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close this bookAssessing Needs in the Health Sector after Floods and Hurricanes (PAHO)
View the document(introductory text...)
View the document1. Introduction
View the document2. Critical decisions
View the document3. Magnitude of the impact
View the document4. Morbidity and mortality
View the document5. Environmental sanitation
View the document6. Vectors
View the document7. Food and nutritional status
View the document8. Evacuation camps
View the document9. The health center
View the document10. Surveillance systems
View the documentBibliography

5. Environmental sanitation

Major disasters often damage basic sanitation services, including the provision of potable water and the disposal of excrete and solid wastes. This may cause an increase in waterborne diseases as well as a proliferation of flies, mosquitoes, and rats. Problems may also arise from overcrowding in evacuation settlements, poor food hygiene, and human and animal corpses.


Water distribution to the population can be hampered either by the physical destruction of water treatment plants, systems, or wells that occurs during earthquakes, or by the comparatively slight damage to the network inflicted by floods. Floods tend to leave large volumes of solid matter in suspension in the plant's water source, making its purification impossible. Therefore the assessment team must check both the water intake duct and the filters themselves for blockage. In addition, because water treatment plants are frequently located near rivers, the plant's foundations should be inspected for erosion. Even if the water service has not been interrupted, there may be cross-contamination from the sewerage systems due to breaks in the network.

When the community water supply comes from a well, physical damages and the possibility of contamination must also be considered. The latter is less likely in deep wells where the soil itself acts as a filter, but the possibility should be verified nonetheless. Sometimes well water is connected to the general system, so that it mixes with water from other sources that may be contaminated. When wells are linked to the general system, power failures and physical damage may also cause contamination of the well through siphonage.

It is extremely difficult to establish a minimum depth for a well that would preclude concern about the possibility of seepage. Numerous factors are involved, such as distance from a possible source of contamination located on higher ground than the well, the kind of soil, and the possible stagnation of sewage in the vicinity of the well.

In many communities, particularly in rural areas, the purity of the drinking water is questionable; the water is often given no treatment whatsoever. For example, in rural areas it is not unusual for the water supply to be pumped directly from a lake into the water system. Flooding such as that caused by the "El Niño" phenomenon would probably not worsen the quality of this water; in fact, floods might bring about dilution, resulting in a decrease in the dose of microorganisms (Levis, 1984). In any case, it must be verified that no new focal points of contamination have been created.

Sources of Information

Frequently more than one ministry is involved in water supply, and different institutions may be responsible at different stages of the supply. The team must determine which institutions are responsible for the water source (e.g., wells, rivers), the treatment plants, maintenance of the distribution network, quality control, and so forth.

Usually the team can get information from the ministries of health, housing, and public works; the municipality; and sometimes private housing development firms.

A. At the community level:

If there is a sanitary engineer or health inspector working in the community, he or she will know the location of the water source and potential contamination sites in the network. The engineer or inspector will probably have records on the water quality over a period of time, as well as drawings and maps of the network.

B. Municipality

If there is no engineer or health inspector, the official in charge of public works may have the information indicated in A.

C. Water quality control

Many places have a regular system to monitor residual chlorine and the bacteriological content of the water. This system may or may not be under the Jurisdiction of the health department. In any case, if the system exists, the assessment team should check water samples for changes that may be related to the disaster. If there is no monitoring system, it should be established as soon as possible.

D. In the absence of any information:

In this event the team must make a quick survey of the affected area to find out:

1) Where is the source of water?

2) How is the water distributed to the community?

- piped to the house?
- public standpipe?
- water distribution trucks?

(In the last two cases it is important to know how the water is stored in the homes, as it may become contaminated there. The inhabitants should be asked if they have seen any broken mains and, if so, where. This information could also come from the health worker at the health center.)

Once the data is obtained, the team should check some of the reported damages or points where there may be cross-contamination from either the sewerage system or some other source and assess the probability of contamination.

In flood areas that normally have access to treated water, the assessment team will have to take water samples at different sites to test for residual chlorine and the presence of coliforms.

E. Water treatment plant:

If the community's water supply comes from a plant, it should be checked for structural and component damage or any interruption of its function from other causes. There is usually a plant operations book or register in which details about the plant's functioning are entered every day or several times a day (e.g., liters/second, interruptions, chlorine content). From this the team can detect any changes that are attributable to the disaster. The interruptions may be due to electric power failures; the plant may have a generator that was damaged or lacks fuel. If the plant operator has not already done it, he should be asked to prepare a detailed damage report.

