National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List: Deletion of the Annapolis Lead Mine Superfund Site, 41487-41495 [2020-14912]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 85, Number 133 (Friday, July 10, 2020)]
[Proposed Rules]
[Pages 41487-41495]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-14912]


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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[EPA-HQ-SFUND-2004-0004; FRL-10011-56-Region 7]


National Oil and Hazardous Substances Pollution Contingency Plan; 
National Priorities List: Deletion of the Annapolis Lead Mine Superfund 
Site

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule; notice of intent.

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

SUMMARY: The Environmental Protection Agency (EPA) Region 7 is issuing 
a Notice of Intent to Delete the Annapolis Lead Mine Superfund Site 
(Site) located in Annapolis, Missouri, from the National Priorities 
List (NPL) and requests public comments on this proposed action. 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 (NCP). The EPA and the state of 
Missouri, through the Missouri Department of Natural Resources (MDNR), 
have determined

[[Page 41488]]

that all appropriate response actions under CERCLA have been completed, 
other than operation and maintenance, monitoring and five-year reviews. 
However, this deletion does not preclude future actions under 
Superfund.

DATES: Comments must be received on or before August 10, 2020.

ADDRESSES: Submit your comments, identified by Docket ID no. EPA-HQ-
SFUND-2004-0004, 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://www.epa.gov/dockets/commenting-epa-dockets.
     Email: [email protected] or [email protected].
     Phone: Public comment by phone may be made by calling 
Jason Gunter at (913) 551-7358, or Elizabeth Kramer at 913-551-7186.
     Written comments submitted by mail are temporarily 
suspended and no hand deliveries will be accepted. We encourage the 
public to submit comments via https://www.regulations.gov.
    Instructions: Direct your comments to Docket ID no. EPA-HQ-SFUND-
2004-0004. 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 through 
https://www.regulations.gov or email that you consider to be CBI or 
otherwise protected. The https://www.regulations.gov website is an 
``anonymous access'' system, which means the 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 the 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, the 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 the EPA cannot read your comment due 
to technical difficulties and cannot contact you for clarification, the 
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 the hard 
copy. Publicly available docket materials are available either 
electronically in https://www.regulations.gov.
    The EPA is temporarily suspending its Docket Center and Regional 
Records Centers for public visitors to reduce the risk of transmitting 
COVID-19. In addition, many site information repositories are closed 
and information in these repositories, including the deletion docket, 
has not been updated with hardcopy or electronic media. For further 
information and updates on EPA Docket Center services, please visit us 
online at https://www.epa.gov/dockets.
    The EPA continues to carefully and continuously monitor information 
from the Centers for Disease Control and Prevention (CDC), local area 
health departments, and our Federal partners so that we can respond 
rapidly as conditions change regarding COVID.

FOR FURTHER INFORMATION CONTACT: Jason Gunter, Remedial Project 
Manager, U.S. Environmental Protection Agency, Region 7 Office, SEMD/
LMSE, 11201 Renner Boulevard, Lenexa, Kansas 66219; (913) 551-7358; 
email: [email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

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

I. Introduction

    The EPA Region 7 is proposing to delete the Annapolis Lead Mine 
Superfund Site (Site) from the National Priorities List (NPL) and is 
requesting public comment on this proposed action. The NPL constitutes 
appendix B of 40 CFR part 300, the National Oil and Hazardous 
Substances Pollution Contingency Plan (NCP), which the EPA promulgated 
pursuant to section 105 of the Comprehensive Environmental Response, 
Compensation and Liability Act (CERCLA) of 1980, as amended. The 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). As described in 40 CFR 
300.425(e)(3) of the NCP, sites deleted from the NPL remain eligible 
for Fund-financed remedial actions if future conditions warrant such 
actions.
    The EPA will accept comments on the proposal to delete this Site 
for thirty (30) days after publication of this document in the Federal 
Register.
    Section II of this preamble explains the criteria for deleting 
sites from the NPL. Section III of this preamble discusses procedures 
the EPA is using for this action. Section IV of this preamble discusses 
the Site and demonstrates how it meets the deletion criteria.

II. NPL Deletion Criteria

    The NCP establishes the criteria the EPA uses to delete sites from 
the NPL. In accordance with 40 CFR 300.425(e), sites may be deleted 
from the NPL where no further response is appropriate. In making such a 
determination pursuant to 40 CFR 300.425(e), the 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.

[[Page 41489]]

    Pursuant to CERCLA section 121(c) and the NCP, the EPA conducts 
Five-Year Reviews (FYRs) 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. The EPA conducts such FYRs even if a site is 
deleted from the NPL. The 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 deletion of the Site:
    (1) The EPA consulted with the state of Missouri before developing 
this Notice of Intent to Delete.
    (2) The EPA provided the state of Missouri 30 working days for 
review of this document prior to publication of it today.
    (3) In accordance with the criteria discussed above, the EPA has 
determined that no further response is appropriate.
    (4) The state of Missouri, through MDNR, has concurred with 
deletion of the Site from the NPL.
    (5) Concurrently with the publication of this Notice of Intent to 
Delete in the Federal Register, a notice is being published in a major 
local newspaper, the Mountain Echo, in Ironton, Missouri. The newspaper 
notice announces the 30-day public comment period concerning the Notice 
of Intent to Delete the Site from the NPL.
    (6) The EPA has placed copies of documents supporting the proposed 
deletion in the deletion docket and has made these items available for 
public inspection and copying at the Site information repositories 
identified above.
    If comments on this document are received within the 30-day public 
comment period, the EPA will evaluate and respond appropriately to the 
comments before making a final decision to delete. If necessary, the 
EPA will prepare a Responsiveness Summary to address any significant 
public comments received. After the public comment period, if the EPA 
determines it is still appropriate to delete the Site, the Regional 
Administrator will publish a final Notice of Deletion in the Federal 
Register. Public notices, public submissions, and copies of the 
Responsiveness Summary, if prepared, will be made available to 
interested parties and in the Site information repositories listed 
above.
    Deletion of a site from the NPL does not itself create, alter, or 
revoke any individual's rights or obligations. Deletion of a site from 
the NPL does not in any way alter the 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 future response actions, should 
future conditions warrant such actions.

