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|Year : 1986 | Volume
| Issue : 4 | Page : 195-8
A survey of Bhopal children affected by methyl isocyanate gas.
Irani SF, Mahashur AA
|How to cite this article:|
Irani S F, Mahashur A A. A survey of Bhopal children affected by methyl isocyanate gas. J Postgrad Med 1986;32:195
The leakage of methyl isocyanate (MIC) gas from an industrial reservoir at Bhopal on 2nd-3rd December 1984 led to widespread mortality and morbidity. In order to assess the damage done by the gas to the population in the exposed area, a study was undertaken by a medical team 105 days after the leakage. The present paper describes the findings of this study in the paediatric population.
The survey was carried out on 2 groups, Group I staying ½ to 2 km away from the Union - Carbide Factory and Group II staying 8-10 km away from this factory. The selection of the samples has already been described. In Group I, there were 164 children (90 males and 74 females) and in Group II there were 47 children (19 males and 28 females). The clinical findings in these children are being reported here.
The detailed information regarding the time of exposure and subsequent events were recorded in triplicate in a specially prepared proforma. All the children were examined in detail and the findings noted in the proforma. Those requiring special attention for the eye, pulmonary functions or gastro-intestinal symptoms were directed to appropriate specialty. All children above the age of five years were sent to the laboratory for investigations described elsewhere in this issue.,  Pulmonary. function tests were carried out in children older than 7 years of age.
[Table - 1] shows that the predominant symptoms in Group I were cough and breathlessness which persisted even one hundred days later. On an average, 48.1% of children had abnormal respiratory findings in the form of rhonchi, rales and wheezing. In Group II, there were no significant abnormal findings at the time of the study. [Table - 2] shows the results of pulmonary function tests carried out in 33 of Group I children and 12 of Group II children. In 28 Group I children, obstructive disability was noted compared to 8 children in Group II. Abnormal radiological findings were noted in 66.1% of Group I subjects compared to only 8.1 % in Group II.
[Table - 3] shows G.I. findings in both the groups. Abdominal pain and anorexia were reported to be more frequent at the time of the survey than immediately after exposure to MIC 100 days earlier. There were no affected children in Group II.
Though 79.8% of Group I subjects had conjunctivitis; however, 10.3% of children had vision abnormality on examination. In Group II, no significant affection of the eye was seen.
[Table - 4] shows neuromuscular findings in Group I children. There was no significant finding in Group II children.
At the time of the survey, out of all children, 8 were newborns. Out of these, 2 had bronchopneumonia and were admitted to the hospital for further treatment. Two had spina bifida and on further information were reported as dead and the postmortem of the lungs showed fibronodular deposits bilaterally.
In a few of the children above the age of 7 years, a definite psychological problem was noticed. They were apprehensive, jittery and very verbal or depressed. However, these children had witnessed the tragedy and some of them had been thought of as dead and kept in mortuary. It was frightening for them to get up from the unconscious state and find themselves lying in a heap of dead bodies. The first reaction many of them had was to run away with the tag of paper stuck on them showing the token number of the dead body. Some of them had witnessed the death of one of their parents or siblings. All these events and many more had left them as disturbed children.
The threshold limit value for MIC toxicity is known to be as low as 0.02 ppm of air. The poisonous gas present in Bhopal on 2nd December, 1984 had concentrations of MIC more than 100 times the stipulated safety level. Other pollutants like carbon monoxide (CO) hydrogen cyanide (HCN) and oxides of nitrogen in the released atmosphere cause toxicity on inhalation. Presence of phosgene also could have lead to the toxic effects.
Hundred days later still, the persistence of respiratory, gastro-intestinal and eye symptoms reveals the chronic effect of the gas. A study of 35 fire-men who were exposed accidentally to fumes of tolune di-isocyanates (TDI) revealed similar symptoms of throat irritation and chest findings. These were due to non-specific irritability of the airways. High concentration of the vapour of isocyanates causes rhinitis, cough and wheezing. In our series, rhonchi were found in 48.1% and wheezing in 43.2%. The pulmonary function tests correlate more satisfactorily with the X-ray findings in our study than the clinical findings. Hence it was found necessary to follow-up the severely affected respiratory cases with pulmonary function tests and X-rays.
Toxic mucosal irritation of the gastrointestinal tract leads to persistent diarrhoea, abdominal pain and anorexia and this is also seen with other aliphatic isocyanates. The persistence of abdominal pain in 58.5% of cases and diarrhoea in 26.2% cases makes us feel that a future endoscopic examination with multiple biopsy studies of the abnormal mucosa would help us in the management of these cases.
The eye symptoms which were present in 34% cases in the form of blurred vision, burning sensation and conjunctivitis could be due to the toxic effects of MIC and its derivatives on the corneal layer of the eyes.
In humans, isocyanates are likely to have an immunosuppresive effect, thereby exposing them to increased risk of infection, teratogenecity and gene mutation. This requires a long term study and time alone will reveal the long standing effect.
We are thankful to the Dean, Seth G. S. Medical College and K.E.M. Hospital, Parel, Bombay-12 and other municipal authorities who kindly permitted us to participate in this survey.
|1.||Acharya, V. N. and Potnis, A. V.: Bhopal gas tragedy; Medical hazards. Science Today, May 1985, pp. 22-23. |
|2.||Hama, G. M.: Symptoms of workers exposed to isocyanate. Arch. Industr. Hyg., 16: 232-233, 1957. |
|3.||Naik, S. R., Acharya, Vidya, N., Bhalerao, R. A., Kowli, S. S., Nazareth, H., Mahashur, A. A., Shah, S., Potnis, A. V. and Mehta, Arundhati, C.: Medical Survey of methyl isocyanate gas affected population of Bhopal. Part I. General medical observations-15 weeks following exposure. J. Postgrad. Med., 32: 175-184, 1986. |
|4.||Naik, S. R., Acharya, Vidya, N., Bhalerao, R. A., Kowli, S. S., Nazareth, H., Mahashur, A. A., Shah, S., Potnis, A. V. and Mehta, Arundhati, C.: Medical survey of methyl isocyanate, gas affected population of Bhopal. Part II. Pulmonary effects on Bhopal victims as seen 15 weeks after MIC exposure. J. Postgrad. Med., 32: 185-191, 1986 |