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FROM :
Erivironmental Science
PHONE NO . : 7733257448
Oct . 04 2006 04:16PM P2/9
RECEIVED
Before the Illinois Pollution Control Board
CLERK'S OFFICE
October 4, 2006
OCT 0 4 2006
In the matter of :
STATE OF ILLINOIS
)
Pollution Control Board
Proposed Amendments to
R04-25
Dissolved Oxygen Standard
35 Ill. Adm . Code 302 .206
1
Testimony of Thomas J. Murphy, Ph . D.
I am Thomas J . Murphy, an emeritus professor of chemistry at DePaul University . I founded
and chaired the Environmental Science Program at DePaul . My research was principally related to
the atmospheric transport and deposition of toxic substances to bodies of water . I was the first to
determine that the atmosphere was an important source of toxic organics to bodies of water . I served
as editor of the Journal of Great Lakes Research for six years
. I have been involved with water
quality issues in Illinois for more than
35 years. As a board member and technical advisor for the
Lake Michigan Federation for 20 years or so, I participated in and commented on many water
quality issues related to nutrients, dissolved oxygen and toxics in the rivers and lakes of Illinois and
their sediments
. I was the scientific advisor to and member of a citizen's task force, Operation
Lakewatch, in the early 1980's . This group uncovered major illegal discharges to Lake Michigan-
including one from the McCormick Place Exposition Center, and spurred the MWRDGC to revamp
its Lake Michigan water quality monitoring programs .
My comments here relate to the physical chemistry of the exchange of gases between air and
water phases, and the driving force for their distribution within these phases . Chemists claim that
chemistry is the fundamental science because
everything is composed of atoms and molecules. and
all exchanges and transformations that occur in the universe, on the earth, in organisms, etc. obey
the laws of chemistry.
The Illinois Association of Wastewater Agencies (JAWA) has proposed amendments to the
Dissolved Oxygen (DO) Water Quality Standards for General Use waters in Illinois to the Illinois
Pollution Control Board (Board), R04-025 . Their request is for a
scientifically defensible
standard to
update the current regulations, which were adopted in
1972 . Testimony before this Board in
subsequent hearings, supports the need to update the DO standards as requested by the IAWA
I agree with the statement in the March 31,
2006,
Recommended Revisions to the Illinois
General Use Water Quality Standards for Dissolved Oxygen," report (IEPA 2006
; Exhibit 23)
by the
Illinois DNR and Illinois EPA that, " . .
.the current standard for Illinois General Use waters is too
simplistic
; it inadequately accounts for the varied DO requirements of aquatic life in these waters ." I
also agree with their recommendation of replacing the current standards with additional levels of
standards that will apply in specific situations
. Their recommendation, however, is not based on the
science of gas exchange, and is deficient in not requiring additional protection during times when
General Use
waters are cold, and higher oxygen saturation levels of DO are required to provide
sufficient DO availability to indigenous aquatic organisms
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The recommendation of the IDNR and the ]EPA for amendments to the DO standards is
described and supported in IEPA 2006
. In this document (p . 2) they describe the 1986 Ambient
Water Quality Criteria Document of the USEPA (USEPA 1986) :
afoundationfrom which to
interpret . . . information applicable to the DO needs of aquatic life in Illinois . ", and cite it 48 times in
the document . But USEPA (1986) suffers from major deficiencies which include :
•
Very few of the studies discussed were on warm water fish, most were on cold water fish
.
•
Almost all of the studies were done in the laboratory which this study and all other relevant
studies admit often have little relevance to the natural world-
- The science in the document is 20 years old .
-
The temperature at which most of the studies referenced in the report were conducted is not
reported, which prevents the determination of the percent saturation of the DO to be determined .
Further discussion of these deficiencies was in my testimony to this Board on April 25, 2006
[Exhibit 27] and is in Appendix A . These deficiencies demonstrate that USEPA (1986) is an
rrutdate4 limited and inadequate foundation', and preclude it from contributing meaningful help to
a scientifically defensible standard-searing procedure . A
house built on such a foundation can not be
expected to stand. Why do the IDNR, the IEPA and the MWRDGC claim it as a `foundation'?
