Health risks and economic costs of exposure to PCDD/Fs from open burning: a case study in Nairobi, Kenya

Abstract

This study assesses the incremental health risk of exposure to dioxins and furans (PCDD/Fs) from indiscriminate burning of wastes in Nairobi and the potential economic benefits of reductions in dioxin-induced cancer mortality contributed by proper waste management. Fugacity models level III incorporated with the Human Health Risk Assessment Protocol (HHRAP) (USEPA 2005a) and CalTOX were utilized to simulate the PCDD/F levels in biotic environmental compartments. PCDD/F concentrations in samples of potatoes, eggs, beef, and long life milk were analyzed and compared with the modeled values. The PCDD/F concentration of 3.35 pg TEQ/g in the milk sample was observed to rank the highest in food samples and exceeded the European Union criteria. Comparison results suggest that the level III + HHRAP is more conservative than CalTOX in health risk assessment. Regularities in the analyzed WHO-TEQ congener profiles for the food samples were discussed. The incremental dietary exposure to PCDD/Fs for the residents in Nairobi was estimated to be 0.08–2.15 pg TEQ/kg-day, falling within the WHO tolerable daily intake of 1–4 pg TEQ/kg-day. Potential excess cancers due to dietary exposure to PCDD/F associated with all illegal waste burning in Nairobi were estimated to be 636 cases over the 30-year time period or 21 cases/year, accounting for 0.05 % of cancer cases in the entire country of Kenya. With the waste recycling rate increased by 5 % and the opening of the new sanitary landfill that can reduce 50 % of waste disposed at the Dandora dumpsite, the economic benefits of avoided cancer deaths is expected to be US$ 0.16–1.93 million. These results indicate that additional actions on waste management, e.g., waste minimization and construction of sanitary landfill, should be implemented for the public health of Kenyans.