ICE~VED

CLERK’S OFFICE

Re: Proposed amendments to dissolved oxygen standard (R04-25)

NOV 03 2004

Dorothy Gunn, Clerk

STATE

OF

ILlINOIS

Illinois Pollution Control Board

Poflut~onControl Board

James R. Thompson Center

100 W. Randolph St.

Suite 11-500

Chicago, IL 60601

Dear Ms. Gunn,

In April 2004, the Illinois Association of Wastewater Agencies (TAWA) submitted a proposal to the Illinois Pollution

Control Board proposing to lower the dissolved oxygen criteria from

5.0

mg/l to

3.5

mg/i during the months of July

through February. I am writing you to ask that you reject IAWA’s request. The proposed reduction in dissolved

oxygen criteria will not improve the condition of Illinois streams such as the Fox River, rather it will have the

opposite effect by further degrading water quality and harming aquatic life. The current Illinois standard for

dissolved oxygen follows U.S. Environmental Protection Agency guidelines and past scientific studies do not

support a lower standard. Therefore, the Illinois Pollution Control Board should reject the proposal to lower

dissolved oxygen standards.

In 2002, the Fox River was categorized as impaired by the Illinois Environmental Protection Agency. One of the

r’easons for the river’s impairment is low dissolved oxygen. The effects of low dissolved oxygen in rivers such as

Fox.are well documented. At extremely low oxygen levels, fish kills result. Low dissolved oxygen levels in the Fox

River will also negatively impact fish species that spawn in late summer, and sportfish such as smallmouth.bass -are

sensitive to low dissolved oxygen levels. Freshwater.musseis and other aquatic macroinvertebrates are also.

negatively affected by low dissolved oxygen. The aquatic fauna in the Fox River is already threatened by

deteriorating water quality with several species becoming extirpated from the watershedin recent decades. Lower

dissolved oxygen will only exacerbate the problems the Fox River faces.

Robert Schanzel made the following comments on behalf of the Illinois Chapter of the American Fisheries Society

regarding the proposal: “The Illinois Chapter of the American Fisheries Society does not support relaxing Illinois’

existing dissolved oxygen standards because insufficient evidence is available that such action will not have serious

and irrevocable consequences for the state’s aquatic biota

-

that is, the science does not support the proposed

changes.” Schanzei also states “To lower quality standards now, would not serve the best interests either of Illinois

citizens or its aquatic resources.”

Thecondition of the Fox River is impacted by multiple stressors. As these stressors become intensified the

ecosystem deteriorates. The degradation of the Fox River has and will continue to affect the well being of its

residents. In February 2004, over 150,000 residents in Aurora were recommended to boil their water. A report

prepared by Weston Solutions indicated that the majority of the blame forthe boil order could be placed on the

deterioration of water quality in the Fox River. The proposed rule change by IAWA will not improve the condition

of the Fox River, but it has the potential to accelerate its declining condition. Thus, it should be rejecte~tiby the

Illinois Pollution Control Board.

Thank you very much foryour time and consideration.

Sincerely,

---

2

Dorothy Gunn, Clerk

Illinois Pollution Control Board

James R. Thompson Center

100 W. Randolph Street

Suite 11-500

Chicago, IL 60601

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