The issues are 1) that the transfer of gases between phases (between air and water across the
water surface ; between water and a fish across a gill surface
; etc.) is driven by the difference in
partial pressure of the two phases ; and 2) that the concentration of oxygen dissolved in the water is a
function of the pressure of oxygen in the atmosphere as well as
the temperature and salinity dof the
water . The problem is that it takes considerably more oxygen (mg/L) to saturate water at 0°C than at
25°C . In other words a mg/I of DO is much more `available' to an organism at 25°C than at 0°C
. A
standard-including the proposed standard (IEPA 2006) that does not take the temperature
dependence of the solubility of oxygen into account could lead to sign fcant oxygen deficiencies
for
organisms at cold temperatures (see discussion in Appendix B) .
The significance of this temperature dependency of oxygen solubility with the proposed DO
amendments (IEPA 2006) is that each of the different proposed time periods has months of the year
when the water in Illinois rivers are zero degrees (Celcius) or close to it-March and February, and
months of the year when the water is often above 25°C-July and August
. IEPA (2006) gives no
explanation or justification why they require a daily minimum of 53% saturation at 30°C (4 mg/L)
but require only 27% saturation at 0' (4 mg/L)
. It could be noted that the oxygen pressure at the
summit of Mt. Everest, often described as in the `death zone', is 33% of the pressure at sea level
.
Inexplicably and unaccountably, the IEPA is proposing DO standards for General Use waters in
Illinois in mass units (mg 02/L) . Perhaps there are scientific reasons for not basing the proposed
standards on pressure (or not exclusively on pressure), but their
support documents are silent on a
scientific justification for this choice, a choice that does not follow the established science of gas
transport and partitioning, as demonstrated in Dejours (1981) and Davis (1975) .
The only document cited that supports the use of a mass-based DO standard is USEPA (1986) .
IEPA (2006) states (p . 5) : "Illinois DNR and Illinois EPA primarily base the recommended revisions
to DO standards on information in USEPA (1986), which provides a sound, scientifically based
foundation
." USEPA (1986) states on its page 1 : "Expressing the criteria in terms of the actual
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amount of dissolved oxygen available to organisms in mv/L is considered more direct and easier to
administer compared to expressing the criteria in terms of percent saturation
. DO
criteria expressed
as percent saturation, such as discussed by Davis (1975 a,b), are more complex and could often
result in unnecessarily stringent criteria in the cold months and potentially unprotective criteria
during times of high ambient temperature or at high elevations ." (emphasis added) .
Clearly USEPA (1986) does not provide a sound, scientifically basedfoumiation for these
proposed DO standards . Is
`ease to administer' the basis on which we should base water quality
standards in Illinois? Do IDNR scientists find it `complex' to convert mg/L at a particular
temperature to percent saturation? Should we have
standards that are not based
on the actual
availability of oxygen to aquatic organisms? Basing standards on assumption (mg/L will work
; the
organisms have evolved with low DO concentrations in the summer months
; the availability of DO
to aquatic organisms is independent of temperature ; etc., are fine, but the standards then are only as
good as the assumptions are valid .
In a paper referenced several times in the IDNR and IEPA background documents, Davis (1975)
arrives at recommended DO criteria essential for the protection of fish populations and lists them for
six different groups . The results for the group of `freshwater mixed fish populations with no
salmonids' are shown in the abbreviated table 10 below. The signicance of Table 10 (see Appendix
C) is that the recommended criteria are in units ofpercent saturation NOT in mg 02/L .
Davis (1975) recommends a constant P02 until 25°, when he recommends a modest increase .
The basis for these recommendations is (p. 2324): `It must be emphasized that . . . fish require both
the correct oxygen tension (pressure) gradient to move 02 into the blood and sufficient oxygen (per
unit volume r
fwater breathed) to fu f ll the requirements of metabolism .
