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

Transcription

1 Determination of Sewage Contamination on Personal Belongings or Equipment Following Flooding or Waste System Malfunctions PO-109 American Industrial Hygiene Conference and Exposition May 13-16, 2006 Chicago, Illinois David Regelbrugge, CIH, CSP Gary N. Crawford, CIH Felice Holcomb, MSPH Jeff Ruhl PH: Copyright

2 Introduction Bacterial monitoring is messy Physically messy especially in the case of sewage back-ups/flooding Monitoring results do not always support original hypothesis 2

3 Background Sewage contamination due to: Natural disasters Flooding Hurricanes Malfunctions Pipe breaks Back-ups in basements 3

4 Background When back-ups occur Occupants may be exposed to raw sewage Building materials become contaminated with sewage 4

5 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 5

6 Background 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. 6

7 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. 7

8 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. 8

9 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 9

10 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 10

11 Case Study 1 Hospital Water Line Break 11

12 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. 12

13 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 13

14 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/m 3 Highest concentration in mechanical room used for comparison purposes Remaining areas had similar GNB concentrations (Ave. 108 CFU/m 3 ) 14

15 Case Study 1 Airborne GPB - GNB Concentrations GPB GNB 15 1st Floor Office Outside Outside Basement Mechanical Rm 6th Fl. Waiting Rm Concentration (CFU/m3) 3rd Fl. Waiting Rm. 1st Fl. Medicine Area 7 Fl. Mechanincal Rm. 6th Fl. Nurses Station 3rd Fl. Nurses Station

16 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. 16

17 Case Study 2 Leaky Drain Pipes 17

18 Case Study 2 Recently purchased home, copper drain lines throughout the home had deteriorated allowing waste water to contaminate wall cavities, ducts, etc. 18

19 Case Study 2 1 st Floor Bathroom, waste lines leaking above ceiling 19

20 Case Study 2 1 st Floor Bathroom, waste lines leaking above ceiling 20

21 Case 2 Damage observed 21

22 Case Study 2 Brown debris on PVC pipes below waste water lines 22

23 Case 2 New owner concerned about potential contamination on personal belongings in home. 23

24 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 24

25 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 25

26 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. 26

27 Bulk Samples Bulk samples of drywall from known contaminated areas (CFU/g) GPB GNB Den Ceiling BR Ceiling Column Den 27

28 Dust Samples (CFU/g) GPB GNB Master Boys' Girl's Den Family Basement Bedroom Room Room Room 28

29 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. 29

30 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 30

31 Case Study 2 Remediation Performed throughout the home Contaminated materials removed 31

32 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 32

33 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. 33

34 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 34

35 Speaker Contact Information: David C. Regelbrugge, CIH, CSP Director, Environmental Health & Safety Boelter & Yates, Inc. 847/