IV. Basis for Site Deletion

    The following information provides the EPA's rationale for deleting 
the Site from the NPL:

A. Site Background and History

i. Site Location and Geography
    The Site is listed under CERCLIS ID MO0000958611 and is located 
east of Annapolis, Iron County, Missouri, on the east side of Iron 
County Road (ICR) 138 approximately three eights of one mile north of 
Missouri State Highway (Highway) 49. The geographic coordinates of the 
Site are latitude 37[deg]21'40'N and longitude 90[deg]40'30' W. The 
Site is located on the Des Arc, Missouri Quadrangle 7.5-Minute 
Topographic Map in sections 13 and 14, township 31 North, range 3 East.
    The Site is situated on relatively rugged terrain that slopes 
westward toward Sutton Branch Creek. The Site is largely forested 
except for the chat/tailings area, and the road cut for ICR 138. The 
land surrounding the Site is predominantly forested, with limited 
agricultural production and isolated residential properties within 
1,000 meters of the Site.
    The Site consists of three operable units (OUs). OU1 is defined as 
the Sutton Branch Creek floodplain from the Probable Point of Entry 
(PPE) to the confluence with Big Creek and includes the historical 
mining area. OU2 is defined as Big Creek from the mouth of Sutton 
Branch Creek downstream to the confluence with the St. Francois River, 
which is a total of approximately 20 miles of stream. OU3 is defined as 
the town of Annapolis.
    OU1 includes the historical mining area and the Sutton Branch Creek 
Floodplain. The total area of OU1 is approximately 200 acres. Prior to 
the removal action, the dominant feature of the Site was a chat/
tailings residue pile that covered approximately 10 acres in the 
northern portion of the Site. The pile was composed of grey- to tan-
colored material that resembled fine-grained sand. The material was 
highly erodible, resulting in steep-sided features and an outwash area 
that fanned westward to Sutton Branch Creek, which flows north to south 
on the west side of ICR 138. The chat/tailings residue dominated the 
substrate of Sutton Branch Creek for approximately 0.75 mile, where 
Sutton Branch Creek merged with Big Creek. Tailings originating at the 
Site could be seen as greyish creek bed sediments in Sutton Branch 
Creek and in portions of the flood plain.
    OU2 includes Big Creek from the confluence with Sutton Branch Creek 
to the residential soil in the town of Annapolis. The EPA sampled OU2 
in 2006 and 2007 and determined that no remedial action was necessary 
to ensure protection of human health and the environment. A No Action 
Record of Decision (ROD) for OU2 was issued on June 28, 2007.
    OU3 is located in Southern Iron County in the Old Lead Belt of 
southeast Missouri. OU3 covers the town of Annapolis. Lead mining 
occurred near the town from approximately 1919 to 1940. The EPA signed 
a ROD for OU3 on June 29, 2007. The EPA determined that the CERCLA 
action necessary for OU3 was to remove lead contamination from the 
driveway of one residence. The lead contamination in the property's 
driveway exceeded 400 parts per million (ppm), the EPA screening level 
for lead. The driveway was removed and taken by dump truck to the 
existing lead-contaminated-material repository at OU1. The contaminated 
driveway was replaced with uncontaminated gravel. No additional 
remedial response action is necessary for OU3.
    The Iron County area is within the St. Francois Mountains 
Physiographic Province of Missouri. Geologically, this area is 
characterized by lower Paleozoic carbonates and siliciclastics 
onlapping the Precambrian highland mass. Faults cutting basement and 
Paleozoic rocks are responsible for much of the Mississippi Valley-type 
mineralization present in the vicinity of the Site. Stratigraphy 
associated with completed groundwater wells includes unconsolidated 
valley alluvium typically 20-25 feet thick, and the underlying Cambrian 
sandstones and dolomites. Cambrian formations within 4 miles of the 
Site include, in descending stratigraphic order, Potosi, Derby-Doerun, 
Davis, Bonne Terre, and Lamotte. The Potosi Formation is moderately 
permeable and is a medium to massively bedded dolomite. The Davis 
Formation is comprised of a shale

