WASHINGTON COUNTY
LEAD DISTRICT - POTOSI

MISSOURI

EPA ID# MON000705023

EPA Region 7

City: Potosi, Cadet, Mineral Point,
Springtown, Happy Hollow, Shibboleth,
Summit, Bates Creek Camp
County: Washington
Other Names:

12/22/2008

SITE DESCRIPTION

The Potosi Site encompasses an area greater than 45 square miles in the eastern portion of
Washington County, Missouri. It primarily includes residential areas within and around the
communities of Potosi, Cadet, Mineral Point, Springtown, Happy Hollow, Shibboleth, Summit,
and other smaller communities, and is a portion of the larger Washington County Lead Mining
District. The Potosi Site is mostly residential, although a number of commercial businesses are
present. Soil and/or groundwater contamination by arsenic, barium, cadmium, and lead at the
Potosi Site is most likely the result of lead and barite mining, milling, and smelting. Continuous
lead mining began in Washington County in 1721 at the surface and near-surface (ten feet or less
below ground surface (bgs)) in an area north of Potosi. Galena, the main lead ore, was mined in
both the red clay residuum, which generally ranged from a few feet to over 30 feet thick, and the
underlying dolomite bedrock. Barite (barium sulfate), another local mineral, became valuable
after the Civil War and barite mining began to boom in the area in 1926. Remnants of mining
activities throughout the area include strip mines, mineshafts, mine dumps, tailing areas, tailings
ponds, and associated dams. There are numerous large tailings impoundments, associated dams,
and leachate ponds with elevated levels of lead in surface soil present at the site.

Site Responsibility:

NPL LISTING HISTORY

The site is currently being addressed through
federal action.

Proposed Date: 09/19/2007

Final Date:

03/19/2008

Deleted Date:


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THREATS AND CONTAMINANTS

Extensive lead contamination in surface soil, at levels exceeding health-based
screening levels, has been identified at 716 residential properties at the site.
Occasional elevated levels of barite, arsenic, and cadmium have also been
identified at the site. In addition to surface soil contamination, 138 private
drinking water wells have been identified with lead levels exceeding the federal
drinking water standard of 15 micrograms per liter.

CLEANUP APPROACH

Response Action Status

Initial Actions: Removal Assessment activities are ongoing and consist of sampling private
properties for lead-contaminated surface soil and drinking water wells. Through Time-Critical
Removal Actions, contaminated surface soil has been replaced at 180 residences, and bottled
drinking water has been provided to 126 residences whose drinking water wells were
contaminated above federal drinking water standards.

Site Studies: The initiation of a Remedial Investigation (RI) occurred in January 2008. The RI
will include the characterization of numerous tailings ponds and streams, determine the extent of
groundwater contamination, and complete the characterization of residential surface soil.
Residential interior dust samples have been collected for developing the Human Health Risk
Asssessment.


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Site Facts: An Action Memorandum was signed on October 17, 2005, for Time Critical

Removal actions to be taken to replace residential surface soil contaminated with
high lead levels and to provide bottled drinking water to residents with
lead-contaminated, private drinking water wells.

ENVIRONMENTAL PROGRESS	

1601 residential properties have been sampled for surface soil metals contamination.
764 private drinking water wells have been sampled for metals contamination.
Lead-contaminated surface soil has been replaced at 180 residetial properties.
Bottled water is being provided to 126 residences.

COMMUNITY INVOLVEMENT

EPA has facilitated several public meetings to inform citizens of site contamination and removal
actions. EPA, with the participation of the Missouri Department of Natural Resources, hosted
meetings to inform the local community about the Washington County Lead District - Potosi Site
on the following dates: May 16, 2005; October 18, 2005; June 7, 2006; and October 24, 2006.
Fact sheets were mailed to invite the local community to site meetings and to inform them about
site activities as follows:: May 2005; October 2005; May 2006; September 2006 and September
2007. Overall, the public has been very supportive of EPA actions taken at the site.


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SITE REPOSITORY

Washington County Library	Superfund Records Center

235 East High Street	901 N. 5th St.

Potosi, MO	Kansas City, KS 66101

Mail Stop SUPR
(913)551-7166

REGIONAL CONTACTS

SITE MANAGER:

E-MAIL ADDRESS:

PHONE NUMBER:

COMMUNITY INVOLVEMENT
COORDINATOR:

PHONE NUMBER:

E-MAIL ADDRESS:

STATE CONTACT:

PHONE NUMBER:

Bruce Morrison/SUPR/R7/USEPA/US
Morrison.Bruce@EPA.GOV
(913)551-7755

Dianna Whitaker

(913)551-7598
Whitaker.Dianna@EPA.GOV

Valerie Wilder
(573)751-7880

MISCELLANEOUS INFORMATION

STATE:	MO

A78D

CONGRESSIONAL DISTRICT:	8th District

EPA ORGANIZATION:	SFD-SPEB

MODIFICATIONS

Created by:	Bruce	Created Date:	02/14/2008 10:11 AM

Morrison/ SUPR/R7/U SEP A/

US

Last Modified by: Bruce	Last Modified Date: 12/22/2008 11:28 AM

Morrison/ SUPR/R7/U SEP A/

US


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