7050.0219 Human Health-Based Criteria And Standards


Published: 2015

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7050.0219 HUMAN HEALTH-BASED CRITERIA AND STANDARDS.


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Subpart 1.

Objective.

Human health-based criteria and standards protect humans from potential adverse effects of eating fish and edible aquatic organisms and incidental ingestion of water while recreating in Class 2 waters and from the consumption of drinking water from Class 1 surface waters (includes Class 2A and 2Bd waters). Human health-based criteria and standards must be determined using the methods in this part.


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Subp. 2.

Applicability of methods.

Human health-based chronic criteria (CC) or chronic standards (CS) must be evaluated based on the pollutant's toxicological profile: noncarcinogen or nonlinear carcinogen (NLC), developmental susceptibility, and linear carcinogen (C).

§
A.

Algorithms for these toxicological profiles by Class 2 subclasses are described in subparts 13 to 15. Other scientifically defensible algorithms may be applied by the commissioner on a chemical-specific basis for evaluating developmental susceptibility to toxic pollutants in fish tissue based on the consideration listed in subparts 3 to 5.


§
B.

The most stringent CC or CS by medium (water or fish tissue), Class 2 subclass, and toxicological profile, or taste and odor criteria as described in part 7050.0218, subpart 8, are the final applicable human health-based CC or CS.



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Subp. 3.

Available and reliable scientific data.

The data and information used to develop a site-specific CC or CS must be approved by the commissioner. The commissioner must consider measures of availability and reliability of the data and information.


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Subp. 4.

Toxicological values.

The RfD used to calculate criteria for noncarcinogenic and nonlinear carcinogenic chemicals (NLC) and the CSF and AFlifetimeor CSF and ADAF used to calculate CC or CS for linear carcinogenic (C) chemicals are obtained from the MDH or developed according to parts 4717.7820, subparts 5 and 21, and 7050.0218, subpart 3.


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Subp. 5.

Exposure values.

Drinking water intake rates are obtained from the MDH. RSC uses a default value of 0.2 for most pollutants, unless:

§
A.

there are no significant known or potential sources other than those addressed for the designated use, then 0.5 must be used; or


§
B.

sufficient exposure data are available to support an alternative pollutant-specific value between 0.2 and 0.8.



§
Subp. 6.

Bioaccumulation factors.

This subpart describes the process and data for deriving bioaccumulation factors (BAF) used in the calculation of the human health-based chronic criteria (CC) or chronic standards (CS).

§
A.

Information used for defining BAF must be consistent with the pollutant form used to derive the RfD or CSF. BAF development must also consider other forms that bioaccumulate in fish tissue. The preferred bioaccumulation data are available and reliable field and laboratory studies.


§
B.

A general description of the steps and data used to determine final state or site BAF are listed in subitems (1) to (6) and described in detail in subparts 7 to 12.

§
(1)

Categorize the pollutant based on certain properties into one of three broadly defined chemical categories: nonionic organic, ionic organic, or inorganic and organometallic chemicals as described in subpart 7.


§
(2)

Define the methods for developing baseline BAF as described in subpart 8. A baseline BAF is the expression of the BAF based on the bioavailable or freely dissolved fraction of a pollutant in the ambient water and normalized concentration of the pollutant within the organism.


§
(3)

Determine the relevant procedure (1 to 6) for identifying the acceptable baseline BAF methods (maximum of four) and their hierarchy for developing individual or aquatic species-specific baseline BAF as described in subpart 9.


§
(4)

Calculate species mean baseline BAF from acceptable individual baseline BAF as described in subpart 10.


§
(5)

Determine final baseline BAF for TL3 and TL4 as described in subpart 11.


§
(6)

Develop final state or site BAF for TL3 and TL4 based on default parameters by Class 2 subclass or site-specific data as described in subpart 12.




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Subp. 7.

Chemical categorization.

For BAF purposes, organic chemicals that have no or negligible ionization at the pH range of ambient surface waters are categorized as nonionic organic chemicals; organic chemicals that undergo ionization at the pH range of ambient surface waters are categorized as ionic organic chemicals and further delineated for BAF development based on subpart 9, item C; organometallic chemicals and other chemicals or elements are categorized as organometallic and inorganic chemicals.


