Unique Applications of Chromatography

Analysis of Estrogens in Wastewater Effluent with the Addition of Humic SubstancesKelly GiffearDr. Victoria Del Gaizo MooreDepartment of ChemistryElon UniversityOverviewBackgroundWastewater treatment plantsEndocrine-disruptor compoundsEPAs responsePast ResearchCurrent ResearchConclusionsFuture Experiments

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Image from biosolids.com.auEndocrine Disruptors (EDC)Any compound that interferes with normal hormone function

Class of compounds defined by biological function rather than chemical nature

Mechanisms of actionMimicBlockStimulateDestroy

EDCsHormonesEstrogensPolychlorinated BiphenylsPesticidesHeavy MetalsSurfactants Alkylphenol EthoxylatesNitrate potential EDC6Hormones estrogenic compoundsSurfactants alkylphenol ethoxylate surfactants

Effects of EDCsEndocrine disruptors (including estrogens) have been found to:

Affect growth, development, reproduction in plants and animals

Cause intersexuality in fish

Affect sex determination in turtles

Cause egg shell thinning in birds

7Endocrine disruptors affect growth, development and reproduction in plants and animals.Specific examples include causing intersexuality in fish where a male fish develops female reproductive organs, interupting sex determination in turtles and egg shell thinning in birds.All of these interactions lead to a decline in a species population.The next question is where are these harmful chemicals coming from?

Location of 139 stream sampling sites.

Koplin, D.W.; Furlong, E.T.; Meyer, M.T.; Thurman, E.M.; Zaugg, S.D.; Barber, L.B.; Buxton, H.T. Environ. Sci. Technol. 2002, 36, 1202-1211.Survey of US watersSurvey of US WatersFrequency of detection of organic wastewater contaminants by general use category. Number of compounds in each category shown above bar.

Koplin, D.W.; Furlong, E.T.; Meyer, M.T.; Thurman, E.M.; Zaugg, S.D.; Barber, L.B.; Buxton, H.T. Environ. Sci. Technol. 2002, 36, 1202-1211.

OHHHHCH3OHOHEstriol (E1)OHHHHCH3OH17b-Estradiol (E2)OHHHHCH3OHCH17a-Ethynyl Estradiol (E3)17OHHHHCH3OEstrone (E4)17Estrogen Structures10For this research, we focused on four estrogens, estriol, 17beta estradiol, 17 alpha ethynylestradiol and estrone 3 of which are found naturally in the human body and 1 synthetic. EPA ResponseThe EPA does not regulate estrogen levels in water

Due to lack of regulation, wastewater treatment may or may not be removing estrogens

In 1996, the EPA identified endocrine disruption as one of its top six research priorities

LTG 1: Provide a better understanding

LTG 2: Determine the extent of impact

LTG 3: Support testing program.

www.epa.gov/endocrine/ 11The Environmental Protection agency does not regulate estrogen levels in water. Due to this lack of regulation it is unknown whether or not wastewater treatment plants are removing estrogens from sewage before it is returned to the river.Recently there has been an increase in research in this area because in 1996 the EPA stated that endocrine disruption was one of its top six research priorities. Past ResearchSolid-phase extraction (SPE)/high performance liquid chromatography (HPLC) analysisSpeciation and concentrations of each estrogen

Extracted estrogens from clean water and wastewater effluentOn site sample extractionElution in labCollected on Alltech high-flow C18 cartridges

Started by Dr. Lisa Ponton - 12Spiked Milli-Q SampleTime (min)0123456785 mAuestriol17b-estradiol17a-ethynyl estradiolestroneE1E2E3E4Spikedconc.23.220.221.320.2MeasConc.8.1915.718.618.6% loss64.822.212.57.9Concentrations in mg/LDr. Ponton, unpublished data0246810Time (min)50 AU6.0 mg/L20.0 mg/L80.0 mg/LPeak Area vs. ConcentrationE1E2E3E4Dr. Ponton, unpublished data14The HPLC produces chromatograms where there is a linear relationship between peak area and concentration. From these series of chromatograms, you can see that as the concentration increases from 6.0mg/L to 80 mg/L, the area of each peak also increases. From doing a series of increasing concentrations and plotting the concentration verses the peak area, we can produce what is called a calibration curve. Calibration CurveR2 0.9996n = 3 to 502468101214161820020406080100Concentration (mg/L)Peak Areaestriolb-estradiol17a-ethynyl estradiolestroneDr. Ponton, unpublished data15The calibration curve illustrates the linear relationship between concentration and peak area. The r squared value for each of the 4 lines was greater than or equal to 0.9996 displaying the accuracy of the relationship because the closer the r squared value is to one, the closer the data is to perfect linearity.

