Evaluation of wastewater treatment by ozonation for reducing the toxicity of contaminants of emerging concern to rainbow trout (Oncorhynchus mykiss)

Abstract

Although conventional wastewater treatment technologies are effective at removing many contaminants of emerging concern (CECs) from municipal wastewater, some contaminants are not removed efficiently. Ozonation may be a treatment option for reducing the concentrations of recalcitrant CECs in wastewater, but this process may generate toxic transformation products. In the present study, we conducted semibatch experiments to ozonate municipal wastewater effluent spiked with 5 commonly detected CECs. The purpose of the present study was to evaluate whether ozonation increased or decreased biological responses indicative of sublethal toxicity in juvenile rainbow trout (Oncorhynchus mykiss) injected intraperitoneally (i.p.) with extracts prepared from ozonated and nonozonated wastewater effluent. Blood, liver, and brain tissues were collected from the fish at 72 h post injection for analysis of a battery of biomarkers. In fish i.p. injected with the extracts from nonozonated wastewater effluent, significant induction of plasma vitellogenin (VTG) was observed, but ozonation of the municipal wastewater effluent spiked with CECs significantly reduced this estrogenic response. However, in fish injected with extracts from spiked municipal wastewater effluent after ozonation, the balance of hepatic glutathione in its oxidized (glutathione disulfide [GSSG]) form was altered, indicating oxidative stress. Levels of the neurotransmitter serotonin were significantly elevated in brain tissue from trout injected with the extracts from ozonated spiked municipal wastewater effluent, a biological response that has not been previously reported in fish. Other in vivo biomarkers showed no significant changes across treatments. These results indicate that ozonation reduces the estrogenicity of wastewater, but may increase other sublethal responses. The increase in biomarker responses after ozonation may be because of the formation of biologically active products of transformation of CECs, but further work is needed to confirm this conclusion. Environ Toxicol Chem 2018;37:274-284. C 2017 SETAC

Toxicity of extracts from municipal wastewater to early life stages of Japanese medaka (Oryzias latipes) to evaluate removals of micropollutants by wastewater treatment

“…In the present study, we used solid phase extraction (SPE) to isolate and concentrate micropollutants and their transformation products from treated and untreated municipal wastewater, and we tested these extracts for toxicity to early life stages of Japanese medaka ( Oryzias latipes ). The concentrations of selected PPCPs and drugs of abuse in extracts prepared from these wastewater samples were previously reported, and in all cases the levels of these compounds were reduced as a result of wastewater treatment (Baalbaki et al ; Baalbaki et al ; Maya et al, ).…”

“…Our previous studies with extracts prepared from wastewater collected from WWTP 3 showed that ozonation significantly reduced the levels of the 5 model CECs but did not reduce oxidative stress (i.e., changes in ratios of reduced and oxidized glutathione) in juvenile trout exposed by intraperitoneal injection over 72 h to the same extracts (Maya et al, ). Treatment of wastewater by ozonation can result in the formation of transformation products that are more toxic than the original parent compounds (Lee and von Gunten ).…”

“…The spiked wastewater was extracted after ozonation (i.e., WW + 5 CECs + O 3 treatment) in experiments using a bench‐scale ozonation system. The semi‐batch ozonation experiment using ozone gas introduced into the reaction vessel was completed as described previously by Maya et al (). The ozone dose used for each experiment was calculated based on the chemical oxygen demand of the wastewater or the spiked reverse osmosis water used in the bench‐scale system.…”

“…Final effluent collected from another WWTP with secondary treatment was further treated by ozonation in a bench‐scale experiment. The sublethal biological responses of juvenile rainbow trout ( Oncorhynchus mykiss ) to exposure to unozonated and ozonated wastewater from this WWTP were previously described by Maya et al (). These 3 WWTPs were selected to evaluate changes in toxicity over a range of treatment technologies.…”

Estudios ecotoxicológicos para la gestión sustentable de efluentes líquidos urbanos y pecuarios

“…obtusa resultaron ser los organismos más sensibles a los efluentes urbanos tratados Los ELUs pueden contener una amplia variedad de compuestos con actividad estrogénica (Botts et al, 1989;Hutchings et al, 2004;Maya et al, 2018;Pessala et al, 2004;Smital et al, 2011) En sus estudios aplicando TIE en aguas residuales de origen doméstico, Bolts (1998) Actualmente no se cuenta con antecedentes de estudios de contenidos de compuestos prioritarios ni datos acerca de la toxicidad, sólo determinación de las concentraciones de metales pesados de interés (Pratts, 2011) en los canales de descarga de las plantas de tratamiento de Santa Rosa.…”