Development of Toxicological Risk Assessment Models for Acute and Chronic Exposure to Pollutants

Abstract

Alert level frameworks advise agencies on a sequence of monitoring and management actions, and are implemented so as to reduce the risk of the public coming into contact with hazardous substances. Their effectiveness relies on the detection of the hazard, but with many systems not receiving any regular monitoring, pollution events often go undetected. We developed toxicological risk assessment models for acute and chronic exposure to pollutants that incorporate the probabilities that the public will come into contact with undetected pollution events, to identify the level of risk a system poses in regards to the pollutant. As a proof of concept, we successfully demonstrated that the models could be applied to determine probabilities of acute and chronic illness types related to recreational activities in waterbodies containing cyanotoxins. Using the acute model, we identified lakes that present a ‘high’ risk to develop Day Away From Work illness, and lakes that present a ‘low’ or ‘medium’ risk to develop First Aid Cases when used for swimming. The developed risk models succeeded in categorising lakes according to their risk level to the public in an objective way. Modelling by how much the probability of public exposure has to decrease to lower the risks to acceptable levels will enable authorities to identify suitable control measures and monitoring strategies. We suggest broadening the application of these models to other contaminants.

Engineered nanoparticles: Hazards and Risk Assessment upon Exposure-A Review

“…Its main outcome is a statement of the probability that when humans or other environmental receptors (e.g., plants, animals) are exposed to a chemical agent, they will be harmed and to what degree. The CRA methodology is internationally recognized and employed by major actors, such as the World Health Organization (WHO) and the Organization for Economic Co-operation and Development (OECD), as well as by several European and U.S. agencies [28].…”

The small, the big, and the beautiful: Emerging challenges and opportunities for waste stabilization ponds in Australia

“…Furthermore, the potential for release of effluent or recycled (reclaimed) water containing both cyanobacterial biomass, as suspended solids, and cyanotoxins, represents a significant risk to both humans and the environment. Releasing water that contains a high concentration of cyanobacterial biomass might adversely affect natural ecosystems, while contact with cyanobacteria cells can also lead to short-lived, irritative symptoms caused by unknown cyanobacterial substances (Ghadouani & Coggins, 2011;Huisman et al, 2018;Reichwaldt & Ghadouani, 2012;Reichwaldt, Stone, Barrington, Sinang, & Ghadouani, 2016;WHO, 2003). Most importantly, releasing water that contains cyanotoxins can pose a severe hazard to the environment and human health.…”

“…Cyanotoxins have an extensive toxicological profile, including hepatotoxins, dermatoxins, cytotoxins, neurotoxins, and lipopolysaccharides. These toxins can induce both acute and chronic effects, and may pose a risk to both humans and ecological systems (Babica, Hilscherova, Bartova, Blaha, & Marsalek, 2007;Carmichael, 2001;Christoffersen, 1996;Dawson, 1998;de Figueiredo, Azeiteiro, Esteves, Goncalves, & Pereira, 2004;Funari & Testai, 2008;Landsberg, 2002;Reichwaldt et al, 2016;Wiegand & Pflugmacher, 2005).…”

“…Please note that cyanobacterial biomass is on a logarithmic scale. WSPs in this case study were divided into three categories requiring different monitoring frequencies, with a requirement for very regular monitoring in the red category as established by a recently developed risk assessment framework (Barrington, Ghadouani, Sinang, & Ivey, 2014; Reichwaldt et al, 2016) cyanobacterial biomass and their toxins were considered. In particular, the reuse schemes where there was the potential of human exposure to toxins were identified and assessed based upon a risk-based approach developed for WSPs .…”

“…In general, the systems could be classified into four categories of increasing severity when both cyanobacterial biomass and their toxins were considered. In particular, the reuse schemes where there was the potential of human exposure to toxins were identified and assessed based upon a risk‐based approach developed for WSPs (Reichwaldt et al, ). The occurrence of high levels of cyanobacterial biomass was not positively correlated with microcystins, and only a small number of sites showed a prevalence of toxins after the water was discharged from the WSP (Figure ).…”