Sodium Metabisulfite Toxicity - Health Effects, Treatment, and Prevention

Introduction:

Sodium metabisulfite is a versatile chemical compound with the chemical formula Na2S2O5. This substance is a crystalline powder with a white or yellowish-white color. It readily dissolves in water and emits a strong sulfur odor. Sodium metabisulfite is a widely employed food preservative and antioxidant, as well as in various industries such as photography, water treatment, and paper manufacturing. It is used as a developing agent and preservative for photographic films and papers.

Sodium pyrosulfite is an alternative name for sodium metabisulfite and is approved as a pharmaceutical excipient. It is utilized for various purposes such as diluent, alkalizing agent, antimicrobial agent, and antioxidant. This chemical compound is also recognized under various synonyms and trade names, such as Disulfurous acid, Disodium salt, Sodium acid sulfite, and Sodium metabisulphite.

What Are the Applications of Sodium Metabisulfite?

Sodium metabisulfite has various applications in the pharmaceutical field due to its antimicrobial and antioxidant properties, which include:

• As a food preservative, sodium metabisulfite extends the shelf life of various food products. It is particularly effective in preserving the color and flavor of dried fruits and vegetables, wine, beer, and other processed foods. It inhibits the process of oxidative browning in food products.

• The primary application of sodium metabisulfite in pharmaceuticals is to act as an antioxidant in various forms, including oral, parenteral, and topical formulations.

• The antioxidant property of this compound is beneficial for cosmetic products to prevent the spoilage of skincare products.

• Sodium metabisulfite is used in water treatment plants to remove excess chlorine from water. People add this substance to water to counteract the potential harm to the environment and aquatic organisms, as it aids in neutralizing chlorine present in the water.

• Sodium metabisulfite is used in the textile industry as a reducing agent for dyeing and printing fabrics. It helps to remove excess dye and improve the color fastness (ability to retain color without fading) of the fabric.

• Sodium metabisulfite is utilized as an antioxidant in the development of photographic film.

What Is Sodium Metabisulfite Toxicity?

Sodium metabisulfite toxicity occurs when an individual is exposed to excessive amounts of the chemical compound sodium metabisulfite. Exposure to this compound can occur through ingestion, inhalation, or skin contact, leading to various health risks and symptoms. National Institute for Occupational Safety and Health (NIOSH) recommends that the airborne exposure limit should not exceed 5 mg/m3 (milligram per cubic meter) on average over a ten-hour work shift. On the other hand, the American Conference of Governmental Industrial Hygienists (ACGIH) recommends an airborne exposure limit of 5 mg/m3 for the eight-hour work shift.

The European Union has established a maximum allowable intake of sodium metabisulfite and other sulfites in food products of 3.5 mg/kg (milligram per kilogram) body weight. At the same time, the World Health Organization has set it at 7.0 mg/kg body weight (calculated as sulfur dioxide). Food Standards regulations require packaged products to disclose the presence of added sulfites on their labels if they exceed 10 mg/kg concentration. This measure aims to protect consumers who may be allergic to sulfites from accidentally consuming them.

What Are the Reasons Behind Sodium Metabisulfite Toxicity?

The following are the reasons for sodium metabisulfite toxicity:

• Consuming excessive amounts of food products containing this compound can lead to sodium metabisulfite toxicity, especially in individuals with increased sensitivities or allergies to sulfites.

• Sodium metabisulfite is used as a preservative in some medications, particularly injectable medications such as Adrenaline (epinephrine) and Lidocaine. Individuals who are sensitive or allergic to sodium metabisulfites may experience toxicity when exposed to these medications.

• Workers in various industries, such as food processing, photography, and water treatment, may be exposed to high levels of sodium metabisulfite, increasing their risk of toxicity. Exposure to these products can occur through various routes like inhalation, skin contact, or ingestion.

What Are the Health Effects of Sodium Metabisulfite Toxicity?

The health effects of sodium metabisulfite toxicity can vary among individuals. It usually exhibits mild symptoms to more severe complications.

Short-Term Effects -

• One of the most common health effects of sodium metabisulfite toxicity is respiratory problems, particularly in individuals with pre-existing asthma. Exposure to sodium metabisulfite can trigger asthma attacks and cause cough, wheezing, and breathing difficulties.

• Skin irritation and allergic reactions such as redness, itching, and swelling of the skin in individuals who are sensitive to sulfites.

• Eye irritation, pain, and redness in case of eye contact with this compound.

• Excessive consumption of foods or medications containing sodium metabisulfite can cause gastrointestinal symptoms such as nausea, vomiting, and diarrhea.

Long-Term Effects -

• High levels of sodium metabisulfite can lead to the breakdown of red blood cells, a condition known as hemolysis. This can cause anemia, jaundice, and kidney damage.

• Exposure to high levels of sodium metabisulfite can lead to central nervous system effects, including headache, dizziness, and confusion.

• Some studies show that excessive ingestion of sodium metabisulfite decreases testosterone levels, lowers sperm count and motility, and increases sperm abnormality. It also results in impaired spermatogenesis (producing mature sperm cells) and changes in epididymal morphometry. Epididymal morphometry refers to the analysis of the size, shape, and structure of the epididymis. This tube-like structure plays a crucial role in the maturation and storage of sperm cells.

What Is the Treatment for Sodium Metabisulfite Toxicity?

The treatment for sodium metabisulfite toxicity is decided depending on the suspected individual’s symptoms and the level and duration of exposure. In less severe cases, treatment may involve avoiding further exposure to sodium metabisulfite and addressing any symptoms. Generally, treatment may involve emergency measures, such as airway management, oxygen therapy, and administration of epinephrine to manage anaphylaxis (a severe and rapid allergic reaction).

In case of eye contamination, it is important to immediately rinse the affected eyes with water. During transport, it is recommended to continuously irrigate each eye with 0.9 % saline (NS). Proparacaine hydrochloride can be used to assist in cases of eye irrigation. If the patient has ingested the substance, it is advised to rinse the mouth and administer up to 6.8 ounces (200 mL) of water for dilution at a dosage of 5 mL/kg (milliliter per kilogram). Gastrointestinal symptoms like nausea and vomiting may be treated with anti-nausea medications and hydration.

Treatment for skin reactions may include antihistamines or corticosteroid creams, while respiratory symptoms may be managed with bronchodilators or other medications to improve breathing. Administer a beta-agonist such as Albuterol in case of severe bronchospasm (a sudden constriction of the airways). Seizures should be treated with Diazepam or Lorazepam.

How to Prevent Sodium Metabisulfite Toxicity?

The following ways help to reduce sodium metabisulfite exposure:

• Individuals who are sensitive or allergic to sulfites should avoid consuming foods and medications that contain sodium metabisulfite.

• Workers in industries that use sodium metabisulfite should follow appropriate safety protocols, such as wearing protective equipment and working in well-ventilated areas. Wear respirators if required.

• Thoroughly cleanse hands right after contact and by the end of the work period.

• If someone suspects that they have encountered sodium metabisulfite and are experiencing symptoms of toxicity, they should seek medical attention immediately.

Conclusion:

Sodium metabisulfite is a widely used chemical compound that may present health hazards when consumed in excessive quantities. The best way to prevent sodium metabisulfite toxicity is to limit exposure to the chemical. Follow the preventive measures properly before encountering this chemical. Proper precautions and timely treatment can minimize the risks of sodium metabisulfite toxicity.