E-mail received from June Weintraub,
San Francisco Department of Public Health
April 4, 2005
Dear John,
Thank you for your emails on March 7 and 28 describing your concerns about the coliform levels at Lake Merced. As you know, Lake Merced is designated an emergency water supply, and as such, swimming and other full body contact uses are prohibited. Because there are no bacteria standards for recreational boating and fishing uses of this body of water, there is not a compliance issue in this case. (Also please note that the standard for full body contact in marine waters for fecal coliform is 400 per 100 ml, not 104 as you stated in your email; you may have been confusing the
standard for enterococcus for marine waters, which is 104 per 100 ml.) Boating and fishing are incidental uses allowed on the lake principally because it is acknowledged that the water would need to be treated in the event it was to be used for drinking water.
We believe that the guidance we issued last year advising users of the lake to take precautions when using the lake are sufficient to protect the users' health at this time. We do not believe that instituting a monitoring program in the absence of a regulatory standard for that body of water will improve protection of the public health. If there is evidence that the coliform levels do present a health threat to these boating and fishing users, we can consider taking action to prohibit those uses.
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June M. Weintraub, ScD
Epidemiologist, Environmental Health Section
City and County of San Francisco Department of Public Health
1390 Market St, Ste 910
San Francisco CA 94102
phone: 415-252-3973, fax: 415-252-3964
email: June.Weintraub@sfdph.org
Reply sent to June Weintraub, April 5, 2005
June:
Thank you for your reply to my two e-mails of the past
month. I am pleased to learn that you received them both, as I
was a little concerned that they were not getting through to you.
First let me observe that your quarrel regarding the
actual E-coli limit for contact recreation is not with me, but with the
PUC. They provided the number 104 MPN, and indicated that applied
to E-coli. I raised the point on two occasions, in conversation
with Greg Bartow and by e-mail with Paula Kehoe, suggesting that this
limit may in fact be too stringent. Greg responded that each
Regional Board establishes its own criteria, and that the local Board
may have chosen the more conservative limit. I have not yet heard
from Paula on this point.
It may also be that as the PUC does not now monitor
enterococci bacteria separately, the more conservative assumption,
that this limit be applied to E-coli bacteria, may
have been adopted. Perhaps the solution is a separate test.
In either case, however, after six months of consecutive
increases in readings of E-coli bacteria in North Lake the observed
level neared the larger limit of 400 MPN in December, and during that
same month two separate readings in South Lake exceeded that limit by
more than double. I believe that being the case some form of
monitor, together with a procedure for public notice of a special
condition when it occurs, is appropriate.
You seem not to agree. Let me be sure that I
understand your position.
First, you say that since Lake Merced is a potential
source of drinking water, state regulations for contact recreation do
not apply. That being the case, to use your expression, there is
no compliance issue for the simple reason that there are no applicable
regulations. I would have thought that in this case concern for
public health and safety would be even greater, and applicable limits
even more conservative. I would also point out that EPA
guidelines do provide specific limits for levels of enterococci
bacteria for infrequently used full-body contact recreation, such
as rowers flipping their boat, or competing dragon boaters dousing each
other after a race.
Second, you suggest that rather than work with the PUC,
and with community groups, boaters and fishermen, to develop an
effective yet practical monitoring system, much as is practiced on
recreational waters throughout the state, you would find it more
expedient to simply shut down Lake Merced for all recreational
activity. I sincerely hope that I have misunderstood this point.
Finally, you refer to an advisory published last year that
provides guidance for prudent use of Lake Merced for recreational
purposes. I had not been aware of that document prior to the
current exchange. I wonder what steps have been and are being
taken to assure that the boating and fishing community is fully
conversant with this advice.
Again, I appreciate your clarification if I have
misunderstood your positions.
John
And a follow-on note sent the same day.
June:
Having done a little more web search, I came across the
following guidelines from the EPA.
Limit for E-coli in infrequently used contact recreation
in fresh water, 575 MPN. This is substantially less than the 985
MPN observed in South Lake in December.
I am far from suggesting that this is a permanent, or even
frequent occurrence, or that the lake should be shut down for
recreational activity. It does seem prudent, however, to identify
those times and conditions under which the lake is especially
vulnerable to E-coli contamination, and to design a monitoring and
public notice procedure that addresses that issue.
John
>>>>>>>>>>>>>>>>>>>>>
John Plummer
Friends of Lake Merced
LakeMerced@aol.com
www.lakemerced.org
John Plummer
Friends of Lake Merced
LakeMerced@aol.com
www.lakemerced.org