Final Revisions to the Polychlorinated Biphenyl Criteria for Human Health and Wildlife for the Water Quality Guidance for the Great Lakes System

SUMMARY: EPA is publishing final revisions to the polychlorinated

biphenyl (PCB) ambient water quality criteria for human health and

wildlife for the final Water Quality Guidance for the Great Lakes

System that was published in March 1995 (the 1995 Guidance). The final

revisions are limited to the method for calculating a composite

baseline bioaccumulation factor (BAF) for PCBs and the method for

calculating a composite octanol-water partition coefficient (Kow)

for PCBs. After reviewing all public comments, EPA concluded that the

approach it proposed in October 1996 for calculating a composite

baseline BAF, using the second alternative proposed for calculating a

composite Kow, for PCBs would be preferable to the approach used

in the 1995 Guidance because it would more appropriately relate the

concentrations of the PCB congeners in tissue to the concentrations of

the PCB congeners in water. Consequently, EPA is today revising the

human health cancer criterion for PCBs from 3.9E-6 ug/L to 6.7E-6 ug/L,

and the wildlife criterion for PCBs from 7.4E-5 ug/L to 1.2E-4 ug/L.

EPA believes that these revisions more accurately represent the

numerical limits necessary to protect human health and wildlife in the

Great Lakes System.

EFFECTIVE DATE: March 12, 1997.

ADDRESSES: The public docket for this rulemaking, including the

proposal, public comments in response to the proposal, other major

supporting documents, and the index to the docket are available for

inspection and copying at U.S. EPA Region 5, 77 West Jackson Blvd.,

Chicago, IL 60604 by appointment only. Appointments may be made by

calling Mary Willis Jackson (telephone 312-886-3717).

FOR FURTHER INFORMATION CONTACT: Mark Morris (4301), U.S. EPA, 401 M

Street, SW, Washington, D.C. 20460 (202-260-0312).

SUPPLEMENTARY INFORMATION:

I. Introduction

A. Potentially Affected Entities

Entities potentially affected by this final rule are those

discharging pollutants to waters of the United States in the Great

Lakes System. Potentially affected categories and entities include:

------------------------------------------------------------------------

Examples of potentially affected

Category entities

------------------------------------------------------------------------

Industry.............................. Industries discharging PCBs to

waters in the Great Lakes

System as defined in 40 CFR

132.2.

Municipalities........................ Publicly-owned treatment works

discharging PCBs to waters of

the Great Lakes System as

defined in 40 CFR 132.2.

------------------------------------------------------------------------

This table is not intended to be exhaustive, but rather provides a

guide for readers regarding entities likely to be affected by this

final rule. This table lists the types of entities that EPA is now

aware could potentially be affected by this action. To determine

whether your facility may be affected by this final rule, you should

examine the definition of ``Great Lakes System'' in 40 CFR 132.2 and

examine 40 CFR 132.2 which describes the purpose of water quality

standards such as those established in this rule. If you have any

questions regarding the applicability of this action to a particular

entity, consult the person listed in the preceding FOR FURTHER

INFORMATION CONTACT section.

B. Great Lakes Water Quality Guidance

In March 1995, EPA promulgated the final Water Quality Guidance for

the Great Lakes System (the 1995 Guidance) required under section

118(c)(2) of the Clean Water Act, 33 U.S.C. 1268(c)(2). See 60 FR

15366-425 (March 23, 1995). The ambient water quality criteria (AWQC)

included in the 1995 Guidance to protect human health and wildlife set

maximum ambient concentrations for harmful pollutants to be met in all

waters in the Great Lakes System unless site-specific criteria are

derived and approved. See 40 CFR Part 132, Tables 3 and 4. Great Lakes

States and Tribes must adopt criteria consistent with EPA's criteria by

March of 1997. CWA section 118(c)(2). If any State or Tribe fails to

meet that deadline, EPA must promulgate criteria that will apply in

that State's or Tribe's jurisdiction. Id. Once the criteria take

effect, permits for discharges of such pollutants into the Great Lakes

System must include limits as necessary to attain the criteria.

EPA promulgated human health and wildlife criteria for a class of

closely related toxic pollutants known as polychlorinated biphenyls

(PCBs). The PCB criteria for human health and wildlife incorporate

bioaccumulation factors (BAFs) which reflect the fact that PCBs magnify

at several steps in aquatic food chains, so that humans and wildlife

that eat fish from the Great Lakes may be exposed to PCB concentrations

many times higher than the PCB concentration in the waters of the

Lakes. Different members of the class of PCBs (called ``congeners'')

have different potentials to bioaccumulate. In the 1995 Guidance, EPA

derived a single baseline BAF for PCBs for each trophic level by

computing a weighted geometric mean baseline BAF from the baseline BAFs

for each trophic level for approximately 50 PCB congeners.

