[Federal Register Volume 84, Number 147 (Wednesday, July 31, 2019)]
[Rules and Regulations]
[Pages 37112-37122]
[FR Doc No: 2019-16192]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[EPA-HQ-SFUND-2006-0759 FRL-9997-47-Region 5]

National Oil and Hazardous Substances Pollution Contingency Plan;
National Priorities List: Partial Deletion of the South Minneapolis
Residential Soil Contamination Superfund Site

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final rule.

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SUMMARY: The Environmental Protection Agency (EPA) Region 5 is
publishing a direct final Notice of Partial Deletion of all but nine of
approximately 3,632

properties located within the South Minneapolis Residential Soil
Contamination Superfund Site in Minnesota from the National Priorities
List (NPL). The NPL, promulgated pursuant to Section 105 of the
Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) of 1980, as amended, is an appendix of the National Oil and
Hazardous Substances Pollution Contingency Plan. This direct final
partial deletion is being published by EPA with the concurrence of the
State of Minnesota, through the Minnesota Department of Agriculture,
because all appropriate response actions for these 3,623 properties
under CERCLA have been completed. However, this partial deletion does
not preclude future actions under Superfund. The nine properties not
included in this partial deletion will remain on the NPL.

DATES: This direct final partial deletion is effective September 30,
2019 unless EPA receives adverse comments by August 30, 2019. If
adverse comments are received, EPA will publish a timely withdrawal of
the direct final partial deletion in the Federal Register informing the
public that the partial deletion will not take effect.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
SFUND-2006-0759 by one of the following methods:
    https://www.regulations.gov. Follow on-line instructions for
submitting comments. Once submitted, comments cannot be edited or
removed from Regulations.gov. The 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. The 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 https://www2.epa.gov/dockets/commenting-epa-dockets.
    Email<EMAIL_ADDRESS>    Mail: Randolph Cano, NPL Deletion Coordinator, U.S. Environmental
Protection Agency Region 5 (ST-6J), 77 West Jackson Boulevard, Chicago,
IL 60604,<PHONE_NUMBER>
    Hand deliver: Superfund Records Center, U.S. Environmental
Protection Agency Region 5, 77 West Jackson Boulevard, 7th Floor South,
Chicago, IL 60604, Phone:<PHONE_NUMBER>. Such deliveries are only
accepted during the Docket's normal hours of operation, and special
arrangements should be made for deliveries of boxed information. The
normal business hours are Monday through Friday, 8 a.m. to 4 p.m.,
excluding Federal holidays.
    Instructions: Direct your comments to Docket ID no. EPA-HQ-SFUND-
2006-0579. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
https://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through https://www.regulations.gov or email. The https://www.regulations.gov website
is an ``anonymous access'' system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an email comment directly to EPA without
going through https://www.regulations.gov, your email address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses.
    Docket: All documents in the docket are listed in the https://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
at https://www.regulations.gov or electronically or in hard copy at:
    U.S. Environmental Protection Agency, Region 5, Superfund Records
Center, 77 West Jackson Boulevard, 7th Floor South, Chicago, IL 60604,
Phone:<PHONE_NUMBER>, Hours: Monday through Friday, 8 a.m. to 4 p.m.,
excluding Federal holidays.
    Minneapolis Central Library, 300 Nicollet Mall, 2nd Floor,
Minneapolis, MN 55401, Phone:<PHONE_NUMBER>. Hours: Monday through
Thursday, 9 a.m. to 9 p.m., Friday and Saturday, 9 a.m. to 5 p.m. and
Sunday, 12 p.m. to 5 p.m.

FOR FURTHER INFORMATION CONTACT: Randolph Cano, NPL Deletion
Coordinator, U.S. Environmental Protection Agency Region 5 (ST-6J), 77
West Jackson Boulevard, Chicago, IL 60604, Phone:<PHONE_NUMBER>, or
via email at<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction
II. NPL Deletion Criteria
III. Partial Deletion Procedures
IV. Basis for Site Partial Deletion
V. Partial Deletion Action

I. Introduction

    EPA Region 5 is publishing this direct final Notice of Partial
Deletion for the South Minneapolis Residential Soil Contamination
Superfund Site (South Minn. Site), from the NPL. The South Minn. Site
includes approximately 3,632 properties located on approximately 1,400
acres within an approximate three-quarter mile radius of the CMC
Hearland Lite Yard State Superfund Cleanup Site. This partial deletion
pertains to all media at approximately 3,623 of the residential
properties, parks, schools, playgrounds associated with church schools
and a cemetery located within the South Minn. Site boundary, and
excludes the nine properties identified in Table 1 in the Docket that
still require sampling and/or remediation due to access issues. The
nine properties identified in Table 1 in the Docket will remain on the
NPL and are not being considered for deletion as part of this action.
    The nine properties that are not included in this partial deletion
are shown generally on the figure labeled South Minneapolis Remedial
Action and are listed in Table 1 in the Docket and include: Three
properties that still require remediation (located on East 23rd Street,
East 21st Street and East 22nd Street); five properties that still
require sampling [located on East 26th Street, 12th Avenue South (two
properties, one of which is now a community garden), 30th Avenue South
and 14th Avenue South]; and one

partially sampled property located on 19th Avenue South.
    Commercial and industrial properties located within the South Minn.
Site boundary do not require deletion because these properties are not
part of the South Minn. Site and are not on the NPL.
    The NPL constitutes Appendix B of the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP), which EPA promulgated
pursuant to CERCLA. EPA maintains the NPL as the list of sites that
appear to present a significant risk to public health, welfare, or the
environment. Sites on the NPL may be the subject of remedial actions
financed by the Hazardous Substance Superfund (Fund). This partial
deletion of the South Minn. Site is proposed in accordance with 40 CFR
300.425(e) and is consistent with the Notice of Policy Change: Partial
Deletion of Sites Listed on the National Priorities List. 60 FR 55466
(Nov. 1, 1995). As described in 40 CFR 300.425(e)(3) of the NCP, a
portion of a site deleted from the NPL remains eligible for Fund-
financed remedial actions if future conditions warrant such actions.
    Section II of this document explains the criteria for deleting
sites from the NPL. Section III discusses the procedures that EPA is
using for this action. Section IV discusses the residential properties,
parks, schools, community gardens, playgrounds associated with church
schools and the cemetery within the South Minn. Site boundary that are
included in this partial deletion and demonstrates how these properties
meet the deletion criteria. Section V discusses EPA's action to
partially delete all, but nine, properties located within the South
Minn. Site boundary from the NPL unless adverse comments are received
during the public comment period.

II. NPL Deletion Criteria

    The NCP establishes the criteria that EPA uses to delete sites from
the NPL. In accordance with 40 CFR 300.425(e), sites, or portions
thereof, may be deleted from the NPL where no further response is
appropriate. In making such a determination pursuant to 40 CFR
300.425(e), EPA will consider, in consultation with the state, whether
any of the following criteria have been met:
    i. Responsible parties or other persons have implemented all
appropriate response actions required;
    ii. all appropriate Fund-financed response under CERCLA has been
implemented, and no further response action by responsible parties is
appropriate; or
    iii. the remedial investigation has shown that the release poses no
significant threat to public health or the environment and, therefore,
the taking of remedial measures is not appropriate.
    Pursuant to CERCLA Section 121(c) and the NCP, EPA conducts five-
year reviews to ensure the continued protectiveness of remedial actions
where hazardous substances, pollutants, or contaminants remain at a
site above levels that allow for unlimited use and unrestricted
exposure. EPA conducts such five-year reviews even if a site or a
portion of a site is deleted from the NPL. EPA may initiate further
action to ensure continued protectiveness at a deleted site if new
information becomes available that indicates it is appropriate.
Whenever there is a significant release from a site deleted from the
NPL, the deleted site may be restored to the NPL without application of
the hazard ranking system.

III. Deletion Procedures

    The following procedures apply to the deletion of all residential
properties, parks, schools, community gardens, playgrounds associated
with church schools and the cemetery located within the South Minn.
Site boundary excluding the nine properties that still require sampling
and/or remediation due to access issues:
    (1) EPA consulted with the State of Minnesota prior to developing
this direct final Notice of Partial Deletion and the Notice of Intent
for Partial Deletion co-published in the ``Proposed Rules'' section of
the Federal Register.
    (2) EPA has provided the State 30 working days for review of this
notice and the parallel Notice of Intent to Partially Delete prior to
their publication today, and the State, through the Minnesota
Department of Agriculture (MDA), has concurred on the partial deletion
of the South Minn. Site from the NPL.
    (3) Concurrent with the publication of this direct final Notice of
Partial Deletion, an announcement of the availability of the parallel
Notice of Intent for Partial Deletion is being published in a major
local newspaper, the Minneapolis Star Tribune. The newspaper notice
announces the 30-day public comment period concerning the Notice of
Intent for Partial Deletion of the South Minn. Site from the NPL.
    (4) The EPA placed copies of documents supporting the partial
deletion in the deletion docket and made these items available for
public inspection and copying at the South Minn. Site information
repositories identified above.
    (5) If adverse comments are received within the 30-day public
comment period on this partial deletion action, EPA will publish a
timely notice of withdrawal of this direct final Notice of Partial
Deletion before its effective date and will prepare a response to
comments and continue with the deletion process on the basis of the
Notice of Intent for Partial Deletion and the comments already
received.
    Deletion of a portion of a site from the NPL does not itself
create, alter, or revoke any individual's rights or obligations.
Deletion of a portion of a site from the NPL does not in any way alter
EPA's right to take enforcement actions, as appropriate. The NPL is
designed primarily for informational purposes and to assist EPA
management. Section 300.425(e)(3) of the NCP states that the deletion
of a site from the NPL does not preclude eligibility for further
response actions, should future conditions warrant such actions.

