UNC Research Links Air Pollution, Suicide

Toxic air pollution could be driving us to despair, says research conducted by a University of North Carolina professor.

The study found that two Salisbury, N.C. communities located near asphalt plants have suicide rates about 16 times the statewide average, suggesting a link between suicide and exposure to air pollutants. The plants mix crushed rock with crude oil derivatives to make asphalt for paving, in the process releasing toxic chemicals including hydrogen sulfide, carbon disulfide, benzene and arsenic.

The research was conducted by Dr. Richard Weisler, professor of psychiatry at UNC-Chapel Hill's medical school and Duke University Medical Center and a volunteer with the nonprofit Blue Ridge Environmental Defense League. His collaborators were Duke professor of psychiatry Dr. Jonathan Davidson, BREDL toxicologist Dr. Lynn Crosby, BREDL Director Lou Zeller, Clean Water for North Carolina Director Hope Taylor-Guevara, Executive Director Sheila Singleton of the N.C. Depression and Bipolar Support Alliance, and Melissa Fiffer and Stacy Tsougas, BREDL interns and undergraduates at Duke’s Nicholas School of the Environment.

“We do not know with scientific certainty that the area suicides are linked to hazardous chemical exposures, but we know enough to recommend that it is not worth taking any more chances on the potential association,” says Weisler, who presented his findings last month to the 17th Annual U.S. Psychiatric and Mental Health Congress in San Diego.

More than 1,500 people live in the neighborhoods, which are situated immediately downwind of a liquid asphalt terminal, an asphalt hot-mix plant, a site where N.C. Department of Transportation dumped solvents used for testing asphalt, and a former petroleum tank farm that’s also contaminated with toxic substances.

From 1994 to 2003, the suicide rate in the neighborhoods as determined by death certificates increased a statistically significant 350 percent, the study found. Two deaths by suicide would be expected for the area over a 10-year period, but seven suicides occurred.

Weisler and his colleagues say a link between hydrogen sulfide and depression is plausible since the substance affects brain neurochemistry, potentially altering moods and triggering the stress response. Carbon disulfide has been linked to personality changes, mood disorders and suicides in occupational settings, according to the researchers.

The U.S. Centers for Disease Control & Prevention and the UNC School of Public Health plan to collaborate on further health studies of the two neighborhoods and other potential sites with chemical exposures. In addition, UNC epidemiologist Dr. Steven Wing and others at the School of Public Health will further investigate the health of residents who died by suicide.