ATSDR -- FY 1999 AGENCY PROFILE AND ANNUAL REPORT
hamster embryo cells when using a mixture of lead, arsenic and
chromium. Several cellular and molecular biomarkers are being
studied. Researchers have also been testing a mixture of arsenic,
1,2-dichloroethane, trichloroethylene, and vinyl chloride.
Mixtures of environmental chemicals such as polycyclic aromatic
hydrocarbons (PAHs) are difficult to characterize, both analytically
and toxicologically. Researchers at Texas A&M University have
developed two microbial assays that can be used to provide an
estimate of genotoxicity (i.e., whether a substance can damage DNA).
In parallel studies, spleen cells in culture are being used to study the
immunotoxic (whether a substance is toxic to the immune system)
effects of mixtures. Together these assays can be used to study a
variety of potential toxic effects of environmental mixtures.
Researchers at North Carolina State University are studying the
dermal absorption of environmental chemical mixtures. The
influence of other chemicals on the absorption of mixtures of
polychlorinated biphenyls (PCBs) and pentachlorophenol (PCP) is
being studied using an in vitro method.
Northeast Louisiana University researchers are studying recovery
and repair mechanisms following exposure to trichloroethylene
(TCE), thioacetamide, allyl alcohol, and chloroform. The roles of
these chemicals and their metabolites in eliciting tissue repair and
injury are being studied. After evaluating individual chemicals,
detailed mixtures studies are planned.
At Wayne State University, experiments were performed to compare
the interactive toxicity of simple mixtures of toxic metals in primary
cultures of rat liver cells, rat osteoblastic bone cells, and monkey
kidney cells. The liver cells were found to be most sensitive and the
osteoblastic bone cells were least sensitive to mixtures of mercury
and cadmium. These results underscore the need for investigators
and risk assessors to be aware of parameters such as target organ
sensitivity in the overall expression of toxicity of a mixture.
ATSDR provides technical assistance 24 hours a day to federal, state, and local
government and emergency-response organizations during emergency
situations resulting from unplanned releases of hazardous substances.
Emergency-response coordinators have immediate access to assistance from
ATSDR experts in the areas of chemistry, toxicology, medicine, and
environmental science. Site-specific consultation teams can usually be
convened within 20 minutes of notification to provide support. On-site
response can be provided anywhere in the continental United States, usually
within 8 hours of a request.