[[Page 41490]]

and dolomite sequence with low permeability; however, vertical jointing 
facilitates localized movement of groundwater. The Bonne Terre 
Formation has several facies and lithologic changes and is quite 
permeable; it also contains the area's lead deposits. In the vicinity 
of the Site, the Bonne Terre Formation rests upon the Precambrian 
basement rocks.
    On-site soils are mainly dark brown, Midco cherty silt loam, 
typically found on 0- to 3-percent slopes downgradient of upland areas. 
Typically, the surface layer is dark brown cherty loam approximately 7 
inches thick. Below this to a depth of 60 inches or more are brown 
strata of very cherty sandy loam and extremely cherty sandy loam. In 
some areas, the dark surface layer is more than 10 inches thick. 
Excessively drained areas, including sandy soils mainly composed of 
chat with gravel bars, are near or in the stream channels. Permeability 
is moderately rapid in the Midco soil, and surface water runoff is 
slow. The available water capacity is low.
ii. Former Use and History of Contamination
    Galena ore (lead-bearing ore) was mined from the Site beginning in 
the 1920s. Mining activities continued sporadically until 1940. The 
mine had one shaft to 450 feet below the ground surface (BGS) with 
several hundred feet of lateral shafts to work the ore bodies. In 
addition to mining the ore, various equipment was used on site to crush 
and mill the ore to concentrate the lead. Annapolis Lead Company, a 
now-defunct company, owned/operated the mine from 1919 to 1931, when 
the majority of ore was extracted. Production figures from 1923 to 1931 
indicated that approximately 1,173,000 tons of mining waste containing 
elevated metals was generated during that time period. The Ozark Lead 
Mining Corporation, a now-defunct company, owned the property from 1931 
to 1934 but apparently did not conduct mining activities. Basic Metals 
Mining Corporation, also now defunct, owned the mine from 1934 to 1941 
and conducted mining activities for a short time between 1938 and 1940 
(no production figures were located for that time period). Apparently, 
no mining occurred on site after that time. American Waste Material 
Corporation owned the property for several months in 1942 then sold the 
property to H. Hoffman, Fred S. Fuld, and J.J. Rubenstein, who deeded 
their rights to St. Joseph Lead Company in 1952. In 1982, St. Joseph 
Lead Company sold the surface rights to Larry W. and Oneta Mayberry, 
but retained the mineral rights until 1987. The Doe Run Company has 
owned the mineral rights from 1987 until present. From 1982 through the 
present, the surface rights to various tracts within the Site were 
conveyed to several owners.
    Site features included numerous former mining operation buildings, 
located primarily in the northern portion of the Site. Most of the 
buildings have deteriorated to where only foundations are present. An 
exception is a single story of a once multi-storied structure near the 
center of the Site, which was last used as a residence in 1997. Mining 
refuse, including boulder-sized chunks of waste rock, is interspersed 
among the former buildings.
iii. Sampling and Removal Activities
    MDNR collected sediment and surface water samples near OU1 in 
September 1992. The analyses showed sediments in Sutton Branch Creek 
contained elevated lead, copper, nickel, and zinc concentrations. Lead 
levels in the creek water were near threshold concentrations for safe 
drinking water and protection of aquatic life, as established by 
Missouri water quality standards at that time. The state of Missouri 
conducted no source area sampling of sediment, soil, surface water, or 
groundwater.
    The EPA's contractor conducted a Screening Site Inspection in June 
1996, collecting data primarily on background information, waste and 
source sampling, groundwater exposure pathways, surface water exposure 
pathways, soil exposure pathways, and air exposure pathways. Results of 
this report were documented in the Removal Assessment.
    In March 1997, the EPA collected dust and wipe samples from the 
then-existing on-site residence, and an X-Ray Flourescence Spectrometer 
(XRF) was used to screen surface soils at the Site. Results from these 
samples, along with the results from blood-lead samples taken from the 
children living at the residence on the Site, were used in making a 
determination that individuals living on the Site were being adversely 
impacted. In May 1997, the EPA performed a removal action which 
resulted in the Iron County Division of Family Services relocating the 
children and their immediate family from the Site. The EPA completed an 
Expanded Site Inspection and Removal Assessment (ESI/RA) of the 
northern segment of the Site in February 1999. Data collected during 
the ESI/RA indicated that the Site has had an impact on the 
environment, primarily through the surface water pathway.
    A removal action was conducted in 2004, as discussed in further 
detail below. During this removal action, 152,868 cubic yards of lead-
contaminated soil was excavated and placed in a repository constructed 
on site. The repository was capped and vegetated to prevent future 
exposure risk. Excavated areas were either backfilled or regraded to 
prevent ponding, and vegetated.
iv. NPL Listing
    The Site was proposed for listing on the NPL on March 9, 2004 (69 
FR 10646). It was listed on the NPL on July 22, 2004 (69 FR 43755) due 
to elevated levels of heavy metals, particularly lead, which were 
present throughout the Site. In addition, surface water bodies 
downstream of the Site contained elevated concentrations of site-
related hazardous substances that could pose a threat to recreational 
fisheries and wetlands in the area.

