Health and environmental impacts of communications and information equipment and safety guidelines Dr. Mohamed El-Zarka

Health and environmental impacts of communications and information equipment and safety guidelines

Dr. Mohamed El-Zarka

Historical review Along the history, philosophers and scientists

have explored and developed several natural phenomena that facilitated the life of the humankind.

The philosopher Thales of Milteus (640-546 B.C) is thought to have been the first person who observed the electrical properties of amber and explored the magnetic properties of lodestone.

People have always watched but few have analyzed that great display of power present in the electrical discharge in the sky called lightning.

The twitch of the leg of a dead frog when dissected with a moisted metal scapel that has been noticed by Galvani in 1786, had led Volta to invent the electric battery .

Ampere defined the electric current in 1820. In 1843, Morse transmitted telegraph signals

from Baltimore to Washington DC. In 1875, Graham Bell invented the

telephone. In 1899 Marconi transmitted radio signals

from South Foreland to Wimereux, England. Armstrong demonstrated FM radio

transmission in 1933. Electronic digital Computer has been

demonstrated in 1946. First Voice Transmission from a satellite was

in 1958. In 1987, Superconductivity demonstrated at 95 K.

Advantages of ICT The Recent growth of ICT has

been astounding. Now we are able to communicate at lightening speed, by using computers, facsimiles and mobile phones.

The globalization of the world’s economies greatly enhances the value of information.

Advantages of ICT (continued..)

The relatively recent explosion of electronic commerce has further increased the pace of business transactions.

The major industrial economies have been transformed into information – based service economics in which knowledge and information become the key ingredients in creating wealth.

Advanced communications and telecommunications infrastructure reduced transportation needs, led to reduction of fuel consumption and consequently reduction of air pollution from carbon monoxide, carbon dioxide, nitrogen oxides, hydrocarbons and other pollutants.


Information technologies, computer aided design , and computer controlled manufacturing are used to increase the efficiency of power plants and industrial processes that decreases pollution, waste and resource consumption and make products that are more readily recycled.


ICT became a crucial tool in all aspects of our life , in education , business , industry, medical diagnosis and treatment, transportation , defense and in protecting man and environment.

A country’s ability to manage and use ICT will be the single determinant of its rate of development.


The Impacts of ICT

As usual every development has a price, and the price of the progress in the amazing, fast, ever-evolving communications and Information Technologies might be negative Impacts on health and Environment , that result from:

The electromagnetic radiation associated with equipment use

Equipment waste disposal

Electromagnetic Radiation

Electromagnetic radiation consists of waves of electric and magnetic energy moving together through space.

All electromagnetic radiation can be classified by frequency from the extremely low to extremely high frequencies.

Extremely high frequency radiation such as Ultraviolet (UV) and X-rays is called “Ionizing Radiation” because it is powerful enough to effect changes in the atoms of matter it strikes, by breaking chemical bonds (ionization) , thus altering their chemical and biological nature .

Electromagnetic radiation at those frequencies below the UV band are generally classified as “Non-Ionizing Radiation” because they typically lack the energy to effect changes in atomic structure.

The Electromagnetic Spectrum

Mobile phones operate at a variety of frequencies between about 800 and 2200 MHz.

Mobile Phones base station antennas emit EMR in the range 1800 – 2000 MHz

Computer monitors emit a broad range of EMR from 30 Hz up to 300 GHz.

The biological effects of RF

The biological effects of RF radiation depend on the rate at which power is absorbed.

This rate of energy absorption is called the Specific Absorption Rate (SAR) and is measured in watts/kilogram (W/kg). SARs are difficult to measure on a routine basis, so what is usually measured is the plane wave power density.

Average whole body SARs can then be calculated from the power density exposure In this document power density is given in mW/cm-sq (milliwatts per square centimeter). Power density can be expressed in several other ways:

W/m-sq (watts per square meter), where 10 W/m-sq = 1 mW/cm-sqµW/cm-sq (microwatts per square centimeter), where 1000 µW/cm-sq = 1 mW/cm-sqnW/cm-sq (nanowatts per square centimeter), where 1000 nW/cm-sq = 1 µW/cm-sq

The power density guidelines are stricter for some frequencies than for others because humans absorb RF radiation more at 860 MHz than at 1800 MHz, and it is the amount of power absorbed that really matters

Specifically, the ICNIRP standard is 0.40 mW/cm-sq at 800 MHz and 0.90 mW/cm-sq at 2000 MHz, while the NCRP guidelines are 0.57 mW/cm-sq and 1.00 mW/cm-sq for these same frequencies.