Based on the petition from the IA WA and the stated objectives of the IDNR and the [EPA that
the new standards be based on science, the proposed amendments to the DO standards now before
the Board are deficient and should not be approved by the Board They are not based on the science
of gas partitioning and they put organisms with high oxygen requirements at risk in cold waters .
The IAWA has invested considerable resources in consultants, legal expertise, and staff time to
have the DO standards for the General Use waters in the state amended based on
defensible science
.
Considerable time and resources have been expended by state agencies to evaluate the large body of
information on the physical and chemical characteristics of the general use water bodies in the state
and their indigenous aquatic organisms, Perhaps the best remedy at this point is to revise the
proposed amendments to increase the dissolved oxygen concentrations at low temperatures . These
revisions would look like the example above from Davis (1975, Appendix C) . It would divide each
of the tiers into two or more sections-each covering a limited temperature range, and would set
separate, higher DO standards (mg 02/L) for the low temperature range based on the percent
saturation (the percent oxygen saturation would be similar at the different temperatures) .
The current water quality standards for
DO have been in place in Illinois for 34 years.
Amending them is clearly a long and complex process
. The Board should not allow this one-in-34-
year opportunity to be only `tweaking the numbers' . While the scientific base of the proposed
amendments is appreciably better than that of the current standards, the changes are only
evolutionary.
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The IAWA petition has presented the Board the opportunity to get it right' Dennis
Strcicher,
the president of the IAWA has testified in these hearings,
good science should not he
negotiated ." If the proposed amendments (IEPA 2006 ; Exhibit 23) are adopted, they will be obsolete
before they go into effect, being bases on 1986 science
. But they may well remain in effect for
many years . Thus, it is important to get them right
Neither the current standards nor the proposed
amendments are based on the science of gas partitioning
. Adopting a DO tier for low temperatures
described above, will be an important step in making the Illinois WQ Criteria for DO protective of
aquatic organisms in the 21 a century.
I urge the Board to delay approving amendments to the DO Water Quality Standards for
General Use waters in Illinois until the amendments are based on current science, a revolutionary
change in the criteria I urge the Board to require the Agencies to develop amended standards based
on the percent saturation of oxygen,
and on the stream and biology data they have already
developed. Such amended standards would satisfy the request for science-based standards from the
IAWA, and should serve to protect the indigenous aquatic organisms in Illinois waters until climate
change necessitates their revision, hopefully well into the future.
References
Cross, Joel (2006) . Pre-Filed Testimony. Hearing on II
. PCB Rule Making R 04-25, Amendments to
Dissolved Oxygen Standard 35111
. Admin
. Code 302206 ; Springfield, IL . April 25 .
Davis, John C
. (1975)
. Minimal DO Requirements of Aquatic Life with Emphasis on Canadian
Species: A Review . Canadian Journal of Fisheries and Aquatic Sciences, 32, 2295-2332
.
Dejours, Pierre (1981), Principles of Comparative Respiratory Physiology,
2cd
Ed., Elsevier
.
IEPA (2006) . Recommended Revisions to the Illinois General Use Water-Quality Standards for
Dissolved Oxygen", March 31 . Pre-Filed Testimony . Hearing on IL PCB Rule Making R 04-25,
Amendments to Dissolved Oxygen Standard 35 Ill . Admin
. Code 302 .206; Springfield, IL
. April 25 .
Smoger, Roy (2006)
. Pre-Filed Testimony
. Hearing on IL PCB Rule Making R 04-25, Amendments
to Dissolved Oxygen Standard 35 Ill . Admin. Code 302_206 ; Springfield, IL
. April 25 .
Truelson (1997) . Ambient Water Quality Criteria For Dissolved Oxygen . Ministry of Environment,
Lands and Parks, Water Quality Branch, Victoria, BC . ; February .
