Diseases Caused by Selenium or Its Compounds

1. Introduction and Definitions

Selenium is a trace mineral essential for human health in small amounts, playing a crucial role in antioxidant defense systems and thyroid hormone metabolism. However, exposure to high levels of selenium or its compounds can be toxic and lead to various health issues. Selenium is used in several industrial applications, including electronics, glass manufacturing, and as a component in certain pigments and pesticides. This article provides comprehensive information on diseases caused by selenium and its compounds, targeting occupational health nurses and doctors.

2. Agent Causes the Disease

Exposure to selenium and its compounds can occur through inhalation of dust or fumes, ingestion, or dermal contact. Common forms of selenium exposure in industrial settings include selenium dioxide (SeO2), selenium sulfide (SeS2), and sodium selenite (Na2SeO3). These compounds are used in processes such as metal refining, electronics manufacturing, and the production of glass, pigments, and pesticides.

3. Workers at Risk of This Disease

Several occupations and tasks put workers at higher risk of exposure to selenium and its compounds, including:

  • Electronics Manufacturing Workers: Handling selenium in the production of electronic components and semiconductors.
  • Glass and Ceramic Industry Workers: Using selenium compounds as decolorizing agents and pigments.
  • Chemical Manufacturing Workers: Handling selenium compounds in various chemical processes.
  • Metal Refinery Workers: Involved in the extraction and refining of selenium-containing ores.
  • Agricultural Workers: Using selenium-based pesticides and fertilizers.
  • Laboratory Technicians: Using selenium compounds in research and analytical procedures.

4. Symptoms

Symptoms of diseases caused by selenium exposure can vary depending on the level and duration of exposure:

  • Acute Exposure: Symptoms include respiratory irritation (coughing, bronchitis), gastrointestinal distress (nausea, vomiting, diarrhea), and eye irritation. Severe acute exposure can lead to pulmonary edema and respiratory failure.
  • Chronic Exposure: Long-term exposure can cause selenosis, characterized by symptoms such as hair loss, nail brittleness, skin lesions, and neurological abnormalities (numbness, tingling, weakness). Chronic exposure can also lead to liver and kidney damage.

5. Diagnosis

Diagnosing diseases caused by selenium involves a combination of clinical evaluation, occupational exposure assessment, and specific tests:

  • Medical History and Physical Examination: Detailed assessment of the patient's work history and symptoms.
  • Pulmonary Function Tests: To assess lung function and detect any obstructive or restrictive patterns.
  • Blood and Urine Tests: Measuring selenium levels to assess exposure and monitor liver and kidney function.
  • Liver and Kidney Function Tests: Monitoring for signs of organ damage.
  • Neurological Evaluation: Including tests for cognitive and motor function if neurological symptoms are present.
  • Skin Examination: For signs of irritation, hair loss, and skin lesions.

6. Treatment

Treatment for diseases caused by selenium focuses on managing symptoms and preventing further exposure:

  • Remove from Exposure: Immediate removal from the source of selenium exposure is crucial.
  • Symptomatic Treatment: Providing medications to manage respiratory, gastrointestinal, and neurological symptoms. Topical treatments for skin irritation and lesions.
  • Supportive Care: Including hydration, nutritional support, and monitoring of liver and kidney function.
  • Chelation Therapy: In cases of severe poisoning, chelating agents such as dimercaprol may be used to bind selenium and enhance its excretion.
  • Long-term Monitoring: Regular follow-up to monitor lung function, liver and kidney health, and overall health status.

7. Prevention

Preventing diseases caused by selenium involves implementing strict control measures in the workplace:

  • Engineering Controls: Using local exhaust ventilation, enclosed processes, and proper maintenance of equipment to reduce airborne exposure to selenium dust and fumes.
  • Work Practices: Implementing safe work practices such as proper handling and disposal of selenium-containing materials, and avoiding eating, drinking, or smoking in areas where selenium is used.
  • Personal Protective Equipment (PPE): Providing and ensuring the use of appropriate respirators, protective clothing, gloves, and eye protection.
  • Health Surveillance: Regular health screenings, including pulmonary function tests, liver and kidney function tests, and monitoring of selenium levels in blood and urine for workers exposed to selenium.
  • Education and Training: Informing workers about the hazards of selenium and safe work practices to minimize exposure.

Workplace Exposure Limits:

  • OSHA PEL (Permissible Exposure Limit):

    • Time-Weighted Average (TWA): 0.2 mg/m³ (as Se).
  • NIOSH REL (Recommended Exposure Limit):

    • TWA: 0.2 mg/m³ (as Se) (averaged over a 10-hour workshift).