Dioxins emissions from bio-medical waste incineration: A systematic review on emission factors, inventories, trends and health risk studies

COVID-19 has aggravated the biomedical waste generation all over the world and the concern for its safe disposal is on the rise. The vast majority of healthcare systems employ incineration as their treatment method considering its agility to reduce the waste volume by up to 95-96% and high-temperature inactivation of infectious biological materials. However, incinerator emission is a significant contributor of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) according to various national inventories across the globe. Bio-Medical Waste Incinerators (BMWIs) are the dominant form of incinerator plants in developing nations and hence BMWI emissions were found to contribute lion's share of national dioxins inventories in most of these countries. The Stockholm Convention on POPs played a key role in imbibing significant urge on the dl-POPs monitoring studies of incinerators internationally and on controlling the average incinerator emission levels. Though many national/international agencies endorse a stringent incinerator stack emission standard of 0.1 ngTEQ/Nm3, there are some differences observed in nation-to-nation regulatory scenarios. This paper reviews and reports on the dioxins emission and health risk studies associated with bio-medical waste incineration over the last three decades (1990-2020) with a comprehensive spatial and temporal emission trend analysis. An overview of important national and international regulations, national inventories and emission factors for the biomedical waste incineration sector is also reviewed in detail. The study observes that continuous regulatory monitoring and logical relaxations can enhance the performance of the existing facilities ensuring low emissions and minimal risk.