Electromagnetic waves may produce biological effects which may sometimes, but not always, lead to adverse health effects. It is important to understand the difference between the two: A biological effect occurs when exposure to

electromagnetic waves causes some noticeable or detectable physiological change in a biological system.

An adverse health effect occurs when the biological effect is outside the normal range for the body to compensate, and thus leads to some detrimental health condition.

Fields at frequencies above about 1 MHz primarily cause heating by moving ions and water molecules through the medium in which they exist. Even very low levels of energy produce a small amount of heat, but this heat is carried away by the body's normal thermoregulatory processes without the person noticing it.

A number of studies at these frequencies suggest that exposure to fields too weak to cause heating may have adverse health consequences, including cancer and memory loss.

Thermal effects The deposition of RF energy in the

human body tends to increase the body temperature.

During exercise, the metabolic heat production can reach levels of 3-5 W/kg. In normal thermal environments, an SAR of 1-4 W/kg for 30 minutes produces average body temperature increases of less than 1°C for healthy adults.

Thus, an occupational RF guideline of 0.4 W/kg SAR leaves a margin of protection against complications due to thermally unfavourable environmental conditions.

For the general population, which includes sensitive subpopulations, such as infants and the elderly, an SAR of 0.08 W/kg would provide an adequate further margin of safety against adverse thermal effects from RF fields.

What levels of RF energy are considered safe?

Various organizations and countries have developed standards for exposure to radiofrequency energy. These standards recommend safe levels of exposure for both the general public and for workers.

The National Council on Radiation Protection and Measurements (NCRP)

The Institute of Electrical and Electronics Engineers (IEEE).

The International Commission on Non-Ionizing Radiation Protection (ICNIRP).

American National Standards Institute (ANSI)

National Council on Radiation Protection and Measurements (NCRP)

U.S Federal Communications Commission (FCC)

The World Health Organization is working to provide a framework for international harmonization of RF safety standards

Exposure standards The NCRP, IEEE, and ICNIRP all

have identified a whole-body Specific Absorption Rate (SAR) value of 4 watts per kilogram (4 W/kg) as a threshold level of exposure at which harmful biological effects may occur.

In addition, the NCRP, IEEE, and ICNIRP guidelines vary depending on the frequency of the RF exposure.

This is due to the finding that whole-body human absorption of RF energy varies with the frequency of the RF signal.

Exposure standards (continued..)

The most restrictive limits on whole-body exposure are in the frequency range of 30-300 MHz where the human body absorbs RF energy most efficiently. For products that only expose part of the body, such as wireless phones, exposure limits in terms of SAR only are specified.


The exposure limits used by the FCC are expressed in terms of SAR, electric and magnetic field strength, and power density for transmitters operating at frequencies from 300 kHz to 100 GHz.


4 W/kg for 30 minutes would result in a body temperature rise of less than 1°C. This body temperature rise is considered acceptable.

A safety factor of 10 is introduced, in order to allow for unfavourable, thermal, environmental, and possible long-term effects, and other variables, thus arriving at a basic limit of 0.4 W/kg.


Implementation of standards

Allocation of responsibility for

measurements of field intensity and interpretation of results

Establishment of detailed field protection safety codes and guides for safe use

What siting criteria are required to ensure that a mobile phone base station antenna will meet safety guidelines?

Antenna sites should be designed so that the public cannot access areas that exceed the 1992 ANSI or FCC guidelines for public exposure.

As a general rule, the uncontrolled (public) exposure guideline cannot be exceeded more than 8 meters (25 feet) from the radiating surface of the antenna.

What siting criteria are required to ensure that a mobile phone base station antenna will meet safety guidelines?

(continued) If there are areas that exceed

the 1992 ANSI or FCC guidelines for controlled (occupational) exposure, make sure that workers know where these areas are, and that they can (and do) power-down (or shut down) the transmitters when entering these areas.

