Student Project Topics

1.  Noncancer Endpoints

Boric acid
 Boric acid is an ingredient in many cosmetic,  pharmaceutical and pesticide products and has been shown to have bactericidal and fungicidal properties.  Boric acid has been under study as a potential developmental and male reproductive toxicant. Because of its widespread commercial and consumer use, the assessment of this chemical has become a public issue and the EPA water standards for boric acid are under reevaluation  Environmental exposures occur due to its presence as a natural salt in many locations worldwide and specifically in the Southwestern regions of the US where it has been mined.  This project will focus on the identification of acceptably safe exposure levels to protect the public from developmental effects.

Diethylhexylphthalate
 Diethylhexylphthalate is colorless liquid that is used as plasticizer for polyvinyl chloride resins for flexible plastics. It is of interest to the CPSC, EPA and FDA as it is widely used in many products ranging from teething rings, pacifiers, vinyl upholstery, adhesives, plastic food wraps and flexible medical tubing.  It is widely distributed in the environment and has been identified in most water sources and municipal waste dumps.  250 industrial facilities produced or use DEHP and under the community-right-to know legislation, reported releases into the environment are over 1.1 million pounds.  It is of interest as a potential animal carcinogen and in particular a male reproductive toxicant.  This project will evaluate the evidence that DEHP is a male reproductive toxicant and develop recommended safe levels of exposure.

2.  Clean Water Issues

Polychlorinated biphenyls (PCBs)

 Polychlorinated biphenyls are a group of related lipophilic compounds that were originally used as fire retarding chemicals in transformers and electrical equipment.  They are also highly persistent in the environment and as a result of widespread use and release contaminate many of our aquatic species. They have been found to be rodent carcinogens. The focus of this project will be to develop fish advisories for humans consuming aquatic species that have complex mixtures of PCB conjenors.  Endpoints of cancer, immunotoxicity or developmental toxicity can be evaluated as the health risks of interest.  Project group should be able to demonstrate use of stucture-activity relationships to predict risk for complex mixtures.
 
 

3.   Pesticides

Chlorpyrifos

 Chlorpyrifos is an organophosphate pesticide that is widely used not only internationally but also in Washington state for control of coddling moth in apple orchards.  It has recently come under enhanced scrutiny by the USEPA for two reasons.  First, exposure studies have shown higher than expected levels of organophosphates in urine of children of agricultural workers (some evidence from Wa state families) and due to increased interest in re-evaluating itís potential to cause developmental neurotoxicity.  Organophosphate pesticides are used widely and if all exposure routes are evaluated, exposures to more than one organophosphate can occur.   This project will focus on risk assessments for children as  susceptible subpopulations with potential for increased sensitivity due both to increased potential for exposure as well as increased sensitivity due to impacts on the developing nervous system.  This project group will use the recent efforts under the Food Quality Protection Act as a policy driver for these reassessments.

 
4.  Carcinogens

Perchloroethylene
 Perchloroethylene (PERC) is a clear liquid used for dry cleaning, textile processing and metal degreasing.  After determining that trichloroethylene was a suspected animal carcinogen, perchloroethyleneís use as an substitute industrial solvent dramatically increased.  NIOSH and OSHA differ in their proposed TLV revisions and the differences center on interpretation of perchloroethyleneís potential to cause human cancers.  Differences in rodent versus human metabolism of perchloroethylene may offer a mechanistic explanation for cross-species differences in cancer potential.  This project will examine these mechanistic explanations and use them in setting appropriate levels of occupational and environmental air standards.
 

Arsenic
 Arsenic is a widely distributed environmental pollutant that has been identified as a human carcinogen.  Although it is a human carcinogen it usually is not carcinogenic in rodent bioassays nor is it mutagenic in short term in vitro gene mutation assays.  The mechanism by which it can cause cancer in humans is unknown although it has been demonstrated to cause chromosomal
aberrations/exchanges and gene amplification. A human methyltransferase polymorphism has been identified and current research is evaluating the relevance of this variation in human genome to determine if it translates into a difference in risk.  USEPA has recently issued revised guidelines for allowable environmental levels of arsenic.  This project would evaluate these new guidelines as the basis for their risk project.  Regionally arsenic is of interest because of the former ASARCO arsenic smelter in Tacoma.

5.  Air Pollution Issues

Particulates
 Particulate matter (PM) is a general term used to describe discrete particles that are present in air arising from dust, fires, plant pollens and many human activities such as agriculture, combustion, transportation, etc.  These particles can range in size, however; the newly proposed National Ambient Air Quality Standards (NAAQS) has focused attention on PM 2.5 particles with a mean aerodynamic diameter less than or equal to 2.5µm.  Recent epidemiological studies have provided the scientific rationale for this change and have shown statistically significant associations of ambient PM levels with a variety of adverse human health impacts including death, respiratory illness, decrement in pulmonary function and hospital admissions.  Some scientists have challenged the interpretation of these studies and questioned the need to spend the dollars needed to obtain compliance under these new regulations.
 
 
 

6.  Issues with Mixed Chemical/Radioactive Hazardous Waste Sites:  Assessment of DOE

 The most challenging sites for hazardous waste site assessment ire the Department of Energy former nuclear weapons complexes.  These sites, which cover over 3,300 square miles, are located  in 36 sites and territories.  The complexity of these sites is immense due to many factors including:  presence of both chemical, radiation and other physical hazards, diversity of past and current activities and uncertainties in future land uses.  The group project that will investigate one of the issues facing the DOE environmental management program responsible for site clean-up will narrow the focus of this environmentally challenging topic to evaluate several defined aspects of remediation.  One example could be a project evaluating occupational risks to remediation workers restoring former purex processing regions or an alternative could be determining environmental risks for adjacent communities if formerly buried wastes are relocated during remediation.  Possilbe contamination of the Columbia River by contaminants found in the vadose zone under leaking radioactive storage tanks in the 200 area of the Hanford site is another example project.  Possible radionucleotides of interst include Strontium 90 or tritium.

Strontium 90

Strontium 90 is a radionucleotide that has been shown to be a contaminate of groundwater at former nuclear reactor and fuel reprocessing area(ex. Hanford 100 and 200 areas).  Health risks for humans have been calculated from study of humans exposed to other forms of radiation such as atomic bomb survivors (leukemia health risks) and radium dial painters (bone cancers).  Studies in dogs exposed to SR 90 reveal bone cancers.  This group project would focus on the effectiveness of "pump and treat" groundwater remediation options for decreasing risk of humans and ecology to SR 90 as well as evaluate the appropriatemenss of the extrapolation of risks from the available animal and human studies to predict Sr 90 risks for humans.
 

Tritium

Tritium is a radioactive form of water which emits B radiation.  As such it does not penetrate skin but can cause health effects after ingestion or inhalation.  It has a half like of 12 years and is present at many nuclear waste sites, including Hanford and Savannah River (SRS).  It is of concern at these sites primarily as a groundwater contaminant.  Recent epidemiology studies have re-opened the question of health effects from tritum.  The Savannah River Stakeholder Advisory Board has prospoed that tritum is one of the key health based risk issues that hey are now facing.  The focus of this potential project will be to help the SRS Advisory bBoard to perform a health risk assessment for tritum.
 

Contact Information: University of Washington
                                  Elaine M. Faustman
                                  phone: 206-685-2269
                                  fax: 206-685-4696