Goal: To evaluate the potential risk of adverse health effects caused from the exposure to contaminants from the North Pole refinery’s history of spills.
The Human Health and Toxicology Subgroup evaluates the toxicity and risk from exposure to sulfolane in drinking water and garden plants, and is identifying other ways people and animals may be exposed to sulfolane and other contaminants released to the environment at the Flint Hills Refinery.
Overseeing:
DEC approved the risk assessment work plan, approving the methods to evaluate potential risks from exposure to chemicals on and off the refinery. The risk assessment report will be used to help guide the selection of cleanup levels at the site.
The Alaska Department of Health and Social Services’ health consultation that reviews the potential ways in which North Pole residents may come in contact with sulfolane from private well water and the potential impacts from those exposures.
EPA’s Provisional Peer-Reviewed Toxicity Values for Sulfolane
A Provisional Peer-Reviewed Toxicity Value (PPRTV) is defined as a toxicity value derived for use in the Superfund Program. PPRTVs are derived after a review of the relevant scientific literature using established Agency guidance on human health toxicity value derivations. All PPRTV assessments undergo an internal review by a standing panel of National Center for Environmental Assessment (NCEA) scientists and an independent external peer review by three scientific experts.
The purpose of this document is to provide support for the hazard and dose-response assessment pertaining to chronic and sub-chronic exposures to substances of concern; to present the major conclusions reached in the hazard identification and derivation of the PPRTVs; and to characterize the overall confidence in these conclusions and toxicity values. It is not intended to be a comprehensive treatise on the chemical or toxicological nature of a substance.
The PPRTV review process provides the much needed toxicity values in a quick turnaround timeframe while maintaining scientific integrity. PPRTV assessments are updated approximately on a 5-year cycle for new data or methodologies that might impact the toxicity values or characterization of potential for adverse human health effects and are revised as appropriate.
2010 Garden Study
During the summer of 2010, a Gardening Sampling Project was conducted to assess how garden produce that used well water with various concentrations of sulfolane was affected.
The study found that:
- Edible garden plants can take up sulfolane that is present in water. People can be exposed to (come in contact with) sulfolane by eating produce that is watered with sulfolane contaminated water.
- Sulfolane was found in all parts of plants that were sampled (leaves, fruits, flowers, stems and roots). Click here to link to the report.
The sulfolane levels in the plants tested from these gardens were low and not likely to cause adverse health effects. However, this sampling project was limited, reflecting the 2010 growing conditions and only the produce from the sampled gardens. The amount of sulfolane in plants can vary based on a number of factors including; the type of produce, different growing conditions (i.e. more or less rainfall), or the amount (concentration) of sulfolane in the well water. Due to the unknown toxicity of sulfolane, it cannot be said with 100% certainty that it is safe to use sulfolane-impacted water for gardening without further study; therefore, watering gardens with sulfolane-free water is preferable until more information is available.
Flint Hills has offered to provide above-ground water tanks for residents to use for gardening in the interim. North Pole residents with detectable levels of sulfolane in their well water have a long-term alternative water source for drinking and cooking purposes. North Pole gardeners should use a water source that has no detectable level of sulfolane for growing edible plants, until more is known on the uptake of sulfolane into fruits and vegetables. You may contact Flint Hills Resources: Marisa Sharrah, Koch Companies Public Affairs, (907) 488-5103, marisa.sharrah@kochps.com.
For more information please contact: Alaska Department of Health and Social Services, Division of Public Health, Epidemiology Section: Nim Ha, acting program manager, Environmental Public Health Program, (907) 269-8028, nim.ha@alaska.gov.
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