Based on issues raised as part of a lawsuit on the 1995 Guidance,

in 1996 EPA proposed a different approach for calculating a single BAF

for the class of PCBs. EPA also decided to call this single BAF a

``composite baseline BAF.'' The new approach also required EPA to

calculate a composite Kow for PCBs. EPA proposed two different

approaches for this calculation. EPA, however, presented calculations

of revised BAFs and revised ambient water quality criteria based on

only one of the two Kow alternatives. For a more complete

discussion of the 1995 Guidance and the revised approach in the 1996

proposal, refer to 60 FR 15366 (March 23, 1995) and 61 FR 54748

(October 22, 1996).

After considering all comments, EPA has decided to follow the

proposed approach. EPA selected the second of the two alternatives to

calculating a composite Kow. As a result, the numerical values for

the final BAFs and the final criteria differ very slightly from those

that EPA presented in the proposal. The discussion below explains the

reasons for the changes.

II. Background

The BAFs in the 1995 Guidance relate the concentration of a

chemical measured in water to the concentration of the same chemical

measured in fish tissue. Under the methodology for the 1995 Guidance,

the calculation of a BAF that is to be used for calculating AWQC for a

non-polar organic chemical involves three steps for each trophic level.

First, EPA obtains a ``total'' BAF based on the total concentrations of

the chemical in the water and in the aquatic biota, based on field

measurements. Second, EPA converts this initial total BAF into a

``baseline'' BAF that reflects the amount of lipid (fat) in the aquatic

biota that was assessed and the amount

[[Page 11725]]

of freely dissolved chemical that was estimated in the water. This

permits better extrapolation of data from one species to another and

from one water body to another. Third, EPA computes a final ``total''

BAF based on the total concentration of the chemical in the water and

the organisms at the site to be protected. In this notice, EPA will

refer to the first ``total'' BAF as the ``initial total'' BAF, and the

final as the ``final total'' BAF. The initial and final total BAFs

generally differ because they usually apply to different bodies of

water.

An important factor in the calculation of the baseline BAF and both

total BAFs for a chemical is the Kow for that chemical. The

Kow is a measure of the affinity of a chemical to partition

between octanol and water and is used as an estimate of the

partitioning between the lipids (fatty tissues) of an aquatic organism

and water. The higher the Kow, all other factors being constant,

the greater the affinity of the chemical to concentrate in fish tissue.

Each chemical has a Kow value. The Kow value for a chemical

is usually reported as the log Kow for the chemical. When

calculating total and baseline BAFs for a chemical, the chemical-

specific Kow is used to estimate the freely dissolved fraction of

the chemical in the water.

When this methodology is used to derive human health and wildlife

AWQC for a class of chemicals, the normal ``single'' values for

baseline and total BAFs for an individual chemical are replaced by

composite baseline and composite total BAFs for the class to simplify

the equations. Using a composite value in a calculation for the class

gives the same result as summing the results of calculations for each

member of the class. When calculating a composite baseline BAF or a

composite total BAF for all of the chemicals in a class at a trophic

level, it is necessary to use a composite Kow. This composite

Kow is used to estimate the composite freely dissolved fraction of

the class of chemicals in the Great Lakes waters.

EPA based the PCB BAFs in the 1995 Guidance on a field study

conducted in the Great Lakes by Oliver and Niimi (1988). The study

collected data on numerous PCB congeners, and EPA calculated a separate

baseline BAF for each congener using separate, congener-specific

Kows. EPA, however, needed to calculate composite baseline BAFs

and composite total BAFs representing all congeners at a trophic level

in order to calculate AWQC for human health and wildlife, because there

is a single ``cancer potency factor'' which is used for evaluating

human health cancer risk for all PCBs. Similarly, for wildlife, there

is a single toxicity factor which is used in the derivation of the

wildlife criterion. Consequently, composite baseline and total BAFs

were needed in order to be consistent with the toxicity data available

to derive human health and wildlife criteria.

In the 1995 Guidance, EPA calculated a composite baseline BAF for

PCBs for trophic level 3 and a composite baseline BAF for trophic level

4 by computing a weighted geometric mean of the baseline BAFs for

individual PCB congeners at each trophic level. The weighted geometric

mean baseline BAF was 55,281,000 for trophic level 3 and 116,553,000

for trophic level 4. As explained above, when calculating a composite

baseline BAF for PCBs, EPA must also use a composite Kow. In the

1995 Guidance, EPA calculated a weighted geometric mean Kow of

3,885,000 (mean log Kow of 6.589) by weighting the log Kows

for the individual PCB congeners by the concentrations of the PCB

congeners in fish. The weighted mean log Kow of 6.589 was then

used to estimate the freely dissolved fraction of the PCB congeners in

the study of Oliver and Niimi (1988). The log Kows for the

individual PCB congeners used in the final Guidance came from Hawker

and Connell (1988).

Using the composite baseline BAF for each trophic level and the

weighted mean log Kow of 6.589, EPA calculated composite final

total BAFs of 520,900 for trophic level 3 and 1,871,000 for trophic

level 4 for use in calculating human health criteria. The PCB human

health cancer criterion calculated using these BAFs was 3.9E-6 ug/L.

