Routes of Entry
Local vs Systemic
Acute and Chronic Health Effects
Acute health effects are characterized by sudden and severe exposure and rapid absorption of the substance. Normally, a single large exposure is involved. Acute health effects are often reversible. Examples: carbon monoxide or cyanide poisoning.
Chronic health effects are characterized by prolonged or repeated exposures over many days, months or years. Symptoms may not be immediately apparent. Chronic health effects are often irreversible. Examples: lead or mercury poisoning, cancer.