Assignment 4
What are some of the human health concerns that research has indicated involves exposures to extremely low frequency (ELF) electromagnetic radiation from equipment such as high voltage transmission lines and video display terminals?
Epidemiological studies have linked exposure to low-intensity 50/60 Hz ELF fields with leukaemia and brain tumours in children and workers in "electrical" jobs. At present either to confirm or rule out a cause-effect link between exposure to ELF electric and magnetic fields and cancer. This issue continues to be researched and debated by scientists
Describe the relationships of these three characteristics and how they relate to the two types of radiation: ionizing and non-ionizing radiation.
Frequency:Measured in cycles per seconds or hertz. Higher the frequency, the higher the energy, and conversely, the lower or smaller the frequency, the lower the energy. Wavelength is measured in units of distance. Higher the wavelength (Angstroms), the lower the energy (eV) Energy (photons) Determines if radiation is ionizing or non-ionizing. Boundary between ionizing and non-ionizing radiation is in the ultraviolet region of the electromagnetic spectrum
Define the term 'Laser' and outline the reasons why laser exposure is a concern in occupational health and safety.
Laser is an acronym for "Light Amplification by Simulated Emission of Radiation". Lasers have many uses and are found in industries where they are used for cutting and welding, in construction where they are used for levelling, in surveying and the building of tunnels, in medical and military fields, and also in domestic fields. Health risk associated with lasers, there are five factors to consider:frequency characteristic ,intensity ,duration ,divergence, nature or type of laser
Describe the major human biological effect associated with exposure to non-ionizing radiation and how this effect interferes with the human biology.
The major biological effect of non-ionizing radiation on the human body is the increase in temperature of the target material it hits. The health effects are caused by the heating effect that non-ionizing radiation has on the protein in the cells. Proteins depend on their 3D structure to be biologically active. Heat causes the proteins to denature; that is, to lose their 3D structure. As a result, the proteins lose their ability to be biologically active. This denaturing is usually irreversible, but it is dependent on the amount of heat and the amino acid composition of the protein.
List the different types of work processes that involve the generation of infrared, radiofrequency, and microwave electromagnetic radiation.
Two major functions of radiofrequency radiation and microwave radiation are communication and heating. Sources of radiofrequency and microwave radiation include: radiofrequency sealers, induction heaters, industrial microwave ovens, radio and TV broadcasting antennae, communication antennae, radar, medical-related radiation devices. Workers that are involved in or are stationed near heating processes based on radiofrequency and microwave radiation may potentially be exposed. Radar manufacturing, communication workers, and certain health care workers also have potential exposure risks.
Name and briefly describe the three categories of controls that can be used to protect against exposure to:
a) Internal radiation hazards: • Provided by engineering means such as isolation and mechanical ventilation, and if not feasible, by the wearing of personal protective equipment. Appropriate types of respirator should be worn to protect against inhalation exposure. Workplace hygiene policy and personal hygiene practices are also important to control potential exposure via ingestion b) External' radiation hazards • Time. The duration of exposure should be reduced to minimize the exposure dose, which is a function of exposure level and the exposure duration. • Distance. Increasing the distance from the radiation source is an important radiation safety control measure. • Shielding is an important control measure where radiation absorbing material or shield is placed between the worker and the source to limit the transfer of energy
Six common musculoskeletal injuries
back injuries, bursitis, carpal tunnel syndrome , tennis elbow ( epicondiytis ) muscle strains , tendonitis, white finger disease, trigger finger
Define the term 'ergonomics' and briefly explain the significance of this science in occupational health and safety.
• "Ergonomic" comes from the Greek words "ergon", meaning work and strength, and "nomos" meaning laws or principles • The scientific study of the relationship between a worker and his work environment. • Conducive to good work performance and effectiveness while promoting worker comfort, health and safety. • Helps us answer questions such as: "How do workers and equipment interact to perform a task in a given environment?" • Ergonomic intervention addresses occupational health problems such as injuries and illnesses arise from conditions such as faulty workstation layout, improper equipment, poor job designs and poor work environment.
Outline the penetrating power of the different types of ionizing radiation and explain the implications of their ability to penetrate.