For wildlife, the composite final total BAFs were 1,850,000 for trophic

level 3 and 6,224,000 for trophic level 4. The PCB wildlife criterion

derived using these BAFs was 7.4E-5 ug/L.

Various industries and trade associations challenged the human

health and wildlife criteria for PCBs. AISI v. EPA, D.C. Cir. No.95-

1348 and consolidated cases. Among the issues they raised was the

calculation of the composite baseline BAF as the weighted geometric

mean for PCBs. The AISI petitioners alleged that the equation was

mathematically inappropriate for a variety of reasons. As a result of

this challenge, EPA re-examined the basis for the calculation of the

composite baseline BAF as the weighted geometric mean. For a more

complete discussion of bioaccumulation and the approach used in the

1995 Guidance, refer to 58 FR 20803 (April 16, 1993), and the Procedure

to Determine Bioaccumulation Factors (``TSD for BAFs'')(EPA-820-B-95-

005).

III. Revised Method for Calculating Composite Baseline BAFs for

PCBs

A. The Proposed Approach

On October 22, 1996, EPA proposed a revised approach for

calculating the composite baseline BAF for PCBs for each trophic level.

The revised approach uses the sum of all concentrations of PCB

congeners in tissue and the sum of all concentrations of PCB congeners

in the ambient water, as reported in Oliver and Niimi (1988), to

calculate a composite initial total BAF for PCBs at each trophic level.

This approach is equivalent to using a weighted arithmetic mean of all

the measured initial total BAFs from the PCB congeners, where the

weights are the concentrations of the PCB congeners in water. EPA

believes this approach is consistent with the definition of

bioaccumulation factor and appropriately relates the sum of the

concentrations of the PCB congeners in tissue to the sum of the

concentrations of the PCB congeners in water. EPA further believes that

this approach will provide an accurate composite initial total BAF for

the class of PCBs.

As part of the October 22, 1996 proposal, EPA also proposed to

revise its approach for calculating the composite Kow used in the

calculation of the composite baseline and total BAFs. EPA proposed two

alternatives: the first alternative used the median log Kow of the

PCB congeners to derive a composite Kow; the second used the sum

of the concentrations of the Kows for all congeners together with

the sum of all of the freely dissolved concentrations of the congeners

in water. For a more complete discussion of the revised approach for

calculating composite BAFs and Kows, refer to 61 FR 54748 (October

22, 1996).

B. Comments on the Proposed Approach

EPA received three comments on the proposal. Two commenters opposed

the revised approach for calculating composite BAFs for PCBs. One of

the commenters who opposed the proposal argued that the revised

approach yielded less stringent criteria for PCBs and that this action

was contradictory to the principle of zero discharge, and inconsistent

with what the public had been told about the 1995 Guidance methodology

being a superior method yielding more stringent criteria. This

commenter also argued that the resulting higher criteria would allow

backsliding for pollution prevention scenarios currently established

and

[[Page 11726]]

operating for existing permitted discharges of PCBs. The other

commenter who opposed the proposal was concerned that data (congener

specific Kows, tissue and water PCB concentrations) used in the

revised approach were taken from reports that were published a decade

ago and that more recent data on the behavior of PCBs in the

environment, their activity as carcinogenic promoters, and the tendency

of ``weathered'' PCBs to be more toxic than the parent compounds, have

not been considered. This commenter argued that the revised approach

did not provide as much protection against the tendency for PCBs to

become more toxic over time. In addition, the commenter argued that, if

EPA were to revise the 1995 approach, it should not use the median

value because the median ignores extremely high or low values,

disregards population trends, and does not weigh skewness, which is a

characteristic of the PCBs. In fact, the commenter recommended that EPA

compute and use a BAF at the 90 percent confidence level. Finally, the

commenter also noted that, since a higher Kow also affects the

amount of pollutant that is freely dissolved, the change in the

Kow value has a large impact on the final criterion. For these

reasons the commenter argued that the 1995 approach, which produces the

lowest composite Kow was preferable. However, the commenter

concluded that, if EPA revised its approach, it should use the second

of the two alternatives proposed, because it produces a lower Kow

than the first alternative.

Finally, one commenter supported the revised approach stating that

the proposed modifications to the equation used to calculate the

composite BAFs for PCBs are scientifically and mathematically

appropriate. However, the commenter further stated that it disagrees

with many other issues arising from the 1995 Guidance and EPA's

derivation of BAFs for PCBs, which are issues outside the scope of this

rulemaking.

