The Assignment Cover Page Share WORLD Open University Malawi Faculty of Health Sciences Department of Health PROGRAMME

The Assignment Cover Page
Share WORLD Open University Malawi
Faculty of Health Sciences
Department of Health
PROGRAMME: PUBLIC HEALTH
YEAR: 2
COURSE NAME: Environmental health
COURSE CODE: PH
TO: Chimwemwe Theu
FROM: Lovemore Alufandika
STUDENT NO: 13BSc02/125PH
ASSIGNEMENT NO: 1A
DUE DATE: 27th August 2017
DATE SUBMITTED: 1st September 2017
Statement on Plagiarism, Collusion & Academic Incompetence
The University unequivocally condemns plagiarism, which it considers to be comparable to falsifying data and cheating in an examination, and warns students that the Academic Board looks gravely upon incidents of plagiarism. Such incidents are classed as Academic Misconduct which results into a student getting a zero grade.

I, Lovemore Alufandika, DECLARE that this work is FREE of plagiarism otherwise I will face consequences thereof if discovered that this work is a ‘cut ; paste’.

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Signed: __________________________ Date:_____________________________
For Lecture’s use only – Marking Guide
Descriptor %Mark Range Student Mark
Work of excellent quality 80% – 100% Work of very good quality 70% -79% Work of good quality 55% – 69% Work of fair but below average quality 50% – 54% Work of marginal quality 45% – 49% Unsatisfactory, failing work 0% – 44% Unjustified absence on failure to hand in assignment work in time 0% Environmental health is the circumstance, object, or conditions by which one is surrounded or is the complex of physical, chemical and biotic factors(as climate change, soil and living things) that act upon organisms or an ecological community and ultimately determine its form and survival. If our focus is on human health, we can consider the environment to be all of the external (or nongenetic) factors. These are biological, chemical, physical, mechanical and psychological factors.

BIOLOGICAL FACTORS
Biological factors include all forms of life, as well as non-living products they produce, and can cause adverse health effects. These hazards are plants, insects, rodents and other animals, fungi, bacteria, viruses and a wide variety of toxins and allegens. The types of biological hazard are called prion which means disease-producing protein particles. Environmental health is largely determined by the health effects of exposure to microorganisms and parasites, whose occurrence and spreading depend on environmental factors.

The biological factors that play a role in the life cycle of the organisms and hazards associated with large species will be treated as an issue of physical safety or as a hazard in transmitting infections. Microorganisms of the concern in environmental health include bacteria, viruses and protozoa like amoeba. Most of these microorganisms and parasites that cause human illness need to grow inside of the human body to cause harm. Bacteria and protozoa can live and multiply outside other living cells, they can survive and multiply for a long period in food and water as long as there are enough nutrients and temperatures are within viability for them. To sustain their life cycle, virus needs to enter either human cells or cells of animals. Many diseases caused by microorganisms are spread directly from one person o another. These diseases are considered person to person environmental health hazards which include tuberculosis, and are greatly increased by poor housing and crowded conditions. The five major infectious killers in the world are acute respiratory infections, diarrhea, tuberculosis measles and malaria. Diseases that can be spread from one person to another are called infectious or communicable disease. They are spread through direct contact between two or more people. Certain bacteria and parasites produce toxins that can cause disease through the poisonous actions. Diseases that are caused by toxins that bacteria produce are not contagious and they do not spread from person to person, but are limited to people who consume the contaminated food. The precautionary measures taken to prevent both bacterial infection and bacterial toxins are the similar or same that is clean food preparation and adequate cookings.

Biological hazards are spread through water that are polluted by human excreta and is the main pathway for the spread of cholera, typhoid fever, dysentery, diarrhea diseases and hepatitis. Inadequate sanitation, dumping of untreated sewages into surface water and poor hygienic practices remain important targets for preventive action in all countries. The complete sewage and water treatment, waterborne diarrhea diseases are prevented. Overcrowding and poor ventilation contribute to airborne transmission of tuberculosis, measles, influenza, pneumonia and sometimes the unhygienic animal husbandry helps to transmit other diseases. Stagnant water, unsanitary housing and refuse dumps are sites that encourage insect production and direct support disease vector. Environmental changes and disturbances to balance of natural habitants may have profound effects on the spread of infectious diseases.
The main exposure routes for biological hazards are air, water, and food. Some parasites enter the body by penetrating the skin and others enter the human body by insect bite. Bacteria and parasites may also spread from contaminated soil to the skin or via dust to the air and others are spread through contact is the important route cause of biological hazards. The spread of microorganism via air mainly occurs with respiration diseases and is in the form of droplets created while coughing or sneezing.

CHEMICAL HAZARDS
A chemical hazard is a type of occupational hazard caused by exposure to chemicals in the workplace. All chemical are toxic to some degree, with health risk being primarily a function of the severity of toxicity and the extent of exposure but most chemicals have not been adequate tested to determine their toxicity (irptc.unep.ch/irptc/databank.html). It is important to distinguish hazard and risk from the term toxicity and this is defined as inherent capacity to cause injury to a living organism that is person, animal and plant. Highly toxic substances will damage an organism even if only amount are present in the body and a substance of low toxicity will not produce an effect unless the concentration in the target tissue is sufficiently high. For the chemical to pose a risk there must be a real or potential exposure to it.

