The Mayapuri metal scrap market tragedy resulting from the callous disposal of equipment containing radioactive source cobalt-60 as scrap by the Chemistry Department of the University of Delhi has highlighted the urgent need to tighten the system of tracking and controlling the possession of such hazardous material. One can understand scrap dealers lacking awareness of what radioactive sources are and their hazards to health and environment. But it is hard to believe that members of a university science department could approve the auction of a radioactive device, flouting the guidelines of the Atomic Energy Regulatory Board (AERB) on safe disposal of such equipment after use. Admittedly, it was a 42-year-old apparatus that has been in disuse since 1985. What is shocking is that a ten-member ‘write-off committee,' comprising scientific members of the university and chaired by the head of the chemistry department, approved the disposal of the Co-60 source, along with other unused equipment of the department, in one lot; and the Vice-Chancellor gave his final approval swiftly.
To blame the deadly disposal on miscalculation, as the top university authorities have done, is to add insult to injury. Calculating the left-over activity in any radioactive source over time is a simple task. Co-60 has a half-life of 5.27 years, which means its activity goes down by half every 5.27 years. Forty-two years is eight half-life periods, which means the activity would have gone down only by 2 to the power of 8, which is 256. The source in question, a GammaCell 220 Irradiator supplied by the Atomic Energy of Canada Ltd, was a very strong source with 3300 Curies(Ci) of initial activity. Depletion by a factor of about 250 after 42 years would still leave a huge amount of residual activity of a few hundred billion decays/sec. On paper, the AERB guidelines take care of the problem of radioactive sources across the length and breadth of the country. But the DU-Mayapuri case has shown how lax observance and enforcement of the rules are on the ground. The temptation to view it as an isolated case must be resisted. As this newspaper pointed out in a recent editorial, a number of ‘sealed sources' containing radioactive waste are turning up in scrap yards; U.S. Customs regulators in 2007 rejected several metal article shipments from India because they were found to be contaminated with radioactive material; and Germany, France, and Sweden have detected cobalt-60 in Indian steel. While we wait for the findings of the inquiry committee, serious lessons must be learned from the Delhi tragedy. The time for the government to clean up is now.
