The Hindu : Assessing risk

Online edition of India's National Newspaper
Friday, Oct 31, 2003

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Assessing risk

By Sagar Dhara

Public discussion revolves around concentration levels of pollutants and not the risk they cause.

TWO CONTROVERSIES related to product and environment quality rocked India recently. The first was about pesticide residues in soft drinks and the second about the proposed uranium mines in Nalgonda district of Andhra Pradesh.

The ensuing debate failed to ask a crucial question: "What is the public health risk in each instance?" That is because Indian standards for product and environmental quality, the few that exist, are based on specifying maximum allowable concentrations for toxic pollutants. Public discussion revolves around concentrations — their measurement, compliance with standards — and not the risk they cause. Concentration is the ratio of a pollutant in a medium (air, water), whereas risk indicates the probability of injury. By neglecting risk, the effort to reduce threats to public health has suffered.

In the soft drinks case, the Centre for Science and Environment (CSE) alleged the presence of high pesticide concentrations in soft drinks, 30 to 36 times the European Economic Commission standards. As sales fell, soft drink companies questioned the CSE's concentration measurement methods. None asked what risk those concentrations caused. Will having one contaminated soft drink cause illness? No. However, several over time may. Dose, a function of exposure time and concentration levels, is a better measure of risk.

The story repeats in the Nalgonda uranium mines case. The environmental impact assessment (EIA) for the proposed mines provides background concentrations of ionising radiation in the air, and uranium concentrations in water and soil at the site. However, it is silent about health risks of these concentrations; and ignores visual evidence of genetic defects amongst people living around the existing uranium mines in Jharkhand in the documentary film, "Buddha weeps in Jaduguda".

For decades after the Second World War, scientists believed that low dose radiation from uranium mines was harmless. Observed biological endpoints of high dose exposures — cancer, genetic damage — in Hiroshima and Nagasaki were linearly extrapolated to predict impact of low dose exposure. Low dose exposure effects were not looked for, therefore not found.

Fortunately science spawns sceptics. The work of Stokke, Petkau, Sternglass, Burlokova, Busby, Bertell over the last three decades indicates that low dose radiation, though not well understood yet, causes cancer and genetic disorder risks that cannot be ignored.

Uranium mine protagonists may conveniently ignore these findings. But it is surprising that the antagonists make no mention of it, particularly as it supports their argument. However, this is understandable as everyone in the Indian subcontinent — regulators, professionals, courts, media, NGOs — has become concentration-centred.

The concept of risk must now be given due importance. In Visakhapatnam city, risk studies showed that small concentrations of cadmium, for which no concentration standards exist, in the city's dust put half its residents at a cancer risk fifty times greater than the levels permitted in north nations. Dust pollution concentrations in the city, though, meet Indian standards. Studies indicate that similar cancer risks exist in other industrial centres too.

To shift focus towards risk requires two moves. The first would be to fix a risk standard, as has been done by many north nations. The move will allow risk sciences to influence public policy by contributing to the debate: "What is the likely injury at different toxic doses?"

A risk standard has several advantages. First, it provides a better basis for regulating toxic pollutants; even those without concentration standards, which is the vast majority. The cumulative effect of all pollutants in an area must not exceed a composite risk standard. Consequently, industry siting is better done with risk standards than with distance (between source and receptor) norms, as is done today. Additional activity in an area may be permitted only if the cumulative risk of all activities, old and new, is below the standard set.

Second, setting standards will enable risk sciences to develop. Risk assessment (R.A.) can determine relative risks of different situations. Risk ranking, a product of R.A., will force a rethink on abatement priorities. This will create the awareness that a small chrome-plating unit causes greater risk than a large cement plant. Similarly, other situations will be debated for their risk potential. Indian EIA studies are fatally flawed. They do no health or ecological R.A., hence cannot claim to do impact assessment. Good R.A. will overcome a part of this deficiency. Risk science also provides a public yardstick to assess the efficacy of abatement programmes. These can be said to be successful only when public health risk decreases over time. Third, after validation, R.A. is an inexpensive way of determining the health risk of existing and proposed projects. The second move to focus on risk should empower people to influence public policy by allowing them to find answers to the question, "What injury levels are acceptable to public?" Heuristic processes that allow people's perception of their risks and people's participation in risk management must come into play to realise the full potential of the well-accepted maxim "risk-bearers are the persons best positioned to mitigate risk they face, provided they have access to the necessary wherewithal (information, resources)." A combination of these two moves will go a long way to reduce public health risk in India.

(The writer is an environmental engineer.)

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