Pollution & Human Health (College Board AP® Environmental Science): Study Guide

Human health & pollution

• A cause-and-effect link between pollution and health problems in people is difficult to establish because people are exposed to many different chemicals and pollutants

• Some sources of pollution (e.g. factories and vehicle exhaust) release more than one chemical into the air and any one of these pollutants could be a disease-causing agent

• Furthermore, other variables, such as genetics, exposure rates and time since the exposure, may be the cause of the illness

• This is why it is difficult to prove that certain pollutants are the cause of certain diseases

• In other cases, the link is relatively straight forward, such as dysentery, cholera, or typhoid from drinking contaminated water

Dysentery

• Dysentery is a type of contagious gastrointestinal infection characterized by the presence of bloody diarrhea

• The condition is caused by the presence of bacteria or parasites in food or water that has been contaminated

• It can also occur from touching surfaces that are contaminated and subsequently touching your mouth

• Symptoms include:

  • abdominal pain

  • cramping

  • very loose and bloody stools

  • fever

  • nausea

  • vomiting

• Dysentery primarily affects developing countries where sanitation conditions are poor

• However, it also occurs in the United States, impacting around 450,000 individuals annually

• Dysentery poses significant risks, particularly for young children and individuals who have compromised immune systems

• According to the World Health Organization, over 1.1 million people die each year from dysentery

Types of dysentery

• Dysentery can be categorized into two primary types depending on the specific microorganism responsible for the infection

• The approach to treatment will depend on the specific type of dysentery diagnosed

Amoebic dysentery (amoebiasis)

• The single-celled parasite Entamoeba histolytica (E. histolytica) is the main cause of amoebic dysentery

• This form of dysentery is more prevalent in tropical regions, especially within developing countries

• The infection can be transmitted via food and water that are contaminated with the parasite

• Additionally, it can spread through contact with contaminated surfaces or feces from an infected individual, followed by touching your mouth

Bacillary dysentery

• Bacillary dysentery is the most common form of dysentery caused by a bacterial infection

• The most common bacteria responsible for bacillary dysentery are Shigella, Salmonella, Campylobacter, and Escherichia coli, commonly referred to as E. coli

Treatment

• Without proper treatment, dysentery may be fatal

• Treatment typically includes antibiotics or antiparasitic drugs, as well as fluid replacement to prevent dehydration

• To prevent the spread of dysentery, there should also be access to clean water and improved sanitation

Mesothelioma

• Mesothelioma is an uncommon and highly aggressive type of cancer, primarily resulting from exposure to asbestos

• Asbestos is a mineral that occurs naturally and was commonly utilized in construction materials and various industrial products until the 1970s

• It was during this time that the connection between asbestos exposure and serious health issues, such as mesothelioma, became recognized

• Asbestos exposure occurs when individuals inhale asbestos fibers

• These fibers can settle in the lining of the lungs and other organs, which results in the development of mesothelioma

• The latency period for mesothelioma can be several decades, showing that symptoms might not manifest until many years following the initial exposure to asbestos

• Asbestos is the main cause of mesothelioma; however, there are other types of pollution that lead to the development of this disease

• For instance, exposure to forms of silica dust and diesel exhaust raises the risk of developing mesothelioma

Treatment

• Mesothelioma is an aggressive cancer that spreads quickly

• For most people, there is no cure, as diagnosis usually occurs past the point where surgery can remove it

• Treatment can include:

  • surgery

  • palliative care

  • chemotherapy

  • radiotherapy

  • immunotherapy

  • targeted therapy

  • clinical trials

Respiratory problems

• To gain energy from food, an organism converts glucose and oxygen into carbon dioxide and water through the process of respiration

• In mammals and other animals, this process occurs in the lungs, where oxygen is inhaled and carbon dioxide is released

• Respiration occurs in two stages: aerobically and anaerobically

• Aerobic respiration is a biochemical process where cells utilize oxygen to generate energy

• This process takes place in the mitochondria, which leads to the production of carbon dioxide and water as byproducts

• Anaerobic respiration is when cells generate energy without oxygen and lead to the formation of lactic acid or ethanol as a by-product

• Respiration is necessary for all living things to generate energy for various functions

  • In humans, the respiratory system is the nose, trachea, bronchi, and lungs

  • The diaphragm, a muscle at the base of the lungs, is essential for breathing

  • Contracting and relaxing the diaphragm helps bring air into the lungs

• Respiratory dysfunction can cause serious health problems

• Hypercapnia is an excess of carbon dioxide in the blood, while hypoxia is a lack of oxygen

• Asthma, COPD, and lung cancer all affect respiration

Troposhperic ozone

• The troposphere, the lowest atmospheric area nearest to Earth, contains tropospheric ozone

• It differs from stratospheric ozone, which naturally protects the Earth from ultraviolet radiation in the upper atmosphere

• Tropospheric ozone is caused by chemical reactions between pollutants from vehicles, power plants, and industrial emissions and natural volatile organic compounds (VOCs) like tree and plant VOCs

• These reactions occur in sunlight

• Urban and industrial areas have the highest tropospheric ozone levels

• Tropospheric ozone can further damage patients with respiratory disorders like asthma and emphysema

• It also harms crops, forests, and other natural resources

• Controlling emissions from industrial facilities, cars, and power plants and increasing public transit, biking, and walking can reduce tropospheric ozone pollution

• Increasing energy efficiency, renewable energy, and sustainable land use can also reduce tropospheric ozone generation