B. Remedial Investigation and Feasibility Study (RI/FS)

i. Scope of Remedial Investigation
    The Remedial Investigation (RI), with expanded sections on surface 
water, sediments, and soil, was completed in August 2005. The purpose 
of the RI was to determine the nature and extent of contamination. A 
Hydrology and Flood Plain Report was conducted to evaluate the existing 
conditions and behavior of the Sutton Branch Creek flood plain.
    The Contaminants of Concern included:

----------------------------------------------------------------------------------------------------------------
                   Soil                              Sediment                         Surface water
----------------------------------------------------------------------------------------------------------------
Lead.....................................  Arsenic.....................  Arsenic.
Cadmium..................................  Cadmium.....................  Cadmium.
Zinc.....................................  Lead........................  Lead.
                                           Zinc........................  Zinc.
----------------------------------------------------------------------------------------------------------------


[[Page 41491]]

    Based on information collected during the RI along with historical 
documentation, four lead-contaminated source areas were delineated for 
assessment purposes: The heavily-eroded chat and tailings waste pile, 
the outwash area of the chat and tailings waste pile, the former mining 
operations area, and the mill slime pond. An estimated 51,677 cubic 
yards of lead-contaminated tailings, chat, and soil (above 500 mg/kg) 
were calculated for these four areas.
    The RI concluded that thousands of cubic yards of mining waste 
(tailings) migrated to the Sutton Branch Creek floodplain via the 
surface water pathway. Waste management practices likely included 
dumping mining waste along a former railroad spur that was located in 
the western portion of the Site. To assess the extent of metals-
contaminated soils and sediments at the Site, the EPA conducted an 
investigation of Sutton Branch Creek and the soils within its 
floodplain. The 100-year floodplain of Sutton Branch Creek contains 
elevated lead concentrations, especially in the depositional areas 
south of Highway 49.
ii. Ecological Risk Assessment
    In August 2005, the EPA prepared a baseline ecological risk 
assessment (BERA), which evaluated risk to aquatic and terrestrial 
systems at the Site. The BERA addressed risks to aquatic and 
terrestrial biota, or animal and plant life, by comparing the maximum 
measured concentrations of contaminants of concern (COCs) to ambient 
water quality criteria and conservative toxicity criteria.
    The EPA determined that the principal threat for OU1 was the 
ecological risk to both the aquatic and terrestrial environments. 
Living organisms within both ecosystems had elevated exposure to 
mining-related metals, and the metals could cause adverse effects on 
some receptors in each ecosystem.
iii. Human Health Risk Assessment
    In August 2005, the EPA also prepared a baseline Human Health Risk 
Assessment (HHRA). The HHRA evaluated current and potential future 
risks to human health associated with the presence of heavy metals, 
particularly lead, in soils, surface water, sediment, and groundwater 
at the Site.
    Based on the results of field investigations and the HHRA, the EPA 
concluded that surficial lead residual contamination in the mine 
operations area was generally below levels of concern for lead; 
however, hotspots exist under the 18'' engineered soil cover in limited 
areas that could be associated with unacceptable exposures to lead. 
Unacceptable exposure could be realized for both future construction 
workers and future residents. In addition, lead exposures for 
recreational visitors to the floodplain soils could reach unacceptable 
levels, but lead exposures for recreational users to surface water and 
sediment in Sutton Branch Creek did not appear to cause unacceptable 
risk.
    In addition, for all other COCs, cancer risks and non-cancer 
hazards for recreational exposures in the floodplain and creek fell 
within the acceptable risk range for cancer and noncancer hazards. 
These results suggested that recreational exposure to COCs other than 
lead may be in an acceptable range.
iv. Findings From Feasibility Study
    The EPA screened the following alternatives in the Feasibility 
Study (FS):
     Alternative 1: No Further Action.
     Alternative 2: Phosphate Amendment of Flood Plain Soils 
with In-Stream Stabilization Techniques and Limited Sediment Removal.
     Alternative 3: Excavation of Sediments in Sutton Branch 
Creek.
     Alternative 4: Excavation of Sediments in Sutton Branch 
Creek and Soil Cap.
     Alternative 5: Complete Source Removal and On-Site 
Disposal.
     Alternative 6: Complete Source Removal and Disposal in an 
Off-Site Landfill.
    After screening the alternatives, the EPA concluded that all of the 
action alternatives would result in significant reductions in metal 
loadings to surface water from floodplain sources. The EPA selected 
Alternative 2 as the preferred remedy for the Site.

C. Selected Remedy

i. Components of the Selected Remedy
    The selected remedy for OU1 included the following actions:
     Addition of phosphate to floodplain soils (away from the 
outer edge of the riparian zone) during the dry season to improve the 
density of vegetation and to reduce the bioavailability of lead to 
terrestrial receptors.
     Mining wastes in heavily forested, thickly vegetated 
areas, such as the riparian buffer, will not be subject to excavation, 
consolidation, or capping.
     Excavation of sediments from Sutton Branch Creek in 
pockets, or depositional areas. The amount of excavation will be 
determined during the Remedial Design (RD) phase.
     Placement of excavated sediments in the existing 
repository area and cap with a simple soil cover.
     Stabilization of the Sutton Branch Creek channel with 
large rock and/or other material to prevent washouts and stream channel 
meandering. The extent of stabilization will be determined during the 
RD phase.
     Implementation of institutional controls.
     Performance of annual monitoring to determine remedial 
effectiveness The monitoring frequency will be evaluated to determine 
whether it should be more frequent or can be extended to periods beyond 
annual monitoring.
     MDNR will manage post-removal maintenance of the 
protective cover consistent with all federal and state laws.
ii. Remedial Action Objectives (RAOs)
1. RAOs for Soils and Source Materials
    The RAOs for soils and source materials were based on the findings 
of the BERA and HHRA. These RAOs were designed to address the potential 
ecological risks associated with direct exposure to COCs in mine and 
mill wastes, and in the affected soils surrounding the wastes. 
Terrestrial vertebrates, specifically vermivores whose diet consists of 
earthworms and other soil-dwelling invertebrates, were identified as 
the receptors of concern based on the information from the BERA. 
Ecological risks associated with source material erosion (as sediment) 
and seepage/runoff were addressed in other RAOs. Due to these findings, 
the following RAO was developed:
    Limit the exposure of terrestrial biota to COCs in surficial 
materials that would potentially result in excessive ecological risks 
associated with intake of site COCs.
    The human health exposure routes were addressed at much of OU1. 
However, surficial contamination in the southern portion of OU1 could 
cause unacceptable exposures. Due to this minor risk, the following RAO 
was developed:
    Limit human ingestion of COCs from on-site soils or source 
materials that would potentially result in cancer risks greater than 
10-6 (one in one million), non-carcinogenic hazard indexes 
greater than 1 (1 or lower means adverse noncancer effects are 
unlikely), or unacceptable blood lead levels that present human health 
risks.
2. RAOs for Surface Water and Sediment
    Aquatic and terrestrial biota are exposed to COCs in surface waters 
or

