The Zika ThreatASM Acts to Counter Zika Virus Outbreak.
Nancy K. Stoner, Acting Assistant Administrator for Water
United States Environmental Protection Agency
Office of Water (4100T)
1200 Pennsylvania Avenue NW
Washington, D.C. 20460
Re: Draft Recreational Water Quality Criteria Docket no. EPA-IAQ-OW-2011-0466
Dear Ms. Stoner:
The American Society for Microbiology (ASM) appreciates the opportunity to comment
on the proposed Recreational Water Quality Criteria (RWQC) for use in managing all US
coastal, inland and Great Lakes waters designated for primary contact recreation.
The ASM is the largest educational, professional and scientific Society dedicated to the
advancement of the microbiological sciences and their application for the common good.
The Society represents more than 38,000 microbiologists professionally employed in a
variety of areas including medical, genomic, molecular, environmental, food
microbiology, and public health.
The ASM commends the US Environmental Protection Agency (EPA) for developing
standards that protect human health from exposure to microbial pathogens and potential
pathogens while using marine and non-marine waters for recreation. The ASM
recognizes that the proposed RWQC is intended to promote public health by limiting
human exposure to levels of microbial contamination that result in unacceptable risks for
illness. The proposed RWQC represents a significant advancement over criteria first
established in 1986 and the advances reflect the outcome of multiple epidemiological
studies including the National Epidemiological and Environmental Assessment of
Recreation, (NEEAR) and the development of new methods and approaches including
qPCR and quantitative microbial risk assessment (QMRA). The ASM strongly supports
the use of QMRA and qPCR for enterococci and applauds the EPA for incorporating
NEEAR results into the RWQC.
We also understand the importance and basis of EPA's use of indicator species as a
means to assess risks of illness for recreational water use. The EPA proposes enterococci
and E. coli as suitable indicators, and has established "statistical threshold values”
(STVs) that are to be applied to all recreational waters, regardless of use intensity. The
use of the proposed indicators and STVs are derived from substantial research effort.
Nonetheless, the ASM is concerned that the proposed RWQC might result in inadequate
control of and exposure to microorganisms that pose significant threats to human health
through contamination of recreational waters and offers the following concerns and
Specific concern: The proposed RWQC emphasizes a select group of bacterial indicator
species, even though the ecological behavior of these indicators is not fully known, which
can confound predictions of risk of illness. Other indicators, e.g., bacteriophages of
Escherichia coli such as F+ coliphage, may prove more reliable and offer methodological
advantages for rapid and extensive monitoring.
Recommendation: The EPA should continue to assess the reliability of existing
indicator species, and evaluate alternatives, including coliphages. Additional research
effort should assess the ecology of indicator species, including persistence and growth in
receiving waters and sediments.
Specific concern: The proposed RWQC incorporates QMRA, for which the ASM is
strongly supportive. However, additional development to merge sanitary surveys with
pathogen monitoring is necessary to fully exploit the power of QMRA.
Recommendation: The EPA should support a microbial transport and fate program,
including an improved understanding of molecular marker transport and degradation.
The latter is especially important for use of existing and emerging molecular-based
Specific concern: The proposed RWQC argues that the state of the science is not
adequate for supporting nationally applicable criteria for exposure to pathogens from
non-human fecal sources, and that adoption of the proposed RWQC will lead to water
quality standards protective of human health. Nonetheless, exposure to pathogens from
non-human fecal contamination remains a risk factor, and one that may increase over
time with due to changes in climate and land use.
Recommendation: The EPA should support research that improves the state of the
science sufficiently to fully evaluate risks from non-human fecal contamination, to
identify suitable indicators for such contamination, and to develop approaches manage
Specific concern: While the proposed RWQC represent a significant and commendable
advance in the application of science-based management of risks of illness from
swimming in recreational waters, important uncertainties and risks remain unresolved.
These include, among others, the level of disinfection necessary for sewage discharge to
recreational waters, risks from secondary recreation contact (e.g., exposure to
contaminated sands, sediments and toxic algae), and adequacy of the existing wastewater
infrastructure to protect health in the context of changing climate regimes.
Recommendation: The EPA should continue to support and expand research to evaluate
relationships between health risks at beaches and sewage discharge, to develop new
indicators (including genomic based methods) for risk, to address risks from secondary
exposure and to assess likely impacts of changing precipitation and land use regimes.
Specific concern: While use of enterococci as an indicator of human fecal
contamination is generally well grounded, results from epidemiological studies in subtropical
and tropical waters do not fully support the standard proposed in the RWQC.
The RWQC provides the States with guidance to develop additional regulatory criteria,
but substantial additional research on sub-tropical and tropical waters is necessary.
Recommendation: Develop and implement additional studies on the distribution of
enterococci in tropical and sub-tropical waters, and relationships with gastrointestinal and
upper respiratory diseases. Such studies should include data on sewage discharges that
impact recreational waters and incorporate unusual weather events that might affect
Specific concern: The RWQC emphasizes primary recreational contact with inland,
coastal and Great Lakes waters. The EPA’s efforts in this context have been highly
commendable. Nonetheless there is significant and likely increasing secondary
recreational contact as well. Risks from such contact remain largely undefined, even
though in some water bodies secondary contact is much more important than primary
Recommendation: Expand the scope of epidemiological research to include secondary
recreational contact, and develop suitable QMRA to identify risks not mitigated by
current RWQC standards.
Since serious human health risks can arise from human and non-human fecal
contamination in recreational waters, the ASM recommends that the EPA continue to
fully evaluate relationships between indicator species and health risks, and to incorporate
in its Criteria a more complete understanding of indicator species ecology, microbial
source tracking and sample statistics for risk indicators.
The ASM is pleased to have the opportunity to provide comments in response to the
proposed rule on water quality standards in recreational waters, and hopes that these
comments and recommendations are of assistance to the EPA.
Roberto Kolter, Ph.D., Chair, Public and Scientific Affairs Board
Gary King, Ph.D., Chair, Environmental Committee, Public and Scientific Affairs Board