Implementation of Swedish Risk Assessment Guidelines in Kodaikanal, India : A Study of Mercury Contamination in an Area Near a Former Thermometer Factory

Sammanfattning: The aim of the project was to make a detailed risk assessment using Swedish guidelines for a factory site in Kodaikanal, South India, and a nearby village called Vellagavi. The study areas were chosen due to previous records of mercury contamination on the factory site and a possible spread to Vellagavi. A comparison between Indian and Swedish guidelines for risk assessment of contaminated areas was performed. The purposes of comparing the two systems were to locate if there were any differences in the legislation, or guidelines, and to find ways of improving the processes. The project also included an evaluation of possible remedial actions that could reverse or prevent environmental damage that might be caused by the former factory. Methods used for the project were literature studies, semi-structured interviews and surveys. The results from the risk assessment were that the Swedish Computer Program for Calculation of Guideline Values (CPCGV), with some adjustments, could be used in order to calculate site specific guideline values for mercury concentrations on sites similar to Swedish conditions, such as climate. The site specific guideline values in soil rangedfrom 0.1-2.4 mg/kg. An Indian court decision had stated that a guideline value of 20 mg/kg should be used for remediation at the factory site. The result from the forward dose calculation showed that when a soil contains 20 mg/kg,the tolerable daily intake of mercury would be exceeded, and therefore pose a risk to human health. The comparison of legislation systems between India and Sweden showed several differences. India did not have any legislation relating directly to polluted soil. Risk assessments in India commonly relied on several different international standards even though the standards were not regulated by law. The results from the remedial evaluation showed that there were several possible remediation methods that could beused on the factory site. Limited remedial actions were suggested for Vellagavi since there were no measurements taken on site. Preferably, remediation should take place at the source of the contamination, i.e. the factory site.