In vitro bioassays have been successfully used to screen for estrogenic activity in wastewater and surface water, however, few have been applied to treated drinking water. Here, extracts of source ...and treated water samples were assayed for estrogenic activity using T47D-KBluc cells and analyzed by liquid chromatography-Fourier transform mass spectrometry (LC-FTMS) for natural and synthetic estrogens (including estrone, 17β-estradiol, estriol, and ethinyl estradiol). None of the estrogens were detected above the LC-FTMS quantification limits in treated samples and only 5 source waters had quantifiable concentrations of estrone, whereas 3 treated samples and 16 source samples displayed in vitro estrogenicity. Estrone accounted for the majority of estrogenic activity in respective samples, however the remaining samples that displayed estrogenic activity had no quantitative detections of known estrogenic compounds by chemical analyses. Source water estrogenicity (max, 0.47ng 17β-estradiol equivalents (E2Eq) L−1) was below levels that have been linked to adverse effects in fish and other aquatic organisms. Treated water estrogenicity (max, 0.078ngE2EqL−1) was considerably below levels that are expected to be biologically relevant to human consumers. Overall, the advantage of using in vitro techniques in addition to analytical chemical determinations was displayed by the sensitivity of the T47D-KBluc bioassay, coupled with the ability to measure cumulative effects of mixtures, specifically when unknown chemicals may be present.
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•Screen of U.S. source and treated water for estrogens and estrogenic activity.•T47D-KBluc bioassay reporting limits were below LC-FTMS method quantitation limits.•Drinking water treatment processes effectively reduced estrogenicity.•All samples were below estimated trigger values for adverse effects.•In vitro bioassay was an effective complement to targeted chemical analysis.
In vitro bioassays are sensitive, effect-based tools used to quantitatively screen for chemicals with nuclear receptor activity in environmental samples. We measured in vitro estrogen (ER), androgen ...(AR), and glucocorticoid receptor (GR) activity, along with a broad suite of chemical analytes, in streamwater from 35 well-characterized sites (3 reference and 32 impacted) across 24 states and Puerto Rico. ER agonism was the most frequently detected with nearly all sites (34/35) displaying activity (range, 0.054–116 ng E2Eq L–1). There was a strong linear relationship (r 2 = 0.917) between in vitro ER activity and concentrations of steroidal estrogens after correcting for the in vitro potency of each compound. AR agonism was detected in 5/35 samples (range, 1.6–4.8 ng DHTEq L–1) but concentrations of androgenic compounds were largely unable to account for the in vitro activity. Similarly, GR agonism was detected in 9/35 samples (range, 6.0–43 ng DexEq L–1); however, none of the recognized GR-active compounds on the target-chemical analyte list were detected. The utility of in vitro assays in water quality monitoring was evident from both the quantitative agreement between ER activity and estrogen concentrations, as well as the detection of AR and GR activity for which there were limited or no corresponding target-chemical detections to explain the bioactivity. Incorporation of in vitro bioassays as complements to chemical analyses in standard water quality monitoring efforts would allow for more complete assessment of the chemical mixtures present in many surface waters.
A hybrid process integrating vapor stripping with vapor compression and vapor permeation membrane separation, termed Membrane Assisted Vapor Stripping (MAVS), was evaluated for recovery and ...dehydration of ethanol from aqueous solution as an alternative to conventional distillation–molecular sieve processes. Ethanol removal/drying performance of the MAVS system with binary ethanol–water mixtures and a yeast fermentation broth were evaluated and the fate of secondary fermentation products in the system was assessed. Simple alcohols, esters, and organic acids displayed varying degrees of recovery in the vapor stripping based on the relative vapor–liquid partitioning of the compounds. All volatilized organic compounds were concentrated to the same degree in the membrane step. Membrane permeance, permselectivity, and overall energy usage of the hybrid process were the same with the fermentation broth as with binary ethanol–water solutions. The MAVS system required less than half the energy of a distillation–molecular sieve system.