• Alpha: Only travel a short distance through matter but produce heavy ionization when doing so. Because of this short travel distance, alpha particles are not considered to be an external hazard to the body, as they cannot penetrate the body's thin layer of skin. However, matter, which emits alpha particles, is considered to be very hazardous when it is taken into the body. Stopped by a sheet of paper. • Beta: Penetrate into the human body further than alpha particles and cause skin burns when high doses penetrate the human body. Beta particles are also considered to be an internal hazard Stopped by a layer of clothing or by a few millimeters of substance such as aluminum. • Gamma Rays: Can penetrate deeply through the human body and are considered to be an external radiation source. Stopped by several feet of concrete or a few inches of lead.
List and give a brief definition of the four scientific disciplines that are involved in the study of ergonomics. Use two specific workplace examples for each of the four disciplines to support your answer.
• Anthropometry: the science of human measurement. Data on body height, girth, arm length, and other values must be gathered. With this data, it was possible to determine how to adjust the workplace to fit the potential workforce. Expressed in percentiles. • Physiology: The science of how the body functions. Biological functions and mechanisms that underlie human work. Tasks must be matched with human capabilities. Consideration of human capacity for physical work, as well as the energy cost of performing the work. • Biomechanics: uses the principles of mechanical engineering and physics to understand human movement. It views the human body as a series of levers (arms and legs) and fulcrums (joints), which are moved by forces generated by the muscles. • Psychology: the study of human motivation, attitudes and behavior. Factors in the workplace influence and affect humans and alter their behaviour. Interactive contact between the worker and the machine where there is an exchange of energy (from worker) and information (from machine). Training, and other social and economic conditions of work will all influence the occurrence or non-occurrence of ergonomic problems, work performance and productivity.
3. X ray and gamma ray are similar because they are both electromagnetic radiation and ionizing radiation. How do you then distinguish between them?
• Are only different on the basis of their origin. X-rays are emitted from processes outside the nucleus, and gamma rays come from the nucleus of atoms. Gamma rays come from the excited, unstable nuclei of radioactive materials.
List the tissues that are sensitive to exposures to ionizing radiation.
• Bone marrow, reproductive cells, lymph nodes, the lining of the digestive tract, and some of the cells of the skin.
Name the four important procedural and organizational factors that have influence on the ergonomic well-being of a workplace. List at least three issues under each factor.
• Design of the job: under-stimulates the worker, over stimulated with a task that is too complex, doing less activity, did not afford much opportunity for independent action and thinking and resulted in a negative impact on the physiology of the body. • Scheduling of the work: number of hours the worker works per day, and what shift he or she is working, • Worker training: receive little or no training at all when they are employed, they tend to learn by trial and error; every time an error is made there is a potential for exposing the worker to health and safety hazard. • The remuneration method : results in a detriment to performance, as the workers may work faster and cut corners and ignore safety procedures, skip rest breaks in exchange of the financial rewards.
1. Ionizing radiation is capable of producing ions by interaction with matter. Explain this statement and describe the effects of exposure of human tissues to ionization radiation.
• Energy transfer process that changes the normal electrical balance of the atom. If these atoms lose negatively charged electrons they become positively charged ions. If these lost electrons approach and interact with other atoms and become attached to these other atoms, the atoms become negatively charged ions. Both positive and negative ions are created. • Difference between ionizing radiation and non-ionizing radiation is the energy of the radiation to ionize matter. It takes approximately 10 electron volts (eV) to ionize a molecule so that any radiation with energy greater than 10 electron volts is considered to be ionizing radiation • Skin -Erythema; necrosis of the skin Bone Marrow & Lymphoid Tissue -degenerative changes of hematopoietic cells; reduce normal replacement of blood cells
Describe the health effects associated with radiofrequency and microwave exposure and the general principles of exposure controls.
• Health effects: cataracts in the eyes, and that sperm production for men insomnia, irritability, headaches, and alterations of the immune and central nervous systems. • Exposure controls: Workplace policy should be implemented to minimize worker's exposure duration where feasible including : maximizing the distance from source, providing shielding, and reducing exposure duration, workers should be located far from the radiation sources, and shielding
List all the factors that affect the quality of the 'work environment'. Describe the reasons (give at least two) why 'lighting' and 'ventilation' are important in this respect.