C. Response to Comments

EPA appreciates those who provided comments on this rulemaking. In

regard to the first comment, EPA disagrees that it has misinformed the

public concerning either the 1995 Guidance methodology or the 1996

revised methodology. EPA also disagrees with the prediction that the

revised criteria will result in backsliding. Although the revised

criteria are less stringent than the 1995 criteria, they are not less

stringent than the PCB criteria currently in effect in the Great Lakes

States. Currently, the range of water quality criteria being

implemented in the Great Lakes Basin to protect human health from PCBs

is 0.1 to 0.00008 ug/L. EPA's revised methodology produces a human

health criterion for PCBs that is about 10 to 10,000 times more

stringent than those currently being implemented. For the protection of

wildlife the disparity is even more dramatic because many of the Great

Lakes States do not have criteria for PCBs to protect wildlife. For the

three Great Lakes States that do have criteria for PCBs to protect

wildlife, EPA's revised approach produces a wildlife criterion that is

approximately 10 to 1,000 times more stringent than those currently

being implemented. Given this information, EPA does not believe that

permit limits for PCBs based on criteria for human health and wildlife

produced by the revised methodology will result in less protection or

backsliding. Further, EPA interprets the concept of zero discharge in

the Great Lakes Agreement as a goal toward which it is working. The

revised PCB criteria, which are still more stringent than criteria

currently in effect in the Great Lakes States, are a reasonable and

substantial step toward that goal.

EPA also disagrees with the comment that asserts that EPA should

chose an approach to calculating a composite Kow that leads to a

more conservative PCB criterion because the current criteria may not

sufficiently take into account the effects of ``weathering'' or data

from new studies suggesting that PCBs might cause reproductive and

developmental toxicity effects. EPA believes that the BAF should

estimate bioaccumulation as accurately as possible. EPA believes it is

more appropriate to account for the commenter's concerns--if

warranted--by adjusting its estimate of PCB's toxicity. Further, EPA

believes that it has adequately accounted for weathering. PCBs were

first introduced into the Great Lakes Basin in the 1930s. Researchers

in the Great Lakes have spent a significant amount of time gathering

data and studying the fate and effects of PCBs in this system. Given

the length of time some of the PCBs have resided in the Great Lakes

Basin, any increased toxicity due to ``weathering'' would be reflected

in the data collected in 1986. Therefore, EPA does not agree that it

needs to retain the 1995 approach to ensure protection against the

possible impacts of weathering.

EPA agrees that some recent data indicate that PCBs, particularly

co-planar PCBs, might cause reproductive and developmental toxicity

through processes such as endocrine disruption. Because concentrations

associated with such potential adverse effects are under evaluation,

EPA can not yet predict whether such effects might occur at

concentrations above or below those associated with the cancer risks

modeled by the 1995 Guidance. EPA does not believe that it has enough

information concerning these additional, potential effects to revise

the criteria at this time. As stated in the 1995 Guidance, EPA is

committed to improving the science supporting its methodologies and

criteria, and will continue to evaluate and revise them in future

rulemakings in light of new information, as appropriate.

EPA agrees with the comment that the median Kow of the PCB

congeners should not be used as the composite Kow and that the

second alternative set forth in the proposal is more appropriate. EPA

also agrees with some of the limitations identified by the commenter

that are associated with using a median. However, EPA's reason for

adopting the second alternative to calculate a composite Kow as

part of this final rule is not because it introduces, as the commenter

suggests, a more protective value, but because EPA believes that the

second alternative more accurately reflects how PCBs behave in the

Great Lakes System. The second alternative provides the same result as

would be obtained by performing the relevant calculations for each

congener and then summing the results.

D. Final Action

As described above, the approach for this final rule uses the sum

of the concentrations of all PCB congeners in tissue and the sum of the

concentrations of all PCB congeners in the ambient water to calculate a

composite initial total BAF for PCBs at each trophic level. The

approach also uses individual PCB congener Kow to calculate the

composite Kow. The calculations of the composite baseline BAFs for

PCBs, the composite final total BAFs to be used in the calculation of

AWQC for wildlife and human health, and the PCB criteria for wildlife

and humans using the new PCB BAFs are presented below. EPA is not

revising the data used in the calculation of the composite BAFs or

composite Kows or other aspects related to the derivation of the

human health and wildlife criteria for PCBs. The fish tissue data,

water column data, and log Kow values used to calculate the new

composite BAFs and composite Kow are identical to those used in

the 1996 proposal.

[[Page 11727]]

1. Calculation of Composite Baseline BAFs for PCBs

The equation used to calculate a baseline BAF for an individual

chemical for each individual trophic level in this final rule is the

same as was used in the 1995 Guidance and the 1996 proposal (61 FR

54748). The equation to calculate a baseline BAF when a field-measured

BAF is available for a chemical, as is the case with PCBs, is (each of

the three components for calculating a baseline BAF is discussed

below):

[GRAPHIC] [TIFF OMITTED] TR12MR97.078

Where:

Measured BAFtT = BAF based on total concentration in tissue

and water (i.e., a total BAF).

fl = fraction of the tissue that is lipid.

ffd = fraction of the total chemical in the ambient water that is

freely dissolved.

By comparison, the equation for calculating a composite baseline BAF

is:

[GRAPHIC] [TIFF OMITTED] TR12MR97.079

a. Composite Initial Total BAF

To calculate a composite initial total BAF for trophic level 4, the

data needed are the total concentration of the chemical in the tissue

of a trophic level 4 species and the total concentration of the

chemical in ambient water at the site of sampling. The trophic level 4

species used in the 1995 Guidance, the 1996 proposal and this final

rule are salmonids. To calculate a composite initial total BAF for

trophic level 3, the data needed are the total concentration of the

chemical in the tissue of a trophic level 3 species and the total

concentration of the chemical in ambient water at the site of sampling.

