Concentrations, profiles, emission inventory, and risk assessment of chlorinated benzenes in bottom ash and fly ash of municipal and medical waste incinerators in northern Vietnam

Abstract

Concentrations and congener profiles of seven di-to hexachlorinated benzenes (CBzs) were characterized in bottom ash and fly ash samples collected simultaneously from one medical waste incinerator (MEWI) and one municipal waste incinerator (MUWI) in northern Vietnam. Total concentrations of seven CBzs in the fly ash samples ranged from 6.98 to 34.4 (median 19.1) ng g −1 in the MEWI, and ranged from 59.1 to 391 (median 197) ng g −1 in the MUWI. Concentrations of CBzs in the bottom ash samples of the MEWI (median 1.95; range 1.53-5.98 ng g −1 ) were also lower than those measured in the MUWI samples (median 17.4; range 14.5-42.6 ng g −1 ). Levels of CBzs in the fly ash samples were significantly higher than concentrations measured in the bottom ash samples, partially indicating the low-temperature catalytic formation of these pollutants in post-combustion zone. In general, higher chlorinated congeners (e.g., hexachlorobenzene, pentachlorobenzene, and 1,2,4,5-tetrachlorobenzene) were more abundant than lower chlorinated compounds. However, compositional profiles of CBzs were different between the ash types and incinerators and even between the same sample types of different sampling days, suggesting that the formation of CBzs in these incinerators is complicated and influenced by many factors. Emission factors and annual emission amounts of CBzs were estimated for the two incinerators by using actually measured data of CBz concentrations in the ash. Daily intake doses and cancer risks of ash-bound CBzs estimated for workers in the two incinerators were generally lower than critical values, but cancer risks caused by other relevant pollutants (e.g., polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and dioxin-related compounds) were not considered.

Study on Analysis of Total Organic Carbon (TOC) and Polycyclic Aromatic Hydrocarbons (PAHs) in Municipal Waste Incinerator Fly Ash and Bottom Ash

“…Tuy nhiên, các quá trình nhiệt độ cao có thể hình thành các chất ô nhiễm hữu cơ một cách không chủ định và các chất này có thể tích lũy trong tro thải, có thể tiềm ẩn những mối đe dọa đối với sức khỏe con người và môi trường [4]. Một số nghiên cứu gần đây đã báo cáo sự có mặt của hydrocarbon thơm đa vòng (PAHs) và các chất ô nhiễm hữu cơ khó phân hủy (POPs) như polychlorinated dibenzo-p-dioxins và furans (PCDD/Fs), polychlorinated biphenyls (PCBs), chlorobenzens (CBzs) trong các mẫu khí thải và tro thải được thu thập từ các lò đốt rác trên cả nước [5][6][7][8][9].…”

Development of a system dynamics model for dioxin flow and its application to the energy sector

“…The Fixed Pollution Sources of Harmful Pollutants Emissions Inventory Report of the US Environmental Protection Agency (USEPA) indicated that the iron and steel industry were the largest contributors to the total dioxin emissions. But the poor combustion techniques may release inorganic and organic pollutants into the environment through flue gas and residual ash (WHO, 1996;Porteous, 2001;Jones and Harrison, 2016;Nguyen et al, 2021).…”