Composite toxicity assays for enhanced assessment of decentralized potable reuse systems

Abstract

Decentralized direct potable reuse systems present new opportunities for resilient and sustainable facilities of the future, but potential risks must be studied carefully using advanced methods that consider potential toxicity from known and unknown oxidation byproducts.

Disinfection Byproduct Recovery during Extraction and Concentration in Preparation for Chemical Analyses or Toxicity Assays

“…While THMs and HAAs have been used to measure DBP exposure for epidemiology studies, there is growing interest in measuring unregulated (semi-)­volatile classes (e.g., haloacetonitriles) based on studies indicating that they could contribute more to the cytotoxicity of disinfected waters and that their concentrations do not correlate with THM concentrations . Recoveries of unregulated, (semi-)­volatile DBPs were lowest for XAD resin extraction (<30%), one of the most frequently employed techniques, ,− , including the U.S. EPA studies. , While recoveries were generally higher with SPE and LLE, they were below 70% for most of the (semi-)­volatile DBPs examined. Even these mediocre recoveries required solvent exchange, risking the potential for toxicity associated with incomplete removal of MtBE or EtOAc from the DMSO during N 2 blowdown.…”

“…As most DBPs occur at relatively low concentrations (ng/L to μg/L levels) in disinfected water, extraction and concentration are needed to identify novel DBPs and facilitate the detection of biological effects in toxicity assays. Solid-phase extraction (SPE) using XAD resins has been used extensively to extract and concentrate DBPs in disinfected waters for bioassays, ,− including a standard operating procedure for studies by the U.S. EPA . XAD resin extraction typically involves passing ≥10 L of disinfected water through a mix of XAD-2 and XAD-8 resins, eluting the sorbed compounds with ethyl acetate, and concentrating the extract to ≤1 mL using rotoevaporation and nitrogen (N 2 ) blowdown .…”

Comparison of Estrogenic, Spectroscopic, and Toxicological Analyses of Pilot-Scale Water, Wastewaters, and Processed Wastewaters at Select Military Installations

“…Water samples (20 L) were collected from four U.S. Army sites that hosted pilot-scale technology demonstrations in Kansas, Missouri, Ohio, and Pennsylvania (United States). Details of the design scenarios, treatment trains, and sampling were previously published. , We used the “CERL” (Construction Engineering Research Laboratory) abbreviations for the water samples that were generated at CERL and used in this study. In brief, four military design scenarios were studied: centralized supply and decentralized low energy wastewater treatment (samples CERL3, CERL2, CERL5, and CERL4), conventional centralized supply and wastewater management (samples CERL7, CERL6, and CERL8), on-site DPR (samples CERL11, CERL13, and CERL12), and onsite gray water recycling (samples CERL1, CERL9, and CERL10) (Table S1).…”

“…8,11−17 We reported the comparative toxicity of waters prior to and post DPR treatments at Army installations. 7,14 Although not federally regulated in drinking waters, 18 EDCs can cause adverse biological effects on vertebrates at very low concentrations (10−100 ng/L). 19 Recently published reviews addressed the concern of the adverse effects of EDCs upon the environment and health.…”

“…These in vitro quantitative bioassays generate estrogen and toxicity metrics across treatment strategies to define processes that may reduce potential health risks from reclaimed wastewaters . A similar approach was used to evaluate the toxicity of DBPs in waters. ,− We reported the comparative toxicity of waters prior to and post DPR treatments at Army installations. , …”