Polycyclic Aromatic Hydrocarbons

Polycyclic Aromatic Hydrocarbons

These compounds (also called polynuclear aromatic hydro-carbons) contain three or more fused benzene rings in varying arrangements that consist of carbon and hydrogen, e.g. benzoanthracene, benzopyrene, anthracene, phenanthrene, benzofluoranthene, chrysene, coronene, dibenzacridine, dibenzanthracene, dibenzocarbazole, dimethylbenzanthracene, 3-methylcholanthrene and pyrene.

Sources

Polycyclic aromatic hydrocarbons (PAHs) are components of most fossil fuels and are ubiquitous in the natural environment.

Forest fires.

Sea food and agricultural products.

Charring, barbecuing, smoking of foods; foodstuffs such as coffee, roasted peanuts; refined vegetable oils, crude coconut oil, heavily smoked ham.

Emissions sources:

·              Cigarette smoke

·              Coal tar pitch

·              Coke production

·              Engine exhaust

·              Engine oil, used

·              Fuel burning, and open burning of refuse

·              Restaurants and smokehouses

·              Roof tarring

·              Sidewalk tarring

·              Wood-burning fireplaces.

Clinical Features

Acute poisoning is rare.

Chronic exposure in the form of inhalation or dermal contact can predispose to lung and skin cancer. Increased incidence of cancers of the skin, bladder, lung and gastroin-testinal tract have been described in PAH-exposed workers. Apart from such carcinogenic potential, PAHs are also responsible for eye irritation and photosensitivity, skin erythema, cough and bronchitis, and haematuria.

Chronic effects include:

––  Photosensitivity and irritation.

––  Respiratory—Irritation with cough and bronchitis.

––  Mouth—Leukoplakia.

–– Dermal— “Coal tar warts” (precancerous lesions enhanced by UV light exposure), erythema, dermal burns, photosensitivity, acneiform lesions, irritation.

–– Hepatic/Renal—Mild hepatotoxicity or mild nephrotoxicity.

––  Genitourinary—Haematuria.

Routine monitoring and physical assessments (e.g. complete blood count, hepatic and renal function tests, chest X-ray and pulmonary function tests, dermal assessments) of individuals with significant exposure is recommended, even in the absence of symptoms.