Effects of Natural Disasters on Environment
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Effects of Natural Disasters on Environment Natural disasters can contribute to the transmission of some diseases, especially since water supplies and sewage systems may be disrupted, sanitation and hygiene may be compromised by population displacement and overcrowding, and normal public health services may be interrupted. Disease Risks The risk for infectious diseases among travelers to affected areas is minimal unless a disease is endemic in an area before the disaster, since transmission cannot take place unless the causative agent is present. Although typhoid can be endemic in developing countries, natural disasters have seldom led to epidemic levels of disease. Floods have been known to prompt outbreaks of leptospirosis and cholera in areas where the organism is found in water sources (see the Leptospirosis and Cholera sections in Chapter 3). When water and sewage systems have been disrupted, safe water and food supplies are of great importance in preventing enteric disease transmission. If contamination is suspected, water should be boiled and appropriately disinfected (see the Water Disinfection for Travelers section earlier in this chapter). Travelers who are injured during a natural disaster should have a medical evaluation to determine what additional care may be required for wounds potentially contaminated with feces, soil, or saliva, or that have been exposed to fresh or sea water that may contain parasites or bacteria. Tetanus booster status should always be kept current. Various vaccine-preventable diseases have been eliminated or are near elimination in some developing countries. However, if someone who has the disease travels to the country, there is a risk of reintroducing those diseases, leading to an outbreak. Therefore, it is very important that people traveling to offer relief or other services in countries affected by natural disasters be protected against such diseases. Injuries
After a natural disaster, deaths are rarely due to infectious diseases and are most often due to blunt trauma, crush-related injuries, or drowning. Travelers should thus be aware of the risks for injury during and after a natural disaster. In floods, people should avoid driving through swiftly moving water. Travelers should exercise caution during clean-up, particularly when encountering downed power lines, water-affected electrical outlets, interrupted gas lines, and stray or frightened animals. During natural disasters, technological malfunctions may release hazardous materials (such as release of toxic chemicals from a point source displaced by strong winds, seismic motion, or rapidly moving water). Floods Physical damage - Can damage any type of structure, including bridges, cars, buildings, sewer systems, roadways, and canals. Casualties - People and livestock die due to drowning. It can also lead to epidemics and waterborne diseases. Water supplies - Contamination of water. Clean drinking water becomes scarce. Diseases - Unhygienic conditions. Spread of water-borne diseases. Crops and food supplies - Shortage of food crops can be caused due to loss of entire harvest.[4] However, lowlands near rivers depend upon river silt deposited by floods in order to add nutrients to the local soil. Trees - Non-tolerant species can die from suffocation.[5] Tertiary/long-term effects Economic - Economic hardship, due to: temporary decline in tourism, rebuilding costs, food shortage leading to price increase ,etc. 26th Flood July Mumbai Mumbai came to an abrupt halt on 26th July, as unprecedented heavy rains Opening of bank accounts made easy for the flood affected persons . Limnic Eruptions Consequences Once an eruption occurs, a large CO2 cloud forms above the lake and expands to the neighbouring region. Because CO2 is denser than air, it has a tendency to sink to the
ground while pushing breathable air up. As a result, life forms that need to breathe oxygen suffocate once the CO2 cloud reaches them, as there is very little oxygen in the cloud. The CO2 can make human bodily fluids very acidic, potentially causing CO2 poisoning. As victims gasp for air they actually hurt themselves more by inhaling the CO2 gas. At Lake Nyos, the gas cloud descended from the lake into a nearby village where it settled, killing nearly everyone. In this eruption, some people as far as 25 km (15.5 miles) from the lake died. A change in skin color on some bodies led scientists to think that the gas cloud may have contained a dissolved acid such as hydrogen chloride as well, but that hypothesis is disputed.[4] Many victims were found with blisters on their skin. This is believed to have been caused by pressure ulcers, which are likely to have formed from the low levels of oxygen present in the blood of those asphyxiated by the carbon dioxide. [5] Thousands of cattle and wild animals were also asphyxiated, but no official counts were made. On the other hand, vegetation nearby was mostly unaffected except for that which grew immediately adjacent to the lake. There the vegetation was damaged or destroyed by a 5-meter (16.4 ft.) tsunami from the violent eruption.
After a natural disaster, deaths are rarely due to infectious diseases and are most often due to blunt trauma, crush-related injuries, or drowning. Travelers should thus be aware of the risks for injury during and after a natural disaster. In floods, people should avoid driving through swiftly moving water. Travelers should exercise caution during clean-up, particularly when encountering downed power lines, water-affected electrical outlets, interrupted gas lines, and stray or frightened animals. During natural disasters, technological malfunctions may release hazardous materials (such as release of toxic chemicals from a point source displaced by strong winds, seismic motion, or rapidly moving water). Floods Physical damage - Can damage any type of structure, including bridges, cars, buildings, sewer systems, roadways, and canals. Casualties - People and livestock die due to drowning. It can also lead to epidemics and waterborne diseases. Water supplies - Contamination of water. Clean drinking water becomes scarce. Diseases - Unhygienic conditions. Spread of water-borne diseases. Crops and food supplies - Shortage of food crops can be caused due to loss of entire harvest.[4] However, lowlands near rivers depend upon river silt deposited by floods in order to add nutrients to the local soil. Trees - Non-tolerant species can die from suffocation.[5] Tertiary/long-term effects Economic - Economic hardship, due to: temporary decline in tourism, rebuilding costs, food shortage leading to price increase ,etc. 26th Flood July Mumbai Mumbai came to an abrupt halt on 26th July, as unprecedented heavy rains Opening of bank accounts made easy for the flood affected persons . Limnic Eruptions Consequences Once an eruption occurs, a large CO2 cloud forms above the lake and expands to the neighbouring region. Because CO2 is denser than air, it has a tendency to sink to the
ground while pushing breathable air up. As a result, life forms that need to breathe oxygen suffocate once the CO2 cloud reaches them, as there is very little oxygen in the cloud. The CO2 can make human bodily fluids very acidic, potentially causing CO2 poisoning. As victims gasp for air they actually hurt themselves more by inhaling the CO2 gas. At Lake Nyos, the gas cloud descended from the lake into a nearby village where it settled, killing nearly everyone. In this eruption, some people as far as 25 km (15.5 miles) from the lake died. A change in skin color on some bodies led scientists to think that the gas cloud may have contained a dissolved acid such as hydrogen chloride as well, but that hypothesis is disputed.[4] Many victims were found with blisters on their skin. This is believed to have been caused by pressure ulcers, which are likely to have formed from the low levels of oxygen present in the blood of those asphyxiated by the carbon dioxide. [5] Thousands of cattle and wild animals were also asphyxiated, but no official counts were made. On the other hand, vegetation nearby was mostly unaffected except for that which grew immediately adjacent to the lake. There the vegetation was damaged or destroyed by a 5-meter (16.4 ft.) tsunami from the violent eruption.