Such areas will be limited to areas within 3 meters (10 feet) of the antennas

In general, the above guidelines will usually be met when antennas are placed on their own towers. Problems, when they exist, are generally confined to:

Antennas placed on the roofs of buildings; particularly where multiple base station antennas for different carriers are mounted on the same building;

What siting criteria are required to ensure that a mobile phone base station antenna will meet safety guidelines? (continued)

Antennas placed on structures that require access by workers (both for regular maintenance, and for uncommon events such as painting or roofing). Note that the occupation safety standards for RF radiation apply only to workers with appropriate RF radiation safety training.

Towers that are placed very close to, and lower than, nearby buildings.

What siting criteria are required to ensure that a mobile phone base station antenna will meet safety guidelines? (continued)

Specific Antenna Installation Guidelines

For roof-mounted antennas, elevate the transmitting antennas above the height of people who may have to be on the roof.

For roof-mounted antennas, keep the transmitting antennas away from the areas where people are most likely to be (e.g., roof access points, telephone service points, HVAC equipment).

Specific Antenna Installation Guidelines(continued)

For roof-mounted directional antennas, place the antennas near the periphery and point them away from the building.

Consider the trade off between large aperture antennas (lower maximum RF) and small aperture antennas (lower visual impact).

Remember that RF standards are stricter for lower-frequency antennas (e.g., 900 MHz) than for higher-frequency antennas (e.g., 1800 MHz).

Take special precautions to keep higher-power antennas away from accessible areas.


Keep antennas at a site as far apart as possible; although this may run contrary to local zoning requirements.

Take special precautions when designing "co-location" sites, where multiple antennas owned by different companies are on the same structure. This applies particularly to sites that include high-power broadcast (FM/TV) antennas. Local zoning often favors co-location, but co-location can provide "challenging" RF safety problems.


Work Practices for Reducing RF Radiation Exposure

Individuals working at antenna sites should be informed about the presence of RF radiation, the potential for exposure and the steps they can take to reduce their exposure.

If radiofrequency radiation at a site can exceed the FCC standard for general public/uncontrolled exposures, then the site should be posted with appropriate signs

Work Practices for Reducing RF Radiation Exposure (continued..)

RF radiation levels at a site should be modeled before the site is built.

RF radiation levels at a site should be measured.

Assume that all antennas are active at all times.

Use personal monitors to ensure that all transmitters have actually been shut down.

"Keep on moving" and "avoid unnecessary and prolonged exposure in close proximity to antennas".


At some site (e.g., multiple antennas in a restricted space where some antennas cannot be shut down) it may be necessary to use protective clothing.

Remember that there are many non-RF hazards at most sites (e.g., dangerous machinery, electric shock hazard, falling hazard), so allow only authorized, trained personnel at a site.


How do you assess compliance with RF radiation guidelines for mobile phone base stations?

Compliance can be assessed through measurements or calculations. Both methods require a solid understanding of the physics of RF radiation.

Measurements require access to sophisticated and expensive equipment. Calculations require detailed knowledge about the power, antenna pattern and geometry of a specific antenna.

Nothing as simple as distance from an antenna site is adequate for assessing compliance or estimating exposure levels

Does RF radiation from mobile phones or mobile phone base stations cause physiological or behavioral changes?

There are un-replicated reports of such effects. There are some studies that suggest that RF radiation from hand-held mobile phones or mobile phone base stations might cause subtle biochemical, physiological or behavioral changes.

However, none of the studies provides substantial evidence that mobile phone base stations might pose a health hazard.

Learning Concentration and Behavioral disorders (e.g attention deficit disorder. ADD)

Extreme fluctuations in blood pressure Heart rhythm disorders Heart attacks and strokes among an

increasingly younger population Brain – degenerative diseases (e.g.

Alzheimer's) Cancerous afflictions: leukemia, brain

tumors

Headaches, migrains Chronic exhaustion Inner agitation Sleeplessness, daytime

sleepiness Nervous and connective tissue

pains, for which the usual causes do not explain

Other Computer Related Health Impacts

As more and more work,

education and recreation involves computers, everyone needs to be aware of the hazard of Repetitive Strain Injury to the hands and arms resulting from the use of computer keyboards and mice.

What is RSI?

Repetitive Strain Injuries occur from repeated physical movements doing damage to tendons, nerves, muscles, and other soft body tissues.

