Assessment of Health Risks from a Closed Landfill with FRAMES Model Using Groundwater and Leachate Monitoring Data

摘要

To assess the health risks from closed case study landfill, leachate quality was evaluated based on existing data and future trends were projected using time series models for contaminants of concern. The selected contaminants detected in leachate were compared with those detected in groundwater wells. The risk assessment was conducted using the Framework for Risk Analysis Multimedia Environmental Systems (FRAMES) program to estimate health risks based on the migration pathway. A total of 46 parameters was monitored in leachate. Among these parameters, 26 were always below detection limit, 8 were always above groundwater maximum concentration limit (MCL), and 10 were below the MCL. The leachate samples collected at the end of the dry season (April) had high contamination levels while the samples collected at the end of the rainy season (August) had lower levels due to dilution by infiltrating rain water. Seasonally in graphs was identified by regularly spaced peaks and troughs which had a consistent direction and approximately the same magnitude every season. Therefore, the data were analyzed by the time series decomposition method which separates the times series into linear and seasonal components as well as error, for forecasting. FRAMES was used for assessment of the health risks due to groundwater contamination. The source in the aquifer, exposure pathways, receptor intakes and health impacts modules were defined based on landfill conditions. Vinyl chloride, chlorobenzene, 1,4 dichlorobenzene, chromium, cadmium, iron, arsenic, and ammonia as nitrogen were found to be groundwater contaminants. Overall human health risks associated with these contaminants were evaluated in terms of carcinogenic and non carcinogenic effects.