IV. Basis for Partial Site Deletion

    The following information provides EPA's rationale for deleting all
residential properties, parks, schools, community gardens, playgrounds
associated with church schools and the cemetery located within the
South Minn. Site boundary from the NPL, excluding the nine properties
that still require sampling and/or remediation:

Site Background and History

    The South Minn. Site (MND 000 509 136) is located in Minneapolis,
Hennepin County, Minnesota, approximately two miles southeast of
downtown Minneapolis. The South Minn. Site includes all residential
properties, parks, schools, playgrounds associated with church schools
and a cemetery located within an approximate three-quarter mile radius
of the CMC Heartland Lite Yard State Superfund Cleanup Site (CMC Site).
The CMC Site is located at the northwest corner of Hiawatha Avenue and
28th Street in Minneapolis. Past operations at the CMC Site
contaminated the South Minn. Site with arsenic. These past operations
are the primary source of the South Minn. Site arsenic contamination.
The CMC Site was cleaned up under MDA's State Superfund Cleanup Program
in 2004-2005 and redeveloped into a 60,000 square foot light industrial
building called the Hiawatha Business Center.
    The South Minn. Site is largely a residential area interspersed
with commercial and industrial properties, municipal properties
including parks and schools, and a cemetery (see Figure

1-1 in the Docket). The South Minn. Site boundary is based on the
results of air dispersion modeling which showed the potential area of
arsenic deposition from past operations at the CMC Site (see Figure 4-1
in the Docket). The commercial and industrial properties located within
the South Minn. Site area are not on the NPL and are not part of the
South Minn. Site.
    The majority of the homes in the South Minn. Site area were built
during the early 1900s through the 1930s. A typical residential block
within the South Minn. Site contains approximately 30 properties with
an average lot size of approximately 5,500 square feet (0.1 acre). The
current land uses at the South Minn. Site have been in place for some
time and are expected to continue. Land use at the South Minn. Site is
controlled by the City of Minneapolis's enforced zoning program.
    The CMC Site property, which is the primary source of the arsenic
contamination at the South Minn. Site, was owned by the Chicago,
Milwaukee, St. Paul and Pacific Railroad Company (Milwaukee Railroad)
beginning in 1880. From 1938 to 1969, Reade Manufacturing Company
(Reade) leased the property from the Milwaukee Railroad.
    From 1938 to 1963, Reade blended, stored and distributed arsenic
herbicides and pesticides at the CMC Site. During the 1940s, Reade also
produced an arsenic-based grasshopper insecticide. As part of its
operations, Reade regularly unloaded arsenic trioxide from railroad
hopper cars onto an open conveyor belt. This caused powdered arsenic
trioxide to be released into the air and onto the CMC Site property.
    From 1963 to 1968, U.S. Borax subleased the CMC Site property from
Reade. U.S. Borax manufactured, shipped and stored borate-based
herbicides. U.S. Borax did not receive new shipments of powdered
arsenic trioxide, however, its operations at the CMC Site disturbed and
dispersed the arsenic contamination that was already present at the
property from Reade's operations.
    In 1968, a storage tank containing liquid sodium arsenite (NaAs02)
ruptured at the CMC Site. This released approximately 3,000 gallons of
liquid sodium arsenite from a 25,000-gallon storage tank onto an area
of approximately 1,000 square meters. U.S. Borax covered the spill with
approximately 6 inches of sand.
    After 1968, Rollins Oil Company and then Bituminous Roadways, an
asphalt road construction company, occupied the CMC Site. By 1996,
after the arsenic contamination was discovered at the CMC Site,
Bituminous Roadways placed one to two feet of crushed asphalt over the
CMC Site property to minimize human exposure to surface soil and to
keep additional dust from blowing off of the property.
    The Minnesota Department of Transportation (MnDOT) discovered the
arsenic contamination at the CMC Site in 1994 when investigating the
Hiawatha Avenue corridor for reconstruction. The MnDOT collected soil
samples from the easternmost part of the CMC Site and detected
organochlorine pesticides and elevated levels of arsenic in some of the
soil borings.
    In 1996, CMC Heartland Partners, the CMC Site property owner at the
time, began investigating the CMC Site under the oversight of the MDA's
Agricultural Voluntary Investigation and Cleanup Program. Later, the
State of Minnesota added the CMC Site to the Minnesota Permanent List
of Priorities, a list of sites eligible for cleanup under Minnesota's
State Superfund Program. In 2003, the MDA formally requested U.S. Borax
and CMC Heartland Partners to investigate and cleanup the CMC Site.
    U.S. Borax's and CMC Heartland Partner's investigations detected
arsenic in surface soil at the CMC Site at concentrations as high as
5,000 mg/kg. Groundwater below the CMC Site contained arsenic
concentrations as high as 320,000 micrograms per liter ([micro]g/L).
The groundwater contamination extended approximately 1,800 feet west-
southwest of the CMC Site.
    U.S. Borax and CMC Heartland Partners cleaned up the CMC Site from
2004 to 2005 under the oversight of MDA's Superfund Program. The
cleanup included the excavation, stabilization and off-site disposal of
contaminated soil and debris from the property and institutional
controls to restrict access to residual soil and groundwater
contamination remaining at and downgradient of the CMC Site.
    There are no private drinking water wells at the CMC Site or within
the South Minn. Site area. The City of Minneapolis supplies all
drinking water to the area from the Mississippi River. The City of
Minneapolis, Minnesota Code of Ordinances Chapter 9, Section 1 requires
that all properties within the city connect to the municipal water
supply.
    The MDH established a Special Well Construction Area (SWCA) to
address the arsenic plume from the CMC Site in 2005. The SWCA applies
to the construction, repair, and sealing of all wells and will remain
in effect until further notice. The SWCA includes the area bounded by
East 26th Street on the north, 26th Avenue on the east, Lake Street on
the south, and Bloomington Avenue South on the west, within the City of
Minneapolis. A copy of MDH's 2005 memorandum concerning the SWCA is
available in the Docket.
    2800 Hiawatha LLC acquired the CMC Site in 2005. 2800 Hiawatha LLC
conducted an additional soil cleanup at the CMC Site under MDA's
voluntary cleanup program, now called the AgVIC program, and
redeveloped the property into the Hiawatha Business Center. 2800
Hiawatha LLC also monitors the arsenic concentrations in groundwater at
the CMC Site.
    Due to the elevated concentrations of arsenic at the CMC Site, in
1999, the Minnesota Department of Health (MDH) recommended that soil
sampling be performed in residential areas near the CMC Site (part of
the area that would come to be known as the South Minn. Site). The
prevailing summer winds were determined to be from the southeast toward
the northwest; therefore, the residential area located directly
downwind of the CMC Site was the focus of this initial sampling effort.
    MDA in conjunction with MDH, conducted the initial, limited
sampling event at residential properties to the west (crosswind) and
northwest (downwind) of the CMC Site in 2001. The results of the 2001
MDA sampling detected arsenic in soil at six of the 11 downwind
properties sampled at concentrations as high as 24 to 210 milligrams
per kilogram (mg/kg).
    Based on the 2001 sampling event and neighborhood concerns, MDA and
MDH determined that additional sampling to the northwest and west of
the CMC Site was warranted. MDA conducted a second study in 2003. MDA
developed the sampling design for the 2003 study to obtain
statistically valid data using a grid overlain on the Phillips
neighborhood with the majority of the samples falling on residential
properties.
    MDA's contractor collected soil samples from a total of 242
locations and 167 properties during the 2003 sampling. MDA's contractor
additionally collected 12 duplicate samples for quality control and 23
co-located samples to give an indication of spatial variability.
    Thirty-five samples collected from 27 of the properties contained
arsenic at concentrations greater than or equal to the Minnesota
Pollution Control Agency (MPCA) unrestricted land use standard of 10
mg/kg. In 11 of the samples, the concentration of arsenic was greater
than 100 mg/kg. Four of those samples

contained arsenic at concentrations exceeding 200 mg/kg.
    In 2004, MDA requested EPA's assistance to determine whether a time
critical removal action was warranted to address the arsenic
concentrations detected in the residential soil. EPA agreed to perform
an additional investigation. EPA collected samples from 192 properties,
primarily in the vicinity of the properties previously identified as
hotspots, from a depth of zero to three inches below ground surface.
    EPA consulted with the Agency for Toxic Substances and Disease
Registry (ATSDR) and determined that arsenic concentrations equal to or
greater than 95 mg/kg in surface soil posed an acute risk to human
health and warranted an emergency removal action. Based on the results
of multiple sampling events conducted in the Phillips neighborhood (the
vicinity of East 26th Street and Bloomington Avenue), EPA identified 30
properties that exceeded the 95 mg/kg criterion.
    EPA conducted a removal action in 2004 to mitigate the threat. EPA
excavated the top 12 inches of soil from the yards and the top 18
inches of soil from play areas and gardens at the 30 identified
properties. EPA removed an average of 106 cubic yards of arsenic-
contaminated soil from each excavated property. EPA also collected
post-excavation soil samples from each property to document the
residual arsenic concentrations remaining in each yard after
excavation. EPA backfilled each property to pre-existing grade with
clean topsoil and seeded the excavated areas with grass seed.
    In 2005, EPA sampled 540 additional properties in the Phillips
neighborhood to ensure that 100 percent of the residential properties
most likely to be impacted by wind deposition from the CMC Site were
evaluated for potential impacts. EPA also sampled another 60 properties
to identify whether areas in other wind directions surrounding the CMC
Site were impacted.
    EPA's sampling effort identified another 31 properties with arsenic
concentrations above 95 mg/kg. EPA began a second removal action in
2005. During the 2005 removal action, EPA excavated and disposed of
arsenic-contaminated soil consistent with the 2004 removal activities.
    Due to the potential health risks posed to residents from exposure
to arsenic-contaminated soil, EPA proposed the South Minn. Site to the
NPL on September 27, 2006 (71 FR 56433). EPA finalized the South Minn.
Site on the NPL on September 19, 2007 (72 FR 53463).
    This partial deletion pertains to all media at all properties
located within the boundary of the South Minn. Site except for nine
properties that still require sampling and/or remediation due to access
issues (see Section I., Introduction, above). This partial deletion
also pertains to all media at all parks, schools, community gardens
(except the community garden located on 12th Avenue South that is one
of the nine properties that still requires sampling and/or
remediation), playgrounds associated with church schools and the
cemetery located within the South Minn. Site boundary.
    The nine properties that still require sampling and/or remediation
as shown generally on the figure labeled South Minneapolis Remedial
Action and as listed in Table 1 in the Docket will remain on the NPL
and are not being considered for deletion as part of this action.
    Commercial and industrial properties located within the South Minn.
Site boundary do not require deletion because these properties are not
part of the South Minn. Site and are not on the NPL.