F. Wells:

If wells are the source of water, they should be inspected for damage to elements such as the structure, components, generator, and tanks. There will probably also be a corresponding operations book; the well operator should be asked to prepare a detailed report. To determine the possibility of contamination, the assessment team must gauge the depth of the well, type of soil, proximity to possible sources of contamination, ruptures of the sewerage system, and so forth.

G. Other sources:

Other water sources, such as rivers and ravines, should also be checked. Even if the water purification system is not highly sophisticated, the team must look for new sources of contamination such as the flooding of septic pits and sewerage overflow. Water truck distribution also deserves special attention. The water in the tank may not only get contaminated en route or at an inadequate source (Fig. 5.2), but the tank itself may be contaminated after being used to transport toxic substances.


In addition to the water supply, the disaster may also affect the sewerage system, either by structural damage, breaks in the network, electric power failures, main blockage from debris, or flooding of the mains and septic pits with consequent sewage overflow.

It is important to determine where the effluent goes, as plant malfunction may result in the discharge of untreated sewage into rivers or canals and eventually contaminate sources of drinking water.

Sources of Information

A. Municipal officers, for example, a public works official (he may have maps of the sewerage system and may already have damage reports).

B. Visits to the plants and quick surveys of the most affected communities to observe possible damage.


Proper solid waste disposal systems are nonexistent in most Latin American countries. In urban centers, garbage is usually collected and transported to a dumping ground for burning; however, absolute combustion is never achieved, partly because the garbage is not sorted. Sometimes local authorities have the rubbish buried, but, on the whole, very few Latin American countries have proper sanitary landfills for adequate solid waste disposal.

Under these circumstances it is easy to imagine how a disaster may affect an already unsatisfactory system. Floods may unearth buried rubbish and carry it to the rivers or other possible sources of drinking water. Rain or floodwater may accumulate in discarded tins and old tires. The normal system of rubbish collection will probably be interrupted by the disaster-be it a flood, hurricane, or earthquake-and the disaster itself may add more rubbish and debris. The problem may be similar to that of some settlements after the Popayán earthquake in 1983; garbage containers and collection trucks had been provided, but the trucks could not get to the containers during the rainy season because the improvised settlement roads were not paved.

Accumulated solid waste creates a public health problem: it is an excellent breeding site for flies, mosquitoes, and rats and attracts dogs and other animals, increasing the risk factors for disease transmission.

Sources of Information

A. A visit to the dump or sanitary landfill. This will reveal both its capacity as a breeding ground and its distance to human habitation; the community's exposure to the vectors can then be deduced.

B. Local authorities. Municipalities are usually responsible for waste collection and disposal; the official in charge should have an assessment of conditions.

C. Observation of community conditions (such as accumulated garbage in the streets and the presence of flies, dogs, and rats).


Some disasters may cause migration of population groups, either because their lives are in danger or because their homes have been destroyed. Other scenarios result in migration because people have lost the normal means of earning a livelihood and are looking for work or food. In most disasters a number of new human settlements emerge, most of which are unauthorized. They tend to be located in inappropriate and insecure areas, where there is danger of landslides or sudden floods. They usually have no treated water supply, and rely on rivers, ravines, and sometimes even on the sewage system. Nor do they have a system of waste disposal or sewerage. The building materials and lighting system used frequently pose fire hazards.

These places require epidemiological and environmental surveillance, as they are a potential source of health problems.

Sources of Information

The municipal authorities, civil defense, Red Cross, and frequently the environmental sanitation section of the local health department have information on the number of settlements, their location, the number of residents, and the sanitary conditions.


When the disaster causes frequent interruptions in the supply of electric power, frozen foods repeatedly thaw and freeze, eventually spoiling. The assessment team should investigate, and recommend that a monitoring system be set up.

Kitchens in evacuation camps and at emergency meal distribution points require special surveillance for a refrigeration system, pest-proof storage, facilities for washing utensils, and garbage disposal.

When foods are cooked in a central kitchen for distribution to the evacuation camps, the possibility of spoilage during transport should be considered.

Food contamination can occur in public markets when they are flooded with sewage water. In addition, lapses in garbage collection, the presence of pests, and lack of water for personal and utensil cleaning increase the possibility of contamination.

Pollution with pesticides or other chemicals while food is in transit or stored should not be overlooked.

Sources of Information

In order of priority, the assessment team should make quick survey visits to some evacuation camps, kitchens, meal distribution sites, emergency' kitchens, markets, and storage places. The health inspector will be the person to provide information on these areas, but health center personnel may also have noticed any outbreaks of food poisoning.