[[Page 41492]]

sediments derived from mill wastes. Site-specific, risk-based 
contaminant levels for aquatic biota have not been established for the 
Site. However, consensus-based sediment quality guidelines were used as 
reference material. Sediment with elevated COC concentrations may pose 
risks to benthic, or bottom-level, communities that live and feed in 
sediment deposits and benthic feeders that may ingest sediment. 
Applicable or relevant and appropriate requirements (ARARs) for 
sediments were not developed for the Site, but consensus-based 
guidelines can be followed. Based on the discussion presented above, a 
surface water RAO and a sediment RAO have been developed. These RAOs 
address the interactions between source materials and surface waters 
and the potential exposure of aquatic biota to COCs from mill waste. 
The surface water and sediment RAOs are as follows:
    a. Limit the exposure of aquatic biota to waters contaminated with 
COCs in Sutton Branch Creek in excess of chronic and acute Federal 
Ambient Water Quality Criteria (AQWC) for such COCs.
    b. Limit the risks to aquatic biota by controlling erosion and 
transport of lead-contaminated mill wastes and sediments containing 
lead-contaminated mill wastes in classified perennial or state-listed 
ephemeral streams or rivers.
iii. Explanations of Significant Differences (ESDs)
1. September 9, 2008 Explanation of Significant Differences #1 (ESD #1)
    The 2005 OU1 ROD included addition of phosphate to floodplain soils 
(away from the outer edge of the riparian zone) during the dry season 
to improve the density of vegetation and to reduce the bioavailability 
of lead to terrestrial receptors. The significant difference under ESD 
#1 was the exclusion of phosphate application as part of the remedy.
    Since the signing of the 2005 OU1 ROD, pilot testing of phosphate 
application to residential soils was conducted in Region 7 and 
reductions in bioavailability were achieved by tilling phosphoric acid 
into the soil. A second finding of the pilot testing was that surface 
application of fertilizer-grade phosphate was ineffective in reducing 
bioavailability. This meant that to have an impact upon 
bioavailability, phosphoric acid would have to be tilled into the lead-
contaminated riparian areas.
    A vegetative cover reduces the potential for human exposure to lead 
in soils under the vegetation. Tilling up the established vegetation 
would, for at least the short term, increase the exposure potential to 
lead in such soils until regrowth of the vegetative cover. The efficacy 
of applying the phosphate fertilizer to the riparian areas as described 
in the ROD was reevaluated. The EPA, in consultation with MDNR, made 
the decision to leave the vegetation in place and omit the phosphate 
treatment because (1) the current vegetative cover was sufficient and 
removing it could cause more harm than good, and (2) surface 
application of phosphate fertilizer would not result in significant 
reductions in bioavailability of the lead in the target soils/
sediments.
2. May 29, 2019 Explanation of Significant Differences #2 (ESD #2)
    The 2005 OU1 ROD's selected alternative regarding institutional 
controls provided for the imposition of restrictive covenants or 
easements. The EPA determined that the voluntary environmental 
covenants described in the 2005 OU1 ROD were not obtainable due to 
property owners refusing to sign and record the environmental 
covenants. Therefore, the EPA determined that an alternative to 
environmental covenants was required. Under ESD #2, the EPA could 
record notices of contamination for each tract of contaminated land 
that did not have an environmental covenant.
    The use of a notice of contamination differs significantly from the 
use of an environmental covenant described in the ROD. An environmental 
covenant can prohibit certain uses of a property and can also require 
that certain actions be taken, thus achieving all the ROD's objectives. 
A notice of contamination cannot prohibit or mandate certain uses or 
actions and only provides information that may inform human behavior. A 
notice of contamination may be effective in achieving the ROD's 
objectives of providing notice to prospective purchasers and occupants 
that there may be contaminants in the subsurface soils and groundwater 
and ensuring that future owners are aware of engineered controls put 
into place as part of the Site's remedial action and under the prior 
removal action. Thus, by recording a notice of contamination with the 
Iron County recorder of deeds office, the goals of minimizing exposures 
to contamination remaining at OU1 and limiting the possibility of the 
spread of contamination may be achieved. The EPA also will conduct 
annual reviews of the deeds to ensure that the notices remain in 
effect.
    In addition to the filing of notices of contamination, the EPA will 
conduct reviews every five years of the protectiveness of the remedy as 
required by section 121(c) of CERCLA. During these reviews, the EPA 
will again engage the owners of all properties where the notices of 
contamination have been recorded and attempt to gain landowner consent 
to the use of an environmental covenant. For properties that have been 
conveyed to new owners, the EPA will engage those new owners to 
determine whether they will agree to the use of environmental 
covenants. Due to the current impossibility of placing environmental 
covenants on all affected properties, the EPA determined that this is 
the most prudent and protective manner to address land use.

