Consumers Association of Penang

Giving voice to the little people...since 1970

Hazards of low-level radiation

Below we reproduce Chapter 5 of "Wasted Lives: Radioactive Poisoning in Bukit Merah" for our readers. It shows the many ill-effects of low-level radiation and its impacts on the residents in Bukit Merah.

What is frightening about radiation is that you cannot see it, feel it, hear it or taste it. You do not have to get into the area of a radioactive dump, dig the soil, bathe in it, or throw it over your head to get hurt.

We do not even have to go near the source. Radioactive gases like radon and thoron can travel with the wind and settle in the lungs of people living hundreds of miles away. Another important route is the food chain. Plant life growing near the radioactive source accumulates radioactive elements in its system. Eaten by cows, it is passed through cows' milk to humans. A similar process occurs for fruits, vegetables and fish if radioactive waste is dumped in a river near farms.

Low-level radiation can be hazardous because it attacks the human body at its most basic unit — the cell. This building block of life absorbs food, excretes waste, builds up proteins and replicates itself. When it is irradiated, the damage is harboured and accumulated in the body for years before ill effects become apparent. Scientists have long known about the harmful effects of radiation on bone marrow which results in the lowering of resistance to disease as the immune system is depressed. Radiation exposure can also lead to cancer and genetic damage which is passed on as birth defects or cancer in the next gener¬ation. The most common form of cancer is leukaemia but radiation-induced cancers can also develop in the pancreas, brain, lung, kidney and large intestines — that is, the soft organs. Blood disorders like aplastic anaemia, benign tumours, cataract, rapid aging and lowered fertility are the other effects.

How many people are aware that ionising radiation can also cause spontaneous abortions and stillbirth, as well as increased chances of getting heart disease, diabetes mellitus, arthritis, asthma or severe allergies? Let us say a young child is given a series of X-rays. As a result, the level of white blood cells may undergo a temporary depression. Two weeks later, he may catch influenza or some other infectious disease. Would his parents have linked the X-raying with his ailment?

There is no “safe” level of radiation as far as these effects are concerned. Even a very small dose has its impact.

When a radioactive substance decays, there are periodical explosions with release of energy. Such bursts of energy in ionising radiation kill or harm human cells in the following way: When radiation penetrates the body, it strips away electrons from the atoms that constitute the body cells. As a result of the loss, these atoms become positively charged. This process is called ionisation. The free radicals now try to make up for their electron loss by “attacking” other molecules. They can, for example, inter¬act with water molecules. In the process, unusual mole¬cules are created which are highly active. They in turn can react with the chemical constituents of the body cells. In the chain reaction set up, the cell thus gradually disinte¬grates, leaving the way open for cancer or other ills.

Genetic effects

Each cell has a nucleus. Within the nucleus are chromosomes containing genetic material called DNA which contains the instructions for the building and functioning of the body.

If the unusual, highly active molecules produced as a result of ionisation due to radiation react with portions of the DNA, the chromosomes could be harmed. A damaged DNA can pass on distorted messages to the cell, causing mutation during reproduction.

Some studies have shown that doses of a few rads accumulated over an extended period can result in an increase in the number of chromosome abnormalities. Also, many laboratory studies with plants and animals have shown that radiation can induce genetic defects in direct proportion to the dose received.

Damage could cause the cell to grow uncontrollably as a cancer cell. A cell divides to replicate itself in the process of growth. What could happen after irradiation is the destruction of the cell's ability to rest after division. As a result, the cell continues to divide unchecked. If enough cells become affected, then tumours are formed, composed of several millions of mutated cells. Or leukaemia may result with the abnormal proliferation of white blood cells. Or an organ itself becomes cancerous. The process usually takes years for the cancer to fully develop after the initial exposure.

The cell is most sensitive to irradiation when it is dividing. Thus foetuses, babies and young children whose cells are rapidly multiplying are most vulnerable. The bone marrow, where blood cells are formed, is also especially vulnerable.

