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Research Overview

Status: Ongoing
Substances: Sulfolane
Nominated: September 2011

Background Information

Sulfolane was nominated in 2011 by several agencies in Alaska after it was found in groundwater and well water in North Pole, Alaska, originating from a petroleum refinery. Water contaminated with sulfolane has also been identified in other sites of natural gas or petroleum refining. As a widely used solvent in industrial settings, it has been used for:

  • Refining natural gas and petroleum
  • Separating out components of wood tars for commercial use
  • Curing of epoxy resins
  • Extracting aromatics
  • Treating textiles for improved usability (e.g., enhanced surface texture and increased durability)

People are exposed to sulfolane through water, since it mixes easily but does not adequately break down in groundwater. It is absorbed by plants, though sulfolane does not accumulate in the aquatic food chain. Exposure may also occur through inhalation or skin contact for those who work in industries using sulfolane.

NTP Studies

NTP is performing a set of studies to evaluate the toxicity of sulfolane. Studies in process evaluate a number of outcomes that include:

  • Potential carcinogenic effects
  • Effects on the immune system
  • Effects on development and reproduction
  • Other health impacts of exposure

The table below describes each of the studies in more detail:

List of sulfolane studies
Study Description
28-day toxicity study Mice, rats, and guinea pigs are given a range of doses to determine if any are more sensitive to sulfolane toxicity than the other species. This study will also aim to identify appropriate dosing levels for longer duration studies.
Absorption, distribution, metabolism, and excretion Mice and rats are given sulfolane to determine how it moves within the body by different routes of exposure, including whether there are any differences between sexes or species.
Subchronic toxicity study Mice and rats from this two-year study will be assessed after three months of exposure to identify effects on development and reproduction, the immune system (rats only), and other endpoints.
Chronic toxicity study This study aims to determine the effects of long-term exposure on rats and mice, including any potential carcinogenic effects.
Immunotoxicity This study will determine the effects on the immune system in mice following three months of exposure by oral gavage. Results will be compared to the subchronic drinking water study.

Research at Other Agencies

United States

Informational Resources

  • NTP Board of Scientific Counselors Meeting, Research Triangle Park, NC, December 2011

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