Remedial Investigation and Feasibility Study (RI/FS)

    EPA conducted a Remedial Investigation (RI) at the South Minn. Site
from 2005 to 2007. The objective of the RI was to have 100 percent of
the residential properties, schools and parks within the modeled
boundaries of the South Minn. Site sampled for total arsenic. EPA also
collected soil samples for arsenic analysis from community gardens,
playgrounds associated with church schools and a cemetery.
    EPA developed the boundary for the South Minn. Site using the
Industrial Source Complex 3 air dispersion model, information from past
operations at the CMC Site and wind-rose data for Minneapolis to
predict where arsenic may have been deposited in soil at concentrations
greater than 10 mg/kg. EPA made slight adjustments to the modeled
boundary so that an entire block would be sampled (see Figure 4-1).
    EPA did not include previously sampled properties in the RI surface
soil sampling unless only one discrete sample had been collected from
that property. The RI also did not address groundwater. Groundwater was
previously investigated and is being addressed as part of the CMC Site
(see Site Background and History section).
    EPA conducted the RI surface soil sampling in 2006. EPA conducted
the sampling by collecting five samples from separate areas of each
property and combining them into one composite sample for analysis. EPA
collected the soil samples from the top three inches of soil, below any
grass if present. EPA collected the soil samples from both the front
yard and the back yard wherever possible. EPA also collected samples
from side yards and gardens depending on their size. For larger
properties, such as parks and schools, EPA divided the property into
sub-areas and collected composite samples from each sub-area.
    The RI also included subsurface soil sampling at 20 soil boring
locations throughout the South Minn. Site. The subsurface soil borings
were located to provide data to characterize the vertical distribution
of arsenic at properties with varying arsenic concentrations. EPA
collected subsurface soil samples from each boring at one foot
intervals from zero to five feet, and at a depth of ten feet.
    The surface soil sampling locations are shown in Figure 3-1 in the
Docket. The subsurface soil sampling locations are shown in Figure 3-2.
    EPA evaluated the 2006 soil sampling results against the previous
soil sampling results collected from 2001 to 2005. EPA determined that
the data were compatible and could be evaluated as a single data set
for the RI. The total number of properties sampled for arsenic from
2001 to 2006 was 3,578. One-hundred and thirty-five properties within
the South Minn. Site remained unsampled because the property owners did
not allow EPA access.
    The results of the surface and subsurface soil investigations at
the South Minn. Site indicated that arsenic was present in the soil at
varying concentrations at properties across the area (see Figure 4-2 in
the Docket). The RI included a statistical evaluation which determined
that the background concentration of arsenic in surface soil from
natural and man-made sources within the South Minn. Site area was 16
mg/kg.
    Arsenic concentrations within the South Minn. Site ranged from
background concentrations up to 2,880 mg/kg. The vertical extent of
arsenic concentrations above background appeared to be no greater than
three feet below ground surface and, in most cases, was within the
upper two feet of soil. This indicated that that the mobility of the
arsenic in the soil was limited.
    Of the 3,578 properties sampled, the majority of residential
properties (2,600 properties) had arsenic concentrations below MPCA's
unrestricted land use standard of 10 mg/kg. Seven-hundred and eighty-
one residential properties contained concentrations of arsenic

below EPA's removal action level for arsenic of 95 mg/kg, but above
MPCA's unrestricted land use standard of 10 mg/kg. One-hundred and
ninety-seven residential properties had arsenic concentrations in soil
above EPA's removal action level of 95 mg/kg.
    The properties with arsenic concentrations above EPA's removal
action level of 95 mg/kg were scattered throughout the South Minn. Site
area. EPA addressed these properties through removal actions EPA
completed by 2008. All sample results from the schools, parks,
playgrounds and the cemetery were within background levels and these
properties did not require remediation.
    EPA's RI included a Human Health Risk Assessment (HHRA) to evaluate
the risks to human health from the arsenic contamination detected at
the South Minn. Site. As part of the HHRA, EPA calculated potential
risks due to varying concentrations of arsenic at residences with and
without vegetable gardens, and for construction workers.
    Using reasonable maximum exposure assumptions, EPA determined that
an arsenic concentration of up to 25 mg/kg (or less) in soil is
protective of adults and children residing within the South Minn. Site
area for up to 50 years with vegetable gardens. This concentration of
arsenic corresponds to a cancer risk of 1 x 10-4 and a
noncancer hazard of 1, which are within EPA's acceptable risk range.
Approximately 486 homes exceeded the 25 mg/kg residential threshold.
The HHRA determined that arsenic concentrations of 261 mg/kg (or less)
are protective of construction workers.
    The HHRA estimated that most of the risk posed by the soil is due
to the incidental ingestion of soil and dust (approximately 70
percent), and to eating garden vegetables (approximately 25 percent). A
small proportion of the estimated risk (approximately 4 percent) is
from dermal contact with soil, and a very small relative proportion of
potential risk (less than 0.05 percent) is from the inhalation of dust.
The calculated risks to residents and construction workers are likely
overestimated due to the uncertainties and conservative assumptions
required throughout the HHRA process.
    The RI included a Screening Level Ecological Risk Assessment
(SLERA) to evaluate potential risks to ecological receptors from the
arsenic-contaminated soil at the South Minn. Site. The SLERA concluded
that no population-level ecological risks were expected from the
arsenic contamination. In addition, EPA's Ecological Soil Screening
Levels for arsenic of 43 mg/kg for avian wildlife and 46 mg/kg for
mammalian wildlife were higher than the 25 mg/kg concentration of
arsenic determined to be protective of people. There are no water
bodies or wetlands within the South Minn. Site.
    EPA conducted a Feasibility Study (FS) to develop and evaluate
cleanup alternatives to address the unacceptable levels of arsenic
found at the South Minn. Site. The FS evaluated six cleanup
alternatives: (1) No action; (2) remove soil with arsenic levels above
25 mg/kg to a depth of 12 inches (18 inches in garden areas); (3)
remove soil with arsenic levels above 16 mg/kg to a depth of 12 inches
(18 inches in garden areas); (4) remove soil with arsenic levels above
25 mg/kg to a depth of 12 inches (18 inches in garden areas) and remove
soil deeper than 12 inches with arsenic levels above 95 mg/kg; (5)
remove all soil with arsenic levels above 25 mg/kg; and (6) remove all
soil with arsenic levels above 16 mg/kg. For all cleanup alternatives
except the no action alternative, the excavated soil would be disposed
of at landfill.

Selected Remedy

    EPA selected a cleanup remedy for the South Minn. Site in a 2008
Record of Decision (ROD). EPA's remedial action objectives for the
arsenic-contaminated soil at the South Minn. Site are to control the
concentrations of arsenic in soil to limit residential contact with
arsenic and minimize the potential for dermal contact, ingestion and
inhalation exposures.
    EPA's selected cleanup standards for arsenic are 25 mg/kg for soil
located zero to 12 inches below grade or to 18 inches below grade in
gardens, and 95 mg/kg for soil down to a depth of 10 feet below grade.
These concentrations of arsenic correspond to a cancer risk of 1 x
10-4 and a noncancer hazard of 1 for residential exposure to
surface soil and a cancer risk of 2 x 10-5 and a noncancer
hazard of 0.4 for construction worker exposure to subsurface soil.
    The subsurface soil cleanup standard of 95 mg/kg corresponds to a
cancer risk of 4 x 10-4 and a noncancer hazard of 4 to
residents. However, residential exposure to deep, subsurface
concentrations of arsenic is only expected in rare circumstances and
for short periods of time, and less frequently than a construction
worker. Any risks from exposure to arsenic contamination in deep soil
would also be mitigated through the inevitable mixing of the deep soil
with the clean, shallow soil above, resulting in lower exposure point
concentrations. Therefore, EPA considered the 95 mg/kg acute exposure-
based removal action level provided by ATSDR to be appropriate for
subsurface soil and protective over the long-term.
    As indicated in the HHRA, most of the risk at the South Minn. Site
was due to the incidental ingestion of soil and dust by residents and
to residents eating garden vegetables. A small proportion of the
estimated risk is from dermal contact with soil, and a very small
relative proportion of potential risk is due to inhalation of dust.
EPA's remedial action objectives for the South Minn. Site take into
consideration that control of the soil concentrations of arsenic will
address each of the exposure pathways contributing to the overall risk.
    The selected remedy in the ROD applied only to the residential and
residential-type properties at the South Minn. Site. The commercial and
industrial properties in the area typically had little open ground and
were mainly covered by asphalt, concrete or buildings which limited the
potential for soil exposure.
    The major components of EPA's selected cleanup remedy for the South
Minn. Site in the ROD, as modified by a slight, non-significant change
documented in a September 23, 2009 EPA memorandum include: (1)
Inventory and document the existing conditions at the areas requiring
the remedy; (2) excavate soil to a depth of 12 inches below grade in
yards or to a depth of 18 inches below grade in garden areas that have
a total arsenic concentration above 25 mg/kg; (3) post-excavation soil
sampling to document arsenic concentrations in the remaining soil; (4)
if the samples at the base of the excavation exceed the deep soil
arsenic cleanup standard of 95 mg/kg, then excavate soil until the deep
soil cleanup standard is met or to a maximum depth of ten feet; (5) if
the samples at the base of the excavation exceed the deep soil arsenic
cleanup standard, place a permanent, permeable highly-visible marker
layer in the bottom of the excavation to provide a visual barrier over
soils that were not excavated during the remedial actions and may
contain residual contamination above the deep soil cleanup standard;
(6) backfill excavations with clean fill and topsoil to the original
grade; (7) restore the excavated areas (i.e., restoring vegetation by
seeding the final graded surface and planting replacement plants
identified prior to excavation during the inventory); (8) collect
samples from excavated soil to confirm the soil is not
characteristically hazardous and may be transported to and disposed of
at a permitted and compliant Resource Conservation Recovery Act (RCRA)

Subtitle D landfill; (9) if soil is found to be characteristically
hazardous, the soil may be stabilized and solidified at a centralized
off-site treatment area and disposed of a RCRA Subtitle D landfill, or
not stabilized and disposed of as a hazardous waste at a RCRA Subtitle
C landfill; and (10) place institutional controls (ICs) on properties
where the arsenic cleanup standard was not met at the bottom of the
excavation in the form of use-restrictions to define areas of remaining
concern or zoning and permit requirements to limit exposure.