D. Response Actions

i. Removal Action
    In September 2003, the EPA proposed a time-critical removal action 
for the Site. The goal of the removal action was to identify, 
consolidate, and stabilize the lead-contaminated waste mine tailings on 
site. The time-critical removal action work began at the Site in May 
2004. When the removal action began at the Site, settling basins were 
constructed to manage storm water runoff. Earth-moving equipment was 
used to form the tailings and contaminated soil into a mound in the 
middle of the ravine where the pile was originally located. All areas 
in the tailings pile vicinity that had a mean lead surface 
concentration greater than 1,000 ppm were delineated and excavated. 
Excavations proceeded to the lesser of a depth of 18 inches or until a 
lead level below 400 ppm was achieved. All excavated areas were 
backfilled with clean material (<240 ppm lead) and excavated soil was 
consolidated into the on-site tailings pile. The tailings pile was 
graded and compacted with an engineered protective cover installed over 
the tailings. The protective cover consists of uncontaminated clay and 
topsoil, allowing for the establishment of vegetative cover.
ii. Remedial Action
    The RI determined that additional actions were required after the 
completion of the Removal Action. The EPA developed the RD, which was 
reviewed by MDNR and approved by the EPA on June 14, 2007. Remedial 
action (RA) on-site construction commenced on July 25, 2007.
    The following paragraphs describe the specific components of the 
selected remedy.

[[Page 41493]]

1. Erosion Work Around the Repository and the Historical Mining Area
    This included the area around the former mining area containing 
significant erosion. Work in this area was required to protect the 
integrity of the existing soil repository and to prevent further runoff 
into Sutton Branch Creek. The specific areas of work included the 
following:
     Point of Entry (POE) Area: Work at the POE Area included 
constructing the channel between the repository and the settling basin.
     Borrow Area: The Borrow Area was a major erosional area. 
It was stabilized to minimize future erosion. This included regrading, 
placement of rock for cover/erosion control, and diverting potential 
runoff around this area through channelization.
     North Area Erosion: This area was stabilized with rock to 
minimize future erosion.
     North Hillside Erosion: This area was regraded and 
stabilized with rock to minimize future erosion.
     North Lower Erosion: This area was regraded, covered with 
rock, and two benches were constructed to slow the water entering the 
Site.
     Repository Drainage Extension: This area consisted of an 
extension of the rock drainage around the perimeter of the existing 
repository, along with a 6-foot rock blanket around the inside 
perimeter of the drainage channel.
2. Additional Blanket on Northeast Side
    This area required regrading and a rock blanket on the northeast 
side.
3. Removal and Disposal of Sediment/Soil
    The selected remedy included excavation and vacuum dredging of 
contaminated sediment from Sutton Branch Creek. Contaminated sediment 
in the depositional areas (pools) was removed to reduce the potential 
of downstream migration of contaminated sediment. Approximately 500 
cubic yards (yd\3\) of contaminated sediment required removal.
    The contaminated sediment was removed until the natural substrate 
was uncovered. The banks of excavated areas were stabilized as needed. 
To minimize disturbance of the natural substrate, the EPA used the most 
non-invasive technique to remove the fine sediment. The specific areas 
that required removal are:
     POE Area: This included the area where the mine runoff 
historically entered Sutton Branch Creek. The EPA removed approximately 
115 yd\3\ of sediment/floodplain soil and placed approximately 100 
yd\3\ of riprap to achieve stability. The removed sediment/soil was 
placed in the new repository cell.
     Sycamore Tree Area: This included the area of Sutton 
Branch Creek where a sycamore tree caused the east stream bank to 
erode. This tree was removed, and the east bank was stabilized. The EPA 
removed approximately 135 yd\3\ of sediment/floodplain soil and placed 
approximately 100 yd\3\ of riprap to achieve stability. The removed 
sediment/soil was placed in the new repository cell.
     Beaver Dam Area: This included the area of Sutton Branch 
Creek where a breached beaver dam was trapping sediment. The remnants 
of the beaver dam were removed along with the sediment on the east and 
west banks and in the channel. The EPA removed approximately 185 yd\3\ 
of sediment/floodplain soil and placed approximately 60 yd\3\ of riprap 
for stabilization. The removed sediment/soil was placed in the new 
repository cell.
     Bridge Area: This was the furthest downstream section 
(furthest southern point) of the project. This section required two 
separate removals: One preceding the other stream work and one 
following the other stream work. During the first stage, approximately 
40 yd\3\ of sediment was removed from the large hole under the bridge 
using vacuum dredging and placed in the new repository cell. During the 
second stage, approximately 30 yd\3\ of sediment was removed and placed 
in the new repository cell.
    An on-site repository exists for disposal of the excavated 
sediment. Approximately 500 yd\3\ of sediment was placed in the 
repository. The existing repository is located on the historical mine 
waste pile. The repository was constructed so that the contaminated 
sediment could be placed on the south side of the repository, thus 
greatly reducing the distance for contaminant transport. The new cell 
on the repository required approximately 300 yd\3\ of clean fill to be 
placed on top of the contaminated sediment. The top 12 inches of this 
fill met the soil criteria in RD specifications and was properly 
graded, stabilized with jute mat, and vegetated using the criteria in 
the RD specifications. The vegetative cover has been inspected 
biannually since 2007 and has provided adequate erosion control.
    Final inspection of the Site by the EPA and MDNR concluded that the 
soils RA had been conducted and completed in accordance with the soils 
RD plans and specifications; a punch list of additional work items was 
not needed. The remedy was complete with approval of the Final Closeout 
Report by the EPA and MDNR in September 2007.

