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HEALTH CONSULTATION

SURFACE SOIL CONTAMINATION

EASTERN MICHAUD FLATS CONTAMINATION
POCATELLO, BANNOCK COUNTY, IDAHO


IV. CONCLUSIONS

Based upon the data and information reviewed, the Agency for Toxic Substances and DiseaseRegistry has drawn the following conclusions:

  1. It is unlikely that the general public, including children, has been, is currently, or will be exposed to significant levels of site-related surface soil contamination. Therefore, it is unlikely that any adverse human health effects have or will occur because of site-related surface soil contamination. The nearest residence to the FMC and Simplot facilities is over one mile away. Analytical results of surface soil samples indicate that there is not any site-related surface soil contamination at levels of health concern within the nearest residential areas. In addition, very few people trespass onto the facilities. The deed restriction on the land near and on the facilities should prevent any of the contaminated land from being used for residential areas.
  2. Workers at the FMC facility may be exposed (ingestion and inhalation) to cadmium contaminated surface soil. The highest concentrations of cadmium in surface soil was found at the FMC facility. These exposures may increase the potential for the workers to develop proteinuria (proteins found in the urine because of damage to the kidneys), particularly workers that smoke. Good occupational practices (e.g., the use of respirators, where appropriate, and frequent hand washing, particularly before eating) can significantly reduce the worker's potential to be exposed to cadmium.
  3. Slag and gypsum pile workers may be exposed to elevated levels of alpha, beta, and gamma radiation. These exposures may increase the risk of a worker to develop cancer. However these exposures can and are significantly reduced by good occupational practices (e.g., shielding provided by vehicles and dust control), thereby significantly reducing the workers' risk of developing cancer.
  4. Given the potential for worker exposures to site-related contaminants in surface soil andthe potential for adverse health effects to occur in exposed workers, ATSDR has classifiedthe Eastern Michaud Flats Contamination NPL site as a Public Health Hazard in regards to surface soil.

V. RECOMMENDATIONS

ATSDR makes the following recommendations:

  1. Appropriate remedial actions and worker protection activities should be instituted or continued to prevent worker exposures to site-related contaminants.
  2. Appropriate remedial actions should be taken to prevent the surface soil contaminants from migrating into the local groundwater and surface water.
  3. The land deed restrictions instituted and planned for the property presently owned byFMC and Simplot should remain in effect so that those lands will not be developed into residential or agricultural areas.

VI. PREPARED BY

Sven E. Rodenbeck, Sc.D., P.E.
Environmental Engineer Consultant
Section A, Superfund Site Assessment Branch
Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry


VII. REFERENCES

  1. Agency for Toxic Substances and Disease Registry (ATSDR). Site Review and Up-Datefor Eastern Michaud Flats Contamination, Pocatello, Bannock County, Idaho. Atlanta,Georgia: U.S. Department of Health and Human Services, Public Health Service; March11, 1997.

  2. Bechtel Environmental, Inc. Remedial Investigation Report for the Eastern Michaud FlatsSite. San Francisco: Bechtel Environmental, Inc.; August 1996.

  3. ATSDR. Preliminary Public Health Assessment for Eastern Michaud Flats Contamination,Pocatello, Bannock County, Idaho. Atlanta, Georgia: U.S. Department of Health andHuman Services, Public Health Service; August 24, 1990.

  4. ATSDR. Toxicological Profile for Arsenic. Atlanta, Georgia: U.S. Department of Healthand Human Services, Public Health Service; April 1993.

  5. ATSDR. Toxicological Profile for Beryllium. Atlanta, Georgia: U.S. Department ofHealth and Human Services, Public Health Service; April 1993.

  6. ATSDR. Toxicological Profile for Lead. Atlanta, Georgia: U.S. Department of Healthand Human Services, Public Health Service; April 1993.

  7. Ecology and Environment, Inc. Baseline Human Health Risk Assessment, EasternMichaud Flats, Pocatello, Idaho. Lancaster, New York: Ecology and Environmental, Inc.;July 1995.

  8. ATSDR. Toxicological Profile for Fluorides, Hydrogen Fluoride, and Fluorine. Atlanta,Georgia: U.S. Department of Health and Human Services, Public Health Service; April 1993.

