THE UNIVERSITY OF NORTH CAROLINA

G
CHAPEL HILL © Rum. D

THE SCHOOL OF PUBLIC HEALTH Chapel Hil! 27514
DEPARTMENT OF

ENVIRONMENTAL SCIENCES AND ENGINEERING

April 23, 1975

Dr. Joshua Lederberg

Dept. of Genetics, S-337
School of Medicine
Stanford University
Stanford, California 94305

Dear Dr. Lederberg:

It was a great pleasure to meet you in San Francisco last week and in
particular to hear your comments on water quality management. While many
professionals in this field are resentful of the intrusions of those who have
not labored in their vineyards, I very much appreciate the interest in our
problems shown by scientists from whatever field. They almost never fail to
bring new insights to bear on problems with which we have been too closely
associated.

As you will note from the papers that I am enclosing, I was delighted to
hear you indicate that you felt one important deficiency in the position
papers was that there was no reference to the economics and feasibility of
dual systems, with segregated supplies for human consumption.

As you can see, I have long been advocating the consideration of this
approach. We have made some studies of the additional costs of dual distri-
bution systems, and for new communities this amounts to approximately 20 percent
higher costs than for conventional distribution. Of course, this would be
often offset by savings in resource development. However, the economic feasi-
bility cannot be determined for the general situation, but must be assessed for
each application. I believe that in California we now have an opportunity to
introduce this as one of the many options available.

My fear is that, should we plan to accept the chemicals in our water
supplies, we may find out too late that we made a decision that is not appro-
priate for large populations. I feel that this may now be the case with London,
where the decision was made in the last century to utilize the Thames downstream.
As noted in Dr. Cooper's report, on page 79, as long ago as 1947 there was found
to be some difference in cancer mortality between those drawing their water from
the Thames in London, as contrasted with several boroughs in southeast London
which draw their water from the Kent chalks. When I was in London last year,

I arranged that similar studies be initiated, particularly as we now haee the
synthetic organic chemicals present in the polluted sources.

‘T' nNaro
Dr. Joshua Lederberg
April 23, 1975
Page 2

A tentative date for our next meeting was set, July 10 and 11, and I
hope that we will have an opportunity to meet once again.

As chance would have it, on my way home I got a lift at the airport from
a friend who was also carrying President and Mrs. Lyman to Chapel Hill; and we
had an opportunity to discuss many mutual friends at Stanford amongst whom IL
should now enjoy the privilege of including you.

Sincerely yours,

¢
sal
el A. Okun

Kenan Professor
of Environmental Engineering

DAO/sah
Enclosure