E. Cleanup Levels

    After the RA construction was complete, the EPA began monitoring 
sediment, surface water, and macroinvertebrates in Sutton Branch Creek 
and Big Creek. This sampling was conducted biannually (each fall and 
spring) from 2007-2011 and was reduced to one sampling event during the 
second FYR, which occurred in July 2017. Sampling occurred at five 
different sites along Sutton Branch Creek and Big Creek. Data was 
collected for the following analytes in sediment and surface water: 
Arsenic, cadmium, cobalt, copper, lead, nickel, and zinc.
    A historic flooding event occurred in the greater Annapolis, 
Missouri, area on April 28-30, 2017. This flooding event dumped upwards 
of 15 inches of rain in a short period of time, resulting in widespread 
flooding. Numerous roads, bridges, and buildings were destroyed. Many 
roads were flooded through the event, including Highway 49 in Iron 
County. Several rivers reached major and historic levels. The U.S. 
Geological Survey Stream Gage #07037300 is located approximately 20 
river miles downstream of the Site on Big Creek. The mean daily 
discharge at this gage from 2006 through 2016 was 272 cubic feet per 
second (cfs). The highest peak flow from 2006 through 2016 was 23,800 
cfs, which occurred on March 18, 2008. In late April of 2017, during 
the record-breaking flood, the gage recorded a peak flow of 17,400 cfs 
on April 29, and a peak flow of 27,500 cfs on April 30. The discharge 
on April 30 was the highest event ever recorded since the gage has been 
in operation, which began in 2006.
    Post-flooding site inspections indicated that the flooding event 
washed chat tailings from the floodplain into Sutton Branch Creek and 
depositional areas around sampling site 3 (Sutton Branch Creek 500 feet 
downstream of the Highway 49 bridge). During the RA, the pool located 
below the Highway 49 bridge was remediated using excavation as well as 
a vacuum truck. This is a major depositional area. The EPA and MDNR 
have visually monitored this area two times per year. Over the last ten 
years, the lead concentration at sampling site 3 has been elevated; 
however, the lead levels that were discovered (2,840 ppm) after the 
large flood in April 2017 exceeded the lead levels that were found 
prior to remediation. The EPA and MDNR have continued to monitor this 
area along

[[Page 41494]]

with sampling site 5 (mouth of Sutton Branch Creek at confluence with 
Big Creek) to determine whether this is having an impact on Big Creek. 
The most recent sampling event was conducted on February 14, 2019, and 
the results for each sampling station are as follows:

 Sampling Site 3 (Sutton Branch Creek south of Highway 49 
Bridge)--438 ppm lead
 Sampling Site 5 (Mouth of Sutton Branch Creek at confluence 
with Big Creek)--19 ppm lead

    As seen in the most recent data set, sediment concentrations 
continue to decline at the monitoring stations. The EPA will continue 
to monitor these areas as part of the FYRs. Corrective measures may be 
taken if the levels do not continue to decrease over time.

