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| > **\"Knowlton, Kim\"      | +---+---------------------------------+  |
| > \<kknowlton@nrdc.org\>** | | T | > Thomas                        |  |
| >                          | | o | > Carpenter/DC/USEPA/US@EPA     |  |
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|                            | | S | > Addendum to NRDC comments on  |  |
|                            | | u | > Docket No.                    |  |
|                            | | b | > EPA-HQ-OW-2007-1189           |  |
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Dear Mr. Carpenter:

Attached are some additional comments for your consideration, as an
addendum to those previously submitted by my NRDC colleagues, re: EPA's
Draft Drinking Water Contaminant Candidate List 3 (CCL3), Docket Number
EPA-HQ-OW-2007-1189. If possible, I would appreciate the inclusion of
these additional comments into the record, since they pertain to two
contaminants listed in the draft CCL3 -- cyanotoxins and *Vibrio
cholerae* -- which were not covered in our comments sent Wed. 5/21/08.

Thank you again for your consideration.

Best regards,

Kim Knowlton, DrPH

Science Fellow, Global Warming and Health

Natural Resources Defense Council

40 West 20^th^ Street

New York, NY 10011

\(212\) 727-4579 phone

\(212\) 727-1773 fax

[[kknowlton@nrdc.org]{.underline}](mailto:kknowlton@nrdc.org_)

PRIVILEGE AND CONFIDENTIALITY NOTICE

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**NRDC [Addendum]{.underline} to Comments**

**on the Draft Drinking Water Contaminant Candidate List 3**

**Docket Number: EPA-HQ-OW-2007-1189**

**May 21, 2008**

Pursuant to the Safe Drinking Water Act Amendments of 1996 (SDWA), the
U.S. Environmental Protection Agency (EPA) is required to publish, every
five years, a list of unregulated contaminants that are known or
anticipated to occur in public water systems and may require regulation
under the SDWA. The Agency then must make a decision about whether or
not to regulate at least five of the contaminants on the list. EPA is on
the third round of this process and has published a list of candidate
contaminants, called the CCL3. The Natural Resources Defense Council
(NRDC) submits the following [additional]{.underline} comments to those
submitted previously by NRDC on EPA's Draft CCL3. These additional
comments pertain specifically to cyanotoxins, chemical contaminants
whose occurrence in drinking water is likely to increase as a result of
projected climate change impacts on natural systems.

**I. SUMMARY**

> NRDC [additionally]{.underline} requests that EPA take the following
> actions concerning the Draft CCL3:

-   Include cyanotoxins (no CAS \# listed) in the CCL3. These chemicals
    are known to cause serious and occasionally fatal human liver,
    digestive, neurological, and skin diseases. Monitoring for these
    chemicals in water sources and drinking water is needed to fully
    assess their risks to human health and determine whether regulation
    is necessary.

-   Address *Vibrio cholerae*, a microbial pathogen, in drinking water
    pursuant to the Safe Drinking Water Act (SDWA). This bacterium is
    known to cause outbreaks of cholera, an acute diarrheal illness
    caused by intestinal infection with the bacterium *Vibrio cholerae,*
    with serious and occasionally fatal human consequences*.* Monitoring
    for this pathogen in water sources and drinking water is needed to
    fully assess their risks to human health and determine whether
    regulation is necessary.

**II. DETAILED COMMENTS**

**EPA must regulate cyanotoxins, which are among the chemicals listed on
the CCL3.**

*Cyanotoxins (3)*. NRDC urges EPA to include
**[cyanotoxins]{.underline}** (no CAS \# listed) in the CCL3, in
particular because these chemicals are produced by cyanobacterial
species whose blooms are likely to expand further as a result of climate
change. Climate change is a "potent catalyst" for the expansion of
harmful cyanobacterial algal blooms in aquatic ecosystems.[^1] Rising
water temperatures and increasingly frequent extreme rainfall events can
contribute to the growth of these blooms, which are caused primarily by
inflows of nutrient-rich runoff, among cyanobacterial algae species.
Alternating periods of drought and deluge, which are also associated
with climate change, promote cyanobacterial blooms in a number of
freshwater lakes. Warming water temperatures, increasingly frequent
extreme rainfall events, and alternating periods of drought and deluge
--each of which can favor the growth of cyanobacteria -- are consistent
with the climate changes projected across much of the U.S. in the coming
decades.[^2]^,^[^3] Ingestion of cyanotoxin-contaminated water can cause
serious human illnesses, including neurological, liver, digestive, and
skin diseases, as well as tumor promotion.[^4]^,^[^5] An increase in
occurrences of the cyanobacteria *Microcystis* in the Great Lakes in
recent years, and associated exposures to the cyanotoxin microcystin in
drinking water, has caused considerable concern.[^6] Preliminary studies
have documented the presence of microcystins in the Great Lakes, at
times exceeding the recommended limit of 1 µg/L established by the World
Health Organization for drinking water supplies.[^7] This argues for the
inclusion of cyanotoxins on the CCL3 list and for monitoring the
distribution and concentration of these substances such as microcystin
which have "demonstrated the potential to jeopardize human health and
drinking water quality."[^8]