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Subp. 8.

Methods for baseline BAF.

The four methods for developing baseline BAF in items A to D are listed in a hierarchy from most preferred to least preferred, except as noted in subpart 9: use of field-measured BAF studies (field BAF); use of field-measured BSAF studies (field BSAF); use of laboratory-measured BCF studies with food chain multipliers (lab BCF*FCM); and use of octanol-water partition coefficients with food chain multipliers (Kow*FCM). Where relevant, differences in the baseline BAF methods are described by chemical categorization.

§
A.

Method 1: Field BAF. The field-measured BAF for a nonionic organic chemical is calculated based on the total concentration of the chemical in the appropriate tissue of the aquatic organism (on a wet tissue basis) and the total concentration of chemical in ambient surface water at the site of sampling (BAFtT).


measured BAFtT = Ct/Cw






where:
BAFtT = field-measured BAF based on total concentration in tissue and water (L/kg)


Ct = total concentration of the chemical in the specified wet tissue (µg/kg)


Cw = total concentration of the chemical in water (µg/L)


The measured BAFtT is converted to a baseline BAF or BAF1fd by the following equation:




where:
baseline BAF1fd = BAF expressed on a freely dissolved and lipid-normalized basis (L/kg)


f1 = fraction of the tissue that is lipid


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


The freely dissolved fraction or ffd is the portion of the nonionic organic chemical that is not bound to particulate organic carbon or dissolved organic carbon and is calculated:



1



ffd

=

_





[1 + (POC x KOW) + (DOC x 0.08 x KOW)]



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


POC and DOC concentrations are obtained from the original study from which the field-measured BAF is determined. If POC and DOC concentrations are not reported in the BAF study, reliable estimates of POC and DOC are obtained from other studies at closely related sites within the same water body. If no study data are available, the USEPA national default DOC and POC values are used, as they are representative of average ambient surface water conditions. The USEPA national default values are DOC of 2.9 mg/L and POC of 0.5 mg/L, converted to kg/L by dividing by 1,000,000.
For the field-measured BAF for a chemical classified as inorganic and organometallic, the field BAF is equal to the baseline BAF and is not expressed on a lipid or freely dissolved fraction basis. Normalization on other characteristics must be supported by chemical-specific data.


§
B.

Method 2: Field BSAF. For nonionic organic chemicals, the field-measured BSAF is determined by relating lipid-normalized concentration of the chemical in the appropriate tissue of the aquatic organism to organic carbon-normalized concentrations of the chemical in surface sediment.



Cl



BSAF
=

_




Csoc



where:
BSAF = biota-sediment accumulation factor for the chemical (kg of sediment organic carbon/kg of lipid)


C1 = lipid-normalized concentration of the chemical in the specified wet tissue (µg/g lipid), calculated as:



Ct



Cl

=

_




fl



where:
f1 = fraction lipid content in the tissue


Other variables as defined under item A


Csoc = organic-carbon normalized concentration of a chemical in surface sediment samples (µg/g sediment organic carbon), calculated as:



Cs



Csoc

=

_




foc



where:
Cs = concentration of chemical in dry sediment (µg/g sediment)


foc = fraction organic carbon in dry sediment


The measured BSAF is converted to a baseline BAF or BAF1fd by the following equation:




(Πsocw)r (Di/r) (KOW)i



(baseline BAF1fd)i

=
(BSAF)i


_





(Kow)r



where:
(baseline BAF1fd)i = BAF expressed on a freely dissolved and lipid-normalized basis for chemical of interest "i" or the chemical that is the basis of the criteria (L/kg)


BSAFi = measured BSAF for the chemical "i" (kg organic carbon/kg of lipid)


(Πsocw)r = sediment to water partition coefficient or sediment organic carbon to freely dissolved concentration ratio of the reference chemical "r." Reference chemicals with (Πsocw)r/(Kow) similar to that of the chemical of interest are preferred for this method (L/kg sediment organic carbon)





where:
(Csoc)r = concentration of the reference chemical "r" in dry sediment normalized to sediment organic carbon (µg/kg sediment organic carbon)


(Cfdw)r = concentration of the reference chemical "r" freely dissolved in water (µg/L)


(Di/r) = ratio between Πsocw/Kow for chemicals "i" and reference chemical "r"; a ratio equal to or close to one is preferred


(Kow)i = octanol-water partition coefficient for the chemical "i"


(Kow)r = octanol-water partition coefficient for the reference chemical "r"


Other variables as defined under item A



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C.