USEPA (1986). Ambient Water Quality Criteria for Dissolved Oxygen,
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Appendix A
•
Most of the studies discussed in USEPA (1986) relate to cold
water
fishes. IEPA (2006)
states (p
. 10)
: "Because USEPA (1986) "warmwater" criteria are based on information for
only a few tested "warmwater" fish species . . .
•
Most of the reports discussed in USEPA (1986) are based on laboratory studies . IEPA (2006)
states (p . 22):
"Moreover, particularly for non-toxic substances like dissolved oxygen, sole
reliance in laboratory-based acute thresholds is not recommended :" and they quote Smale
and Rabeni (1995), "Considerable difference have been found between laboratory tolerance
values and lethal conditions in natural situations
(Moore 1942 ; Davis 1975) .
•
Very few studies of stream macroinvertebrates are discussed in USEPA (1986) . IEPA (2006)
states (p . 15) : " . . .USEPA (1986)
. .- relied primarily on only two studies of relatively few
types of insects from streams in . . ."
•
The absence in USEPA (1986) of any information from the last 20 years .
•
Most of the reports of DO concentrations in USEPA (1986) do not include the temperature of
the measurement . This precludes the determination of the percent saturation of the oxygen in
the sample.
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Appendix B
The partitioning of gases between different phases and their movement within phases are well
understood physical phenomena discussed in all physical chemistry and even most intro chemistry
texts- The partitioning and movement is driven by differences in pressure (activity ; percent
saturation)
. The occurrence of differences in pressure, within or between phases drive and control
such processes as the exchange of oxygen, water vapor, carbon dioxide, nitrogen, etc . between the
atmosphere, soils, and bodies of water, and the uptake and distribution of gases to and within all
organisms .
A standard reference book on the principles of respiratory physiology by Pierre Dejours, 1981,
Principles of Comparative Respiratory Physiology,
discusses the science of gas exchange in many
organisms, including fishes and other aquatic organisms . In the chapters relevant to aquatic
organisms, I counted 88 equations that related in one way or another to gas exchange or transport in
the functioning of organisms . In all
of those equations the concentrations of the gas was given in
units of pressure . In this text on the science of gas transport in organisms, I looked through the entire
book and did not find one reference to a concentration in mg/L as a driving force for molecular
movement .
Truelson (1997) states that, "fish physiology specialists commissioned by the ITC (1980)
concluded that the rate of oxygen transfer across fish gills is governed by diffusion down a
concentration gradient and is dependent on the mean difference in oxygen partial pressure across the
gills."
In contrast, IEPA (2006) uses units of mass mg O2/L for the concentrations of oxygen in the
proposed amendments and in the discussion supporting the changes
. While there is a proportionality
between pressure units and mass units, the proportionality factor differs depending on the
temperature
. The factor depends on the maximum solubility of the gas in water at that temperature,
and oxygen has a higher solubility in cold water than in warm water
. For instance, its solubility in
water is 14.6 mg 02/L at 0°C, and 7.5 mg 02/L at 30'
. Thus water with 7.5
mg 02/L present at 30° is
100% saturated the pressure of oxygen in the water is the same as in the atmosphere, while at 0° the
water is only 51% saturated-the oxygen pressure in the water is only half of an atmosphere
. While
the same mass ofoxygen is present (7.5
mg 02/L) at both temperatures, its percent saturation-what
an organism experiences, is only one-half as much at the lower temperature as it does at the higher
temperature .
It could be mentioned here that water at 20°C in equilibrium with the atmosphere-the
pressure of the oxygen in each phase is 0.21
atm, contains 9.1 mg 02/L while the air contains 284
mg 022 .
In discussions with IDNR and JEPA personnel, they indicated that one of the other documents
they relied on for justification of their use of mass units rather than percent saturation for DO, was
the Ambient Water Quality Criteria for Dissolved Oxygen (Truelson 1997)
. This document
considers the use of percent saturation but also ultimately rejects it in favor of mass units
. In their
rational for this choice in Section 4 .7,2, they make several errors and several assumptions
.