The trophic level 3 species used in the 1995 Guidance, the 1996

proposal and this final rule are sculpins and alewives. The average of

the values for the sculpins and alewives is used to represent the

trophic level 3 values. The equation to calculate a composite total BAF

is:

[GRAPHIC] [TIFF OMITTED] TR12MR97.080

For trophic level 4, the total concentration of PCB congeners in

fish tissue (salmonids) is 4057.3 ng/g and the total concentration of

PCB congeners in ambient water is 1006.1 pg/L. For trophic level 3, the

average of the total concentrations of PCB congeners in tissue from

sculpins and alewife is 1393.15 ng/g. These values were derived in the

1996 proposal from Oliver and Niimi (1988).

[GRAPHIC] [TIFF OMITTED] TR12MR97.081

The resulting composite initial total BAF is 4,033,000 for trophic

level 4 and 1,385,000 for trophic level 3 (rounded to four significant

figures as discussed on page G-2 of the TSD for BAFs).

b. Composite Fraction Freely Dissolved

To estimate the fraction of PCBs that are freely dissolved in the

ambient water requires information on the particulate organic carbon

(POC) and dissolved organic carbon (DOC) in the ambient water where the

samples were collected and the Kow of the chemical. As in the 1995

Guidance and the 1996 proposal, the equation for calculating the

fraction freely dissolved for an individual chemical is:

[GRAPHIC] [TIFF OMITTED] TR12MR97.082

Where:

POC=concentration of particulate organic carbon (kg/L).

DOC=concentration of dissolved organic carbon (kg/L).

Kow=n-octanol water partition coefficient for the chemical.

[[Page 11728]]

By comparison, to calculate a composite fraction freely dissolved for a

group of chemicals, the equation is:

[GRAPHIC] [TIFF OMITTED] TR12MR97.083

The log Kows used for the individual PCB congeners come from

Hawker and Connell (1988), which were included in the 1996 proposal. To

calculate the composite Kow, as explained above, EPA will not

employ the first alternative that uses the median log Kow from the

log Kows presented in Table 1 of the 1996 proposal (61 FR 54752),

but will instead use the second alternative for calculating a composite

Kow. As proposed, the formula for calculating the second

alternative composite Kow is:

Where:

[GRAPHIC] [TIFF OMITTED] TR12MR97.084

Where:

i=1, 2, * * * n congeners.

Ctw=total concentration of the congener in water.

Cfdw=freely dissolved concentration of the congener in water.

The second alternative for calculating the composite Kow was

derived algebraically from the following definition of the fraction

freely dissolved, ffd, for a single congener, as given in the 1995

Guidance and the 1996 proposal :

[GRAPHIC] [TIFF OMITTED] TR12MR97.085

In the second alternative for the composite Kow, the ratio of

the sum of the total concentrations of all of the congeners in water

over the sum of the freely dissolved concentrations of all of the

congeners in water is substituted for the ratio of the total over

freely dissolved concentration of a single congener in water. Using the

data provided in Table 1 of the 1996 proposal, these equations yield a

composite Kow of 2,189,000 (rounded to four significant figures).

[GRAPHIC] [TIFF OMITTED] TR12MR97.086

This differs slightly from the composite Kow value of

2,238,721 derived in the proposal using the median log Kow

approach.

In the 1995 Guidance and the 1996 proposal, the POC value used was

0.0 kg/L and the DOC value used was 2.0 x 10-6 kg/L for the study

of Oliver and Niimi (1988). In this final rule, EPA is not changing

these values. Using these values and the revised composite Kow

value of 2,189,000 the composite fraction freely dissolved in this

final rule is 0.6955, as shown below:

[GRAPHIC] [TIFF OMITTED] TR12MR97.087

Again, this differs slightly from the fraction freely dissolved

presented in the 1996 proposal. The difference stems from the use of

the second alternative for calculating a composite Kow.

c. Fraction Lipid

In addition, EPA is not changing the fraction lipid content of the

salmonids (0.11) or sculpin (0.08) or alewife (0.07) that were used in

the 1995 Guidance and the 1996 proposal for the study of Oliver and

Niimi (1988). The average fraction lipid for sculpin and alewife is

0.075.

d. Composite Baseline BAF

Based on the information presented above and using the equation for

calculating composite baseline BAFs, EPA calculates for this final rule

a new composite baseline BAF for PCBs for trophic level 4 of 52,720,000

and a new composite baseline BAF for PCBs for trophic level 3 of

26,550,000 (rounded to four significant figures). Composite Baseline

BAF TL4

[GRAPHIC] [TIFF OMITTED] TR12MR97.088

[[Page 11729]]

2. Calculation of Composite Final Total BAFs for Use in AWQC

The data required to calculate a composite final total BAF for use

in deriving a AWQC for PCBs are the composite baseline BAF, the

fraction lipid of the aquatic species consumed by the population of

interest whether that is humans or wildlife and the composite fraction

freely dissolved in the ambient water for the area of interest.

