Chemical Agents in the Workplace: Health and Safety

Posted on Dec 12, 2024 in Biology

Comparison of Chemical Agents

  • Fiber and Particle: A fiber has a diameter of less than 1/3 of its length.
  • Gases and Vapors: Gases are substances whose state is a gas under high pressure and temperature. Vapors come from solids or liquids under normal conditions and are now acting on the vapor pressure or temperature.
  • Mists and Fogs: Mists have a size between 0.01 and 10 microns, are produced by condensation of a gaseous state, and fog condensation and disintegration of a liquid. Its size is between 2 and 60 microns.
  • Mutagen Category 1A and Mutagenic Substance of Category 2: Category 1A are substances that are known to be mutagenic, establishing the existence of a cause-effect relationship between exposure and genetic damage. Category 2 substances have potential mutagenic effects in man, but the results of the studies are insufficient for inclusion in Category 1A.
  • External Dose or Exposure and Local Dose: External dose is used for environmental monitoring, and local dose is the absorbed dose that reaches a certain organ or system.
  • Dose-Effect and Dose-Response: Dose-effect is the relationship between exposure to the substance and the intensity of the effect experienced. Dose-response is the relationship between exposure to the substance and the percentage of individuals in the population exposed.

Definitions

  • Respirable Dust: Airborne particulate matter smaller than 5 microns from physical processes of disintegration that can penetrate the alveoli.
  • Asphyxiating Contaminant Simple: This is a contaminant that decreases the concentration of oxygen during breathing.
  • Absorption of a Poison: A toxic substance’s path to the circulatory system after passing through biological membranes.
  • Explosive Substance: Substances and preparations that may explode even without O2.
  • Flammable Substances: Liquid substances and preparations having a low flash point.
  • Occupational Toxicology: Studies the health damage of workers expressed as toxicological processes generated from exposure to chemicals used in the workplace.
  • Biological Half-Life of a Poison: The time needed to halve the amount of a substance. It differs for the same compound as the tissue where it is found. It determines the time that a toxin remains localized in a particular tissue.
  • Absorbed Dose: The amount of poison in the body at any given time due to an external dose of an agent.

Standards

RD 374/2001 of 6 April on…

INSHT Document: Exposure Limits for Chemical Agents

  • How often is the INSHT document “Exposure Limits for Chemical Agents in Spain” published?

Published annually.

Dust Classification by Size

  • What categories is dust classified into according to their size?
    • Visible: > 40 microns
    • Sediment: 10 to 15 microns
    • Inhalable: < 10 microns (can penetrate the respiratory system)
    • Respirable: < 5 microns (can penetrate the alveoli)

Types of Solids Produced by Mechanical Means

  • What types of solids suspended in the air are produced by mechanical means?

Dust and fibers

Types of Toxin Exposure

  • How many types of toxin exposure are there?
    • Acute: Direct contact with the products or very high concentrations.
    • Subacute: Repeated exposure for a period of several days or even weeks.
    • Chronic: Contact with low concentrations of the agent over extended periods of time.

Stages of the PADME Process

  • What stages are in a process called PADME?
    • Penetration: Routes of entry (inhalation, skin, digestive, parenteral, and mucosal).
    • Absorption: Into the circulatory system after passage through biological membranes.
    • Distribution: Some substances exert their effects at points where they enter, and some are transported and exert their effects in other areas or accumulate.
    • Location and Accumulation
    • Biotransformation: Metabolism, the biochemistry of toxic transformation catalyzed by enzymes leading to new inactive substances more or less toxic than the original.
    • Elimination: Excreted.

True or False

  • All substances can be retained in the trachea by the resonant ciliated epithelium. False
  • The skin secretes substances (sweat and oil) that prevent the entry of toxic substances. False, it can increase or decrease.

Factors Influencing Gastric Absorption of Poisons

  • What factors influence the gastric absorption of the poison at work?
    • Degree of solubility of fats
    • Emulsifying effect of bile
    • Stability of toxic
    • Speed through the gut
    • pH of the stomach and intestine
    • Presence of food
    • Possibility of mixing with other compounds
    • Task characteristics

Factors Influencing the Location of Poisons

  • What factors influence the location of the poison?
    • Solubility:
      • Hyposoluble: Retention in many organs.
      • Soluble: Accumulate in organs rich in lipids.
    • Type of Poisoning:
      • Acute
      • Chronic
    • Biological Half-Life

Examples of Chemical Contaminants and Their Effects

  • Give an example:
    • Contaminant Gaseous: Chlorine
    • Contaminant Mist: Sulfuric acid
    • Chemical Pollutants in the Form of Fiber: Asbestos
    • Chemical Contaminant in the Vapor State: Mercury vapor
    • Toxic to the Kidney: Chloroform
    • Toxic to the Liver: Paracetamol
    • Toxic to the Blood: Benzene
    • Impaired Occupational Lung: Asthma
    • Harmful Effects on the Nervous System: Symptoms of Parkinson’s

Biotransformation of Toxins

  • What problem can exist when the biotransformation of a toxic occurs?

The final metabolite may have a toxic effect greater than the original substance.

Excretion Pathways

  • List excretion pathways:

Urinary

Biliary

Stomach

Salivary Glands

Milk

Airway

Stool

Skin

Appendages (hair and nails)

15. Acute, reversible, stochastic, not cumulative, local.