The estrogens are found in very low concentrations in large samples of water. In order to be able to detect them, we must remove the estrogens in order to make a sample with only a little bit of liquid and a lot of estrogens. In order to do this, a procedure called an extraction is performed.

Wastewater Effluent Sampling SiteGraham wastewater treatment facility

Sample StorageAcidified to pH ~3 Stored at 4 C

Wastewater Effluent Chromatogram02468101214161820Time (min)50 mAuNo estrogens extractedPeak observed has unknown identityDr. Ponton, unpublished data17An effluent sample was filtered, run through solid phase extraction and then analyzed using high performance liquid chromatography. This chromatogram resulted.One main peak of an unretained species with unknown identity was observed. There are no peaks displayed that demonstrate estrogen presence in the sample.We wanted to get an idea of what an effluent chromatogram with estrogens present would look like so we spiked a sample with estrogens and ran it through the analysis.Spiked WW Effluent Chromatogram10 mg/L water sample concentrationNo estrogens detected02468101214161820Time (min)5 mAuDr. Ponton, unpublished data18For this sample a water concentration of 10mg/L of each of the four estrogens was created. Once again, from the chromatogram you can see that there are no estrogens detected because there are no peaks present.This was quite alarming and raised question because we knew that there were estrogens in the water but the analysis was telling us otherwise.So we went back to the literature to see if we could find a possible explanation. 3 hypothesesIrreversible binding to something

Reversible binding/equilibrium

Not bound, but blocking activity and masking concentration

Humic Substances to Blame?Yamamoto, H. Environ. Sci. Technol. 2003, 37, 2646-2657

Alginic Acid2

Tannic Acid21 Stevenson F.J. (1982): Humus chemistry. Genesis, composition, reactions. John Wiley and Sons. 2 http://www.genome.jp/Humic Acid120One paper suggests that humic substances could be interfering with the extraction of the estrogens. Estrogens have a high affinity for humic substances due to their polar characteristics, as can be seen from the many polar functional groups present.It is expected that the estrogens bind to the humic substances which are not extracted by the SPE method currently used. The humic substances are large and very polar causing them to prefer the water phase rather than the non polar C18 stationary phase. The next step is to test this theory. Macromolecule (>1000 MW), Decomposition of vegetation, Classified on solubility, Humic acid, Fulvic acid, and Humin3 possibilities = irreversibly bindings, masking activity, or equilibriumProject GoalsAre humic substances interfering with estrogenic activity in wastewater?Clean water and wastewater samples

If so, how are humic substances interfering with estrogenic activity?

MethologyYeast -Galactosidase AssayNeeded an assay effectively assess estrogens in wastewater using a colormetric scaleKit from ThermoScientific

Bakers YeastFrom Dr. Balsiger (University of Texas)Deleted PDR5 geneInsert pG/ER and pUCSS-ERE plasmids

Assay ProtocolGrow yeast cultures in SC-UW media overnight at 37CDilute cultures to OD650=0.08-0.1Add treatments (estrogen and/or humic substances)Incubate at 37C for 2 hoursRecord OD650 and A450 for baseline dataAdd assay bufferRecord OD650 and A450 at 15 and 30 mins.Are recombinant yeast estrogen sensitive?1 = Media and Yeast; 2= Media, Yeast, Estrogen; n=6Do Humic Substances have estrogenic activity?Relative concentrations of HS 1=0.1;2=0.01;3=0.001;4=0.0001; n=1Preliminary results with Humic Substancesn=1ConclusionsYeast incubated with estrogen are 3-5 times as sensitive than yeast without estrogen

Humic substances do not inherently have estrogenic activity

Humic substance added to estrogen decreases the estrogenic activity ten-fold

Future Experiments Repeating experiments in wastewater effluent Does protocol translate in true environment settingSpiked samples vs. natural samples

ELISA assay with pure water spiked with estrogen and humic substancesHow do estrogen and humic substances bind

ELISA assay with wastewater effluent Spiked samples vs. natural samples

AcknowledgementsFunding

Elon University Chemistry Department

Elon University Lumen Scholars Program

Elon College Fellows Program

MentorsDr. Victoria Del Gaizo MooreDr. Lisa M. Ponton

YeastDr. H.A. Balsiger

Samples

Graham Wastewater Treatment Facility