Human Health and Environmental Impact: A Comprehensive View
Human Health and Disease
The World Health Organization (WHO) defines health as a state of complete physical, mental, and social well-being, not merely the absence of disease. Given the agent that causes disease, diseases can be classified into:
- Infectious
- Non-infectious
Infectious Diseases
Infectious diseases are caused by a pathogen that enters the body and, in most cases, can spread to other people.
Non-infectious Diseases
In non-infectious diseases, a living organism is not directly involved in their origin.
How Infectious Diseases Spread
There are several routes of transmission of pathogens. The most common are:
- Across the water: The use of water contaminated with microorganisms for human consumption causes diseases such as cholera.
- Through food: Deficiencies in food preservation can cause salmonellosis.
- Through the air: Micro-droplets of moisture or dust containing airborne microorganisms from persons, which produce diseases such as influenza, colds, measles, and tuberculosis.
- Through skin wounds: Any break in the skin is a portal of entry for microorganisms existing in their own skin, in the object that caused the wound, on clothing, or on the floor, like those that cause tetanus.
- Sexually transmitted diseases like AIDS, syphilis, and hepatitis B.
- Through animals such as lice, fleas, mosquitoes, and flies that contain microorganisms transmitted to humans through bites or food contamination and can cause diseases such as malaria and sleeping sickness.
Immune System
Living beings have developed an intricate network of defenses to prevent the entry of microorganisms such as viruses, bacteria, protozoa, fungi, or molecules produced by them. These defenses can be:
- External barriers
- Skin
- Mucous membranes
- Secretions
The skin and mucous membranes are the first defensive structures of an organism. The skin is a very effective barrier because microorganisms can pass through only if there is a breakage or injury. The mucous membranes are much more fragile. But in body openings, the mucous cells that cover them produce secretions with antimicrobial activity. For example, in the eyes, lacrimal glands secrete a substance with tears, lysozyme, which prevents the development of bacterial cells. Specialized cells secrete mucus, trapping solid particles that may have entered with inspired air. At the same time, the movement of the cilia pushes all this material to the exterior.
Phagocytes: The Body’s Second Line of Defense
The second barrier of defense that a microorganism encounters after overcoming external barriers such as skin and mucous membranes is formed by cells that “ingest” foreign elements, treating them as if they were food and subsequently destroying them.
Environment
The environment encompasses all physical, chemical, biological, and social factors and their interactions. The environmental impact is the effect of particular human actions, either directly or indirectly, on the environment in its various aspects. Environmental problems are the attacks that originate from environmental impact, creating situations that adversely affect humans or ecosystems.
Resources
A resource is any natural component, whether matter or energy, that is of interest for human use.
- Renewable resources: Regenerate after use.
- Non-renewable resources: Cannot regenerate, or their renewal rate is very slow.
- Renewable material: High renewal rate, e.g., fishing.
- Non-renewable material: Renewal rate is low or negligible, e.g., minerals.
- Renewable energy: From natural sources or high renewal, e.g., solar, biomass.
- Non-renewable energy: Energy source with a low or negligible renewal rate, eventually becoming exhausted.
Pollution
Pollution is an undesirable change in the characteristics of air, water, or soil that affects the health, survival, or activities of living things. Examples include chemicals or physical substances like CFCs and toxic nuclear waste.
Water Treatment
Water treatment, also known as purification, involves the following steps:
- Pre-treatment: Water is filtered.
- Primary sedimentation: Small solid matter settles at the bottom, forming sludge.
- Treatment regimen: Organic matter is digested by microorganisms.
- Secondary sedimentation: Sludge and water are separated.
- Sludge treatment: Sludge is treated for use as fertilizer.
Greenhouse Gases
Greenhouse gases like water vapor, CO2, NO2, and NO3 let in light and heat but prevent heat from escaping.
Acid Rain
Acid rain is formed when sulfur oxides and nitrogen expelled by the burning of coal and oil react with water vapor to form acids. When it rains, it produces acid rain.
Ozone Layer Depletion
Ozone (O3) is a gas that prevents harmful UV radiation from reaching living beings. CFCs destroy O3.
Soil
Soil is a mixture of inorganic materials (fragments of minerals and rocks), decaying organic matter, water, air, and millions of living organisms. Ground is the resource.
Soil Degradation and Loss
- Deforestation: Caused by indiscriminate logging or fire.
- Overexploitation of crops: Soil impoverishment and abuse of fertilizers that pollute the soil.
- Overgrazing: Excessive consumption of pasture by cattle, leaving the soil unprotected.
- Expansion of urban areas: Involves the development of transport networks.
Desertification
The factors mentioned above cause desertification. To prevent soil loss, it is necessary to reduce deforestation and overgrazing, protect vegetation, and promote reforestation.
Causes of Environmental Impacts
- Population
- Consumption
- Technology
Individual Solutions
- Reduce consumption of materials and energy.
- Reuse objects, such as using both sides of paper.
- Recycle by depositing garbage in the appropriate container.
Government Action
The government can also act to limit polluting emissions from factories. The population can vote for the political party they deem most suitable to address these issues.