Response Actions

    EPA conducted the Remedial Design (RD) phase of the South Minn.
Site cleanup from 2008 to 2009. EPA conducted the majority of the
Remedial Action (RA) construction work for the South Minn. Site from
2009 to 2011. In 2016 and 2018, EPA conducted additional remedial
activities and/or sampling at properties where EPA was not previously
able to obtain the owners' consent for access.
    EPA conducted the RA activities independently at each remediated
property, but sequenced the work so that the contractor could move to
nearby area as access to properties became available. The typical RA
activities conducted at each property included: (1) Pre-construction
survey; (2) plant inventory; (3) preconstruction property owner
meetings; (4) locating utilities; (5) clearing and grubbing; (6) soil
excavation; (7) transport and disposal; (8) post-excavation sampling
and survey; (9) backfill placement; (10) topsoil placement; (11)
restoration; (12) post-construction survey; (13) landscaping; (14)
punch list activities; and 15) post-construction property owner
meetings.
    EPA implemented dust control measures throughout the RA to minimize
potential hazards associated with airborne respirable dust. Dust
control measures at residential properties included keeping the soil
wet, hand sweeping the sidewalks and streets adjacent to the remediated
properties, and using a vacuum truck to sweep streets daily during
earthwork activities. Dust control measures at the Hennepin Avenue
laydown yard included covering soil piles except when being loaded/
unloaded, partial covering during loading/unloading as practicable,
water spray for any visible dust, wetting and vacuuming pavement, using
a rumble strip to remove dirt on trucks, inspecting trucks and full
stormwater collection.
    EPA performed health and safety monitoring during construction to
determine the effectiveness of the dust control measures and to assess
potential risks to human health. EPA used field dust monitors to
compare respirable dust concentrations at residential properties and at
the laydown yard with site-specific exposure limits. EPA considered a
15-minute average limit of 1.6 milligrams per cubic meter (mg/m\3\) to
be protective of dust inhalation based on a maximum arsenic
concentration of 385 mg/kg in soil. EPA calibrated the monitors daily
and stationed them upwind and downwind of excavation activities at each
property and at the laydown yard.
    A few isolated exceedances of the dust criteria occurred during
soil remediation activities, but each of the exceedances was caused by
monitoring anomalies, such as instrument calibration errors,
construction equipment exhausting into the monitor, monitors falling to
the ground, or exceedances at upwind monitoring locations not
attributable to construction activities. Additionally, the dust limit
was modeled based on an arsenic concentration of 385 mg/kg, which was
generally an order of magnitude greater than the actual concentrations
of arsenic at the properties or at the laydown yard. When considering
the actual arsenic concentrations present at these properties and the
laydown yard relative to the modeled concentration of 385 mg/kg, the
construction activities did not appear to have caused an unacceptable
risk due to dust inhalation. This is supported by monitoring performed
at the Hennepin laydown yard. EPA analyzed a limited set of dust
samples for arsenic to confirm that exposure limits were not exceeded
and arsenic was not detected in any of the samples.
    EPA also compared dust monitoring readings to the particulate
matter maximum 24-hour primary and secondary criteria of 0.26 mg/m\3\
and 0.15 mg/m\3\, respectively, per Minnesota Administrative Rule
7009.0080. Dust monitoring indicated a limited number of exceedances of
the primary and secondary particulate matter standards, but the
readings appeared to be due to the monitoring anomalies as discussed
above, and are not believed to represent actual exceedances.
    EPA performed the RA in accordance with the ROD with a few minor
exceptions. In a few instances, based on a property owner's request or
physical construction limitations, a small area of a property was not
excavated even though the arsenic concentration in that area was above
the surface soil cleanup level of 25 mg/kg. EPA determined that these
areas did not present an unacceptable risk when evaluating the property
as a whole; therefore these properties meet the criteria for partial
deletion. These properties include:
    (1) One property located on 11th Ave. South (front yard, arsenic
concentration 31 mg/kg). The file review indicates the front yard was
not cleaned up during the earlier removal action. EPA determined that
remedial action was not required given the small size of the yard and
the arsenic concentration relative to the cleanup limits. The area-
weighted average arsenic concentration for the property is 15.6 mg/kg,
which is below the surface soil cleanup level of 25 mg/kg.
    (2) A property located on 15th Ave. South (around a tree, arsenic
concentration 33 mg/kg). No remediation was performed due to the
limited extent of the soil area. The tree was encircled by concrete and
excavation could not be performed while maintaining a safe distance
from the tree trunk (so as to not harm the tree).
    (3) A property located on 19th Ave. South (garden area, arsenic
concentration 51.2 mg/kg). After the yard was sampled and before the
cleanup could occur, the yard was re-landscaped and a permanent
structure was built in the garden area. Thus, it could not be accessed
for cleanup.
    (4) A property located on 20th Ave. South (garden area, arsenic
concentrations of 25.7, 38, and 39.4 mg/kg). EPA determined that
remedial action was not required given the small size of the garden
area and the arsenic concentrations relative to the cleanup limits. The
area-weighted average arsenic concentration for this property is 14.4
mg/kg, which is below the surface soil cleanup level of 25 mg/kg.
    By 2011, EPA had completed the soil cleanup at a total of 611
properties: 137 properties remediated through EPA's Emergency Removal
Program prior to 2009 that did not require additional response; 56
properties that underwent an Emergency cleanup but required additional
soil cleanup during the RA; two properties cleaned up by a developer
after entering into an agreement with EPA; and 416 properties requiring
an RA soil cleanup only.
    During the 2009 to 2011 RA, EPA was not able to complete the
sampling and/or remediation at 54 properties due to access issues.
These properties included (1) 14 properties that exceeded the cleanup
criteria for arsenic, but could not be remediated because the property
owners did not respond to requests for access or refused to provide EPA
with access to clean up their property; (2) nine properties that EPA
was not able to

obtain permission to sample to determine whether they are contaminated
with arsenic; and (3) 31 residential properties that could not be
completely sampled because portions of the yards were inaccessible due
to fenced areas with no entrance provided, locked gates, pets in the
yard, etc. during the RI.
    EPA and MDA contacted the owners of the 54 unsampled and/or
unremediated properties in 2016 and 2018 to provide the property owners
with another opportunity to allow EPA to complete the sampling and/or
cleanup activities. By 2018, EPA was able to remediate 12 additional
properties (one by EPA's Removal Program in 2018), and determine that
33 of the 40 unsampled or partially sampled properties had arsenic
concentrations below the cleanup level and did not require remediation.
    As of 2018, all, but nine, properties within the South Minn. Site
have been remediated and/or sampled and determined to be below cleanup
standards. The nine properties that EPA was not able to remediate and/
or sample (due to access issues) are shown generally on the figure
labeled South Minneapolis Remedial Action and listed in Table 1 in the
Docket and include: Three properties that still require remediation
(located on East 23rd Street, East 21st Street and East 22nd Street);
five properties that still require sampling [located on East 26th
Street, 12th Avenue South (two properties, one of which is now a
community garden), 30th Avenue South and 14th Avenue South]; and one
partially sampled property located on 19th Avenue South. These nine
properties are not included as part of the South Minn. partial deletion
and will remain on the NPL.
    EPA demobilized from the South Minn. Site in 2011, then again in
2016 and 2018 after completing the construction and sampling activities
for all, but nine, properties at the South Minn. Site. Reports
documenting the completion of the RA for the properties included in
this partial deletion are available in the Docket in the following
reports: 2012 Final Remedial Action Report; 2016 Final Remedial Action
Report; 2018 Data Evaluation Report; 2014 Five-Year Review and 2019
Five-Year Review.

Cleanup Levels

    The cleanup standards for the South Minn. Site arsenic
contamination in the ROD are 25 mg/kg for soil located zero to 12
inches below grade or 18 inches below grade in gardens and 95 mg/kg for
soil down to a depth of 10 feet below grade. EPA confirmed that the
cleanup levels were met at each excavation during the 2009 to 2011 RA
using field x-ray fluorescence (XRF) followed by laboratory
confirmation sampling.
    Based on a statistical analysis EPA conducted during the RD, EPA
determined that the lower 95 percent confidence interval for a
laboratory arsenic result of 95 mg/kg was an XRF reading of 62 mg/kg.
For a laboratory result of 25 mg/kg, the lower 95 percent confidence
interval was an XRF reading of 8 mg/kg, and the upper 95 percent
confidence interval was an XRF reading of 44 mg/kg. During the RA, XRF
readings above 62 mg/kg were considered to be above the 95 mg/kg
cleanup level and further excavation was performed. XRF sample
detections in surface soil above 44 mg/kg were considered to be above
the 25 mg/kg cleanup level and additional excavation was performed. If
XRF sample results in surface soil were between 8 mg/kg and 44 mg/kg,
EPA submitted the soil sample for laboratory analysis to determine
whether additional excavation was required.
    After the lower extent of an excavation was reached, EPA collected
a 5-point composite sample from the excavation floor for laboratory
analysis. The laboratory analysis indicated that all excavated yards
were determined to be below the surface and subsurface cleanup criteria
of based on the XRF readings and confirmed by the post-excavation
analytical results. EPA submitted post-excavation confirmation samples
for each excavation area at each property to provide 100 percent
laboratory verification. In all instances, the confirmation results
from the laboratory confirmed the determination that the excavation was
complete based on the XRF readings. The placement of demarcation fabric
and ICs were not required in any excavation.
    During the RD and the 2009 to 2011 RA, EPA resampled properties
that were cleaned up between 2004 and 2008 by the Emergency Removal
Program at a depth of 1 foot below ground surface if the 2004 to 2008
post-excavation results were greater than the subsurface criteria of 95
mg/kg. EPA used the results to assess if re-excavation was necessary
during the RA. Based on this evaluation, EPA determined that additional
soil excavation was required at 56 properties.
    The post-excavation confirmation sampling results from the 2004 to
2008 removal actions and the 2009 to 2011 RA are included in Appendix
D-3 of the 2012 Final Remedial Action Report in the Docket.
    During the 2016 RA, EPA conducted delineation sampling during
predesign activities prior to construction in lieu of post-excavation
confirmation sampling. A summary of the investigation activities and
delineation sampling results for the 2016 RA is provided in the 2018
Data Evaluation Report in the Docket.

