Final answer:
Substances that can cause acute or chronic illness are classified as toxic, which can include environmental contaminants, heavy metals, and other hazardous substances. Carcinogenic substances specifically cause cancer, and their effects can depend on various factors like dose and metabolism.
Step-by-step explanation:
Any substance that can cause acute or chronic illness to the human body due to exposure can be classified as toxic. Diseases can manifest quickly after high-level exposure or over time with low-level, chronic exposure to a substance. For example, the effects of prolonged low-level exposure to contaminants like cigarette smoke or moderate alcohol use may take years to become apparent.
Carcinogenic substances specifically refer to those chemicals that are known to cause cancer, with their effect often dependent on the dosage and the individual's or species' metabolism. This can make the determination of a substance's carcinogenic properties complex, as some chemicals become carcinogenic only after being metabolized into another compound in the body.
Environmental contaminants can include a wide array of substances, hazardous chemicals, or even naturally occurring biological agents like mold or toxic algae blooms. At high concentrations, these substances can become environmental health hazards. Toxic chemicals such as heavy metals (like lead, mercury, arsenic), persistent organic pollutants, and radioactive materials can accumulate in biological tissues causing long-term health effects. Exposure to these chemicals poses a significant health risk ranging from nervous system damage to respiratory illness and in some cases, cancer.