Occupational Hazards and Environmental Health
Agents of Occupational Disease
Noise, Dusts, Toxic heavy metals and their fumes, Carbon monoxide, Chemicals, Ionizing radiation, Microbial agents, Lifting heavy weights, Repetitive motion, Accidents
Diseases and conditions associated with occupational hazards:
- Allergic and irritant dermatitis
- Respiratory diseases (e.g., chronic obstructive pulmonary disease, asthma)
- Fertility and pregnancy abnormalities
- Hearing loss caused by noise
- Infectious diseases
- Musculoskeletal disorders
- Traumatic injuries and fatalities
- Conditions associated with job stress
Prevention of Occupational Disease and Disability
Engineering controls:
- Quieter machinery
- Installation of protective guards
- Improved building ventilation
Administrative controls:
- Organization of work shifts and rotation of employees
Modification of work practices:
- Safety education and training programs
Radiation
Types of Radiation:
- Non-Ionizing: sun, tv, microwave
- Ionizing: medical X-rays
Half-life:
The amount of time it takes for a given isotope to lose half of its radioactivity
Elements of Radiation Protection:
- Time that a person is exposed to ionizing radiation
- Shielding used to protect a person
- Distance between a person and a radioactive substance
Radon:
A radioactive gas that comes from the normal decay of uranium found in nearly all soils and water. It is part of the background radiation you receive every day.
Injury Prevention
Causes of Injuries:
- Mechanical Energy (moving objects)
- Thermal
- Electric
- Chemical
- Radiation
Leading Causes of Unintentional Injuries in the United States:
- Transport-related
- Poisonings
- Falls
Leading Cause of Unintentional Injury by Age Group:
- Suffocation
- Drowning
- Car crash
- Poisoning
- Falling
Components of Injury Control:
- Monitor incidence
- Identify risk factors
- Intervene
- Evaluate
Waste Management
Types of Waste:
- Solid waste: any unwanted or discarded material we produce that is not a liquid or a gas (e.g., packaging, appliances, organic materials, food waste, papers, electronics)
- Hazardous waste: threatens human health or the environment because it is poisonous, dangerously chemically reactive, corrosive, or flammable (e.g., industrial solvents, hospital medical waste, car batteries, household pesticide products, dry-cell batteries, ash from incinerators and coal-burning power plants)
Source Reduction Priorities:
- Reduce packaging materials
- Make products last longer
- Reuse, repair, recycle, compost
- Buy reusable/recyclable products
Importance of Recycling:
- Reduces emissions of greenhouse gases
- Prevents pollution generated by the use of new materials
- Decreases the amount of materials shipped to landfills
- Preserves natural resources
- Opens up new manufacturing employment opportunities
- Saves energy
Landfills:
Landfills are designed with a clay bottom sealed with plastic to hold toxic chemicals. A sump collects leachates, and garbage is piled in rows, compacted, and covered with soil. Decomposition of materials produces methane gas. Megafills can handle 5,000-10,000 tons of trash per day.
Water Pollution
Hydrological Cycle:
Water evaporates from the ocean, water vapor condenses to form clouds, moisture is transported and returns to the surface as precipitation.
Types of Surface Water:
- Surface water: natural sources like rivers, lakes, streams, ponds, and oceans (typically dirtier)
- Groundwater: stored below ground in aquifers (typically cleaner)
Human Impacts on Water:
Quantity:
- Hydrology changes: construction of structures like dams, levees, culverts, and canals to redirect water movement and for flood protection
- Reservoirs: built for water storage
- Pumping: groundwater may be pumped for agricultural use, industry, or potable purposes
Quality:
- Chemical contamination
- Point source pollution: directly discharged from a pipe or lagoon, typically industrial pollution
- Non-point source pollution: from water draining over a broad area, across parking lots, urban areas, and agricultural fields
Routes of Exposure to Water Contaminants:
- Ingestion (drinking, cooking)
- Dermal absorption (bathing)
- Inhalation (volatile organic chemicals while showering)
Water Protection Laws:
- The Clean Water Act: regulates pollution discharges to natural water bodies
- Safe Drinking Water Act: regulates contaminants in drinking water that might pose a threat to human health
Foodborne Illness
Common Causative Agents:
- Salmonella Typhi
- Escherichia coli
- Norovirus
- Pesticides
Outbreak vs. Cluster:
- Outbreak: two or more cases of a similar illness
- Cluster: more cases than expected in a geographical area
Food Safety Roles:
- Epidemiologist: analyzes data
- Public health nurse: interviews patients
- Lab investigator: interprets test results
- Environmental health investigator: focuses on food
- FDA: food regulation
- USDA: meat and poultry
Food Additives and the Delaney Clause:
The Delaney Clause prohibits the approval of food additives that have been shown to cause cancer in humans or animals. This clause is part of the Food Additives Amendment of 1958 to the Federal Food, Drug, and Cosmetic Act. The Food Quality Protection Act of 1996 amended the Delaney Clause to allow for negligible risk considerations.