Factors that might be considered when assessing the risk posed by toxic substances include the quantity of substance actually absorbed that is a dose, how the body metabolises the substance, and the nature and extent of the introduced health effect at a given level of exposure that is dose- response or dose-effect relationship. The dose, in turn depends on the route of exposure and the length, duration and frequency of exposure. We must also consider individuals in the population who might be more sensitive to the toxin and whether injury is permanent or reversible. The identification and categorize chemical hazards but to do this knowledge is needed of following: their physical and chemical properties, their route of entry, their distribution and metabolism and the effect they have on body systems. Finally it is also necessary to know how to identify chemical hazards in real setting. There are numerous chemical classification systems available. For those without a basic chemistry background it is useful to be aware of the classification of chemical into two major classes which are inorganic chemicals- which contain none or very few carbon atoms and organic chemicals- which have a structure based on carbon atoms. Once the chemicals entered the body, it may metabolize, excreted or accumulated and when the chemicals absorbed from the lungs, the skin, or the rectum they may enter direct in the blood circulation and be rapidly spread through the body in a modified form. The modification process in the liver and, to a lesser extent, in other organs is called biotransformation.

Toxic chemical have effects on both male and female reproductive systems. Exposures of concern may occur before or after conception. They may affect fertility, sexual function and lipido, but of particular concern are the potential effect on the fetus, which may include genetic abnormalities, interference with normal development, and poisoning the fetus before birth.

PHYSICAL HAZARDS
Physical hazards are defined factor within the environment that can harm the body without necessarily touching it. These are forms of potentially harmful energy in the environment that can result in either immediate or gradually acquired damage when transferred in sufficient quantities to expose individuals. A variety of different energy types can pose physical hazards, for example sound wave, radiation, light energy, thermal energy and electrical energy.

Noise and vibration
Noise is defined as unwanted sound and sound travels as waves in air that make eardrum vibrate. Eardrum passes these vibrations on the three bones in the middle ear, which in turn pass the vibrations to the fluid contained in the cochlea.

Light and laser
Visible light is one of nonionizing radiation. It is not as powerful as AV radiation and mainly causes damage to the eye after overexposure. Laser is a light that has been synchronized such that the radiation is of one specific frequency and the light waves are all travelling in phase in pulse and this delivers much larger energy direct to the eye than normal light. The lighting needed for fine tasks increases significantly with age, because of the natural deterioration of eye sight with age. A 40 year-old person needs twice as much light as a 20-year-old person to see an object with the same clarity.

MECHANICAL HAZARDS
Mechanical hazards are those posed by transfer of mechanical or kinetic energy which is energy of motion. The transfer of mechanical energy can result immediate or gradually acquire injury in exposed individuals. The term injury and the trauma are used an interchangeably to refer to the harm that may result from mechanical hazards and the events of injuries are referred to as accidents.

Socioeconomic factors are also important to consider when addressing the problem of mechanical hazards. Mechanical hazards cannot be considered in isolation from other hazards and realities of day-to-day life. Consider the risk of sleeping in a poorly constructed shark that would collapse in an earthquake versus the risk of having no shelter at all, the risk of travelling through an unsecured zone of conflict to obtain food versus the risk of starving, and the risk of driving on the crowded freeway to work rather than taking a safer public transit for the benefit of saving time and preserving independence and in injury control issue, socioeconomic context must be appreciated. Injury is a major cause of mortality throughout the world and has been described as the most under recognized major public problem. There are factors common to each type of injury that can be modified. Equipment must be purchased, with care given to the physical layout of the worksite to ensure appropriateness. Workers must be trained to recognize the hazards and the use safety equipment properly. Poverty has also been associated with increased rates of injury and this may be due to greater exposure to environmental hazards, as poor, untrained and undereducated people may perform the most dangerous jobs and live in poorly maintained houses in urban areas.

PSYCHOLOSOCIAL HAZARDS
Uncertainty, anxiety and lack of a feeling control over one’s own life situation or environment lead to what is popularly called stress. The word stress is sometimes used to describe a stimulus which is a specific event or situation that causes a mental or physiological reaction or is the state of pressure that a person experience. Stress is a human response to stressors and stress process consist of two stages, the first one involves deciding whether the event indeed poses a hazard, and the second involves appraising the possibilities of dealing with situation. For many people all over the world both developing and developed countries, stress is the part of daily life and it may lead to a variety of serious health effects including depression, suicide, substance abuse violence. Psychosocial hazards are those that create a social environment of uncertainty, anxiety and lack of control.
The occupation environment is another setting in which health can be damaged by a high mental burden. The major determinants of health at work are indeed those workplace organizational factors that determine psychosocial well-being of workers. Five categories of potential sources of work-related psychosocial stress can be distinguished like factors intrinsic to the job, the role of work in the organization, career development, interpersonal relationships at work and organizational structure and climate. In the private social environment, the death of a close friend or family member, divorce or other family-related events can also be seen as psychosocial hazards. In urban environment have its psychosocial hazards for example poor or nonexistent urban planning, overcrowded residential area, lack of sufficient recreation areas.
The effects of stress, when the individual continuously exposed to environmental stressors. The physiological characteristics of stress reaction include increases in heart rate, blood pressure, respiration and blood transport to skeletal muscle.

REFERENCES
Health people, homepage. 2005 (http//www.healthpeople). Accessed on 16.03.2018
Public health foundation, homepage. 2005 (www.pdf.org). Accessed on 19.03.2018 to local. Sam Francisco, CA
Frumkin, H. 2005 environmental health; from global