Protecting Our Water Environment

BOARD OF COMMISSIONERS

Terrence J. O'Brien
President

Kathteen Therese Meany
Vice President

Gloria Alitto Majewski
Chairman of Finance

James “Jim* Haris

PAOLA ALAIN IOLA NAA AIAN,

Metropolitan Water Reclamation District of Greater Chicago — Synniain sano
100 EASTERIE STREET CHICAGO, ILLINOIS 60611-2803 312/751-5600 Hay "Bua" Vouret!

Cecil Lue-Hing
Director of Hesuarch & Development

July 28, 1999
312/751-5190

Gulf of Mexico Hypoxia Working
Group National Centers for
Coastal Ocean Science

WS 13446 SSMC4

1305 East-West Highway

Silver Spring, MD 20910

Ladies and Gentlemen:
Subject: Hypoxia in the Gulf of Mexico

This responds to the notice in the Federal Register on May
4, 1999, inviting comments on the integrated assessment of the
causes and consequences of hypoxia in the Gulf of Mexico. The
MetropolitanWater Reclamation District of Greater Chicago has
the following comments on the reports for Topics 3 and 5.

Topic 3 = Flux and Sources of Nutrients in the Mississippi-
Atchafalaya River Basin

1. Executive Summary, page 13. In addition to report-
ing the mean annual flux of nutrients for the com-
bined period 1980-1996, it would be helpful to
include the mean annual flux for a more recent pe-
riod, 1994-1997. Comments should then be included
regarding recent trends in the data.

2. Introduction, page 18. If available, include per-
cent of fertilizer and pesticide usage in the Mis-
sissippi River basin compared to the United States.

3. Methods, page 20. Phosphorus atmospheric deposi-
tion should be included as a source of nutrients to
the Mississippi River Basin.

4. Methods, page 21. Include sample collection fre-
quency during the 1970s and 1980s for the. United
States Geological Survey’s National Stream Quality
Accounting Network program.



Ladies and Gentlemen 2 July 28,

Subject: Hypoxia in the Gulf of Mexico

Research Needs, page 75. Additional research is
needed as to the role of instream nitrification and
denitrification in reducing nitrogen in urban riv-
ers and streams.

Recommendation 2, page 78. It is recommended to
establish an effluent monitoring program for deter-
mining nutrient loading from municipal and indus-
trial point sources. Under the current National
Pollutant Discharge Elimination System program, all
dischargers monitor constituents of concern, in-
cluding nutrients, in permitted effluents and sub-
mit Discharge Monitoring Reports to the permitting
authority. Thus, this recommendation is not re-
quired.

Figure 3.1. The time period for this figure is not
given. Assuming that it is a long interval, an ad-
ditional figure showing nutrient data for a recent
period (1994 through 1997) should be included to
indicate recent trends.

. = Reduci Nutri Load tall _
trate-Nitrogen, to Surface Water, Groundwater, and the Gulf
of Mexico

1.

Introduction, page 7. The report states that
Goolsby et al. (1999) was unable to provide accu-
rate estimates of nutrients in urban runoff. Sug-
gest that the authors refer to Polls, I. and R.
Lanyon, 1980. “Pollutant Concentrations from Ho-
mogenous Land Uses.” Journal of the Environmental
Engineering Division, ASCE, Volume 106, No. EEl,
pages 69-80.

Results, page 35. The two constructed wetland case
studies received inflows with nitrate concentra-
tions averaging 2-4 mg/L. The effect which con-
structed wetlands would have on reducing nutrients
if the nitrate inflows were greater than 4 mg/L
should be included.

1999


Ladies and Gentlemen 3 July 28, 1999

Subject: Hypoxia in the Gulf of Mexico

3. Recommendation 4, page 102. Based on the fact that
the annual nitrogen input to the Mississippi River
Basin from municipal point sources is one percent,
and that few new wastewater plants will be con-
structed in the future, it makes no sense in terms
of economics to recommend that new wastewater
plants control nitrogen through tertiary treatment.
This is not a cost-effective approach for reducing
nutrient loadings to the Gulf of Mexico.

If there are any questions regarding the above comments,
please contact Mr. Irwin Polls, Biologist III, at (708) 588-4219.

Very truly yours,

Cecil Lue-Hing, D.Sc.,
Director

Research and Develop

CLH:RL:js
cc: John Field, National Ocean
Service

Mary Belefski, United States
Environmental Protection
Agency

Ken Kirk, Association of
Metropolitan Sewerage
Agencies

Hugh H. McMillan

John Farnan

Thomas K. O'Connor