Superfund Information Systems: Site Profile

Superfund Site:

MISSISSIPPI PHOSPHATES CORPORATION
PASCAGOULA, MS

Health & Environment

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What Are the Risks at the Site?

Without daily active wastewater management and additional surge capacity, there may be a release of acidic wastewater and nutrients (phosphorous, ammonia and nitrogen) to Bayou Casotte and the Grand Bay Estuary Reserve. The wastewater, if improperly discharged, may be toxic to fish and other forms of marine life, and can also cause algal blooms.

Large, catastrophic releases of acidic, nutrient-rich wastewater occurred in 2005 and 2013 (before EPA began overseeing wastewater treatment operations on-site). Previous releases have caused devastating fish kills in Bayou Casotte and the Grand Bay Estuary Reserve. The public uses Bayou Casotte and the Grand Bay Estuary Reserve for fishing and recreation. 

EPA samples multiple locations throughout Bayou Casotte twice a day—and even after previous intentional bypass events—the concentrations have remained at levels that do not pose long-term risks to the environment.

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Contaminant Information

EPA treats the wastewater with lime during normal operations, or sodium hydroxide during bypasses, to neutralize pH and prevent any acute toxicity impacts to aquatic wildlife. The other contaminants in the wastewater, including nitrogen, phosphorous and ammonia, are associated with nutrient loading which poses chronic risk to aquatic wildlife only after long-term exposure.

View a full list of contaminants of concern for this site.

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Performance Measures

EPA uses performance measures to track environmental results at Superfund sites. If you have any questions or concerns about the measures at this site, please contact the site team members listed under Site Contacts.

Read more about Superfund Remedial Performance Measures.

Performance
Measure
Status at this
Superfund Site
What does this mean?
Human Exposure Under Control Insufficient Data Yes means assessments indicate that across the entire site:
  1. There are currently no unacceptable human exposure pathways; and
  2. EPA has determined the site is under control for human exposure.

No means an unsafe level of contamination has been detected at the site and a reasonable expectation exists that people could be exposed.

Insufficient data means that, due to uncertainty regarding exposures, one cannot draw conclusions as to whether human exposures are controlled, typically because:
  1. Response to the contamination has not begun; or
  2. The response has begun, but it has not yet generated information sufficiently reliable to evaluate whether there are currently any unacceptable human exposure pathways at the site.
Groundwater Migration Under Control Insufficient Data

Yes means EPA reviewed all information on known and reasonably expected groundwater contamination. EPA concluded the migration of contaminated groundwater is stabilized and there is no unacceptable discharge to surface water. EPA will conduct monitoring to confirm that affected groundwater remains in the original area of contamination.

No means EPA has reviewed all information on known and reasonably expected groundwater contamination, and the migration of contaminated groundwater is not stabilized.

Insufficient data means that due to uncertainty regarding contaminated groundwater migration, EPA cannot draw conclusions as to whether the migration of contaminated groundwater is stabilized.

Construction Complete No

Yes means the physical construction of the cleanup is complete for the entire site.

No means either physical construction is not complete or actions are still needed to address contamination.

Sitewide Ready for Anticipated Use No Yes means:
  1. All cleanup goals affecting current and reasonably anticipated future land uses of the entire site have been achieved, so there are no unacceptable risks;
  2. All required land-use restrictions or other controls have been put in place; and
  3. The site has achieved Construction Complete status.

No means that one or more of these three criteria have not been met. However, a site listed as no may still have redevelopment occurring on portions of the site and may be eligible for additional redevelopment.

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