Method 3: Lab BCF*FCM. The laboratory-measured BCF for nonionic organic chemicals is calculated based on the total concentration of the chemical in the appropriate tissue of the aquatic organism (on a wet tissue basis) and the total concentration of chemical in the study water (BCFtT).



Ct



measured BCFtT

=

_




Cw



where:
Cw = total concentration of chemical in the laboratory test water (µg/L)


Other variables as defined under item A





Baseline BAF1fd equation:





where:
ffd = fraction of the total chemical in the test water that is freely dissolved, where POC and DOC or reasonable estimates based on total organic carbon (TOC) values measured in the test water are used, unless not available, then the following defaults are used based on typical lab water characteristics: DOC of 2.5 mg/L and POC at 0 mg/L, converted to kg/L by dividing by 1,000,000


FCM = food chain multiplier


Other variables as defined under item A


For ionic organic, inorganic, and organometallic chemicals, based on available data, the laboratory BCF is equal to the baseline BAF and is not expressed on a lipid or freely dissolved fraction basis. Normalization on other characteristics must be supported by chemical-specific data. FCM must come from field BAF studies.


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D.

Method 4: Kow*FCM. In this method, Kow is assumed to be equal to the baseline BAF1fd for certain nonionic organic chemicals described in the procedures.


baseline BAF1fd = (FCM) x (Kow)


where:
Variables as defined under items A and C




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Subp. 9.

Hierarchy of acceptable baseline BAF methods.

Determine the hierarchy of acceptable baseline BAF methods available under subpart 8 for appropriate use based on the chemical categorization of the pollutant and other relevant properties as described under Procedures 1 to 6.

§
A.

Procedures 1 to 6 are used for defining the hierarchy and use of the four baseline BAF methods based on chemical categorization and a chemical's ionization state in ambient surface waters, hydrophobicity, biomagnification, and metabolism in aquatic organisms, primarily freshwater fish species. Table 1 provides the basic information for identifying the acceptable procedures and hierarchy for baseline BAF methods as described under items B to D:


Table 1.
Chemical Categorization

Nonionic Organic and Ionic (negligible ionization)
Organic Chemicals
Inorganic, Organometallic, and Ionic
Chemicals

Hydrophobicity
Biomagnification Factor (BMF)

log Kow ≥ 4
log Kow < 4
BMF ≤ 1,000
BMF > 1,000

Metabolism in Aquatic Organisms (Fish)

Low or Unknown
High
Low or Unknown
High

Procedures:

Procedure 1
Procedure 2
Procedure 3
Procedure 4
Procedure 5
Procedure 6

1) Field BAF
2) Field BSAF
3) Lab BCF*FCM
4) Kow*FCM
1) Field BAF
2) Field BSAF
3) Lab BCF
1) Field BAF or
Lab BCF
2) Kow

Field BAF or
Lab BCF
Field BAF or
Lab BCF
1) Field BAF
2) Lab
BCF*FCM


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B.

For nonionic (neutral) organic chemicals, defined as chemicals that have no or negligible ionization in ambient surface water, Procedures 1 to 4 describe the hierarchy of acceptable baseline BAF methods to use.

§
(1)

Procedure 1 applies to nonionic organic chemicals with moderate to high hydrophobicity defined as log Kow greater than or equal to (≥) 4 and either a low level of documented metabolism in aquatic organisms or lack of sufficient data to characterize metabolism. All four baseline BAF methods are available for use based on the stated hierarchy in Table 1 and availability of acceptable data.


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(2)

Procedure 2 applies to nonionic organic chemicals with moderate to high hydrophobicity defined as log Kow ≥ 4 and a high level of documented metabolism in aquatic organisms. The acceptable methods are field BAF, BSAF, and lab BCF*FCM, where FCM is equal to one.


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(3)

Procedure 3 applies to nonionic organic chemicals with low hydrophobicity defined as log Kow less than (