What are the Symptoms? Tightness, discomfort, stiffness,

soreness or burning in the hands, wrists, fingers, forearms, or elbows

Tingling, coldness, or numbness in the hands

Clumsiness or loss of strength and coordination in the hands

Pain that wakes you up at night Feeling a need to massage your

hands, wrists, and arms Pain in the upper back, shoulders, or

neck associated with using the computer.

How to Prevent It?

Correct typing technique and posture, the right equipment setup, and good work habits are much more important for prevention than ergonomic gadgets like split keyboards or palm rests.

Figure shows proper posture at the computer.

•TAKE LOTS OF BREAKS TO STRETCH and RELAX

Here are some stretches you can do,

Hold the mouse lightly Keep your arms & hands warm Eliminate unnecessary computer

usage Consider voice recognition. DON'T TUCK THE TELEPHONE

BETWEEN YOUR SHOULDER AND EAR TAKE CARE OF YOUR EYES

Health and environmental impacts of disposing equipment’s waste

In general, computer equipment is a complicated assembly of more than 1,000 materials, many of which are highly toxic

According to some estimates there is hardly any other product for which the sum of the environmental impacts of raw material, extraction, industrial, refining and production, use and disposal is so extensive as for printed circuit boards.

In short, the product developers of electronic products are introducing chemicals on a scale which is totally incompatible with the scant knowledge of their environmental or biological characteristics.

The health impacts of the mixtures and material combinations in the products often are not known.

The production of semiconductors, printed circuit boards, disk drives and monitors uses particularly hazardous chemicals, and workers involved in chip manufacturing are now beginning to come forward and reporting cancer clusters.

In addition, new evidence is emerging that computer recyclers have high levels of dangerous chemicals in their blood.

Materials used in a desktop computer and the efficiency of current recycling processes

Composition of a Desktop Personal Computer Based on a typical desktop computer, weighing ~60 lbs.

Table presented in: Microelectronics and Computer Technology Corporation (MCC). 1996. Electronics Industry Environmental Roadmap. Austin, TX: MCC.

Name Content (% of total weight)

Weight of material in computer (lbs.)

Recycling Efficiency (current recyclability)

