Assessing the Detoxication Efficiencies of Wastewater Treatment Processes Using a Battery of Bioassays/Biomarkers

Abstract

Abstract. A battery of in vitro bioassays, including a Neutral Red (NR) assay using MCF-7 cells for predicting cytotoxic chemicals, an ethoxy resorufin-O-deethylase (EROD) activity assay using H4IIE cells to check for dioxin-like chemicals, and a recombinant gene yeast assay for screening estrogenic chemicals, was conducted to assess the removal efficiencies of trace toxic chemicals by different treatment processes in the waste water treatment plant (WWTP). The effluents were extracted by solid phase extraction (SPE) and were fractionated into three fractions based on polarities. The battery of bioassays was performed for each fraction. In the battery, the toxicities of the effluents were described according to their modes of actions (MOA) or biomarkers and the properties of the toxic chemicals were categorized by their polarities and MOAs. The proposed procedure could be used as a tool to diagnose the toxic characteristics of the complicate mixture. The results showed that cytotoxic, dioxin-like and estrogenic chemicals could be detected in all samples. In the influent, cytotoxic and dioxin-like chemicals were mainly in polar fraction and estrogenic chemicals were in non-polar and moderate-polar fractions. The secondary treatment (active sludge) could remove a small amount of these toxicants. Among different types of advanced treatments, flocculation was good enough to remove most of the cytotoxic chemicals and a combination of flocculation, ozone oxidation, and post-biological treatment could eliminate most of the dioxin-like and estrogenic chemicals.

Combined chemical and toxicological long-term monitoring for AhR agonists with SPMD-based virtual organisms in drinking water Danjiangkou Reservoir, China

“…The bioavailable water concentrations of AhR activity TEQ bio in SPMDs from DJK were much lower compared to effluents from wastewater treatment plants in ng TCDD EQ L À1 ) Macova et al, 2010), and also lower than some Chinese effluents (<14 pg TCDD EQ L À1 ) (Ma et al, 2005). Since very few references could be available on study of AhR activity in surface or drinking water, it is hard to compare the results of the present study to other water bodies in the world.…”

“…This enzymatic assay is a sensitive biomarker to characterize the existence of toxic organic pollutants in complex environmental media that can disrupt CYP1A enzyme system. The combination of the EROD bioassay with chemical analysis has been largely used to evaluate the AhR activity in sediment and soil (Kinani et al, 2010;Shen et al, 2008;Qiao et al, 2006;Hong et al, 2012), and effluents of wastewater treatment plants (Dagnino et al, 2010;Ma et al, 2005;Reungoat et al, 2010). But few references could be available on evaluating AhR activity in surface water (Rastall et al, 2004).…”

Water exposure assessment of aryl hydrocarbon receptor agonists in Three Gorges Reservoir, China using SPMD-based virtual organisms

“…Our finding indicates that AhR agonist pollution was highly affected by urbanization. The bioavailable water concentrations of more persistent AhR agonists in VOs from TGR ranged from 0.8 to 4.8 pg TCDD L −1 which were much lower compared to effluents from wastewater treatment plants in Australia (0.59-0.98 ng TCDD L − 1 ) Macova et al, 2010), and also lower than some Chinese effluents (b14 pg TCDD EQ L −1 ) (Ma et al, 2005). These values were close to a drinking water reservoir in China (Wang et al, 2014b) and were also below the Drinking Water Maximum Contaminant Level (MCL value) (30 pg TCDD L −1 ), recommended by the US EPA (2011).…”

Chlorination by-products of bisphenol A enhanced retinoid X receptor disrupting effects

“…The yeast assay was carried out according to our previous works [29,32]. All samples were determined at least in triplicate.…”