Microcystins are toxic peptides that can be produced by cyanobacteria in harmful algal blooms (HABs). Various analytical techniques have been developed to quantify microcystins in drinking water, ...including liquid chromatography tandem mass spectrometry (LC/MS/MS), enzyme linked immunosorbent assay (ELISA), and oxidative cleavage to produce 2-methyl-3-methoxy-4-phenylbutyric acid (MMPB) with detection by LC/MS/MS, the “MMPB method”. Both the ELISA and MMPB methods quantify microcystins by detecting a portion of the molecule common to most microcystins. However, there is little research evaluating the effect of microcystin chlorination by-products potentially produced during drinking water treatment on analytical results. To evaluate this potential, chlorinated drinking water samples were fortified with various microcystin congeners in bench-scale studies. The samples were allowed to react, followed by a comparison of microcystin concentrations measured using the three methods. The congener-specific LC/MS/MS method selectively quantified microcystins and was not affected by the presence of chlorination by-products. The ELISA results were similar to those obtained by LC/MS/MS for most microcystin congeners, but results deviated for a particular microcystin containing a variable amino acid susceptible to oxidation. The concentrations measured by the MMPB method were at least five-fold higher than the concentrations of microcystin measured by the other methods and demonstrate that detection of MMPB does not necessarily correlate to intact microcystin toxins in finished drinking water.
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•Three analytical methods for microcystins were compared to evaluate interference from chlorination by-products.•An indirect method detecting MMPB yielded high concentrations due to chlorination by-products for all microcystins tested.•Interferences with an ELISA method were only detected when the site of modification occurred on a variable amino acid.
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•A suite of in vitro assays was applied to detect biological activity.•Estrogenic and glucocorticoid activity in effluent was corroborated by multiple bioassays.•Estrogenic activity ...verifies estrogen concentrations below chemical detection limits.•Most biological activity was below method detection limits in unfinished treated drinking water.
Although endocrine disrupting compounds have been detected in wastewater and surface waters worldwide using a variety of in vitro effects-based screening tools, e.g. bioassays, few have examined potential attenuation of environmental contaminants by both natural (sorption, degradation, etc.) and anthropogenic (water treatment practices) processes. This study used several bioassays and quantitative chemical analyses to assess residence-time weighted samples at six sites along a river in the northeastern United States beginning upstream from a wastewater treatment plant outfall and proceeding downstream along the stream reach to a drinking water treatment plant. Known steroidal estrogens were quantified and changes in signaling pathway molecular initiating events (activation of estrogen, androgen, glucocorticoid, peroxisome proliferator-activated, pregnane X receptor, and aryl hydrocarbon receptor signaling networks) were identified in water extracts. In initial multi-endpoint assays geographic and receptor-specific endocrine activity patterns in transcription factor signatures and nuclear receptor activation were discovered. In subsequent single endpoint receptor-specific bioassays, estrogen (16 of 18 samples; 0.01 to 28 ng estradiol equivalents E2Eqs/L) glucocorticoid (3 of 18 samples; 1.8 to 21 ng dexamethasone equivalents DexEqs/L), and androgen (2 of 18 samples; 0.95 to 2.1 ng dihydrotestosterone equivalents DHTEqs/L) receptor transcriptional activation occurred above respective assay method detection limits (0.04 ng E2Eqs/L, 1.2 ng DexEqs/L, and 0.77 ng DHTEqs/L) in multiple sampling events. Estrogen activity, the most often detected, correlated well with measured concentrations of known steroidal estrogens (r2 = 0.890). Overall, activity indicative of multiple types of endocrine active compounds was highest in wastewater effluent samples, while activity downstream was progressively lower, and negligible in unfinished treated drinking water. Not only was estrogenic and glucocorticoid activity confirmed in the effluent by utilizing multiple methods concurrently, but other activated signaling networks that historically received less attention (i.e. peroxisome proliferator-activated receptor) were also detected.
BACKGROUND
In Part1 of this work, a process integrating vapor stripping, vapor compression, and a vapor permeation membrane separation step, ‘membrane assisted vapor stripping’ (MAVS), was predicted ...to produce energy savings compared with traditional distillation systems for separating 1‐butanol/water and acetone‐butanol‐ethanol/water (ABE/water) mixtures. Here, the separation performance and energy usage of a MAVS pilot system with such mixtures and an ABE fermentation broth were assessed.
Results
The simple stripping process required 10.4 MJ‐fuel kg–1‐butanol to achieve 85% butanol recovery from a 1.3 wt% solution. Addition of the vapor compressor and membrane unit and return of the membrane permeate to the column raised 1‐butanol content from 25 wt% in the stripping vapor to 95 wt% while cutting energy usage by 25%. Recovery of secondary fermentation products from the ABE broth were based on their relative vapor–liquid partitioning. All volatilized organic compounds were concentrated to roughly the same degree in the membrane step. Membrane permeance, selectivity, and overall MAVS energy usage were the same with the broth as with the ABE/water solution.