  9. ATSDR. Toxicological Profile for Cadmium. Atlanta, Georgia: U.S. Department ofHealth and Human Services, Public Health Service; April 1993.

  10. National Research Council. Health Risks of Radon and other Internally deposited Alpha-Emitters BEIR IV. Washington, D.C.: National Academy Press; 1988.

  11. National Research Council. Health Effects of Exposure to low levels of IonizingRadiation BEIR V. Washington, D.C.: National Academy Press; 1990.

Table 1.

Concentration of Various Site-Related
Contaminants in Ore, Slag, and Gypsum at the Eastern
Michaud Flats Contamination National Priorities List Site,
Pocatello, Bannock County, Idaho
-
Contaminant
and Units
Maximum
Concentration
at FMC
Maximum Concentration at Simplot
Gypsum
Background Levels According to EPA ATSDR Comparison Value for Ingestion and Source*
Ore Slag
Arsenic mg/kg 14.6 0.6 0.9 7.5 0.5 CREG
Beryllium
mg/kg
1.9 2 2.8 1 0.2 CREG
Cadmium
mg/kg
77.8 103 37 1.9 500 Adult
EMEG
Fluoride
mg/kg
13,200 7,800 7,650 600 35,000 Adult EMEG
Gross Alpha
pCi/g
~200 240 ~200 25** 15
Gross Beta
pCi/g
400 1,100 46 31** 50
Gross Gamma Árem/h 50 52 30 15** None
* - A description of the various comparison values is presented in Appendix B. Unless indicated
otherwise, the comparison values listed are for chronic exposures (greater than 365 days).
** - EPA did not select a background level for gross alpha, gross beta, and gross gamma. The
background levels report for these three contaminants were developed by the consultant for the
companies.
EPA is the U.S. Environmental Protection Agency
mg/kg is milligrams of contaminant per kilogram of soil.
pCi/g picocurie per gram of soil.
Árem/h is microrems per hour.


Table 2.

Surface Soil Contamination Found at the FMC or J.R.
Simplot Facilities, Eastern Michaud Flats Contamination National
Priorities List Site, Pocatello, Bannock County, Idaho
Contaminantand Units Maximum Concentration
at FMC
Maximum Concentration
at Simplot
Background
Levels
According to
EPA
Comparison
Value and Source*
Arsenic mg/kg27.1557.50.5 CREG
Beryllium mg/kg2.95.210.2 CREG
Cadmium mg/kg5,1101311.9500 AdultEMEG
Fluoride mg/kg221,000123,00060035,000 AdultEMEG
Lead mg/kg<5002,37029.1400 EPA Screen
Gross Alpha
pCi/g
21640625**15
Gross Beta
pCi/g
13313.831**50
Gross Gamma
Árem/h
452515**None
* - A description of the various comparison values is presented in Appendix B. Unless
indicated otherwise, the comparison values listed are for chronic exposures (greater than 365 days).
** - EPA did not select a background level for gross alpha, gross beta, and gross gamma. The
background levels report for these three contaminants were developed by the consultant for the
companies.
EPA is the U.S. Environmental Protection Agency
mg/kg is milligrams of contaminant per kilogram of soil.
pCi/g picocurie per gram of soil.
Árem/h is microrems per hour.


Table 3.

Surface Soil Contamination Found Beyond the FMC or
J.R. Simplot Facility Fence Lines, Eastern Michaud Flats
Contamination National Priorities List Site, Pocatello, Bannock
County, Idaho
Contaminantand UnitsMaximumConcentrationDetected Maximum
Mean
Concentration
Detected within
a Sector
Background
Levels
According to
EPA
ComparisonValue andSource*
Arsenic mg/kg18.48.287.70.5 CREG
Cadmium mg/kg18962.21.9 500 Adult
EMEG
Fluoride mg/kg27,2007,532600 35,000 Adult
EMEG
* - A description of the various comparison values is presented in Appendix B. Unless
indicated otherwise, the comparison values listed are for chronic exposures (greater than 365 days).
EPA is the U.S. Environmental Protection Agency
mg/kg is milligrams of contaminant per kilogram of soil.
pCi/g picocurie per gram of soil.
mrem/h is millirems per hour.


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