Monday, February 27, 2012

how to used pressed pellet

video below show how to make a pellet for EDXRF measurement using Fusion Machine. clean all the tools that need to be used using acetone. follow the step carefully. video below show the preparation for soil samples. other solid sample apply the same methods.


video

Hope this will help

Thanks for watching...




Sunday, July 17, 2011

Toxic Heavy Metals

Toxic Heavy Metals

(Source: caobisco)

1. Lead (Pb)

· The main sources of lead pollution in the environment are: Industrial production processes and their emissions, road traffic with leaded petrol, the smoke and dust emissions of coal and gas-fired power stations, the laying of lead sheets by roofers as well as the use of paints and anti-rust agents.

· Lead can trigger both acute and chronic symptoms of poisoning. Acute intoxications only occur through the consumption of relatively large single doses of soluble lead salts.

· In 1993, the joint FAO/WHO Expert Committee for Additives and Contaminants (JECFA) reduced the value it had provisionally specified for adults in 1972, for tolerable lead consumption per week (PTWI - provisional tolerable weekly intake), from 0.05 mg/kg body weight to 0.025 mg (or 25 µg).

· The lead content in drinking water presents a problem in many countries. Thus, the present WHO guideline of 50 µg/l is exceeded in Great Britain, for example, in 34 % of households.

2. Cadmium (Cd)

· Cadmium (world production in 1972, 15 000 t) exists in low concentrations in all soils. It is actively extracted from its ores for commercial purposes and is also emitted in industrial processes such as metal melting and refining, coal and oil-fired power stations, electroplating plants, etc.

· Cadmium is today regarded as the most serious contaminant of the modern age. It is absorbed by many plants and seacreatures and, because of its toxicity, presents a major problem for foodstuffs. Contamination through fertilisers becomes an increasing problem.

· Unlike lead, cadmium contamination cannot be removed from plants by washing them; it is distributed throughout the organism. It is often difficult to be certain of the cause of a cadmium content found in fruit or vegetables, as the substance in its natural form exists everywhere in the soil and is absorbed by the roots.

· Cadmium is concentrated particularly in the kidneys, the liver, the blood forming organs and the lungs. It most frequently results in kidney damage (necrotic protein precipitation) and metabolic anomalies caused by enzyme inhibitions.

· Cadmium, like lead, is a cumulative poison, i.e. the danger lies primarily in the regular consumption of foodstuffs with low contamination.

· In most countries, there are legal regulations regarding permissible cadmium contamination levels. As a rule, these are based on the PTWI value last set by the JECFA of the FAO/WHO in 1989 of about 7 µg/kg body weight, corresponding with a quantity of 0.4-0.5 mg per person (70 kg) per week.

· One problem of a special kind is the smoking of tobacco. 20 cigarettes a day provide a cadmium input of 4 µg.

3. Mercury (Hg)

· Passes into the environment through emissions from chemical plants (paints, paper, chlorine, plant pesticides) and power stations, mostly in effluents and sludge.

· Mercury becomes concentrated in shellfish, crustaceans and fish and thus also passes, in the form of highly toxic mercury methylate, into the human food chain.

· Mercury in the form of its methyl compounds is specifically the most toxic of the heavy metals.

· When consumed orally, it first passes into the liver, the kidneys and the brain.

· In the case of chronic consumption, first cause tiredness, loss of appetite and weight loss. In the end the kidneys fail. Muscular weakness and paralysis are typical.

· The FAO/WHO Expert Committee (JECFA) has set a provisional maximum acceptable value for mercury consumption at 5 µg per kg body weight per week.

4. Arsenic (As) (source)

· Arsenic is the most common cause of acute heavy metal poisoning in adults and is number 1 on the ATSDR's "Top 20 List."

· Arsenic is released into the environment by the smelting process of copper, zinc, and lead, as well as by the manufacturing of chemicals and glasses.

· Arsine gas is a common byproduct produced by the manufacturing of pesticides that contain arsenic.

· Arsenic may be also be found in water supplies worldwide, leading to exposure of shellfish, cod, and haddock. Other sources are paints, rat poisoning, fungicides, and wood preservatives.

· Target organs are the blood, kidneys, and central nervous, digestive, and skin systems (Roberts 1999; ATSDR ToxFAQs for Arsenic).

5. Others Heavy Metals

· Some heavy metals (the so-called trace elements) are essential in very small concentrations for the survival of all life forms, for example, copper, iron, zinc, chromium, molybdenum and others.

