evaluate the area prior to re-occupancy.

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Assessment Strategy

• How is the IH to approach assessing these situations?– Visual inspection combined with moisture

measurements• No samples

• Clients usually wants physical evidence– Want simple yes/no answers– Present or Not Present– Air, bulk or swab samples usually collected

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Assessment Strategy

• Bacterial samples commonly collected– Air

• Bacterial ID, Gram Positive Bacteria (GPB)/Gram Negative Bacteria (GNB)

– GNB usually associated with moisture/sewage

– Wipe/swab– GPB, GNB, bacterial ID, total coliform, fecal coliform and

E-coli absence/presence

– Dust/bulk– GPB, GNB, bacterial ID, total coliform, fecal coliform and

E-coli absence/presence

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Case Study 1

Hospital Water Line Break

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Case Study 1

• Hospital had a break in a chilled water that directly affected an office on the first floor. The water was discolored and had a foul odor. Repairs and remediation were performed but the hospital wanted a visual inspection of the affected areas and collection of air samples for bacteria.

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Case Study 1

• Assessment Strategy– Ten Culturable Airborne Samples Collected

• NIOSH method 0800– Anderson N-6 Impactor– On tryptic soy agar (TSA)– At 28.3 liters per minute– Collected over a 2 minute period– Sent overnight to an AIHA EMLAP accredited laboratory

• Samples collected in concern and non-concern areas as well as outside

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Case Study 1

• Results– Limited bacterial ID and the presence of GPB - GNB

• GNB often associated with moisture/sewage– Bacillus and Actinomycetes identified in a few of the

samples– GPB and GNB identified in almost all of the samples – Concentrations of GNB

• Non-detectable to 636 CFU/m3

• Highest concentration in mechanical room used for comparison purposes

• Remaining areas had similar GNB concentrations (Ave. 108 CFU/m3)

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Case Study 1

Airborne GPB - GNB Concentrations

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1st F

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ffice

Outside

Outside

Basem

ent M

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6th Fl. W

aiting R

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3rd Fl. W

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Rm.

1st F

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icine

Area

7 Fl. M

echa

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6th Fl. N

urses

Stat

ion

3rd Fl. N

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tation

Con

cent

ratio

n (C

FU/m

3)

GPBGNB

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Case Study 1

• Conclusions– GPB and GNB found both in concern and

non-concern areas as well as outside the building.

• Results difficult to interpret due to prevalence of both GPB and GNB in environment.

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Case Study 2

Leaky Drain Pipes

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Case Study 2

• Recently purchased home, copper drain lines throughout the home had deteriorated allowing waste water to contaminate wall cavities, ducts, etc.

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Case Study 2

1st Floor Bathroom, waste lines leaking above ceiling

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Case Study 2

1st Floor Bathroom, waste lines leaking above ceiling

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Case 2

• Damage observed

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Case Study 2

Brown debris on PVC pipes below waste water lines

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Case 2

• New owner concerned about potential contamination on personal belongings in home.

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Case 2

• Assessment Strategy – Pre-remediation

• Collect surface dust and swab samples from known contaminated areas as well as personal belongings

• All samples collected using aseptic techniques

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Case 2

• Pre-Remediation samples – Samples collected

• 3 bulk samples from contaminated areas• 6 dust samples from personal belongings

– Samples analyzed for bacterial ID & presence of GPB and GNB

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Case 2

• Results– Pre-remediation dust sample results

• All dust samples analyzed for GPB and GNB– Highest concentrations of GNB found in a contaminated

wall cavity (1,700,000 CFU/g) – Two other samples collected in contaminated areas

indicated “no growth” or no GNB.– GPB and GNB found on personal belongings in similar

concentrations throughout the home.

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Bulk Samples

0

1000000

2000000

3000000

4000000

5000000

6000000

DenCeiling

BRCeiling

ColumnDen

GPBGNB

Bulk samples of drywall from known contaminated areas (CFU/g)

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Dust Samples (CFU/g)

0

500000

1000000

1500000

2000000

2500000

3000000

MasterBedroom

Boys'Room

Girl'sRoom

Den FamilyRoom

Basement

GPB GNB

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Case Study 2

• Pre-remediation swab samples– 10 swab samples collected

• 4 from suspected contaminated areas• 6 from personal belongings

– Analyzed for:• Presence/absence of E-coli• Total coliforms • Fecal coliforms.

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Case Study 2

• Results– Pre-remediation swab sample results

• E.-coli and fecal coliforms absent from all samples – including known contaminated areas

• Total coliform results mixed– Absent in contaminated areas – Present on the majority of personal belongs tested

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Case Study 2

• Remediation – Performed throughout the home– Contaminated materials removed

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Case Study 2

• Post remediation sampling performed– 3 Swab samples collected– Analyzed for fecal coliforms, total coliforms

and E.-coli• All were absent from the final samples

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Conclusions

• Bacterial sampling is easy, interpretation of the results is difficult.

• Samples do not always support your hypothesis

• GNB and total coliforms are often isolated in normal environmental samples

• Results difficult to interpret

• Presence/absence of fecal coliforms and E-coli in dust/swab samples give a clear answer

• Samples may give false negatives – based on the age/condition of sample.

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Recommendations

1. If possible avoid sampling- Samples may confuse the situation

2. Visual inspections are generally more useful than sampling

3. To avoid false negatives, sample for fecal coliforms or E.-coli as soon as possible after the incident

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Speaker Contact Information:

David C. Regelbrugge, CIH, CSPDirector, Environmental Health & Safety

Boelter & Yates, Inc.847/685-9276

dcr@boelter-yates.com