Canal study irrefutably shows human pathogens
EDITOR:
On Feb. 7, the Keynoter published a letter to the editor from Dr.
John Clark titled “Conservancy’s canal study fuzzy.” This was written in
response to a press release issued by The Nature Conservancy announcing
the results of its canal water-quality monitoring program, Florida Keys
Watch. As the project manager for this monitoring effort, I feel that I
must clarify some misinformation printed in the letter.
The objective of Florida Keys Watch was to conduct a science-based
study designed to inform the general public and the scientific community
on the condition of canal water quality and the source of potential
contamination.
Over the course of the study, more than 600 water samples were
collected from a series of 17 canals in various locations throughout the
Keys. We analyzed these samples for enterococcus bacteria levels, which
the U.S. Environmental Protection Agency has determined to be the best
indicator of human sewage contamination for marine waters. Following
months of monitoring, it soon became clear that many of these canals
consistently contained high levels of enterococcus well above the EPA’s
recommended guideline.
The canals with poor water quality were then sampled for the presence
of human viral pathogens. The results from these samples would confirm
whether human waste was present in the canal water.
Twenty-five samples were collected from 10 different canals. Six of
these 10 canals tested positive for human viral pathogens at least once.
Dr. Clark’s letter challenges The Nature Conservancy’s claim that
human viruses were found throughout the Keys by stating, “Only two
canals in the Lower Keys and two canals in Key Largo consistently showed
human-related viruses....”
As mentioned above, we identified six canals containing these viruses
on the following Keys: Geiger Key, Cudjoe Key, Big Pine Key, and three
different locations in Key Largo.
The writer goes on to point out that “virus data are the strength of
the study because the Conservancy research report dismisses the value of
its own extensive enterococcus bacteria test.” This is certainly not the
case. Our long-term enterococcus data set indicated the presence of
human sewage in the majority of the canals monitored. This proved to be
accurate in the fact that it “predicted” that we’d find human viruses.
The unfortunate truth is that many of our canals contain high levels
of bacteria, and in our small-scale study, human sewage turned out to be
the cause. If anyone has any further questions regarding the results,
please contact me.
Brad Rosov, program manager
Marine conservation
The Nature Conservancy
Summerland Key |