· Nickel has often been associated recently with allergies (contact with jewellery and jeans buttons containing nickel). There is no established knowledge of effects of this type when it is absorbed in the gastro-intestinal tract. Cocoa is one of the foodstuffs with higher than average natural nickel contents.

· The copper content of tomato dishes prepared in copper pots and having a copper content of 0.1-0.2 mg/kg body weight has already been found to cause digestive disturbances in sensitive consumers! This is in spite of the specified tolerable quantity for daily consumption of 0.5 mg/kg.

· Chromium, copper and zinc play major roles in modern industry and, in the vicinity of extraction or processing plants, the emissions arising are certainly capable of causing an undesirable contamination of agricultural products. Considerable quantities have been found in fruit and vegetables. However, no adverse effects on health are known. It is nevertheless recommended not to omit these metals a priori from scrutiny.

Monday, June 27, 2011

Ionizing Radiation

What is Ionizing Radiation?

Ionizing radiation is energy in the form of waves or particles that has enough force to
remove electrons from atoms (USEPA).

Radiation that falls within the ionizing radiation" range has enough energy to remove tightly bound electrons from atoms, thus creating ions. This is the type of radiation that people usually think of as 'radiation.' We take advantage of its properties to generate electric power, to kill cancer cells, and in many manufacturing processes.

and..

Radiation that has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough to remove electrons, is referred to as "non-ionizing radiation." Examples of this kind of radiation are sound waves, visible light, and microwaves.

The energy of the radiation shown on the spectrum below increases from left to right as the frequency rises.


Longer wave length, lower frequency waves (heat and radio) have less energy than shorter wave length, higher frequency waves (X and gamma rays). Not all electromagnetic (EM) radiation is ionizing. Only the high frequency portion of the electromagnetic spectrum which includes X rays and gamma rays is ionizing (WHO).


Friday, June 10, 2011

What is Radon

About Radon, (source: WHO)

Radon is a chemically inert, naturally occurring radioactive gas. It has no smell, colour or taste. Radon is produced from the natural radioactive decay of uranium, which is found in rocks and soil. Radon can also be found in water.

Radon escapes easily from the ground into the air, where it

disintegrates through short-lived decay products called radon progeny. As radon progeny decay, they emit radioactive alpha particles and attach to aerosols, dust and other particles in the air. As we breathe, radon progeny are deposited on the cells lining the airways where the alpha particles can damage DNA and potentially cause lung cancer.

Outdoor radon levels are usually very low. The average outdoor radon level varies between 5 and 15 Bq/m3 [Radon radioactivity is measured in Becquerel (Bq). One Becquerel corresponds to the transformation (disintegration) of one atomic nucleus per second. Radon concentration in air is measured by the number of transformations per second in a cubic metre of air (Bq/m3)]. Indoors, radon levels are higher, with highest levels found in places such as mines, caves and water treatment facilities.

Exposure of radiation:


How Radon enters a house?

Radon enters homes through:
  • cracks at concrete floor-wall junctions
  • gaps in the floor
  • small pores in hollow-block walls
  • sumps and drains.



Radon levels in homes can be reduced by:
  • improving the ventilation of the house
  • avoiding the passage of radon from the basement into living rooms
  • increasing under-floor ventilation
  • installing a radon sump system in the basement
  • sealing floors and walls
  • installing a positive pressurization or ventilation system.




Risk Assessment (source)

Exposure to radon, no matter how much exposure, does not mean you will get lung cancer. The risks associated with contracting lung cancer are in relationship to the amount of time exposed and the average Radon concentration levels.

Most radiation protection specialists believe, (at a minimum), that if you are continuously exposed to levels at or above 4 pCi/L then you are at risk. The US EPA's action level for Radon is 4 pCi/L. The World Health Organization has recently suggested that the action level should be 2.7 pCi/L, 33% lower than the current EPA action level.

The EPA has identified radon exposure as the number one cause of lung cancer in non smokers, and second only to smoking overall. Smokers generally have about 10 times higher risk than non smokers. Risk assessments associated with elevated radon concentrations are considered to be linear, meaning higher levels and longer duration of exposure increase risk assessment accordingly to the increase in concentration and amount of time exposed.

EPA risk assessment data from radon exposure is based on a lifetime of exposure.
  • Not everyone exposed to even high levels of radon will contract radon induced lung cancer.
  • All radon levels can be lowered, which lowers the risk assessment.


read more about radon: