[Federal Register Volume 81, Number 30 (Tuesday, February 16, 2016)]
[Pages 7784-7786]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-03119]



[EPA-HQ-OW-2015-0469; FRL-9942-26-OW]

Draft Technical Support Document: Recommended Estimates for 
Missing Water Quality Parameters for Application in EPA's Biotic Ligand 

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of availability.


SUMMARY: The Environmental Protection Agency (EPA) is announcing 
availability of the draft technical support document: Recommended 
Estimates for Missing Water Quality Parameters for Application in EPA's 
Biotic Ligand Model for public comment. In 2007, EPA published updated 
criteria for freshwater copper using the Biotic Ligand Model (BLM), a 
bioavailability model that relies on ten water quality input parameters 
to estimate copper criteria protective of aquatic life in freshwater. 
This draft technical support document summarizes data analysis 
approaches EPA used to develop recommendations for default values for 
water quality parameters used in the Freshwater Copper BLM when data 
are lacking. These default values may also be used to fill in missing 
water quality input parameters in the application of other metal BLM 
models as well, when data are lacking. Following closure of this 30 day 
public comment period, EPA will consider the comments, revise the 
document, as appropriate, and then publish a final technical support 
document that will serve as a source of information for states, tribes, 
territories, and other stakeholders.

DATES: Comments must be received on or before March 17, 2016.

[[Page 7785]]

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OW-
2015-0469, to the Federal eRulemaking Portal: http://www.regulations.gov. Follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or withdrawn. EPA 
may publish any comment received to its public docket. Do not submit 
electronically any information you consider to be Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Multimedia submissions (audio, video, etc.) must be 
accompanied by a written comment. The written comment is considered the 
official comment and should include discussion of all points you wish 
to make. EPA will generally not consider comments or comment contents 
located outside of the primary submission (i.e., on the web, cloud, or 
other file sharing system). For additional submission methods, the full 
EPA public comment policy, information about CBI or multimedia 
submissions, and general guidance on making effective comments, please 
visit http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Kathryn Gallagher, Health and 
Ecological Criteria Division, Office of Water (Mail Code 4304T), 
Environmental Protection Agency, 1200 Pennsylvania Avenue NW., 
Washington, DC 20460; telephone: (202) 564-1398; email address: 
[email protected].


I. General Information

A. How can I get copies of this document and other related information?

    1. Docket: All documents in the docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in www.regulations.gov or in hard copy at the Water Docket, EPA/DC, EPA 
West, Room 3334, 1301 Constitution Ave. NW., Washington, DC. The Public 
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Public 
Reading Room is (202) 566-1744, and the telephone number for the Water 
Docket is (202) 566-2426. For additional information about EPA's public 
docket, visit EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.

II. What is the relationship between state or tribal water quality 
standards and the draft technical support document?

Recommended estimates for missing water quality parameters for 
application in EPA's biotic ligand model?

    As part of the water quality standards triennial review process 
defined in section 303(c)(1) of the CWA, the states and authorized 
tribes are responsible for maintaining and revising water quality 
standards. Water quality standards consist of designated uses, water 
quality criteria to protect those uses, a policy for antidegradation, 
and may include general policies for application and implementation. 
States and authorized tribes must adopt water quality criteria that 
protect designated uses. Protective criteria are based on a sound 
scientific rationale and contain sufficient parameters or constituents 
to protect the designated uses. States and authorized tribes have four 
options when adopting water quality criteria for which EPA has 
published section 304(a) criteria. They can:
    (1) Establish numerical values based on recommended section 304(a) 
    (2) Adopt section 304(a) criteria modified to reflect site-specific 
    (3) Adopt criteria derived using other scientifically defensible 
methods; or
    (4) Establish narrative criteria where numeric criteria cannot be 
established or to supplement numerical criteria (40 CFR 131.11(b)).
    The current 304(a) criteria recommendation for freshwater copper 
relies on implementation of the BLM model. The model requires 10 inputs 
to determine the criteria. This technical support document provides 
default values for 8 of the 10 parameters, where site-specific data are 
not available, and thereby facilitates the use of the BLM model. The 
document describes the methods used to estimate missing parameters.

III. Information on the Draft Technical Support Document

Recommended Estimates for Missing Water Quality Parameters for 
Application in EPA's Biotic Ligand Model

    The Biotic Ligand Model (BLM) is used to derive Aquatic Life 
Ambient water quality criteria for copper in freshwater. The BLM 
requires 10 input parameters: Temperature, pH, dissolved organic 
carbon, alkalinity, calcium, magnesium, sodium, potassium, sulfate, and 
chloride to derive water quality criteria. In 2007, EPA published 
updated criteria for freshwater copper using the biotic ligand model. 
An ongoing implementation challenge for state water quality standards 
is completing a parameter database for BLM use when a site has missing 
model input parameters. EPA developed approaches to estimate missing 
water quality parameters including geochemical ions (calcium, 
magnesium, sodium, potassium, sulfate, chloride, and alkalinity) and 
dissolved organic carbon (DOC). For geochemical ions (GI) parameter 
estimates, specific conductivity was combined with geostatistical 
techniques (Kriging) to generate protective estimates for use in the 
BLM when data are not available. DOC estimates were derived using 
several water quality databases including the National Organic Carbon 
Database, Storage and Retrieval Data System, National Waters 
Information System, Wadeable Stream Assessment, and National River and 
Stream Assessment (NRSA) database.
    This draft support document provides default recommended values 
that could be used to fill in missing water quality input parameters 
when data are lacking for 8 of 10 BLM parameters. Default recommended 
values for GI parameters are 10th percentile ecoregional, stream-order 
specific values. Default recommended values for DOC are 10th percentile 
ecoregional values. These default values could also be used to fill in 
missing water quality input parameters in the application of other 
metal BLM models as well, when data are lacking. In addition, the 
document also recommends that the other two parameters, temperature and 
pH, be measured directly in the field. Site-specific data are always 
preferable for use in the BLM and should be used to develop copper 
criteria via the BLM when possible. Users of the BLM are encouraged to 
sample their water body of interest, and to analyze the samples for the 
constituent (parameter) concentrations as a basis for determining BLM 
inputs, when possible.
    This document underwent an internal EPA review and an independent 
contractor-led external peer review.

IV. Solicitation of Scientific Views

    EPA is soliciting additional scientific views, data, and 
information regarding the science and technical approach used in the 
derivation of this draft technical document.

[[Page 7786]]

    Dated: February 4, 2016.
Elizabeth Southerland,
Director, Office of Science and Technology.
[FR Doc. 2016-03119 Filed 2-12-16; 8:45 am]