*Vibrio cholerae*. NRDC urges EPA to include *Vibrio cholerae* in the
CCL3, in particular because the occurrence of this microbial pathogen is
likely to expand further as a result of climate change.[^9] Rising water
temperatures and increased climate variability, which can result in
higher stream flow rates, are projected to occur as climate change
continues and "could favor conditions that increase the occurrence of
*V. cholerae* in Chesapeake Bay."[^10] The adverse health effects of
cholera outbreaks can be devastating, with an estimated one in 20
infected persons developing "severe disease characterized by profuse
watery diarrhea, vomiting, and leg cramps"[^11] which, without
treatment, can prove rapidly fatal. *Vibrio cholerae* is a natural
inhabitant of aquatic environments, and there is concern that as
environmental changes associated with climate change continue, natural
populations of *V. cholerae* may serve as a "precursor for new
pathogenic or epidemic strains"[^12] when ingested via inadequately
treated drinking water or contaminated shellfish. Cholera cases from
domestic source exposures continue to be reported in the U.S.,[^13]
mostly from contaminated seafood, yet concerns about potential drinking
water exposures under a changing climate argue for enhanced monitoring
for these pathogens in water sources, to fully assess the risks they
pose to human health.

III\. **RECOMMENDATIONS**

> We urge EPA to add cyanotoxins to the CCL3. These contaminants meet
> EPA's criteria to be listed in CCL3. Their health effects are known
> and they are likely to occur in drinking water sources. Their
> occurrence is also likely to expand as climate change continues, which
> makes it appropriate to include them in the CCL3.
>
> We also urge EPA to add *Vibrio cholerae* to the CCL3. This microbial
> pathogen meets EPA's criteria to be listed in CCL3. The adverse health
> effects of exposures to *Vibrio cholerae* are known and they are
> likely to occur in drinking water sources. Their occurrence is also
> likely to expand as climate change continues, which makes it
> appropriate to include this pathogen in the CCL3.
>
> Finally, we recommend that the Agency act to promptly assess the risks
> associated with these and the other contaminants nominated to the CCL3
> and take appropriate regulatory action under the SDWA to establish
> Maximum Contaminant Levels (MCLs) as necessary.

Respectfully submitted,

/s/

Kim Knowlton, Dr.P.H.

Scientist, Global Warming and Health Science Fellow

Health and Environment Program

Natural Resources Defense Council

[^1]: Paerl HW, Huisman J. 2008. Blooms like it hot. *Science* 320:57-58
    (4 April 2008).

[^2]: Intergovernmental Panel on Climate Change (IPCC). 2007. Climate
    Change 2007: The Physical Science Basis. Contribution of Working
    Group I to the Fourth Assessment Report of the Intergovernmental
    Panel on Climate Change \[Solomon S, Qin D, Manning M, Chen Z,
    Marquis M, Averyt KB, Tignor M, Miller HL (eds.)\]. Cambridge
    University Press, Cambridge, United Kingdom and New York, NY, USA.

[^3]: Confalonieri U, Menne B, Akhtar R, Ebi KL, Hauengue M, Kovats RS,
    Revich B, Woodward A. 2007. Human health (Chapter 8). *Climate
    Change 2007: Impacts, Adaptation and Vulnerability. Contribution of
    Working Group II to the Fourth Assessment Report of the
    Intergovernmental Panel on Climate Change*, Parry ML, Canziani OF,
    Palutikof JP, van der Linden PJ, Hanson CE, Eds. Cambridge
    University Press, Cambridge, UK.

[^4]: U.S. Centers for Disease Control and Prevention (US CDC). 2008.
    *Environmental hazards and health Effects - Facts about
    cyanobacteria and cyanobacterial harmful algal blooms*. Accessed May
    21, 2008, available at:
    <http://www.cdc.gov/hab/cyanobacteria/facts.htm#cyanotoxins>.

[^5]: Paerl and Huisman (2008).

[^6]: National Centers for Coastal Ocean Science, National Oceanic and
    Atmospheric Administration (NOAA), Silver Spring, MD. 2004. "Examine
    Environmental Regulation of Toxin Production by Cyanobacteria
    Capable of Disrupting Ecosystems and Endangering Drinking Water
    Supplies," available at:
    <http://www8.nos.noaa.gov/nccos/npe/projectdetail.aspx?id=385&fy=2004>.

[^7]: *Ibid*.

[^8]: National Oceanic and Atmospheric Administration (NOAA). 2008.
    "Harmful Algal Blooms and Hypoxia in the Great Lakes Region,"
    available at:
    <http://www.cop.noaa.gov/stressors/extremeevents/hab/habhrca/GL_fact_09-06.pdf>.

[^9]: Confalonieri et al. (2007).

[^10]: Louis VR, Russek-Cohen E, Choopun N, Rivera ING, Gangle B, Jiang
    SC, Rubin A, Patz JA, Huq A, Colwell RR. 2003. Predictability of
    *Vibrio cholerae* in Chesapeake Bay. *Appl Environ Microbiol*
    69(5):2773-2785.

[^11]: U.S. Centers for Disease Control and Prevention (US CDC). 2008.
    *Cholera*. Accessed May 21, 2008, available at:
    <http://www.cdc.gov/nczved/dfbmd/disease_listing/cholera_gi.html>.

[^12]: Louis et al. (2003).

[^13]: U.S. Centers for Disease Control and Prevention (US CDC). 2008.
    "Cholera and Other Vibrio Illness Surveillance System (COVIS),"
    available at:
    <http://www.cdc.gov/nationalsurveillance/cholera_vibrio_surveillance.html>.