Use/Location

Plastics 22.9907 13.8 20% includes organics, oxides other than silica

Lead 6.2988 3.8 5% metal joining, radiation shield/CRT, PWB

Aluminum 14.1723 8.5 80% structural, conductivity/housing, CRT, PWB, connectors

Germanium 0.0016 < 0.1 0% Semiconductor/PWB

Gallium 0.0013 < 0.1 0% Semiconductor/PWB

Iron 20.4712 12.3 80% structural, magnetivity/(steel) housing, CRT, PWB

Tin 1.0078 0.6 70% metal joining/PWB, CRT

Copper 6.9287 4.2 90% Conductivity/CRT, PWB, connectors

Barium 0.0315 < 0.1 0% in vacuum tube/CRT

Nickel 0.8503 0.51 80% structural, magnetivity/(steel) housing, CRT, PWB

Zinc 2.2046 1.32 60% battery, phosphor emitter/PWB, CRT

Tantalum 0.0157 < 0.1 0% Capacitors/PWB, power supply

Indium 0.0016 < 0.1 60% transistor, rectifiers/PWB

Vanadium 0.0002 < 0.1 0% red phosphor emitter/CRT

Terbium 0 0 0% green phosphor activator, dopant/CRT, PWB

Beryllium 0.0157 < 0.1 0% thermal conductivity/PWB, connectors

Gold 0.0016 < 0.1 99% Connectivity, conductivity/PWB, connectors

Europium 0.0002 < 0.1 0% phosphor activator/PWB

Titanium 0.0157 < 0.1 0% pigment, alloying agent/(aluminum) housing

Ruthenium 0.0016 < 0.1 80% resistive circuit/PWB

Cobalt 0.0157 < 0.1 85% structural, magnetivity/(steel) housing, CRT, PWB

Palladium 0.0003 < 0.1 95% Connectivity, conductivity/PWB, connectors

Manganese 0.0315 < 0.1 0% structural, magnetivity/(steel) housing, CRT, PWB

Silver 0.0189 < 0.1 98% Conductivity/PWB, connectors

Antinomy 0.0094 < 0.1 0% diodes/housing, PWB, CRT

Bismuth 0.0063 < 0.1 0% wetting agent in thick film/PWB

Chromium 0.0063 < 0.1 0% Decorative, hardener/(steel) housing

Cadmium 0.0094 < 0.1 0% battery, glu-green phosphor emitter/housing, PWB, CRT

Selenium 0.0016 0.00096 70% rectifiers/PWB

Niobium 0.0002 < 0.1 0% welding allow/housing

Yttrium 0.0002 < 0.1 0% red phosphor emitter/CRT

Rhodium 0 50% thick film conductor/PWB

Platinum 0 95% thick film conductor/PWB

Mercury 0.0022 < 0.1 0% batteries, switches/housing, PWB

Arsenic 0.0013 < 0.1 0% doping agents in transistors/PWB

Silica 24.8803 15 0% glass, solid state devices/CRT,PWB

Note: plastics contain polybrominated flame retardants, and hundreds of additives and stabilizers not listed separately.

Risks related to some e-toxics found in computers

Lead

Lead can cause damage to the central and peripheral nervous systems, blood system and kidneys in humans.

Effects on the endocrine system have also been observed and its serious negative effects on children’s brain development have been well documented.

Lead accumulates in the environment and has high acute and chronic toxic effects on plants, animals and microorganisms

Cadmium Cadmium compounds are classified as

toxic with a possible risk of irreversible effects on human health.

Cadmium and cadmium compounds accumulate in the human body, in particular in kidneys.

Cadmium is adsorbed through respiration but is also taken up with food.


Cadmium (continued..)

Due to the long half-life (30 years), cadmium can easily be accumulated in amounts that cause symptoms of poisoning.

Cadmium shows a danger of cumulative effects in the environment due to its acute and chronic toxicity


In electrical and electronic equipment, cadmium occurs in certain components such as SMD chip resistors, infrared detectors and semiconductors. Older types of cathode ray tubes contain cadmium. Furthermore, cadmium is used as a plastic stabilizer.

Cadmium (continued..)


Mercury When inorganic mercury spreads out in

the water, it is transformed to methylated mercury in the bottom sediments.

Methylated mercury easily accumulates in living organisms and concentrates through the food chain particularly via fish. Methylated mercury causes chronic damage to the brain.


It is estimated that 22 % of the yearly world consumption of mercury is used in electrical and electronic equipment.

It is basically used in thermostats, (position) sensors, relays and switches (e.g. on printed circuit boards and in measuring equipment) and discharge lamps.

Furthermore, it is used in medical equipment, data transmission, telecommunications, and mobile phones

Mercury (continued..)


Hexavalent Chromium (Chromium VI)

Chromium VI can easily pass through membranes of cells and is easily absorbed producing various toxic effects within the cells.

It causes strong allergic reactions even in small concentrations.

Asthmatic bronchitis is another allergic reaction linked to chromium VI. Chromium VI may also cause DNA damage.


Hexavalent Chromium (Chromium VI) (continued..)

In addition, hexavalent chromium compounds are toxic for the environment. It is well documented that contaminated wastes can leach from landfills.

Incineration results in the generation of fly ash from which chromium is leach able, and there is widespread agreement among scientists that wastes containing chromium should not be incinerated.


PVC The use of PVC in computers has been

mainly used in cabling and computer housings, although most computer moldings are now being made of ABS plastic.

PVC cabling is used for its fire retardant properties, but there are concerns that once alight, fumes from PVC cabling can be a major contributor to fatalities and hence there are pressures to switch to alternatives for safety reasons. Such alternatives are low-density polyethylene and thermoplastic olefins.


Brominated Flame Retardants

Brominated flame-retardants are a class of brominated chemicals commonly used in electronic products as a means for reducing flammability.

In computers, they are used mainly in four applications: in printed circuit boards, in components such as connectors, in plastic covers and in cables.


Brominated Flame Retardants (continued..)

Various scientific observations indicate that Polybrominated Diphenylethers (PBDE) might act as endocrine disrupters..

Research has revealed that levels of PBDEs in human breast milk are doubling every five years and this has prompted concern because of the effect of these chemicals in young animals.


Other studies have shown PBDE, like many halogenated organics, reduce levels of the hormone thyroxin in exposed animals and have been shown to cross the blood brain barrier in the developing fetus.

Thyroid is an essential hormone needed to regulate the normal development of all animal species, including humans.

Brominated Flame Retardants (continued..)


