Cadmium: Overview and Structure

Cadmium: Overview and Structure

**Cadmium (Cd)** is a chemical element with the atomic number 48. It is a soft, bluish-white metal that is chemically similar to zinc and mercury. Cadmium typically occurs in zinc ores and is a byproduct of zinc production.

Structure:

- **Atomic Number:** 48

- **Atomic Weight:** 112.41

- **Electron Configuration:** [Kr] 4d¹⁰ 5s²

- **Crystal Structure:** Hexagonal close-packed (hcp) at room temperature.

Chemical Compounds of Cadmium

Cadmium forms several compounds, the most common of which include:

1. **Cadmium Oxide (CdO):** Used in batteries and electroplating.

2. **Cadmium Sulfide (CdS):** Used as a pigment (cadmium yellow) and in solar cells.

3. **Cadmium Chloride (CdCl₂):** Used in electroplating and in the production of pigments.

4. **Cadmium Nitrate (Cd(NO₃)₂):** Used in dyeing and printing fabrics.

5. **Cadmium Sulfate (CdSO₄):** Used in electroplating and as a laboratory reagent.

Health Hazards of Cadmium

Cadmium exposure can have severe health effects. The major routes of exposure are inhalation, ingestion, and dermal contact. Key health hazards include:

1. **Acute Exposure:**

- **Inhalation:** Can cause flu-like symptoms known as "cadmium blues," including chills, fever, and muscle pain.

- **Ingestion:** High doses can cause severe gastrointestinal irritation, vomiting, and diarrhea.

2. **Chronic Exposure:**

- **Respiratory System:** Long-term inhalation can lead to chronic obstructive pulmonary disease (COPD), emphysema, and lung cancer.

- **Kidneys:** Cadmium can cause kidney damage and dysfunction, leading to proteinuria (excess protein in urine) and renal failure.

- **Bones:** Can result in osteomalacia and osteoporosis, making bones weak and brittle.

- **Carcinogenicity:** Classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC), meaning it is carcinogenic to humans.

Occupational Health: Prevention and Risk Information

In occupational settings, cadmium exposure can occur in industries such as battery manufacturing, metal plating, and pigment production. To minimize risks:

1. **Engineering Controls:**

- Use closed systems for processes involving cadmium.

- Install local exhaust ventilation to capture cadmium fumes and dust.

- Ensure proper maintenance of ventilation systems.

2. **Administrative Controls:**

- Implement safe work practices and procedures.

- Provide regular training on cadmium hazards and safe handling practices.

- Conduct routine environmental and biological monitoring to assess exposure levels.

3. **Personal Protective Equipment (PPE):**

- Use appropriate respirators to prevent inhalation of cadmium dust or fumes.

- Wear protective clothing, gloves, and eye protection to prevent dermal exposure.

4. **Hygiene Practices:**

- Prohibit eating, drinking, or smoking in areas where cadmium is handled.

- Provide facilities for workers to wash hands and face before breaks and at the end of the shift.

- Implement procedures for safely handling and disposing of cadmium-containing waste.

Health Impacts in Occupational Health

- **Monitoring and Medical Surveillance:**

- Regular health check-ups for workers exposed to cadmium, focusing on kidney and lung function.

- Biological monitoring of cadmium levels in blood and urine.

- **Regulations and Guidelines:**

- Adhere to occupational exposure limits set by agencies such as OSHA (Occupational Safety and Health Administration) and ACGIH (American Conference of Governmental Industrial Hygienists).

- Follow guidelines and recommendations from NIOSH (National Institute for Occupational Safety and Health) and WHO (World Health Organization).

Summary

Cadmium is a hazardous metal with significant health risks, particularly in occupational settings. Proper preventive measures, including engineering controls, administrative controls, PPE, and stringent hygiene practices, are essential to protect workers from cadmium exposure and its associated health impacts. Regular monitoring and adherence to regulatory guidelines are critical components of an effective occupational health program for cadmium.

Dr Aravind Reddy