The first error is to assume that regardless of the percent saturation of the water, that the mass
transfer coefficient is sufficiently high that the mass concentration limits the oxygen transfer
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regardless of the pressure difference
. This is not true, of course if the saturation in the water is lower
than the concentration in the organism, a condition that can arise in cold waters with little oxygen in
them, the condition 1 am concerned with and am addressing in this testimony
.
They also claim that the partial pressure of oxygen in saline waters would "unacceptably
decrease" as the salinity increases . This is not correct. It is true that the saturation concentration of
oxygen (mg/L) will decrease as the salinity increases, but the partial pressure (the activity
; the
percent saturation
; the availability of oxygen to an organism) will be
unchanged as the salinity
changes. Saturation is saturation
; 100% is 100% . This is just another reason for using percent
saturation in place of mg/L to measure oxygen availability to an organism. It is independent of
salinity as well as being independent of temperature
.
Truelson (1997) claims that a plot in Davis (1975 ; Fig 16) of oxygen response data (mg/L) for
freshwater fish plotted against test temperature showed the absence of any relationship
. It's true that
the line is flat, no change in response with temperature
. However, the correlation coefficient for the
correlation was less than 0
.01, meaning that the absence of a relationship was without any
significance, that a direct positive or negative relationship was equally as likely
.
Truelson (1997) also uses the "added complexity" of percent saturation based standards as a
justification for mass-based standards, also disregarding the fact that with most measurements today
being made with electronic sensors, the percent saturation, the activity of the oxygen is the response
produced by the sensor .
Both USEPA (1986) and Truelson (1997) reference other studies that show a temperature effect
on the availability of DO to aquatic organisms, results in accord with gas exchange science .
However, they continue to base their conclusions of the large majority of studies that did not
measure temperature effects
.
USEPA (1986) implicitly acknowledges the decreased availability of DO at low temperatures
when it states, "Many states have more stringent DO standards for cooler waters
."
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Appendix C
Table 10
. Oxygen criteria based on percentage saturation values derived with three levels of protection
in the text
. P02's and values of mg O2/L were extracted from Table 9 and rounded off for use here . The
values shown for mg 02/L were calculated from the values of mg 02/L in this table
.
The criteria essential for protection of aquatic fish populations are expressed as percentage saturation
values at various temperatures
. They were derived from both P02 and mg 02/L values, as both oxygen
tension and oxygen content are critical factors
. At the lower temperatures, the percentage saturation value
was determined using the P02 values essential for maintaining the necessary oxygen tension gradient
between water and blood for proper gas exchange
. Higher percentage saturation values are necessary at the
higher temperatures to provide sufficient oxygen content to meet the requirement of respiration as defined by
the mg 02/L values .
Percentage saturation values are defined as 'oxygen minima' at each level of protection
. Graphical
presentation of the results is found in Fig . 19 . The temperatures corresponding to the percent saturation
criteria are defined as "seasonal temperature maxima ."
Davis (1975)
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S
%W
Freshwater Mixed Fish Populations with no Salmonids
Protection
Level
P02 mg 02/L
% Saturation for Criteria
5° 10° 15° 200 250
A
95
^
5.5
60 60 60 60 60
66
B
75
4.0
47 47
47
47
47 48
C
55
2.5
35 35 35 35
35 36
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FROM :
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From Thomas J. Murphy
DePaul University
773-338-3165
773-325-7447 Fax
Mr. McGill,
Mark Anderson was quite helpful, but I was still unable to get onto the COOL
system to submit this online_ I will continue to try to get you an electronic copy, but for
now it is better to get a copy to you today .
Tom Murphy
Fax Message
Richard McGill
Illinois Pollution Control Board
Re: R04-025
4 October 2006
RECEIVEDCLERK'S
OFFICE
OCT 0 4 2006
Pollution
STATE OFControl
ILLINOISBoard
a
