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CARDIOVASCULAR OR BLOOD TOXICITY

Cardiovascular and blood toxicity is defined as adverse effects on the
cardiovascular or hematopoietic systems that result from exposure to
chemical substances. The cardiovascular system is composed of the
heart and blood vessels; the hematopoietic system is composed of
various blood cell types: erythrocytes (red blood cells), leukocytes
(white blood cells), and platelets. Exposure to cardiovascular
toxicants can contribute to a variety of diseases, including elevated
blood pressure (hypertension), hardening of the arteries
(arteriosclerosis), abnormal heartbeat (cardiac arrhythmia),and
decreased blood flow to the heart (coronary ischemia). Exposure to
hematopoietic toxicants can reduce the oxygen carrying capacity of
red blood cells, disrupt important immunological processes carried out
by white blood cells, and induce cancer. Because the cardiovascular
system is complex, adverse effects resulting from exposure to
chemicals can arise through a variety of mechanisms. Toxicants can
contribute to cardiovascular disease by directly damaging cardiac and
blood vessel tissue, initiating arteriosclerotic plaque formation,
stimulating the inflammatory response, or causing kidney-related
hypertension. Lead, carbon disulfide, arsenic, cadmium, ozone, and
vinyl chloride have been implicated in the etiology of cardiovascular
disease. These chemicals may produce functional changes, such as
cardiac arrhythmias, that can have serious and often lethal
consequences. They can also induce hypertension, a major cause of
cardiac hypertrophy and heart failure. Several toxicants have been
found to aggravate preexisting cardiovascular disease. Carbon
disulfide and arsenic can irreversibly accelerate coronary heart
disease.

The blood cells of the hematopoietic system can also be severely
affected by chemical substances. For example, benzene, a component of
motor fuel, is a hematopoietic toxin. Chronic exposure to benzene
vapors leads to the decreased production of all types of blood cells
(pancytopenia). The long-term effect of exposure to benzene is
leukemia, a cancerous proliferation of white blood cells. For further
general information on chemicals and cardiovascular and blood
toxicity, see the following references:

Balazs, T., J. Hanig, and E. Herman. Toxic Responses
of the
Cardiovascular System. Chapter 14 in Casarett and
Doull's Toxicology,
edited by C. Klaassen, M. Amdur, and J. Doull. New
York: Pergamon
Press, 1996.

Baskin, S. I. Principles of Cardiac Toxicology. Boca
Raton, Fla.: CRC
Press, 1991.

Smith, R. Toxic Responses of the Blood. Chapter 8 in
Casarett and Doull's
Toxicology, edited by C. Klaassen, M. Amdur, and J.
Doull. New York:
Pergamon Press, 1996.

Taylor, A. E. Cardiovascular Effects of
Environmental
Chemicals.
Otolaryngology, Head and Neck Surgery. 114(2):
209-211. 1996.

Wilcosky, T. C. Solvent Exposure and Cardiovascular
Disease. American
Journal of Industrial Medicine. 19:569-586 1991.