In vitro bioassays to evaluate complex chemical mixtures in recycled water

Abstract

With burgeoning population and diminishing availability of freshwater resources, the world continues to expand the use of alternative water resources for drinking, and the quality of these sources has been a great concern for the public as well as public health professionals. In vitro bioassays are increasingly being used to enable rapid, relatively inexpensive toxicity screening that can be used in conjunction with analytical chemistry data to evaluate water quality and the effectiveness of water treatment. In this study, a comprehensive bioassay battery consisting of 36 bioassays covering 18 biological endpoints was applied to screen the bioactivity of waters of varying qualities with parallel treatments. Samples include wastewater effluent, ultraviolet light (UV) and/or ozone advanced oxidation processed (AOP) recycled water, and infiltrated recycled groundwater. Based on assay sensitivity and detection frequency in the samples, several endpoints were highlighted in the battery, including assays for genotoxicity, mutagenicity, estrogenic activity, glucocorticoid activity, aryl hydrocarbon receptor activity, oxidative stress response, and cytotoxicity. Attenuation of bioactivity was found to be dependent on the treatment process and bioassay endpoint. For instance, ozone technology significantly removed oxidative stress activity, while UV based technologies were most efficient for the attenuation of glucocorticoid activity. Chlorination partially attenuated genotoxicity and greatly decreased herbicidal activity, while groundwater infiltration efficiently attenuated most of the evaluated bioactivity with the exception of genotoxicity. In some cases, bioactivity (e.g., mutagenicity, genotoxicity, and arylhydrocarbon receptor) increased following water treatment, indicating that transformation products of water treatment may be a concern. Furthermore, several types of bioassays with the same endpoint were compared in this study, which could help guide the selection of optimized methods in future studies. Overall, this research indicates that a battery of bioassays can be used to support decision-making on the application of advanced water treatment processes for removal of bioactivity.

Predicting trace organic compound attenuation with spectroscopic parameters in powdered activated carbon processes

“…Advanced oxidation processes (AOPs) like ozone and UV with addition of hydrogen peroxide and other oxidants has proven to remove many TOrCs present in municipal wastewater (Wert et al, 2009;Wols et al, 2013;Park et al, 2015). However, studies also have shown that these AOPs result in transformation products, some of which are more toxic than the precursor compounds (Rizzo, 2011;Jia et al, 2015). Adsorption processes like granular activated carbon (GAC) and powdered activated carbon (PAC) are capable of removing significant amounts of TOrCs from water without forming byproducts Redding et al, 2009;Altmann et al, 2014).…”

Overview of Monitoring Techniques for Evaluating Water Quality at Potable Reuse Treatment Facilities

“…The conclusions of the study demonstrated that while there are limitations to bioassay techniques, they are a valid tool for water quality assessment that complement chemical analyses. A recent study incorporating 36 bioassays covering 18 biological endpoints indicated that a suite of bioassays can be useful in characterizing multiple toxicological pathways relevant to human health and can guide decision-making with regard to the treatment processes (Jia et al 2015). The science advisory panel, which convened in 2018 to evaluate risks from CECs in water treated for reuse, recommended that estrogen receptor alpha and the aryl hydrocarbon receptor bioassays be used to respectively assess estrogenic and dioxin-like biological activities in recycled water (Drewes et al 2018).…”

Qualitative and quantitative assessment of genotoxins usingSRRzlysis reporter under the control of a newly designed SOS responsive promoter inEscherichia coli

“…Especially, there are many chemicals are not readily identied because of their unknown structure, lack of pure sample preparation and detection method. 4,43,44 The rapid, less expensive and highthroughput technology was pursued, that could screen thousands of chemicals for potential genotoxicity in a relatively simple way. The rst use of a toxicity equivalence-like method for risk assessment purposes was described by Eadon et al (1986).…”

“…2,3 Moreover, these chemical monitoring methods are generally targeted to specic individual or groups of compounds, and do not provide information about health impacts or cumulative effects from complex mixture interactions. 4 These push forward the development of sensitive, cost-effective and relatively simple bacterial bioassays which can indicate the presence of unknown genotoxic chemicals, also estimate the contribution of unknown chemicals and chemicals below detection limits to the overall mixture effect.…”