RADIOACTIVITY AND HUMAN GROWTH

RADIOACTIVITY AND HUMAN GROWTH

INTRODUCTION

The study of human growth has over 300 years of history. The most prominent factors of humanity is the ability to change size, shape, function and form from a baby or infant to a fully grown adult. Human are a very successful species in terms of population size. Another characteristics of human success as a species is the flexibility to adapt and grow to environmental or ecological stress. Different population has different types of growth pattern either endocrinologically and genetically. Others factors that affect human growth are cultural, behavioral and economical issues. All these contribute to a healthy development of human species. The study of human growth is important as we can study the genetic mechanisms from infant period to adulthood and from that we can know more about the patterns of human growth hence use this as reference tool in improving health issues of human populations (S. J. lijaszek et al 1998).

The graph below shows the human growth curve:

Available from http://www.stat.washington.edu/wxs/past-research-projects.htm

The human growth curve is a sigmoid curve and there are four stages of growth that is infant, childhood; adolescent and adulthood. They grow rapidly from the stage of infant to adolescent and slows down in adulthood. Humans are a very successful species in terms of population size and continuation of the species. Our brains are more developed compared to other organisms and thus, gave us a big advantage in the metabolic and ecological terms as compared to other species. Another characteristic is the flexibility to adapt and grow despite of the environmental and ecological stress.

Radioactivity was discovered by Henri Becquerel. His discovery opens a pathway for physic, chemistry and biology to combine and grow in terms of helping human to understand more about ourselves and the surrounding environment. Radioactivity has found its way in many aspect include industry, power, medicine, agriculture and etc. Research on radioactivity has been carried out constantly as radioactivity may use as a tool for treating serious and lethal disease such as cancer as well as other application to help us grow and live a longer yet healthier life. Radioactivity is the spontaneous process of decaying and unstable atomic nuclei together with nuclear particles and electromagnetic radiation emission. Nuclear radiation and radioactivity are closely related. The quantity and quality of our food have close relationship to radioactive sources which hence lead us to a healthy growth and thereby increasing our lifespan (H. Becquerel, 1896). Marie and Pierre Curie were the pioneer in using radium to treat cancer (Curie, 1905). Follow by Rutherford who introduced the first artificial emission of stable isotope oxygen-17 (Rutherford, 1919). In 1931, Ernest Lawrence invented the first cyclotron for accelerating proton or alpha particles in order to penetrate atomic nuclei. This produces stable and prominent radioactive isotopes that further applied on human health, medicine and biological sciences. These developed applications also aids in treating cancer, various diseases and also affects our human growth curve (E. Lawrence, 1931).

Radioactivity is the spontaneous process of decaying and unstable atomic nuclei together with nuclear particles and electromagnetic radiation emission.  There are two distinct types of radiation; ionizing and non-ionizing. Both ionizing and non-ionizing radiation can be harmful to organisms and can result in changes to the natural environment. Radioactivity has found its way in many aspects of our life which include industry, power, medicine, agriculture and etc. Research on radioactivity has been carried out constantly as radioactivity may use as a tool for treating serious and lethal disease such as cancer as well as other application. However, exposure to radioactivity has many harmful effects on human and especially upon human growth.

Cause and Effects of Radioactivity on human growth

There are two types of radiation, non-ionizing and ionizing. Infrared radiation, radio waves, hand phone radiation and the radiation that we used to cook in microwaves are the examples of non-ionizing radiation. This kind of radiation does not break chemical bonds, and it does not have significant effects on human health. On the other hand, ionizing radiations are much more dangerous because it will break the chemical bonds and further cause cancer. X-rays, gamma rays, the positron emission tomography (PET) and single photon emission tomography (SPET) are the examples of ionizing radiation.

Living places and working ground also affects the radiation exposure. Example living near a nuclear power plant or near old government radiation testing grounds may lead us to a higher than normal radiation exposure. Working in uranium mining, uranium or plutonium processing which expose the workers to radiation, the contaminant exposure is definitely above normal. Lastly the victim of a nuclear attack, they usually involve in sudden single large exposure to radiations.