Operation and Maintenance

    There is no operation, maintenance or monitoring at the properties
included in this partial deletion. All of the properties included in
this partial deletion meet the cleanup standards for surface and
subsurface soils in the ROD, as confirmed through investigation,
delineation and/or confirmation sampling. These properties have either
been cleared for unrestricted use/unlimited exposure (UU/UE) or
returned to UU/UE through the excavation and off-site disposal of
contaminated soil. Because EPA returned these properties to UU/UE,
institutional controls to limit land use are not required.
    Nine properties have not been sampled and/or remediated due to
access issues. These properties are not included in this partial
deletion. EPA provided the owners of the three properties with known
arsenic contamination above criteria with information concerning the
health risks and practices to minimize contact with soil contaminants.
EPA also worked with the City of Minneapolis to ensure that utility and
construction workers, and prospective buyers are put on notice of the
contaminant levels at these properties.
    All Minneapolis property owners are required, by City of
Minneapolis (City) Code of Ordinances Section 248.30, to disclose to
potential buyers environmental testing performed on the property by or
under the direction of EPA or other governmental agencies. All
Minneapolis rental property owners are also required, by City Code of
Ordinances Title 12 Section 244.275, to: (1) Notify tenants of
environmental testing results and (2) to cooperate with EPA regarding
any necessary cleanup.
    Added protection is also provided by the City in the form of a flag
in their city permits databases for the three properties with
contamination above cleanup levels to ensure that: (1) Rental permits
are not issued for the properties, and (2) utility and construction
workers are notified of the presence of contamination when a building
or construction permit is sought for these properties until cleanups
occur.
    In April 2019, EPA and MDA contacted the owners of the nine
properties that still require sampling and/or remediation to request
access,

but EPA's and MDA's requests for access continued to be denied. If EPA
cannot obtain consent for access for sampling and/or remediation after
continued efforts, EPA may pursue recorded ICs in the future on the
uncooperative properties and/or may pursue other options for requiring
access.

Five-Year Reviews

    The ROD requires EPA to conduct statutory five-year reviews (FYRs)
for the South Minn. Site if cleanup standards are still exceeded at the
maximum practicable excavation depth at a property, resulting in
hazardous substances, pollutants or contaminants remaining above levels
that allow for UU/UE. Because EPA could not sample and/or remediate
nine properties at the South Minn. Site, EPA is required to conduct
statutory FYRs of the South Minn. Site until these remaining properties
are either sampled and cleared for UU/UE or remediated.
    EPA conducted the first FYR of the South Minn. Site in 2014. EPA
conducted the most recent FYR for the South Minn. Site in May 2019. The
2019 FYR concluded that the remedy at the South Minn. Site is
protective of human health and the environment because immediate
threats have been addressed and the remedy is functioning as intended
by the ROD.
    The FYR confirms that the arsenic cleanup standards were met at the
bottom of each excavation for all properties that were remediated, with
the exception of four properties where minor areas of soil above
criteria were left in place based on a property owner's request or
physical construction limitations. EPA reviewed the information for
these properties (provided in the 2012 RA Report) during the 2014 and
2019 FYRs and determined that these residual areas of soil
contamination did not present an unacceptable risk when evaluating each
property as a whole. (See the Response Actions section above).
    The 2019 FYR concluded that for the three contaminated properties
that still require remediation (not included as part of this partial
deletion) effective governmental ICs are in place. Also, the FYR site
inspection did not find any changes in land use at these properties
that would cause an unacceptable risk. The contaminated soil at these
properties is generally in lawn areas and covered by grass. Sampling
throughout the South Minn. Site also demonstrates that the arsenic is
generally not mobile and will not affect neighboring properties.
    During the 2019 FYR, EPA and MDA contacted the owners of the three
properties that still require remediation and the owners of the six
properties that still require sampling to obtain access and were again
refused (these properties are not included as part of this partial
deletion). If EPA cannot obtain consent for access for sampling and/or
remediation after continued efforts, EPA may pursue recorded ICs in the
future on the uncooperative properties and/or may pursue other options
for requiring access.
    EPA will conduct the next FYR at the South Minn. Site on or before
May 2023. If EPA is able to complete the sampling and any necessary
remediation at the nine remaining properties at the South Minn. Site,
however, EPA will propose to delete the South Minn. Site from the NPL
in its entirety and FYRs will no longer be required.

Community Involvement

    EPA actively engaged with the community and strived to advocate and
strengthen early and meaningful community participation throughout
EPA's remedial activities at the South Minn. Site, satisfying the
provisions of Sections 113(k) and 117 of CERCLA, 42 U.S.C. 9613(k) and
9617.
    EPA developed a Community Involvement Plan (CIP) for the South
Minn. Site in July 2005. The CIP outlined the community involvement
activities that EPA conducted and would continue to undertake during
the remedial activities planned for the South Minn. Site.
    Since 2004, the year that EPA became involved with the South Minn.
Site, EPA held 22 public meetings and availability sessions about the
South Minn. Site investigations and cleanup. EPA held major meetings at
the YWCA located at 2121 East Lake Street in Minneapolis, and other
meetings at other locations throughout the affected area in an effort
to make the meetings more available to all of the communities impacted
by the South Minn. Site. EPA held meetings at Powderhorn Park, the
Franklin Avenue Safety Center, and the Minneapolis Public Library Lake
Street Branch.
    EPA issued its proposed cleanup plan for the South Minn. Site and
held a public comment period on its proposal from June 2, 2008 to July
1, 2008. EPA also held a public meeting on June 11, 2008 at the YWCA to
discuss the contamination at the South Minn. Site, the cleanup
alternatives being considered, and to answer questions and accept
public comments on the proposed cleanup plan. Approximately 40 people
attended the meeting. EPA received approximately 31 public comments
during the comment period.
    EPA mailed out post cards announcing the public meetings and fact
sheets updating the community on the status of the project throughout
the entire removal and remedial process. EPA sent mailings out to
approximately 10,000 homes. Because of the multi-lingual nature of the
area EPA translated the mailings into four languages: English, Spanish,
Hmong and Somali. EPA eventually limited the translations to English
and Spanish, but continued to make Hmong and Somali translations
available upon request.
    EPA developed and maintained public local information repositories
for the South Minn. Site at four locations: (1) Green Institute, 2801
21st Ave. S, Suite 100, Minneapolis, MN; (2) City of Minneapolis Police
Department, 1201-B E Franklin Ave., Minneapolis, MN; (3) Minneapolis
Central Library, 300 Nicollet Mall, 2nd Floor Minneapolis, MN; and (4)
Minneapolis Public Library, East Lake Branch, 2727 E Lake St.,
Minneapolis, MN. EPA also developed and maintains a web page for the
South Minn. Site located at: http://epa.gov/region5/sites/cmcheartland.
    EPA involved state and local government officials in the 2014 and
2019 FYR process by notifying them at the start of the FYR. EPA
interviewed the former 9th Ward Alderman of the City of Minneapolis,
the Minneapolis City Engineer, and an MDH Environmental Research
Scientist during the 2014 FYR and included summaries of the interviews
in the FYR Report. EPA conducted the 2014 and 2019 FYR site inspections
jointly with MDA project staff and provided MDA an opportunity to
review and provide input on the FYRs.
    EPA notified the community about the 2014 FYR by publishing a
newspaper announcement in the Minneapolis Southside Pride at the start
of the FYR. The newspaper announcement invited the community to submit
any concerns about the South Minn. Site to EPA and directed the
community to EPA contacts and the South Minn. Site's web page for
additional information. EPA notified the community about the 2019 FYR
by publishing a newspaper announcement in the Minneapolis Star Tribune.
    EPA made copies of the 2014 and 2019 FYR Reports available on the
internet and at the information repository located at the Minneapolis
Central Library.
    EPA satisfied public participation activities for this partial
deletion of the South Minn. Site as required by CERCLA section 113(k),
42 U.S.C.

9613(k), and CERCLA section 117, 42 U.S.C. 9617. EPA published a
document announcing this proposed direct final Partial Deletion and
announcing the 30-day public comment period in the Minneapolis Star
Tribune concurrent with publishing this partial deletion in the Federal
Register.
    Documents in the deletion docket, which EPA relied on for
recommending the partial deletion of the South Minn. Site from the NPL,
are available to the public in the information repositories and at
http://www.regulations.gov. Documents in the Docket include maps which
identify the South Minn. Site boundary, the contamination detected at
the South Minn. Site and the nine properties that are not included as
part of this partial deletion, which are also listed in Table 1 in the
Docket.

Determination That the Criteria for Partial Deletion Have Been Met

    All properties located within the boundary of the South Minn. Site
except for the nine properties that still require sampling and/or
remediation due to access issues meet all of the site completion
requirements specified in Office of Solid Waste and Emergency Response
(OSWER) Directive 9320.22, Close-Out Procedures for National Priorities
List Sites for all media. The properties that are not included in this
partial deletion are shown generally on the figure labeled South
Minneapolis Remedial Action and are listed in Table 1 in the Docket and
include: Three properties that still require remediation (located on
East 23rd Street, East 21st Street and East 22nd Street); five
properties that still require sampling [located on East 26th Street,
12th Avenue South (two properties, one of which is now a community
garden), 30th Avenue South and 14th Avenue South]; and one partially
sampled property located on 19th Avenue South. All parks, schools,
community gardens (except the community garden located on 12th Avenue
South that is one of the nine properties that still requires sampling
and/or remediation), playgrounds associated with church schools and the
cemetery located within the South Minn. Site boundary also meet all of
the site completion requirements specified in Office of Solid Waste and
Emergency Response (OSWER) Directive 9320.22, Close-Out Procedures for
National Priorities List Sites for all media.
    All cleanup actions and remedial action objectives for the
properties included in this partial deletion as set forth in the ROD
have been implemented for all pathways of exposure. The selected
remedial action, remedial action objectives and associated cleanup
levels for surface and subsurface soil for these properties are
consistent with EPA policy and guidance. No further Superfund response
is necessary to protect human health or the environment at the
residential properties, parks, schools, community gardens, playgrounds
associated with church schools or the cemetery located within the
boundary of the South Minn. Site, excluding the nine properties that
still require sampling and/or remediation.
    Section 300.425(e) of the NCP states that a Superfund site or a
portion of a site may be deleted from the NPL when no further response
action is appropriate. EPA, in consultation with the State of
Minnesota, has determined that all required response actions have been
implemented for all residential properties, parks, schools, community
gardens, playgrounds associated with church schools and the cemetery
located within the boundary of the South Minn. Site, except for the
nine properties that still require sampling and/or remediation, and
that no further response action by EPA is appropriate for these
properties.