Conclusion
Energy usage of the MAVS experimental unit corroborated process simulation predictions. Simulations of more advanced MAVS designs predict 74% energy savings compared with a distillation–decanter system. Published 2013. This article is a U.S. Government work and is in the public domain in the USA
Steroid hormones are vital for regulation of various biological functions including sexual development. Elevated concentrations of natural and synthetic androgenic steroids have been shown to ...adversely affect normal development in indigenous aqueous species. Androgens and their synthetic analogs released from agricultural activities and wastewater discharge may be introduced into drinking water sources. The fate of androgenic steroids during drinking water treatment, specifically the use of chlorine for biological control, has not been extensively studied. As such, this study focuses on the hypochlorite oxidation of a select number of androgenic compounds that vary in their structural composition. Where a favorable reaction is observed, we also attempt to describe the product distribution. The results show compounds that possess a ketonic functional group conjugated with a double bond inhibit oxidation by hypochlorite in the absence of biological or indirect oxidative pathways. Oxidative reactivity in the presence of hypochlorite was favorably correlated with the presence of isolated unsaturated carbon bonds and resulted in various transformation products.
The National Exposure Research Laboratory of the U.S. Environmental Protection Agency conducts research to measure exposure of individuals to chemical pollutants through the diet. In support of this ...research, methods are being evaluated for the determination of pesticides in dietary composite samples. In the present study, Soxhlet, blender, microwave-assisted, pressurized fluid, and supercritical fluid extraction methods were compared for the determination of incurred and added pesticides in 4 dietary composites, which varied in fat and water content. Incurred pesticides were chlorothalonil, chlorpyrifos, DDE, dicloran, dieldrin, endosulfan I, malathion, cis- and trans-permethrin, and trifluralin. Added pesticides were alpha- and gamma-chlordane, hexachlorobenzene, and fonofos. Concentrations of the individual pesticides were between 0.2 and 20 ng/g composite. All 5 methods tested could extract pesticides from dietary composites. Most incurred pesticides were recovered from the dietary composites within the range of 59-140% of expected values. Recoveries of added pesticides were between 60 and 130%. Microwave-assisted extraction led to significantly higher concentrations of 7 pesticides. Blender extraction yielded significantly higher concentrations of chlorothalonil and fonofos. Water content was a significant factor in the recovery of chlorothalonil, and fat content was a significant factor in the recovery of fonofos. In designing an exposure study, the selection of the extraction method would be determined by number of samples to be extracted, analyte stability, and cost.
Ten low-order streams draining headwater catchments within the East Fork Little Miami Watershed were evaluated throughout one year for the presence of six steroidal hormones, the antibiotic ...sulfamethoxazole, the antimicrobials triclosan and triclocarban, and the artificial sweetener sucralose. The wastewater management practices in the catchments included septic systems, sanitary sewers, a combination of both, and a parkland with no treatment systems. The concentrations and detection frequencies of sucralose showed a significant positive correlation with the septic density in each catchment. A similar relationship was found for sulfamethoxazole. Both sucralose and sulfamethoxazole are hydrophilic and unlikely to be removed effectively by sorption during septic treatment. The concentrations and detection frequencies of the antimicrobials were also positively correlated with septic density. The presence of the antimicrobials in the streams indicates that although they are hydrophobic, removal during septic treatment was incomplete. The target analytes that correlated with septic density were also detected in stream samples collected below a wastewater treatment plant located within the same watershed. The steroidal hormone estrone was the most frequently detected analyte at all sites. However, the estrone concentrations and detection frequencies did not correlate with the septic density due to multiple non-point sources.
A correlation between occurrence of four xenobiotic contaminants in headwaters and septic density in catchments was observed over one year.
Ten low-order streams draining headwater catchments within the East Fork Little Miami Watershed were evaluated throughout one year for the presence of six steroidal hormones, the antibiotic ...sulfamethoxazole, the antimicrobials triclosan and triclocarban, and the artificial sweetener sucralose. The wastewater management practices in the catchments included septic systems, sanitary sewers, a combination of both, and a parkland with no treatment systems. The concentrations and detection frequencies of sucralose showed a significant positive correlation with the septic density in each catchment. A similar relationship was found for sulfamethoxazole. Both sucralose and sulfamethoxazole are hydrophilic and unlikely to be removed effectively by sorption during septic treatment. The concentrations and detection frequencies of the antimicrobials were also positively correlated with septic density. The presence of the antimicrobials in the streams indicates that although they are hydrophobic, removal during septic treatment was incomplete. The target analytes that correlated with septic density were also detected in stream samples collected below a wastewater treatment plant located within the same watershed. The steroidal hormone estrone was the most frequently detected analyte at all sites. However, the estrone concentrations and detection frequencies did not correlate with the septic density due to multiple non-point sources.
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