257933 Impact of flooding on water contamination, Tennessee and Kentucky, 20102011

Wednesday, October 31, 2012

Ellen Yard, PhD , National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA
Matthew Murphy, PhD , National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA
Kanta Sircar, PhD , National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA
Chandra Schneeberger, BS , National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA
Jothikumar Narayanan, PhD , National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA
Judy Manners, MS , Communicable and Environmental Disease Services, Tennessee Department of Health, Nashville, TN
L. Rand Carpenter, DVM , Communicable and Environmental Disease Services, Tennessee Department of Health, Nashville, TN
Elizabeth Hoo, MPH , Centers for Disease Control and Prevention, Office of Surveillance, Epidemiology, and Laboratory Services, Kentucky Department for Public Health, Division of Public Health Protection & Safety, Frankfort, KY
Alexander Freiman, MPH , Centers for Disease Control and Prevention, CSTE Applied Epidemiology Fellow, Kentucky Department for Public Health, Division of Epidemiology & Health Planning, Frankfort, KY
Lauren Lewis, MD , National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA
Vincent Hill, PhD, PE , National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA
Background: Floods are the most common natural disaster in the U.S. In addition to posing the immediate risk of drowning, floods can increase exposure to toxic chemicals and pathogens by flushing contaminants from industrial, agricultural, and waste facilities into rivers and residential areas, and potentially contaminating drinking wells. Despite these concerns, limited information exists on flood water contaminants. Objective: We characterized contaminants in flood water during two flood events and assessed the impact of flooding on well water contamination. Methods: In 2010, we collected flood water (n=10), post-flood river water (n=3), and post-flood well water (n=19) samples in Tennessee. In 2011, we collected flood water (n=15) and post-flood river water (n=8) samples in Kentucky. We collected grab samples and filtered water via dead-end ultrafiltration. We analyzed water samples for microbial indicators (total coliforms, E. coli, and enterococci), human pathogens (including Salmonella, E. coli O157:H7, Campylobacter, Cryptosporidium, Giardia, enterovirus, and adenovirus), nitrates, and atrazine. Additionally, we tested metals in 2011. We compared flood and post-flood concentrations from similar geographic locations using t-tests. Results: E. coli, enterococci, and Salmonella were present in all flood water samples tested for microbial indicators (n=23). In Kentucky, these contaminants were more concentrated in flood water compared to river water sampled three months post-flood (p<0.05). Arsenic and lead were also more concentrated in Kentucky flood water compared to post-flood river water (p<0.05). In Tennessee, one inundated drinking well disinfected prior to the flood contained E. coli, enterococci, Salmonella, and Campylobacter when tested post-flood. Discussion: Our results suggest that flood water contains higher concentrations of some microbial, pathogenic, and chemical contaminants than river water, and also suggest that flood water may cause well water contamination. These findings reinforce commonly recommended guidelines to limit flood water exposure and sanitize potentially contaminated drinking wells prior to use.

Learning Areas:
Environmental health sciences
Epidemiology
Occupational health and safety
Protection of the public in relation to communicable diseases including prevention or control

Learning Objectives:
List four pathogens commonly found in flood water. List two ways that flood water can contaminate drinking wells. Describe the dead end ultrafiltration method for collecting surface water samples. Identify five challenges to consider when collecting flood water samples.

Keywords: Disasters, Water Quality

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have been the principal or co-principal investigator of several studies evaluating human exposure to environmental toxins.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.