The Hazards of Incinerating Computer Junk

The stream of Waste from Electronic and Electrical Equipment (WEEE) contributes significantly to the heavy metals and halogenated substances contained in the municipal waste stream.

Because of the variety of different substances found together in electroscrap, incineration is particularly dangerous.

For instance, copper is a catalyst for dioxin formation when flame-retardants are incinerated.

This is of particular concern as the incineration of brominated flame retardants at a low temperature (600-800°C) may lead to the generation of extremely toxic polybrominated dioxins (PBDDs) and furans (PBDFs)

The Hazards of Incinerating Computer Junk (continued..)

The Hazards of Landfilling Computer Junk

It has become common knowledge that all landfills leak. Even the best "state of the art" landfills are not completely tight throughout their lifetimes and a certain amount of chemical and metal leaching will occur.

The situation is far worse for older or less stringent dump sites.

The Hazards of Landfilling Computer Junk (continued..)

Mercury will leach when certain electronic devices, such as circuit breakers are destroyed.

Not only the leaching of mercury poses specific problems. The vaporization of metallic mercury and dimethylene mercury, both part of WEEE, is also of concern.

The same is true for PCBs from condensors. When brominated flame retarded plastic or cadmium containing plastics are landfilled, both PBDE and the cadmium may leach into the soil and groundwater.

It has been found that significant amounts of lead ions are dissolved from broken lead containing glass, such as the cone glass of cathode ray tubes, when mixed with acid waters which commonly occur in landfills.


In addition, uncontrolled fires may arise at the landfills and this could be a frequent occurrence in many countries.

When exposed to fire, metals and other chemical substances, such as the extremely toxic dioxins and furans (TCDD -Tetrachloro-dibenzo-dioxin, PCDDs, PBDDs and PCDFs - polychlorinated and polybrominated dioxins and furans) from halogenated flame retardant products and PCB containing condensers can be emitted.


The Hazards of Recycling Computer Junk

Recycling of hazardous products has little environmental benefit – it simply moves the hazards into secondary products that eventually have to be disposed of. Unless the goal is to redesign the product to use non-hazardous materials, such recycling is a false solution.

A STEP IN THE RIGHT DIRECTION: EXTENDED PRODUCER RESPONSIBILITY AND E-TOXICS PHASE-OUTS

The European Union is developing a solution that will make producers responsible for taking back their old products. This legislation – which includes "take-back" requirements and toxic materials phase-outs -- also encourages cleaner product design and less waste generation.

This is known as Extended Producer Responsibility.

The aim of EPR is to encourage producers to prevent pollution and reduce resource and energy use in each stage of the product life cycle through changes in product design and process technology.

This includes upstream impacts arising from the choice of materials and from the manufacturing process as well as the downstream impacts, i.e. from the use and disposal of products. However, product take-back needs to go hand-in-hand with mandatory legislation to phase-out e-toxics.

What the European Union has proposed as a solution for E-scrap:

The draft WEEE Directive will phase-out the use of mercury, cadmium, hexavalent chromium and two classes of brominated flame-retardants in electronic and electrical goods

It puts full financial responsibility on producers to set up collection, recycling and disposal systems.

Between 70% to 90% by weight of all collected equipment must be recycled or re-used. In the case of computers and monitors, 70% recycling must be met.

"Recycling" does not include incineration, so companies won’t be able to meet recycling goals by burning the waste.

For disposal, incineration with energy recovery is allowed for the 10% to 30% of waste remaining. However, components containing the following substances must be removed from any end of life equipment which is destined for landfill, incineration or recovery:

lead, mercury, hexavalent chromium, cadmium, PCBs, halogenated flame-retardants, radioactive substances, asbestos and beryllium.

WHAT IS A CLEAN COMPUTER?

Electronic products should actually be considered chemical waste products.

Their number is increasing and their life is decreasing.

Electronic waste piles are growing, as is their pollution potential.

Most of these problems have their source in the development and design of the products concerned."

Many companies have shown they can design cleaner products. Industry is making some progress to design cleaner products but we need to move beyond pilot projects and ensure all products are upgradeable and non-toxic

Sustainable product design asks that we consider:

1. Rethink the product design

2. Use renewable materials and energy

3. Use non-renewable materials that are safer

Documents

Health and environmental impacts of communications and information equipment and safety guidelines Dr. Mohamed El-Zarka