V. Deletion Action

    EPA, with concurrence of the State of Minnesota, through the MDA,
has determined that all appropriate response actions under CERCLA have
been completed for all residential properties, parks, schools,
community gardens, playgrounds associated with church schools and the
cemetery located within the boundary of the South Minn. Site, excluding
the nine properties that still require sampling and/or remediation.
Therefore, EPA is deleting all residential properties, parks, schools,
community gardens, playgrounds associated with church schools and the
cemetery located within the boundary within the boundary of the South
Minn. Site from the NPL except for the nine properties that still
require sampling and/or remediation.
    Because EPA considers this action to be noncontroversial and
routine, EPA is taking it without prior publication. This action will
be effective September 30, 2019 unless EPA receives adverse comments by
August 30, 2019. If adverse comments are received within the 30-day
public comment period, EPA will publish a timely notice of withdrawal
of this direct final Notice of Partial Deletion before its effective
date and the partial deletion will not take effect. EPA will prepare a
response to comments and continue with the deletion process on the
basis of the notice of intent to partially delete and the comments
already received. There will be no additional opportunity to comment.

List of Subjects in 40 CFR Part 300

    Environmental protection, Air pollution control, Chemicals,
Hazardous waste, Hazardous substances, Intergovernmental relations,
Penalties, Reporting and recordkeeping requirements, Superfund, Water
pollution control, Water supply.

    Dated: July 19, 2019.
Cheryl Newton,
Acting Regional Administrator, Region 5.

    For the reasons set out in this document, 40 CFR part 300 is
amended as follows:

PART 300--NATIONAL OIL AND HAZARDOUS SUBSTANCES POLLUTION
CONTINGENCY PLAN

0
1. The authority citation for part 300 continues to read as follows:

    Authority: 33 U.S.C. 1321(d); 42 U.S.C. 9601-9675; E.O. 13626,
77 FR 56749, 3 CFR, 2013 Comp., p. 306; E.O. 12777, 56 FR 54757, 3
CFR, 1991 Comp., p. 351; E.O. 12580, 52 FR 2923, 3 CFR, 1987 Comp.,
p. 193.

0
2. Table 1 of Appendix B to part 300 is amended by revising the entry
under ``South Minneapolis Residential Soil Contamination'', ``MN'' to
read as follows:

Appendix B to Part 300--[Amended]

                                       Table 1--General Superfund Section
----------------------------------------------------------------------------------------------------------------
               State                          Site name                 City/county              Notes (a)
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
MN.................................  South Minneapolis            Minneapolis...........  P
                                      Residential Soil
                                      Contamination.

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
(a) * * *
* P = Sites with partial deletion(s).

[FR Doc. 2019-16192 Filed 7-30-19; 8:45 am]
 BILLING CODE 6560-50-P


UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

PC Code: 128008

 DP Barcode: 367184

 Date: September 24, 2009

MEMORANDUM

SUBJECT:	Drinking Water Exposure Assessment for New Uses of Boscalid on Alfalfa Forage and Hay, Citrus group 10, and an Increase in Tolerance on Stone Fruit group 12.

TO:		Bryant Crowe, Risk Manager Reviewer (RM Team 22)

		Fungicide Branch/Registration Division (7505P)

			Tony Kish, Risk Manager (RM Team 22)

			Fungicide Branch/Registration Division (7505P)

FROM:			David Lieu, Chemist Trainee

			Environmental Risk Branch IV

			Environmental Fate and Effects Division (7507P)

REVIEWED

BY:		R. David Jones, Ph.D. Senior Agronomist

		Environmental Risk Branch IV

		Environmental Fate and Effects Division (7507P)

APPROVED

BY:		Elizabeth Behl, Branch Chief

		Environmental Risk Branch IV

		Environmental Fate and Effects Division (7507P)

Executive Summary

This memo includes a drinking water exposure assessment for proposed new uses of boscalid (PC code: 128008) on alfalfa forage and hay, and citrus group 10.  The petition also requested an increase in tolerance on stone fruit (crop group 12) based on residues exceeding the 1.7 ppm tolerance found in samples of sweet and tart cherries and in peaches from field trials conducted by BASF. The proposed increase in tolerance to stone fruit group does not necessitate a change to the label and therefore does not trigger the need for a new drinking water assessment.

Previous drinking water assessments have estimated drinking water concentrations (EDWCs) for boscalid in surface water and groundwater using the screening models FIRST and the regression model SCI-GROW. Three previous assessments (D336183, D341459 and D343753) have all used application to turf as the maximum application rate allowed. The proposed new uses on alfalfa (forage and hay) and citrus (crop group 10) have lower maximum rates per application than that on turf.  The recommended EDWCs based on the existing turf use are listed in Table 1. The half-life for boscalid was recalculated to include unextractable residues, which affected the input parameters for calculating EDWCs in SCIGROW and FIRST.

Table 1. Maximum Tier 1 Estimated Drinking Water Concentrations (EDWCs) for drinking water assessment based on aerial application of boscalid on turf.

Drinking Water Source (Model used)	Use/rate Modeled (lb a.i./A) Estimated Drinking Water Concentration (EDWC; ppb)

Groundwater (SCI-GROW2)	Ground spray/0.35 x 6 applications; annual total of 2.1	Acute and Chronic	1.51

Surface Water (FIRST)	Ground spray/0.35 x 6 applications; annual total of 2.1	Acute	105.3

	Ground spray/0.35 x 6 applications; annual total of 2.1	Chronic	30.2

Problem Formulation

This is a Tier I drinking water assessment that uses modeling and available monitoring data to estimate the ground water and surface water concentrations of pesticides in drinking water source water (pre-treatment) resulting from pesticide use on sites that are highly vulnerable. This initial tier screens out chemicals with low potential risk.

Analysis

Use Characterization

Boscalid is currently registered for use on alfalfa, dry and succulent beans, berries, head and stem brassicas, leafy brassica greens, bulb vegetables, canola, carrots, celery, citrus fruits, cotton, cucurbit vegetables, fruiting vegetables, grapes, hops, leafy greens, leafy petioles, lettuce, peanuts, succulent and dried shelled peas, pistachios, pome fruit, potatoes, root and tuber vegetables, certain seed treatments, soybeans, spinach, stone fruit, strawberries, sunflowers, tree nuts, tropical fruits, turf, and ornamentals. Boscalid is mixed with a second active ingredient, Pyraclostrobin, in Pristine Reg. No. 7969-199 and Endura Reg. No. 7969-197. Boscalid is applied aerially or through ground equipment.

The proposed new uses for alfalfa (forage and hay) and citrus group 10 have a maximum seasonal application rate less than that previously allowed for turf (1.44 lbs a.i./A/season for Alfalfa, Endura Reg. # 7969-197, compared to 2.1 lbs a.i./A/season for turf). This information is summarized in Table 2.

Table 2. Application rates for the proposed new uses of boscalid on alfalfa, citrus (group 10) and the maximum current use rate for turf.

Crop Type	Single Maximum Application Rate (lbs a.i./A)	Maximum Number of Application	Maximum Seasonal Application Rate (lbs a.i./A/season) Minimum Interval Between Applications (days)	Application Method

Alfalfa (Pristine, Reg. # 7969-199)	0.28	3	0.85	14	Aerial Spray

Alfalfa (Endura, Reg. #7969-197)	0.48	3	1.44	14	Aerial Spray

Citrus, group 10 (Pristine, Reg. # 7969-199)	0.29	4	1.17	10	Aerial Spray

Turf (reference DP Barcode: D343753)	0.35	6	2.1	14	Ground Spray

Environmental Fate and Transport Characterization

Boscalid, o (2-chloro-N-(4´-chlorobiphenyl-2-yl)-nicotinamide nicotinamide -IUPAC name)

2-chloro-N-(4’chloro(1,1’-biphenyl)2-yl-3-pyridinecarboxamide - CAS name) is a persistent compound with low mobility in most soils. The primary degradation pathway is aerobic soil metabolism, which proceeds slowly and results in the formation of intermediates which are relatively rapidly transformed into CO2 or were in unextracted unidentified soil residues. In anaerobic soil, boscalid is degraded very slowly and is considered to be stable to microbial degradation as the disappearance of the parent compound was mainly due to conversion to unextracted, unidentified residues. There is no significant degradation of boscalid and by photolysis on soil and in water. The compound is also not transformed to any significant extent in either aerobic or anaerobic aquatic systems. Boscalid is also no significant hydrolysis at environmentally relevant pHs and temperatures. Boscalid may sorb to aquatic sediments given its moderate soil mobility (Koc ranges from 507 to 1110mL/g). Terrestrial field dissipation studies show that the maximum leaching depth for boscalid ranged from 0-7.5 cm (MRIDs 454052-19, -20, -21, -22;EPA, 2003). These data support results from batch equilibrium studies that indicate moderate mobility in soil. A higher potential for leaching exists for the compound in soils which are low in organic matter content, as is often the case with coarse-textured soils. Boscalid is likely to reach surface water through spray drift when applied using ground and aerial spray. Given its persistence, transport of boscalid to surface water via runoff water is probably. The slow biodegradation of boscalid in most soils will increase the potential for both groundwater and surface water contamination. Because boscalid does not biodegrade in aquatic systems, but can bind to sediments, the compound may accumulate in the sediment phase of these environments (MRIDs 45405213 and 45405214). The boscalid degradate 2-chloronicotinic acid is very mobile in soil and is not expected to bind to aquatic sediments. However, the degradate is metabolized rapidly in aerobic soil, and is mineralized to CO2 or transformed to bound residues. A summary of the fate and transport properties can be found below in Table 3.  More details on the environmental fate and transport of boscalid can be found in the original environmental fate and ecological risk assessment performed for registration, titled “Environmental Fate and Ecological Risk Assessment for the Registration of BAS 510F (Nicobifen): 2-chloro-N-(4’chloro(1,1’-biphenyl)-2-yl-3-pyridinecarboxamide”.

Table 3. Summary of physical/chemical and environmental fate and transport properties of boscalid.

PARAMETER	VALUE(S) (units)	SOURCE	COMMENT

Chemical Name	boscalid	-	-

Molecular Weight	343.2 g/mole	-	-

Solubility (20ºC)	6 mg/L	MRID 45405205	-

Vapor Pressure (25ºC)	<1x10-8 torr (<1x10-6 Pa)	-	-

Hydrolysis Half-life (pH 5, 7, 9; (25ºC)	no signficant degradation	MRID 45405205	Stable at all pHs.

