Occurrence and fate of bacterial endotoxins in the environment (air, water, wastewater) and remediation technologies: An overview

Endotoxins as the outer membrane of most Gram-Negative Bacteria (GNB) and typical toxic biochemical produced by microorganisms are identified as one of the emerging pollutants. These microbial by-products are harmful compounds that can be present in various environments including air, water, soil, and other ecosystems which were discussed in detail in this review. Environmental and occupational exposure caused by endotoxin occurs in water and wastewater treatment plants, industrial plants, farming, waste recovery, and composting facilities. Even though the health risk related to endotoxin injection in intravenous and dialysis are well identified, the harmful effects of ingestion, inhalation, and other way of exposure are not well quantified and there is insufficient information on the potential health risks of endotoxins exposure in water environments, and another exposure. Because of limited studies, the outbreaks of diseases related to endotoxins in the various source of exposure not been well documented. Endotoxin removal from different environments are investigated in this review. The results of various studies have shown that conventional treatment methods have been unable to remove endotoxins from water and wastewater, therefore, monitoring the effectiveness of these processes in controlling this contaminant and also using the appropriate removal method is essential. However, management of water and wastewater treatment processes and the use of advanced processes such as Advanced Oxidation Processes (AOPs) can be effective in monitoring and reducing endotoxin levels during water and wastewater treatment. One of the limitations of endotoxin monitoring is the lack of sufficient information to develop monitoring levels. In addition, the lack of guidelines and methods of controlling them at high levels may cause irreparable disaster. [Display omitted] •Endotoxins produced by bacteria are identified as one of the emerging pollutants in environment.•The exposure route, environmental and health risks in different environments are reviewed.•The concentration of endotoxin in bio-aerosols and processes of water and wastewater treatment are reviewed.•The removal and inactivation of endotoxins by different treatment processes were compared.