lec 6 Microwaves Biological and Chemical Hazards

Microwaves, Biological and Chemical Hazards
By
Ashraf Hussain
MBChB, PhD- Com
Non Ionizing Radiation
"Radiofrequency (or RF) radiation" applies to electromagnetic fields with frequencies
between 3 kHz and 300 MHz, while "Microwave (or MW) radiation" covers fields
from 300 MHz to 300 GHz.
Since they have similar characteristics, RF and MW radiation are usually treated
together.
The lower-frequency boundary of RF radia on is o en extended to 3 kHz in order to
include emissions from commonly used devices such as radio and television
transmitters, computer network hubs, wireless internet (Wi-Fi) routers, Bluetooth
devices, cordless telephones, cellular phones and their transmitting towers, and
microwave ovens.
The nature and the degree of the health effects of overexposure to RF/MW fields
depend on the frequency and intensity of the fields, the duration of exposure, the
part of the body exposed, the distance from the source, any shielding that may be
used and other factors.
Occupations with RF/MW exposures
Television transmitter station
Induction and dielectric heaters
Diathermy applicators
Military exposure
surface-to-air missile system radars.
Aircraft and helicopters.
Communication devices,
Airport radars.
Radio navigation systems
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Health Effects
The main effect of exposure to RF/MW fields is heating of body tissues as energy
from the fields is absorbed by the body.
For frequencies from 3 MHz to 10 MHz, worker over-exposure to time-varying
electric and/or magnetic fields may result in short-term nerve stimulation including
headaches, fatigue, stress and sleeplessness.
Localized heating, or "hot spots," may lead to heat damage and burns to skin and/or
internal tissues.
There is a higher risk of heat damage with organs which have poor temperature
control, such as the lens of the eye and the testes.
Hot spots can be caused by the interaction of the fields with metallic implants, for
example, cardiac pacemakers or aneurism clips.
Cancers or congenital defects are still not proven.
Biological Hazards:
biological agents: “any microorganism, cell culture, or human endoparasite,
including those who have been genetically modified, which may cause any infection,
allergy, toxicity, or otherwise create a hazard to human health.”
Additionally, biohazards encompass biological substances including medical waste,
or samples of body tissues or fluids from a biological source, which may contain
microorganisms, viruses or toxins that can adversely affect human health.
Biohazards may exert an effect on a human, either by direct contact with the
causative agent (e.g. a bite from a venomous snake) or by transmission of zoonotic
agents through contact with animals, animal matter or animal products (e.g.
brucellosis).
Also Plant and plant products: Contact with certain plants, plant materials may cause
non-infectious poisoning, stinging, allergic reactions (e.g. anaphylaxis, mushroom
workers’ lung, and bagassosis in the sugar cane industry), and irritant-contact or
allergic-contact dermatitis
Chemical hazards
refer to health hazards caused by hazardous substances, compounds and particles.
There are an es mated 650,000 exis ng hazardous chemical products, and hundreds
of new ones are being introduced annually. Theses poses serious problems for
exposed workers and their employers.
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Major Types
1. Primary Irritants - cause intense redness or swelling of skin or eyes on
contact. No permanent tissue damage
2. Corrosives - cause tissue damage and burns on contact with skin or eyes
3. Carcinogens - may cause cancer
4. Teratogens - may cause birth defects
5. Organ Specific hazards - damage to specific organ systems such as liver or
lungs
The employees have both a need and a right to know the hazards and identities of
the chemicals they are exposed to when working.
They also need to know what protective measures are available to prevent adverse
effects from occurring
Labels, Tags and Markings
The employer must ensure that each container of hazardous chemicals in the
workplace is labeled, tagged or marked with the following:
Identity of the hazardous chemical
Appropriate hazard warnings
This above labeling information required is of the manufacturer so the employer
must ensure that the original labels from the manufacturer are on all containers and
remain legible
Material Safety Data Sheets (MSDS)
one of the most important tools available to employers for providing information,
and protection to workers from hazardous chemicals which are used in the
workplace.
It is a technical document which provides detailed and comprehensive information
on a controlled product related to:
1. health effects of exposure to the product
2. hazard evaluation related to the product’s handling, storage or use.
3. measure to protect workers at risk of exposure.
4. Emergency Procedures
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MSDS may be kept in any form including operating procedures
It may be more appropriate to address the hazards of a process rather than
individual hazardous chemicals
MSDS, required information
1. Identity of the chemical
2. Physical and chemical characteristics
3. Physical hazards
4. Chemical hazards
5. Primary routes of entry
6. PEL’s or other exposure limits
7. Control measures
8. Emergency procedures
9. Whether the hazardous chemical is listed in the National Toxicology Program
(NTP) Annual Report on Carcinogens
10. precautions for safe handling and use
11. Date of preparation
12. Name, address and telephone of the manufacturer
Trade Secret Exemptions
Information may be withheld to protect industries’ right to protect confidential
business information.
This information is referred to as trade secrets.
The producer of the product can withhold the name and concentration of any
ingredient.
Doctors and nurses can access withheld information however this information
remains confidential.
Control of Chemical Hazards and Exposures
1. Elimination or substitution
2. Engineering and Mechanical Controls
3. Personal Protective Equipment
4. Administrative and Procedural Controls
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