Aqueous Photolysis half-life	no signficant degradation	MRID 45405206	-

Soil Photolysis Half-life	no signficant degradation	MRID 45405207	-

Aerobic Soil Metabolism Half-life for Parent only (days)	182,

578,

408,

289	MRIDs

45405208(Supplemental)

45405209(Supplemental)

45643802(Acceptable)	-

Aerobic Soil Metabolism Half-life for Parent and unextracted residues (days)	1000,

1609,

848,

2553	MRIDs

45405208(Supplemental)

45405209(Supplemental)

45643802(Acceptable)	t1/2 were calculated incorporating unextracted residues to the total extractable residues

Aerobic Aquatic Metabolism Half-life	no signficant degradation	MRID 45405214	Study was classified as supplemental

Anaerobic Aquatic Metabolism Half-life	no signficant degradation	MRID 45405213	-

Organic Carbon Partition Coefficient (Koc) in mL/g	507 (sandy loam)

594 (loamy sand)

655 (soam)

776 (sandy clay loam)

987 (soamy sand)

1110 (sandy/loamy sand)	MRIDs

45405216(Supplemental)

45405217(Supplemental)	Supplemental status due to absence of material balance data.

Soil Partition Coefficient (Kd) in mL/g	3.3 (loam)

3.9 (loamy sand)

6.5 (loamy sand)

7.6 (sandy loam)

26.4 (sandy clay loam)

27.8 (sandy/loamy sand)	MRIDs

45405216(Supplemental)

45405217(Supplemental)	Supplemental status due to absence of material balance data.

Drinking Water Exposure Modeling

SCIGROW (Screening Concentration in Ground Water) is a regression model used as a screening tool to estimate pesticide concentrations found in ground water used as drinking water. SCIGROW was developed by fitting a linear model to groundwater concentrations with the Relative Index of Leaching Potential (RILP) as the independent variable. Groundwater concentrations were taken from 90-day average high concentrations from Prospective Ground Water studies; the RILP is a function of aerobic soil metabolism and the soil-water partition coefficient. The output of SCIGROW represents the concentrations that might be expected in shallow unconfined aquifers under sandy soils, which is representative of the ground water most vulnerable to pesticide contamination likely to serve as a drinking water source.

	FIRST (FQPA Index Reservoir Screening Tool) is a metamodel of PRZM and EXAMS used as a screening tool to estimate pesticide concentrations found in surface water used as drinking water. FIRST was developed by making multiple runs of PRZM using varying sorption coefficients and determining the concentration in the EXAMS index reservoir scenario after a two-inch single storm event. (The Index Reservoir is a standard water body used by the Office of Pesticide Programs to assess drinking water exposure (office of Pesticide Programs, 2002). It is based on a real reservoir (albeit not currently in active use as a drinking water supply), Shipman City lake in Illinois, that is known to be vulnerable to pesticide contamination.) The single runoff event moves a maximum of 8% of the applied pesticide into the reservoir. This amount can be reduced by degradation or effects of binding to soil in the field. Additionally, FIRST can account for spray drift and adjusts for the area within a watershed that is planned with the modeled crop (percent Cropped Area). Spray drift (modeled as direct deposition of the pesticide into the reservoir) is assumed to be 16% of the applied active ingredient for aerial application, 6.3% for orchard air blast application, and 6.4% for other ground spray application. Despite being a single even model, FIRST can account for spray drift from multiple applications. The default a Percent Cropped Area (PCA) is 87% for agricultural crops. The default PCA for turf is 1.0 since turf is often grown on land that is not agricultural. The PRZM scenario used for FIRST development was among the most vulnerable, and thus resulting surface water concentration represents the upper bound values on the concentrations that might be found in drinking water from the use of a pesticide.

Modeling Approach and Input Parameters

The following Tables 4 and 5 represent the input parameters used for the surface and groundwater modeling applications, SCIGROW and FIRST. The input parameter for aerobic soil metabolism was calculated both as parent only and as parent plus unextracted residues. The parent plus unextracted residue half-life was calculated using the total toxic residues (TTR) method (Scientific Advisory Panel “White Paper on Methods for Assessing Ecological Risks of Pesticides with Persistent, Bioaccumulative and Toxic Characteristics”). The unextracted residues in some studies were over 50%. There is insufficient information to verify that the extraction methods used, methanol and then methanol and water, were efficiently extracted all unbound residues. Then the EECs in Table 6. are based on the TTR method. The calculations are in Appendix A.

Table 4. SCI-GROW input parameter values for boscalid use on Alfalfa (Hay and Forage), Citrus (group 10) and Turf.

Model Input Parameter (units)	Input Values 	Source	Comments

Application Rate (lbs a.i./A/application)	0.28 (Alfalfa, Pristine®)

0.48 (Alfalfa, Endura®)

0.29 (Citrus, Pristine®)

0.35 (Turf, DP D343753)	Proposed Label	-

Maximum No. of Applications/Year	3 (Alfalfa, Pristine®)

3 (Alfalfa, Endura®)

4 (Citrus, Pristine®)

6 (Turf, DP D343753)	Proposed Label	-

Organic Carbon Normalized Partition Coefficient Koc (mL/g)	821	MRID 45405216	Represents the median value for six soils.

Aerobic Soil Metabolism Half-life (days)	1503 (Parent + Unextracted)*

364 (Parent Only)	MRIDs

45405208(Supplemental)

45405209(Supplemental)

45405210(Unacceptable)

45643802(Acceptable)	Mean of four values in the acceptable study.

* Value represents total toxic residues which include parent and unextracted residues which we assume to be unextracted parent residues.

Table 5. FIRST input parameter values for boscalid use on Alfalfa (Hay and Forage), Citrus (group 10) and Turf.

Parameter (units)	Value(s)	Source	Comments

Application Rate (lb a.i./A)	0.28 (Alfalfa, Pristine®)

0.48 (Alfalfa, Endura®)

0.29 (Citrus, Pristine®)

0.35 (Turf, DP D343753)	Proposed Label	-

Number of Applications	3 (Alfalfa, Pristine®)

3 (Alfalfa, Endura®)

4 (Citrus, Pristine®)

6 (Turf, DP D343753)	Proposed Label	-

Interval between Applications (days)	14 (Alfalfa, Pristine®)

14 (Alfalfa, Endura®)

10 (Citrus, Pristine®)

14 (Turf, DP D343753)	Proposed Label	-

Percent Cropped Area (decimal)	0.87 (Alfalfa & Citrus)

1.0 (Turf)	EFED PCA Guidance	No PCA Factors for Non-agricultural use sites (Turf)

Organic Carbon Partition Coefficient (Koc; L/kg-oc)	655	MRID 45405216 Represents the lowest non-sand Koc for six soils

Aerobic Soil Metabolism Half-life (days)	2073 (Parent + Unextracted)*

490 (Parent Only)	MRIDs

45405208(Supplemental)

45405209(Supplemental)

45405210(Unacceptable)

45643802(Acceptable)	90th percentile of the upper confidence bound on the mean half-life of four soils

Wetted in:	No	Input parameter guidance	-

Depth of Incorporation (inches)	0	Input parameter guidance	-

Method of Application	Aerial spray (Alfalfa & Citrus)

Ground spray (Turf, DP D343753)	Proposed Label	-

Solubility in water (mg/L or ppm)	6	MRID 45405205	pH 5-7, 20ºC

Aerobic Aquatic Metabolism Half-life (days)	4146 (Parent + Unextracted)**

980 (Parent Only)	Input parameter guidance	Twice the aerobic soil metabolism

Hydrolysis half-life (days)	0	MRID 45405205

	Stable

Aquatic Photolysis Half-life @ pH 7 (days)	0	MRID 45405206	Stable

* Value represents total toxic residues which include parent and unextracted residues.

** Value was affected by the new aerobic soil metabolism input

Modeling Results

	SCIGROW concentration (ppb) represents the groundwater concentration that might be expected in shallow unconfined aquifers under sandy soils. The outputs located in Appendix B are used for both acute and chronic endpoints. FIRST concentrations (ppb) represent untreated surface water concentrations. The one-in-10-year peak concentration is used for acute endpoints and the 1-in-10-year annual average concentration used for chronic endpoints. The estimated concentrations provided in this assessment are conservative estimates of concentrations in drinking water. The output files are located in Appendix C. The summary of EDWCs for each new use and the existing use on turf is shown below in Table 6 for groundwater using FIRST and Table 7 for surface water using SCIGROW.

.

Table 6. Summary of Tier 1 Surface Water EDWCs based on application of boscalid on turf and proposed new uses on Alfalfa Forage and hay, and Citrus Group 10 run with FIRST.

Estimated Drinking Water Concentration (EDWC; ppb)

Use	Use/rate Modeled (lb a.i./A)	Acute	Chronic

Alfalfa (Pristine)	Aerial spray/0.28 x 3 applications; annual total of 0.85	38.09	11.25

Alfalfa (Endura)	Aerial spray/0.48 x 3 applications; annual total of 1.44	65.30	19.29

Citrus Group 10 (Pristine)	Aerial spray/0.29 x 4 applications; annual total of 1.17	52.58	15.54

Turf (Parent + Unextracted)	Ground spray/0.35 x 6 applications; annual total of 2.1	105.3	30.2

Turf (Parent Only)	Ground spray/0.35 x 6 applications; annual total of 2.1	101.4	26.8

Table 7. Summary of Tier 1 Groundwater EDWCs based on application of boscalid on turf and proposed new uses on Alfalfa Forage and hay, and Citrus Group 10 run with SCIGROW.

Estimated Drinking Water Concentration (EDWC; ppb)

Use	Use/rate Modeled (lb a.i./A)	Acute and Chronic

Alfalfa (Pristine)	Aerial spray/0.28 x 3 applications; annual total of 0.85	0.61

Alfalfa (Endura)	Aerial spray/0.48 x 3 applications; annual total of 1.44	1.04

Citrus Group 10 (Pristine)	Aerial spray/0.29 x 4 applications; annual total of 1.17	0.84

Turf (Parent + Unextracted)	Ground spray/0.35 x 6 applications; annual total of 2.1	1.51

Turf (Parent Only)	Ground spray/0.35 x 6 applications; annual total of 2.1	0.59

Conclusions

	The EDWCs for boscalid in surface water and groundwater were determined to be lower than those estimated for the maximum application rate given by turf. Risks for the new uses should therefore be less than that of those maximum rates already established by turf. There were a number of uncertainties in the drinking water exposure assessment. These include the application method for the new uses. It was assumed that the applications would be aerial, which would have a higher percentage of spray drift. The label did not specify which application method is to be used but mentioned both aerial and ground applications. Another assumption that was factored into the assessment is the addition of the unextracted residues in the calculation of the aerobic soil metabolism half-lives and its associated input parameters for FIRST and SCIGROW. This value was also used in the determination of aerobic aquatic soil metabolism input parameter. There is also the uncertainty that comes with the modeling with FIRST and SCIGROW.