The presence of dead bodies, human or animal, always causes anxiety among the population, and newspaper headlines about epidemics created by corpses are common. In fact, the psychological problem is greater than that of health. If people who died in disasters had not been suffering from communicable diseases, as is generally the case, they do not represent an urgent public health problem. In theory, the proximity of the bodies to water sources may cause contamination by coliforms, and eventually also the proliferation of synanthropic flies, but it is highly doubtful that corpses represent a greater risk than do other side effects of a disaster. The disposal of bodies should take second priority to the needs of the living.

An earthquake may disinter bodies, as happened in Popayán in March 1983, or a cemetery may be flooded, as occurred in Ecuador in 1983, but this does not represent a serious health problem. However, health authorities may be forced to take some measures in order to calm the population. Burning is never a satisfactory system of disposal. It takes a vast amount of fuel and may even be dangerous. The most satisfactory disposal method is burial, although this may be difficult in terrain that has been flooded for months, for example, in Bolivia in 1982 when thousands of cattle died. Special flame-throwers can be used for a large number of animal carcasses. Throwing lime on corpses has no effect other than psychological among the population (it was done for this reason in the cemetery of Popayán

Sources of Information

The mood of the population can be often be gauged from the newspapers. In addition, local health authorities will have received complaints from community leaders.

A quick survey of the community will reveal the extent of the problem and whether the bodies represent a serious health problem, particularly if they are close to or in the water supply.

Public works officers will know whether adequate machinery is available for large excavation and mass burial. It is also important to know whether there are disaster provisions in the law for the disposal of bodies without previous identification and postmortem.


Water Supply

Basic questions

· Has the disaster affected the water supply?

- Is there structural damage?
- Is there functional damage?

· Has the disaster affected the water quality?

· What are alternative means of supply?

· What equipment is needed for restoration of the supply?

Sources of information

· Organizations responsible for the supply

- Ministry of health
- Ministry of housing
- Public works
- Municipality
- Housing development

· At community level

- Sanitary engineer
- Public health inspector
- Official in charge of public works

· In the absence of information

- Quick community survey

* where does the water come from?
* how is the water distributed to the community?
* how is the water stored in the homes?
* are there rumors of breaks in the system? (If yes, visit)
* samples of water: residual chlorine coliforms

Water treatment plant

· Physical damage to the structure
· Plant operations book
· Interruption of service
· Interruption of electric power


· Damages to physical structure
· Operations book
· Depth of well
· Proximity to potential sources of contamination
· Type of soil
· Breaks in sewerage system

Other water sources

· Sources of contamination
· Overflowing of pits
· Contamination of water carriers

Sewage Disposal
Basic questions

· How has the disaster affected sewage disposal?

- Structural/physical damage
- Functional damage

* blockage of the network
* overflowing of septic pits

· Is it creating a public health hazard?

· What equipment is needed for restoration?

Sources of information

· Public works official at the municipality
· Visit to the plant
· Survey of the area

Solid Waste Disposal

Basic questions

· How has the disaster affected the normal waste disposal system?
· How is the sanitary landfill or dump being affected?
· What is the potential health hazard?
· What new waste has been originated by the disaster?
· What equipment is required to solve the problem?

Sources of information

· Municipality
· Visit to the dump
· Observation of the community

- Accumulation of rubbish
- Stray animals
- Flies

Human Settlements

Basic questions

· Is the disaster creating migration/evacuation of large human groups?
· Are new settlements being created?
· What are the sanitary/health conditions in these settlements?
· What are the potential health problems in the settlements?

Sources of information

· Municipal authorities
· Civil defense
· Red Cross
· Environmental officer at local health department

Food Hygiene

Basic questions

· Is the disaster creating food hygiene problems?
· Is the central kitchen hygienic?
· Is the food being contaminated "en route"?
· Is environmental sanitation in the markets satisfactory?
· Is the donated/received food inspected?

Sources of information
· Local health authorities
· Inspection
· Central kitchen
· Emergency kitchens
· Markets
· Food storage depots
· Occurrence of food-borne disease outbreaks


Basic questions.

· Are there a large number of unburied bodies?
· Are they close to/in sources of water?
· What are the legal regulations for disposal of bodies?
· What are the local customs for disposal of bodies?

Sources of information

· Local health authorities
· Registries of births and deaths
· Hospital/police/municipal morgues
· Inspection/quick survey