F. Operation and Maintenance

i. Ongoing and Completed Operation and Maintenance
    Approximately one month after construction, the EPA and MDNR 
inspected the Site to observe the condition of the cap, identify any 
erosional features, and assess the success of each remedial component. 
After inspection, the EPA and MDNR considered each of these areas 
construction complete, although several areas were identified where 
improvement was required. One major issue was the concern that erosion 
would occur where vegetation was not established. Therefore, the EPA 
and MDNR focused the majority of their efforts on revegetating the Site 
in 2008. Approximately 1,015 trees were planted, along with a site-
specific seed mix, to help stabilize the Site. Additionally, the EPA 
and MDNR performed inspections every six months along with monitoring 
and maintenance activities. Some of the trees that were planted are now 
over 25 feet tall and the improved vegetation has stabilized the slopes 
and decreased sediment accumulation in the settling basin.
    During the reporting period for the second FYR, one major area of 
concern was the north repository drainage channel. During high water 
events, the water would occasionally overflow the existing channel onto 
the surrounding area instead of down to the settling basin. Due to the 
concern of the water flowing out of the channel, MDNR performed 
maintenance activities in October 2012. MDNR modified the north 
repository drainage channel as well as the channel below the repository 
downgradient to the settling basin. he large rock that had been placed 
in the channel was pulled out to the channel edges. The filter rock was 
left in place within the channel. The goal was to allow additional flow 
through the channel down to the settling basin during high water 
events. The report of these activities is included in the second FYR. 
In June 2013, MDNR performed maintenance activities to repair a leak in 
the outlet pipe in the settling basin. The report of these activities 
is included in the second FYR.
    During the reporting period for the third FYR, the northeast branch 
of the drainage channel around the tailings pile that washed out was 
repaired. MDNR developed engineered designs to repair the channel and 
construct a detention pond dam to reduce the flow velocity in the 
channel during high rainfall events. MDNR hired a contractor to perform 
the repairs. The contractor finished the repairs in April 2019.
ii. Institutional Controls
    Under the selected remedy, the EPA required implementation of 
institutional controls at properties where elevated lead concentrations 
remain on site. The EPA determined that 13 parcels were subject to the 
institutional controls. Two different mechanisms were used as part of 
the Site's Institutional Control Plan: Environmental covenants and 
notices of contamination. On May 21, 2019, one of the 13 property 
owners recorded an environmental covenant with the Iron County Recorder 
of Deeds. On August 29, 2019, the EPA recorded notices of contamination 
regarding the 12 remaining properties with the Iron County Recorder of 
Deeds.
    As discussed in depth above, the use of a notice of contamination 
differs significantly from the use of an environmental covenant 
described in the ROD, but still may be effective in achieving the ROD's 
objectives. Therefore, as documented in 2019, the EPA issued ESD #2 
that provided for the EPA to record notices of contamination instead of 
entering into environmental covenants at the contaminated properties. 
The EPA also will conduct annual reviews of the deeds to ensure that 
the notices remain in effect.
    In addition to the filing of notices of contamination, the EPA will 
conduct reviews every five years of the protectiveness of the remedy as 
required by section 121(c) of CERCLA. During these reviews, the EPA 
will again engage the owners of all properties where the notices of 
contamination have been recorded and attempt to gain landowner consent 
to the use of an environmental covenant. For properties that have been 
conveyed to new owners, the EPA will engage those new owners to 
determine whether they will agree to the use of environmental 
covenants.

G. Five-Year Reviews

    Statutory FYRs are required for the Site due to the fact that 
hazardous substances, pollutants, or contaminants remain at the Site 
above levels that allow for unlimited use and unrestricted exposure.
    Two FYRs have been conducted at the Site, the most recent being the 
Second FYR, which was completed on September 29, 2017. The 
protectiveness determination was Short-term Protective, and included 
the following protectiveness statement: The remedy currently protects 
human health and the environment because soils and sediments with 
elevated lead levels have been excavated or capped and no unacceptable 
exposures are occurring. In order to be protective in the long term, to 
reduce the potential for future risk, ongoing pursuit of the 
[institutional control]s must occur along with routine Operation and 
Maintenance indicative of an engineered soil cover. In order for the 
remedy to be protective in the long term, [institutional control]s 
should be implemented. Additional routine maintenance of the eroded 
areas around the repository should be implemented to prevent future 
exposure.
    Issues from the Second FYR included the following:
     Institutional Controls had not been implemented. The 
recommendation was to implement the institutional controls by 7/31/
2018. Please note: The EPA implemented institutional controls on 9/13/
2019.
     During the reporting period for the Second FYR, 
significant erosion had formed on the north end of the repository 
drainage channel. The recommendation was to repair the drainage channel 
by 7/31/2018. Please note: MDNR repaired the area in April 2019.
     A small amount of lead-contaminated sediment (less than 60 
cubic yards) was deposited below the Highway 49 bridge in the pool that 
was excavated during the RA after the large flood in April 2017. The 
EPA and MDNR will continue to monitor this area along with the mouth of 
Sutton Branch Creek from 2018 to 2021. If this area continues to be 
elevated with COCs, further action may be taken to remove the sediment 
from the pool above sampling site 3. As these levels have significantly 
declined, no response is anticipated. Please note: This will be 
assessed during the third FYR.

[[Page 41495]]

H. Community Involvement

    Before and during the RAs, the EPA held multiple public meetings on 
site. The EPA has updated the public regarding the FYRs by placing ads 
in the local newspaper, as well as updating the local information 
repository and the Site's web page. Community involvement activities 
associated with the deletion will include making the notice of intent 
to delete available for public comment. In addition, the Region 7 
Superfund Records Management Service Center will construct a special 
document collection that will include the listed document IDs for the 
deletion docket documents. This collection will be available for public 
review and is located on the Site's web page and the Regulations.gov 
website.

I. Determination That the Site Meets the Criteria for Deletion in the 
NCP

    In accordance with 40 CFR 300.425(e), EPA Region 7 finds that the 
Annapolis Lead Mine Site (the subject of this deletion action) meets 
the substantive criteria for deletion from the NPL. The EPA has 
consulted with and has the concurrence of the state of Missouri. All 
appropriate Fund-financed response under CERCLA was implemented, and no 
further response action by responsible parties is appropriate.
    The implemented remedy at the Site has achieved the degree of 
cleanup specified in the ROD for all pathways of exposure. All selected 
RA objectives and associated cleanup levels are consistent with agency 
policy and guidance. No further Superfund response is needed to protect 
human health and the environment.

List of Subjects in 40 CFR Part 300

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

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

    Dated: July 2, 2020.
James Gulliford,
Regional Administrator, Region 7.
[FR Doc. 2020-14912 Filed 7-9-20; 8:45 am]
BILLING CODE 6560-50-P