The exposure of a fetus to radiation is called prenatal radiation exposure. This occurs when the mother's abdomen is exposed to radiation. Also, if accidentally swallow or breathes in radioactive materials, it may be absorbed into her bloodstream. Radioactive materials in the mother’s blood may pass through the umbilical cord to the baby or concentrate in areas of the mother's body near the womb such as the urinary bladder, liver and kidneys thus exposing the fetus to radiation. The health consequences can be severe, even at radiation doses too low to make the mother sick. Such consequences can include stunted growth, deformities, abnormal brain function, or cancer that may develop sometime later in life.

There are also lots of effects that radiation can cause on the human body, example lost of hairs, damage to nerve cells and small blood vessels or even the reproductive tract. The damage may range from mild to fatal like cancer or immediate death depending on the radiation exposure. In terms of health, there is fatigue, where the subjects feel tired and easily exhausted. Skin may also be irritated by radiation and cause redness in treatment area. Darkening and peeling of skin may also occur. Subjects will experience loss of taste and dryness in throat as well. 

In terms of growth, radiation may cause genetic mutation and cause abnormal growth in our offspring. For example, if we consume food with radioactive iodine ingested, it will enter the blood and absorbed preferentially in the thyroid gland. The radioactive iodine will then emit high-energy gamma radiation which can destroy thyroid cells, and thus reducing the total thyroid hormone production in the individual. The damage to the thyroid of a developing fetus can cause mental retardation and other severe developmental anomalies. Examples are retarded growth in height or other abnormal development of organ which will definitely affects the growing of a normal individual. Radiation may also lead to mutation in our hormonal system where the secretion of hormone varies and results in other serious or even deadly diseases that further endanger our normal growth.

Apart from that, radiation can also cause mutation in the DNA. Mutation of DNA is the change in DNA sequence. The mutation can disturb the growth of human as protein and enzymes are synthesized from DNA transcription. If there are any changes in the DNA sequence, the protein is not able to be synthesized and hence lacking of that particular protein may cause stunted growth. Example, if a code for a certain amino acid is missing or altered, the protein being synthesized will not have the same function as the protein with that amino acid. This mutation might also happen to germ cells like sperm and ovum and causes the offspring to have genetic diseases such as myotonic dystrophy, Down syndrome, neurofibromatosis and etc.

Prevention:

The best way to prevent radiation sickness is minimize the radiation exposure or reduce the dose rate. Keeping a distance from the radiation source is one of the best ways to minimize the exposure. It is believe that time is also a factor that affects the dose rate, the longer that human are subjected to the radiation, the larger the dose will be and this is why the radiation workers are taught to work as quickly as possible when handling a task which exposes them to the radiation. If radioactive iodine is breathed in, it will concentrate in the thyroid gland and thus increase the risk of getting thyroid cancer, however by taking pills of potassium iodide immediately after exposure will help to protect the thyroid and reduce the risk of getting cancer in the long term. Lastly avoid consumption of food like vegetables and dairy products which are produced in the vicinity of the power plant can also reduce exposure.

Extra information

Currently there are no effective medical treatments available for potentially fatal radiation doses. Treatments that can save include blood transfusions and bone-marrow transplants. Bone-marrow transplants rejuvenate the supply of blood cells i.e. red blood cells and white blood cells. Potassium iodide,(KI) may be used to protect the thyroid from ingested radioactive iodine in the event of an accident or attack at a nuclear power plant, or the detonation of a nuclear explosive.

First aid for radiation sickness:

1. Check the person's breathing and pulse.
2. Start CPR, if necessary.
3. Have the person's remove their clothing and place the items in a sealed container. This stops ongoing contamination.
4. Vigorously wash body with soap and water.
5. Dry the body and wrap with soft, clean blanket.
6. Call for emergency medical help and take the person to nearest emergency medical facility.

Conclusion

        

        Therefore, we conclude that radioactivity do affect human growth. Although researches that are done cannot directly relate the effects on radioactivity on human growth, but can only prove that it does affect human growth in certain ways. We still strongly believe that radioactivity does affect human growth as we have stated above.