Composite Total BAF for AWQC = [(Composite Baseline BAF)(Fraction Lipid

of Aquatic Species Consumed) + 1](Composite ffd)

a. Composite Baseline BAF

The new composite baseline BAFs derived above in section III.D will

be used: 52,720,000 for trophic level 4 and 26,550,000 for trophic

level 3.

b. Composite Freely Dissolved Fraction

The equation for calculating the composite freely dissolved

fraction is presented above. EPA is using the same values for POC and

DOC used in the 1995 Guidance and the 1996 proposal (4.0 x 10-8

kg/L for POC and 2.0 x 10-6 kg/L for DOC). These values represent

POC and DOC concentrations in Lake Superior and were used to calculate

all of the final total BAFs that were used to derive the AWQC in the

1995 Guidance. Both the composite Kow and the composite freely

dissolved fraction must be calculated using the Lake Superior values

for POC and DOC. The relative total concentrations of the PCB congeners

in Lake Superior will be assumed to be the same as in Oliver and Niimi

(1988). The resulting composite Kow is 2,107,000 and the composite

ffd is 0.6642 (both rounded to four significant figures).

[GRAPHIC] [TIFF OMITTED] TR12MR97.089

[GRAPHIC] [TIFF OMITTED] TR12MR97.090

The freely dissolved fraction of 0.6642 differs slightly from the

value of 0.6505 presented in the 1996 proposal. The difference is due

to the change in the method for calculating the composite Kow.

c. Lipid Fraction

EPA is not changing the lipid values used in the 1995 Guidance and

the 1996 proposal. The lipid fraction of the aquatic species consumed

by humans in the Great Lakes region is 1.82 for trophic level 3 and

3.10 for trophic level 4. For wildlife, the lipid fraction for trophic

level 3 is 6.46 and for trophic level 4 is 10.31.

d. Composite Final Total BAFs for Calculating AWQC

Using the above values for the composite baseline BAFs, composite

freely dissolved fraction for Lake Superior and fraction lipid, EPA

today is promulgating the following composite final total BAFs (rounded

to four significant figures) to be used in deriving the human health

and wildlife AWQC for PCBs:

Human Health BAF for Trophic Level 4 = [(52,720,000)(0.0310) +1] 0.6642

= 1,086,000

Human Health BAF for Trophic Level 3 = [(26,550,000)(0.0182) +1] 0.6642

= 321,000

Wildlife BAF for Trophic Level 4 = [(52,720,000)(0.1031) +1] 0.6642 =

3,610,000

Wildlife BAF for Trophic Level 3 = [(26,550,000)(0.0646) +1] 0.6642 =

1,139,000

3. Human Health Cancer Criteria

Based on the BAFs presented above, EPA today is revising the human

health cancer criteria for PCBs in Table 3 of the 1995 Guidance from

3.9E-6 g/L to 6.7E-6 g/L. The equations used to

calculate the human health cancer criteria for PCBs in this final rule

are the same as were used in the 1995 Guidance and the 1996 proposal

(61 FR 54753).

4. Wildlife Criterion

For wildlife, EPA today is revising the PCB criterion from 7.4E-5

g/L to 1.2E-4 g/L based on using the BAFs presented

above. The equations used to calculate the wildlife criterion for PCBs

in this final rule are the same as were used in the 1995 Guidance and

the 1996 proposal (61 FR 54754).

IV. Effective Date

Section 553(d)(3) of the Administrative Procedure Act requires

Federal agencies to publish final rules at least 30 days before they

take effect unless they find that they have ``good cause'' to waive the

notice requirement. EPA finds that it has good cause to waive the 30-

day notice requirement for these revisions to the PCB criteria. EPA

needs to make this rule effective as soon as possible to maximize the

ability of the States and Tribes to use the new criteria in their

Guidance submissions that are due in March 23, 1997. Also, in this case

an immediate effective date does not conflict with the goal of the

notice requirement (giving the public the opportunity to adjust

behavior before the rule imposes penalties). The revised criteria will

not affect any member of the public until they are adopted by a Great

Lakes State or Tribe (or promulgated by EPA where a State or Tribe

fails to submit adequate criteria). EPA anticipates that these

processes will take at least 30 days, so that the public will receive

adequate notice of the revised requirements before they become binding.

V. Executive Order 12866

Under Executive Order 12866 (58 FR 51735, October 4, 1993), EPA

must determine whether the regulatory action is ``significant'' and

therefore subject to

[[Page 11730]]

Office of Management and Budget (OMB) review and the requirements of

the Executive Order. The Order defines ``significant regulatory

action'' as one that is likely to result in a rule that may:

(1) Have an annual effect on the economy of $100 million or more or

adversely affect in a material way the economy, a sector of the

economy, productivity, competition, jobs, the environment, public

health or safety, or State, local, or Tribal governments or

communities;

(2) Create a serious inconsistency or otherwise interfere with an

action taken or planned by another agency;

(3) Materially alter the budgetary impact of entitlements, grants,

user fees, or loan programs or the rights and obligations of recipients

thereof; or

(4) Raise novel legal or policy issues arising out of legal

mandates, the President's priorities, or the principles set forth in

the Executive Order.

Pursuant to the terms of Executive Order 12866, it has been

determined that this final rule is not a ``significant regulatory

action'' and is therefore not subject to OMB review.

VI. Submission to Congress and the General Accounting Office

Under 5 U.S.C. 801(a)(1)(A) as added by the Small Business

Regulatory Enforcement Fairness Act of 1996, EPA submitted a report

containing this rule and other required information to the U.S. Senate,

the U.S. House of Representatives and the Comptroller General of the

General Accounting Office prior to publication of the rule in today's

Federal Register. This rule is not a ``major rule'' as defined by 5

U.S.C. 804(2).

VII. Regulatory Flexibility Act as Amended by the Small Business

Regulatory Enforcement Fairness Act of 1996

The Regulatory Flexibility Act (RFA) provides that, whenever an

agency promulgates a final rule under 5 U.S.C. 553, after being

required to publish a general notice of proposed rulemaking, an agency

must prepare a final regulatory flexibility analysis unless the head of

the agency certifies that the proposed rule will not have a significant

economic impact on a substantial number of small entities. 5 U.S.C. 604

& 605.

Under the CWA, EPA's promulgation of water quality standards

establishes standards that the States implement through the National

Pollutant Discharge Elimination System (NPDES) permit process. The

States have discretion in deciding how to meet the water quality

standards and in developing discharge limits as needed to meet the

standards. While State implementation of federally-promulgated water

quality standards may result in new or revised discharge limits being

placed on small entities, the standards themselves do not apply to any

discharger, including small entities.

Today's rule imposes obligations on the Great Lakes States but, as

explained above, does not itself establish any requirements that are

applicable to small entities. As a result of EPA's action here, the

Great Lakes States will need to ensure that permits they issue include

any limitations on discharges necessary to comply with the criteria in

today's rule. Until actions are taken to implement the 1995 Guidance,

there will be no economic effect of the 1995 Guidance on any entities,

large or small. States and Tribes must both adopt their own criteria

and implement them before impacts are felt. The implementation

regulations provide States and Tribes with a variety of flexible

alternatives which can affect the burden felt by any small entity as a

result of State or Tribal action to implement this final rule,

including total maximum daily load (TMDL) calculations and waste load

allocations (WLAs). Impacts will not be felt until States and Tribes

select and put in place implementation measures.

The RFA requires analysis of the impacts of a rule on the small

entities subject to the rules' requirements. See United States

Distribution Companies v. FERC, 88 F.3d 1105, 1170 (D.C. Cir. 1996).

Today's rule establishes no requirements applicable to small entities,

and so is not susceptible to regulatory flexibility analysis as

prescribed by the RFA. (``[N]o [regulatory flexibility] analysis is

necessary when an agency determines that the rule will not have a

significant economic impact on a substantial number of small entities

that are subject to the requirements of the rule,''' United

Distribution at 1170, quoting Mid-Tex Elec. Co-op v. FERC, 773 F.2d

327, 342 (D.C. Cir. 1985) (emphasis added by United Distribution

court).) The Agency is thus certifying that today's rule will not have

a significant economic impact on a substantial number of small

entities, within the meaning of the RFA.

Furthermore, today's final rule results in human health cancer

criteria and wildlife criteria less stringent than those currently in

the 1995 Guidance. If States or Tribes adopt criteria consistent with

today's final rule, they should reduce any adverse economic impact that

might have been imposed by State or Tribal adoption of the 1995

criteria. Consequently, the economic effect of today's final rule

relative to the 1995 Guidance should be positive. Any adverse economic

impact on small entities associated with measures taken to implement

the current provisions of the 1995 Guidance should be reduced by

adoption of the final revisions.

VIII. Unfunded Mandates Reform Act

Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public

Law 104-4, establishes requirements for Federal agencies to assess the

effects of their regulatory actions on State, local, and Tribal

governments and the private sector. Under section 202 of the UMRA, EPA

generally must prepare a written statement, including a cost-benefit

analysis, for proposed and final rules with ``Federal Mandates'' that

may result in expenditures to State, local, and Tribal governments, in

the aggregate, or to the private sector, of $100 million or more in any

one year. Before promulgating an EPA rule for which a written statement

is needed, section 205 of the UMRA generally requires EPA to identify

and consider a reasonable number of regulatory alternatives and adopt

the least costly, most cost-effective or least burdensome alternative

that achieves the objectives of the rule. The provisions of section 205

do not apply when they are inconsistent with applicable law. Moreover,

section 205 allows EPA to adopt an alternative other than the least

costly, most cost-effective or least burdensome alternative if the

Administrator publishes with the final rule an explanation why that

alternative was not adopted.

Before EPA establishes any regulatory requirements that may

significantly or uniquely affect small governments, including Tribal

governments, it must have developed under section 203 of the UMRA a

small government agency plan. The plan must provide for notifying

potentially affected small governments, enabling officials of the

affected small governments to have meaningful and timely input in the

development of EPA regulatory proposals with significant Federal

intergovernmental mandates, and informing, educating, and advising

small governments on compliance with the regulatory requirements.

As noted above, this final rule is limited to the method for

deriving a composite BAF for PCBs and for deriving a composite Kow

for PCBs, which will result in human health cancer criteria and

wildlife criteria for PCBs less stringent than those currently in the

1995 Guidance. If States or Tribes adopt criteria consistent with

today's final rule, they will reduce any adverse economic impact that

might have been imposed by State or Tribal adoption of

[[Page 11731]]

the 1995 criteria. Consequently, EPA has determined that this final

rule contains no regulatory requirements that might significantly or

uniquely affect small governments. EPA has also determined that this

final rule does not contain a Federal mandate that may result in

expenditures of $100 million or more for State, local, and Tribal

governments, in the aggregate, or the private sector in any one year.

Thus, today's final rule is not subject to the requirements of sections

202 and 205 of the UMRA.

IX. Paperwork Reduction Act

There are no information collection requirements in this final rule

and therefore there is no need to obtain OMB approval under the

Paperwork Reduction Act, 44 U.S.C. 3501 et seq.

X. References

Great Lakes Water Quality Technical Support Document for the

Procedure to Determine Bioaccumulation Factors (EPA-820-B-95-005). NITS

Number: PB95187290. ERIC Number: D049.

Great Lakes Water Quality Initiative Criteria Documents for the

Protection of Human Health (EPA-820-B-95-006). NITS Number: PB95187308.

ERIC Number: D050.

Great Lakes Water Quality Initiative Criteria Documents for

Protection of Wildlife: DDT; Mercury; 2,3,7,8-TCDD; PCBs (EPA-820-B-95-

008). NITS Number: PB95187324. ERIC Number: D052.

Hawker D.W. and D.W Connell. 1988. Octanol-Water Partition

Coefficients of Polychlorinated Biphenyl Congeners. Environ. Sci.

Technol., 22(4):382-387.

Oliver, B.G. and A.J Niimi. 1988. Trophodynamic Analysis of

Polychlorinated Biphenyl Congeners and Other Chlorinated Hydrocarbons

in the Lake Ontario Ecosystem. Environ. Sci. Technol., 22(4):388-397.

U.S. Environmental Protection Agency. Water Quality Guidance for

the Great Lakes System and Correction; Proposed Rules. Vol. 58, No.72.

April 16, 1993. pp.20802-21047.

U.S. Environmental Protection Agency. Water Quality Guidance for

the Great Lakes System; Notice of Data Availability. Vol. 59. August

30, 1994. pp.44678-44685.

U.S. Environmental Protection Agency. Final Water Quality Guidance

for the Great Lakes System; Final Rule. Vol. 60, No.56. March 23, 1995.

pp.15366-15425.

U.S. Environmental Protection Agency. Proposed Revisions to the

Polychlorinated Biphenyl Criteria for Human Health and Wildlife for the

Water Quality Guidance for the Great Lakes System; Proposed Rule. Vol.

61, No.205. October 22, 1996. pp.54748-54756.

List of Subjects in 40 CFR Part 132

Environmental protection, Administrative practice and procedure,

Great Lakes, Indians--lands, Intergovernmental relations, Reporting and

recordkeeping requirements, Water pollution control.

Dated: March 6, 1997.

Carol M. Browner,

Administrator.

For the reasons set out in the preamble title 40, chapter I of the

Code of Federal Regulations is amended as follows:

PART 132--WATER QUALITY GUIDANCE FOR THE GREAT LAKES SYSTEM

1. The authority citation for Part 132 continues to read as

follows:

Authority: 33 U.S.C. 1251 et seq.

2. Table 3 to Part 132 is amended by revising the entry for

PCBs(class) to read as follows:

Table 3.--Water Quality Criteria for Protection of Human Health

----------------------------------------------------------------------------------------------------------------

HNV (ug/L) HCV (ug/L)

Chemical -----------------------------------------------------------------------------

Drinking Nondrinking Drinking Nondrinking

----------------------------------------------------------------------------------------------------------------

* * * * * *

*

PCBs(class)....................... .............. .............. 6.7E-6 6.7E-6

* * * * * *

*

----------------------------------------------------------------------------------------------------------------

3. Table 4 to Part 132 is amended by revising the entry for

PCBs(class) to read as follows:

Table 4.--Water Quality Criteria for Protection of Wildlife

------------------------------------------------------------------------

Chemical Criteria (ug/L)

------------------------------------------------------------------------

* * * * *

PCBs(class)................................ 1.2E-4

* * * * *

------------------------------------------------------------------------

[FR Doc. 97-6215 Filed 3-11-97; 8:45 am]

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