If the cell in question is a reproductive cell in the sperm or ovary, the genetic material could produce mutations which are then transmitted to the next generation. A damaged chromosome could, for example, result in the birth of a child with brain damage or deformed hands. Or. if the damage is too extensive, stillbirth or miscarriage could occur. Radiation exposure in fathers has been shown to result in cancer in their children. Many studies have shown abnormally high levels of childhood leukaemia around the United Kingdom's nuclear installations where workers are exposed to higher than background levels of radiation. A 1990 study by epidemiologist Professor Martin Gardener of the Medical Research Council of Britain found that blood cancer in children around Sellafield's nuclear power station in Cumbria was nearly 10 times the nation¬al average. An exposure to 100 millisieverts or more was associated with a six- to eight-fold increase in risk of leu¬kaemia in the workers' children.

Teratogenic effects

It has been observed in humans as well as laboratory animals that low-level radiation can cause teratogenic damage, that is, malformation of the embryo or foetus. For this reason medical or industrial exposure of pregnant women is disallowed nowadays. In fact doctors recommend that elective fluoroscopy or other abdominal exposure of women of childbearing age be restricted to the first 10 days after the start of menstruation to avoid irradiating unsuspected foetuses.

The foetus is up to a thousand times more sensitive to radiation than adults. The unborn child is most vulnerable because of its rapid rate of cell division. It is most sensitive during the first trimester of pregnancy (especially in the first two weeks after conception), a period when most women are not yet aware of their pregnancy. At this stage it is 15 times more vulnerable to radiation-induced cancer than when it is six to nine months old in the womb.

When rapid growth is taking place in the different organs of the foetus, the effect of radiation may be to slow down growth. Should this occur in the brain or nervous system, microcephaly. central nervous system defects, mental retardation and behavioural problems could result after birth.

According to the US Committee on the Biological Effects of Ionising Radiation in its 1990 BEIR V report, “Within the critical gestational age period of 8 to 15 weeks, the prevalence of severe mental retardation can be linearly related to the absorbed dose received by the foetus." In other words there is no safe dose. BEIR V also states that –“radiation has been observed to increase the incidence of tumours in the nervous system in humans and laboratory animals ... Although the dose-incidence relation is uncertain, the data indicate the brain to be relatively sensitive to the carcinogenic effect of radiation."

Other congenital defects like blindness or deafness could occur as well as cancer in later years.

Studies show that children exposed to radiation like X- rays while they were in the womb have a much higher chance of developing cancer in the first 10 years of life. For instance, the pioneering work of epidemiologist and paediatrician Dr Alice Stewart on childhood cancers estimates that 53 per cent of the childhood cancer of children aged four to seven years are due to exposure to additional ionising radiation during pregnancy. According to her, exposure to extra radiation in the first trimester of pregnancy increased the risk six times.

Before Dr Stewart's finding, X-rays had routinely been used to detect multiple births or abnormal conditions in the uterus, and to determine the outlines of the mother's pelvis as an aid to delivery. Her findings in the fifties raised doubts, even controversy, about this practice of X- raying pregnant women — fuelled then by the belief that radiation exposure was safe so long as a threshold (of about 10 rads) was not exceeded.

However, despite confirmation from other studies, little had been done to warn the public, even in the twenty years after Dr Stewart published her research. In the United States, Dr Karl Morgan, founder of the profession of radiation health physics, stated at a 1980 hearing for radiation victims that he and other scientists had been fighting for years to stop the practice of giving X-rays in the pelvic and abdominal region to women of childbearing age except during emergency situations and except during the 10-day interval following the beginning of menstruation. The failure of the X-ray industry to comply was, he said, "one of the biggest problems in reducing the harmful effects of radiation".

It was only in 1980 that the Bureau of Radiological Health and the American College of Obstetricians and Gynaecology in the United States launched a large public education programme, warning of the damaging effects of radiation (among other things) on pregnancies.

