Introduction
Styrene is used for the production of various industrial products. Other chemical molecules are added to styrene to improve its chemical properties for the production of industrial products. Yearly, large quantities of styrene molecules are produced for industrial products like food containers, plastics, pipes, automobile parts, rubber, fiberglass, and styrene insulators. Humans are exposed to styrene during industrial processes and through plastic waste. Acute exposure causes eye, skin, and respiratory irritations. Long-standing exposure will cause adverse health effects on organs.
What Is Styrene?
Styrene is a benzene derivative. It is a colorless, flammable, oily liquid. Styrene is majorly used for the industrial production of polystyrene. It is a homopolymer made from styrene monomers. Polystyrene resins constitute a significant component of household appliances, plumbing equipment, and insulation products. More than 50 percent of styrene produced is used to make polystyrene products. Other chemical substances produced from styrene are thermosetting resins, Expanded Polystyrene (EPS), elastomers, Acrylonitrile Butadiene Styrene (ABS), elastomers, Styrene-Acrylonitrile (SAN), and polymer dispersions.
What Are the Uses of Styrene?
Styrene and styrene-derived products are used to produce multiple products used daily. It includes the following:
1. Polystyrene (PS) - They produce the following products.
-
Food containers.
-
Insulation appliances.
-
Lenses.
-
Electrical appliances.
-
Food packing products.
-
Wall tiles.
-
Plastic bottle caps.
-
Flotation devices.
-
CD (compact disc) cases.
-
Envelop windows.
-
Surfboards.
2. Styrene-Butadiene Rubber (SBR) - It is also known as synthetic rubber. Styrene-butadiene rubber is used to manufacture products like automobile tires and aircraft tires.
3. Styrene-Butadiene Latex (SBL) - Latex produced using styrene monomers is used to manufacture bathroom carpets and paper coatings.
4. Styrene-Butadiene Plastic - They produce small household appliances, medical devices, luggage, and liners used in refrigerators.
5. Acrylonitrile (SAN) - They are styrene-maleic anhydride copolymers. It is used in producing optical fibers, automobile parts, food containers, and small electric appliances.
6. Acrylonitrile and Butadiene (ABS) - They are heat-resistant, hard, and rigid plastics produced from styrene. It produces automobile parts, electric appliances, and pipe fittings.
What Is Styrene Toxicity?
Styrene is a commonly used raw material for producing various industrial products like resins, rubber, plastics, and insulators. Styrene molecules reach the environment through industrial wastes. Minor quantities of styrene are released into the atmosphere from motor vehicle exhaust emissions, cigarette smoke, and burning plastic products containing styrene.
Polymers from styrene, such as polystyrene and Acrylonitrile-Butadiene-Styrene (ABS), are present in commercial food containers and packaging materials. Styrene monomer residues in these plastic products can contaminate food and reach the human body. After reaching the human cells, styrene molecules are metabolized to styrene oxide. This styrene oxide metabolite is toxic to the stomach cells and induces genotoxic effects in the stomach.
What Are the Symptoms Caused by Styrene Toxicity?
Symptoms caused by styrene toxicity include:
-
Health effects caused by acute exposure in industrial workers during manufacturing processes. Following dermal contact or inhalation, styrene is readily absorbed and distributed in the body tissues. Acute inhalation of styrene vapors causes throat and nasal irritation, cough, increased nasal discharge, wheezing, and pulmonary edema. Inhalation of large amounts of styrene vapors will lead to central nervous system depression and a condition named styrene sickness. It includes symptoms like headache, vomiting, dizziness, nausea, fatigue, weakness, and ataxia. Acute dermal exposure to styrene molecules causes skin irritation, itching, and contact dermatitis.
-
Long-term or chronic exposure to styrene in industrial workers has shown toxic effects on the central nervous system. Neurotoxicity may cause memory loss, brain damage, decreased concentration, and altered coordination. Chronic exposure has shown liver failure and increased incidence of cancer in industrial workers.
What Are the Harmful Health Effects of Styrene Toxicity?
-
Neurotoxicity - Toxic metabolites produced from styrene may cause neurotoxicity. Neurotoxicity due to styrene exposure results in symptoms like headache, weakness, central nervous system dysfunction, memory loss, reduced intellectual functions, and depression.
-
Carcinogenicity - Styrene is considered a potent carcinogen. They can disrupt normal metabolic processes and induce carcinogenesis. Styrene exposure through inhalation, dermal contact, and ingestion may cause carcinogenic effects. Styrene molecules are converted to styrene oxide by the action of cytochrome P450. Styrene oxide is responsible for carcinogenic effects on the human body. Studies have shown an increased incidence of leukemia (blood cancer) and lymphoma (lymph node cancer) in individuals exposed to styrene. Chronic inhalation of styrene vapors results in respiratory irritation and pulmonary adenomas (lung tumors).
-
Reproductive Toxicity - Chronic exposure to styrene may cause reproductive defects in males and females. Alteration in testicular sperm morphology is observed in males. Increased incidence of miscarriages is reported in females exposed to styrene.
-
Developmental Defects - Occupational exposure to styrene in a pregnant woman is associated with an increased risk of birth defects in the baby.
-
Genotoxicity - After reaching human cells, styrene is converted to toxic metabolites like styrene oxide and styrene 7,8-oxide. These toxic metabolites are responsible for the genotoxic effects of styrene. Styrene 7,8-oxide is capable of causing chromosomal defects and DNA damage.
-
Mutagenicity - Toxic metabolites produced from styrene are capable of causing chromosomal aberrations, gene mutations, Sister Chromatid Exchanges (SCE), micronuclei mutations, and DNA (Deoxyribonucleic Acid) damage.
-
Hepatotoxicity - Studies have shown that styrene metabolites cause damage to liver cells. Styrene oxide may cause toxic effects, altering hepatocyte morphology and function. The changes include hepatic cell inflammation and hydropic degeneration. Continued damage to the hepatic cells will lead to altered liver function, eventually leading to liver damage.
Conclusion
Styrene is a commonly used industrial raw material for producing various plastic products. They are used as monomers for manufacturing commercial polymeric products. Occupational exposure to styrene through dermal contact, inhalation, and eye contact may cause acute health effects. Protective eyewear, face masks, and gloves must be introduced in workers to avoid acute exposure. Chronic exposure to styrene in industrial workers has shown dangerous health effects. Environmental exposure to styrene occurs through industrial waste materials and the burning of plastic waste. Accurate disposal methods must be monitored to avoid exposure to styrene and dangerous health effects.