• Lighting: Quantity and Quality . Enough lighting to prevent accidents and injuries in a workplace. Poor lighting can contribute to tired and sore eyes, headaches, and blurred visions. Lighting quality is determined by the types of lighting fixtures, the lighting colour, the distribution of the lighting sources, the presence of glare in the work environment, and the contrast between the task and the background. • Temperature and humidity controls • Ventilation and indoor air quality: Necessary to control the potential exposure to trace levels of air pollutants in an office environment. • Noise • Vibration exposure.
Describe the three different effects of electromagnetic type of ionizing radiation.
• Photoelectric effect: This effect occurs when an electron is ejected from its orbit by the x-ray or gamma ray. All the energy of the x-ray or gamma ray is imparted to the electron, creating a high-energy electron. • Compton effect : This effect involves the glancing collision of gamma or x-ray with an orbital electron. With this glancing collision only part of the energy of the x-ray or gamma ray is passed on to the electron and the lower energy gamma or x-ray goes off in a different direction to interact further. • Pair production: Example of a direct conversion of energy into mass. This occurs when the gamma and x-rays come in close contact with the nucleus of another atom. With pair production there is a conversion of the x-ray and gamma ray into a pair of particles, an electron and a positron
Using an office workstation as an example, discuss the important design principles with respect to 'work space'.
• Physical makeup of the worker population. The second consideration is the specific body parts involved in particular tasks, and third, whether the workstation features are fixed or adjustable. • Desk heights, access to tools, and space clearances can comfortably fit the range of body sizes. • Seated work with insufficient leg room under work tables is a problem because workers have to adopt awkward postures.
List three different types of personal monitoring devices used to sample for ionizing radiation exposures.
• Pocket Dosimeter :This is a direct reading instrument where quartz crystals absorb the ionizing radiation. These dosimeters record a cumulative dose, which can be read on a scale while working with radiation. • Film Badge:This is a chemically treated film that is sensitive to ionizing radiation. After wearing the badge for a specified time period, the film is developed which gives a record of individual exposure. Its major drawback is that it is not easily read and must be processed in a lab for proper analysis of absorbed dose. • Thermoluminescence Detectors (TLD) :This type of detectors contains a lithium fluoride chip which releases energy when bombarded by radiation. This energy is stored in a storage compartment or sink of the TLD which is later delivered to a laboratory for the follow-up analysis. When the storage sink is heated, it releases energy quantitatively as light which can be measured to provide an indication of absorbed radiation dose.
8. List the two general types of biological effects to human as a result of exposure to ionizing radiation. Outline their differences and give an example in each case
• Somatic effects: Injuries to individuals. An example of this is skin erythema: a reddening or inflammation of the skin accompanied in severe cases by blistering. Large x-ray doses to the skin and superficial tissues can cause erythema. • Genetic effects: Injuries to the reproductive cells, so that changes are passed on to future generations. The reproductive cells we refer to are the female ovum and the male sperm. An example, chronic exposure can damage the bone marrow, which affects the leucocytes or white blood cell production. This may result in the development of leukemia.
Explain how the designs and requirements of a 'work task' could affect the potential for injuries (ergonomic hazards) associated with manual material handling.
• Work physiology - impact of the work on the body's functions and metabolism; • Biomechanics - the effects of the force requirements of the job on the different body parts, the body's motion and strength characteristics; and • Stress related health problems - the effects of work task related psychosocial stress. • The issues of work physiology and biomechanics are of great importance in the assessment of ergonomic hazards associated with manual material handling involving lifting, pushing, pulling, and carrying. NIOSH and "Snook and Ciriello" have developed guidelines regarding loads and forces found acceptable by workers for continuous manual material handling jobs. The acceptable maximum loads or force levels are recommended based on factors such as the weight of load, frequency of task, duration, distance of body movements, posture, gender.
List the common names used to describe WMSD.
• Work-related Musculoskeletal Disorders (WMSD) are also known as Repetitive Strain Injuries (RSI), Cumulative Trauma Disorders (CTD), or Repetitive Motion Injuries (RMI).Awkward body position, Forceful exertion, repetitive motions, Duration, contact stress, workplace conditions