Somatic effects

When enough cells are damaged by irradiation, causing, for example, an organ system made up of these cells to malfunction, the body as a whole then experiences an illness. There is no threshold below which one can assume one is safe. Exposure at any level of ionising radiation causes some degree of damage, while it simultaneously creates a long-term risk of cancer like leukaemia. Children are more at risk since they are two to four times more sensitive to radiation than adults, say, between 25 and 30 years old. Also at high risk are old people who have weakened immune systems. Women are estimated to be doubly sensitive to radiation than men because of their predominance in getting breast and thyroid cancers.

In the case of the radioactive waste produced by ARE, thorium itself is a powerful cancer-causing agent and toxic substance. Even minute amounts of ingested thorium are dangerous because of persistent alpha radiation to the surrounding tissue in the body. Scientists have found that the cancer risk for each rad of alpha radiation recorded is 20 times that for a same level of gamma rays and X-rays.

After absorption thorium is stored in the liver and spleen as well as the lymph nodes, bone, lung and kidney. The victim can develop leukaemia and bone marrow failure. It is the bone marrow or the core of the bones that produces new blood cells for the body. Radiation reduces the ability of the marrow to produce these cells. Thus fewer blood cells circulate in the body. As a result, the ability to carry oxygen or fight infections is lessened.

Radon gas, released in the milling of monazite or mining of uranium, can cause lung cancer if inhaled. The Environmental Protection Agency of the United States takes the position that there is no safe level of radon exposure. Studies in many countries show a relation between the incidence of lung cancer in uranium miners and cumulative exposure of radiation from radon and its daughters. In one study of 700 uranium miners in the southwest of the United States, researcher Dr Victor Archer of the National Institute of Occupational Safety and Health found a ten-fold increase in cancer risk among these workers.

It is too early for lung cancer cases to show up in Bukit Merah because the average latency period, that is, the period between exposure to radon and the onset of the disease, is about 20 years.

Inhaled radon and its daughters become attached to the lining of the lungs. They can pass through the lung tissue and enter the bloodstream, irradiating the surrounding tissue. Meanwhile, the radon decays to radioactive lead, bismuth and polonium, among others. The short- and long-lived radon daughters become selectively deposited in various organs. The kidney is the favourite target for polonium and bismuth. Animal experiments show renal lesions as well as a shortened lifespan.

Another decay product, radioactive lead which has a half-life of 21 years, lodges itself in bone, remaining for almost a lifetime. It kills the white blood cells needed by the body for fighting infection. The result is an abnormal blood count which can lead to blood diseases like aplastic anaemia. Also, the immune system is depressed. Thus children exposed to radiation are more susceptible to infections than children who are not. This finding has been illustrated by Dr Jayabalan's survey of Bukit Merah children.

Several studies have also found an apparent increase in the rate of coronary vessel diseases in populations exposed to radiation. A study of the Indian Rare Earth in Kerala found that the chance of its workers dying of heart disease was 2.5 times that of workers in other factories. Uranium miners face a similarly increased incidence of heart diseases.

Radiation effects in Bukit Merah

Although it has only been a decade since ARE began production in Bukit Merah, already the effects of radiation have been demonstrated in the community there. Not only do its children have low white blood counts, they have been found to be more susceptible to infections. The leukaemia rate among them is 35 times above the observed rate in Peninsular Malaysia. In addition, about 14 per cent of Bukit Merah mothers in the period 1982-86 experienced unexplained miscarriages or perinatal and neonatal deaths, while the rate of perinatal deaths in 1982 was about three times the national average rate.

Dr Rosalie Bertell, President of the International Institute of Concern for Public Health, warned the court at the ARE hearing in 1988. “I think that there are already signs of poor public health in Bukit Merah. I do not think that we should wait for dead bodies to appear before we begin to take action against ARE."

Besides closing down ARE, what authorities can do is to re-evaluate safety standards for radiation exposure which are not stringent enough and which do not take into account public health.