When using the parent plus unextracted to calculated groundwater and surface water EDWCs the acute EDWC for surface water was least affected, changing from 101.4 ppb to 105.3 ppb giving a 3.8% change. The chronic surface water was slightly little more affected than the acute surface water changing from 26.8 ppb with the parent only to 30.2 ppb with the parent plus unextracted, which gives a 12.7%. The greatest change came from the EDWCs calculated from groundwater which went from 0.59 ppb to 1.51 ppb. This is an overall 156% increase in the EDWC for groundwater. This uncertainty may be resolved with more data or further studies which could include different extraction solvents or additional physical characterization techniques such as NMR.

Appendix A. Aerobic Soil Metabolism Half-life Calculation

	A	B	C	D	E	F	G	H

1	Before Calc

After re-Calc

	2	MRID	Half-life

MRID	Half-life

	3	45643802	182

45643802	1000

	4	45643802	578

45643802	1609

	5	45643802	408

45643802	848

	6	45643802	289

45643802	2553

	7

8

9

10	Mean	364.25

Mean	1502.5	=AVERAGE(G3:G6)

11	STDEV	169.7849

STDEV	773.6858	=STDEV(G3:G6)

12	n^0.5	2

n^0.5	2	=4^0.5

13	t90	1.476

t90	1.476	from input parameter guidance

14

15	tinput	489.5513

tinput	2073.48	=G10+((G13*G11)/G12)

Appendix A. (Continued)

SUMMARY OUTPUT Illinois Silt Loam

Regression Statistics

	Multiple R	0.925907944

	R Square	0.85730552

	Adjusted R Square	0.83946871

	Standard Error	0.037516789

	Observations	10

	ANOVA

 	df	SS	MS	F	Significance F

	Regression	1	0.067650305	0.067650305	48.06383647	0.000120481

	Residual	8	0.011260076	0.001407509

	Total	9	0.078910381

	 	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%	Lower 95.0%	Upper 95.0%

Intercept	4.571314246	0.016564229<PHONE_NUMBER>	3.32732E-17	4.533117066 4.609511	4.533117	4.609511

X Variable 1	-0.000693253	9.99959E-05	-6.9328087	0.000120481 -0.000923844	-0.00046	-0.00092	-0.00046

Appendix A. (Continued)

SUMMARY OUTPUT Idaho Clay Loam

Regression Statistics

	Multiple R	0.927848957

	R Square	0.860903687

	Adjusted R Square	0.843516648

	Standard Error	0.022941401

	Observations	10

	ANOVA

 	df	SS	MS	F	Significance F

	Regression	1	0.026059663	0.026059663	49.51410533	0.000108603

	Residual	8	0.004210463	0.000526308

	Total	9	0.030270126

	 	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%	Lower 95.0%	Upper 95.0%

Intercept	4.584678672	0.01012496	452.80955	6.33625E-19	4.561330472 4.608027	4.56133	4.608027

X Variable 1	-0.000430665	6.12033E-05	-7.03662599	0.000108603	-0.0005718 -0.00029	-0.00057	-0.00029

Appendix A. (Continued)

SUMMARY OUTPUT California Clay Loam

Regression Statistics

	Multiple R	0.964142142

	R Square	0.929570069

	Adjusted R Square	0.920766328

	Standard Error	0.029828543

	Observations	10

	ANOVA

 	df	SS	MS	F	Significance F

	Regression	1	0.093946142	0.093946142<PHONE_NUMBER>	6.92635E-06

	Residual	8	0.007117936	0.000889742

	Total	9	0.101064078

	 	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%	Lower 95.0%	Upper 95.0%

Intercept	4.59590763	0.013164533<PHONE_NUMBER>	5.07445E-18	4.565550164 4.626265	4.56555	4.626265

X Variable 1	-0.000817701	7.95769E-05	-10.27560564	6.92635E-06 -0.001001206	-0.00063	-0.001	-0.00063

Appendix A. (Continued)

SUMMARY OUTPUT North Dakota Loam

Regression Statistics

	Multiple R	0.936554482

	R Square	0.877134298

	Adjusted R Square	0.861776085

	Standard Error	0.013476664

	Observations	10

	ANOVA

 	df	SS	MS	F	Significance F

	Regression	1	0.010372661	0.010372661	57.11174276	6.56337E-05

	Residual	8	0.001452964	0.00018162

	Total	9	0.011825625

	 	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%	Lower 95.0%	Upper 95.0%

Intercept	4.590231719	0.00595015<PHONE_NUMBER>	8.92778E-21	4.576510647 4.603953	4.576511	4.603953

X Variable 1	-0.000271457	3.59202E-05	-7.557231157	6.56337E-05 -0.00035429	-0.00019	-0.00035	-0.00019

Appendix B. SCIGROW Output Files

SCIGROW

VERSION 2.3

ENVIRONMENTAL FATE AND EFFECTS DIVISION

OFFICE OF PESTICIDE PROGRAMS

U.S. ENVIRONMENTAL PROTECTION AGENCY

SCREENING MODEL

FOR AQUATIC PESTICIDE EXPOSURE

SciGrow version 2.3

 chemical:Boscalid on Turf (Parent + Unextracted)

 time is  9/10/2009  10:26:38

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

  Application      Number of       Total Use    Koc      Soil Aerobic

  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)

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

      0.350           6.0           2.100      8.21E+02     1503.0

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

 groundwater screening cond (ppb) =   1.51E+00

 *********************************************************************** *

SciGrow version 2.3

 chemical:Boscalid on Turf (Parent Only)

 time is  9/10/2009  11:22: 1

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

  Application      Number of       Total Use    Koc      Soil Aerobic

  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)

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

      0.350           6.0           2.100      8.21E+02      364.0

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

 groundwater screening cond (ppb) =   5.88E-01

 *********************************************************************** *

 SciGrow version 2.3

 chemical:Boscalid on Alfalfa (Pristine)

 time is  9/10/2009  10:24:21

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

  Application      Number of       Total Use    Koc      Soil Aerobic

  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)

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

      0.280           3.0           0.840      8.21E+02     1503.0

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

 groundwater screening cond (ppb) =   6.05E-01

 *********************************************************************** *

Appendix B. SCIGROW Output File (continued)

SciGrow version 2.3

 chemical:Boscalid on Alfalfa (Endura)

 time is  9/10/2009  10:25:26

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

  Application      Number of       Total Use    Koc      Soil Aerobic

  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)

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

      0.480           3.0           1.440      8.21E+02     1503.0

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

 groundwater screening cond (ppb) =   1.04E+00

 *********************************************************************** *

SciGrow version 2.3

 chemical:Boscalid on Citrus (Group 10)

 time is  9/10/2009  10:26: 3

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

  Application      Number of       Total Use    Koc      Soil Aerobic

  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)

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

      0.290           4.0           1.160      8.21E+02     1503.0

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

 groundwater screening cond (ppb) =   8.35E-01

 *********************************************************************** *

Appendix C. FIRST Output Files

RUN No.   4 FOR Boscalid         ON   Turf          * INPUT VALUES *

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

    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .350(  2.076)   6  14     655.0    6.0   GROUND( 6.4) 100.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.)

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

   2073.00        2          N/A       .00-     .00   ******   4146.00

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0  JAN 1, 2007

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)

          CONCENTRATION             CONCENTRATION

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

            105.338                     30.175

Appendix C. FIRST Output Files (continued)

   RUN No.   5 FOR Boscalid         ON   Turf          * INPUT VALUES *

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

    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .350(  2.000)   6  14     655.0    6.0   GROUND( 6.4) 100.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.)

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

    490.00        2          N/A       .00-     .00   980.00    980.00

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0  JAN 1, 2007

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)

          CONCENTRATION             CONCENTRATION

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

            101.358                     26.754

Appendix C. FIRST Output Files (continued)

RUN No.   1 FOR Boscalid         ON   Alfalfa       * INPUT VALUES *

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

    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .280(   .836)   3  14     655.0    6.0   AERIAL(16.0)  87.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.)

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

   2073.00        2          N/A       .00-     .00   ******   4146.00

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0  JAN 1, 2007

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)

          CONCENTRATION             CONCENTRATION

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

             38.089                     11.254

Appendix C. FIRST Output Files (continued)

RUN No.   2 FOR Boscalid         ON   Alfalfa       * INPUT VALUES *

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

    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .480(  1.433)   3  14     655.0    6.0   AERIAL(16.0)  87.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.)

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

   2073.00        2          N/A       .00-     .00   ******   4146.00

   UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0  JAN 1, 2007

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

        PEAK DAY  (ACUTE)      ANNUAL AVERAGE (CHRONIC)

          CONCENTRATION             CONCENTRATION

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

             65.296                     19.292

Appendix C. FIRST Output Files (continued)

   RUN No.   3 FOR Boscalid         ON   Citrus        * INPUT VALUES *

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

    RATE (#/AC)   No.APPS &   SOIL  SOLUBIL  APPL TYPE  %CROPPED INCORP

     ONE(MULT)    INTERVAL    Koc   (PPM )   (%DRIFT)     AREA    (IN)

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

   .290(  1.154)   4  10     655.0    6.0   AERIAL(16.0)  87.0    .0

   FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

   METABOLIC  DAYS UNTIL  HYDROLYSIS   PHOTOLYSIS   METABOLIC  COMBINED

    (FIELD)  RAIN/RUNOFF  (RESERVOIR)  (RES.-EFF)   (RESER.)   (RESER.)

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

   2073.00        2          N/A       .00-     .00   ⨪⨪⨪†㐠㐱⸶〰഍†乕剔䅅䕔⁄䅗䕔⁒佃䍎⠠䥍剃 䝏䅒卍䰯呉剅⠠偐⥂
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          CONCENTRATION             CONCENTRATION

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

             52.583                     15.536

 PAGE

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