Potential health risks due to toxic contamination in the ambient environment of certain Indian states.

Toxic or hazardous substances pose two types of risks in the environment, namely 'short-term or acute risk' and 'long-term or chronic risk'. The short-term risk is associated with the one-time acute exposure to potentially hazardous substances accidentally released in the environment, whereas the long-term risk is resulted from continuous exposure to potentially harmful substances present in different environmental media. This article deals with the assessment of potential health risks related to certain carcinogens and non-carcinogens (e.g. cadmium, chromium and nickel) present in three environmental media, viz. air, water and food in different Indian states (regions). Appropriate dose-response models have been identified and used for this purpose with the assumptions and input data as per the Indian context. Mean values of ambient air concentration levels of Cd, Cr and Ni have been used to estimate the individual and societal risks of extra cancer in different states of India. The hazard quotients and hazard index representing the non-carcinogenic chronic health effects caused by chromium and cadmium due to their long-term exposure through water and food have also been estimated. The risk results have been compared with the disease surveillance data. A definite correlation between the estimated risk results and the reported number of lung cancer cases and chronic liver diseases have been observed in different regions. As a matter of fact, it is not possible to derive precise risk estimates due to various uncertainties included both in available data and in the models which are used to calculate potency factors and effective concentration. However, average risk levels as estimated and presented in this article are quite useful for planning purposes.