Vrije Universiteit Brussel

Novel passive sampling for steroid hormones in aquatic environments using DGT andthe ERE-CALUX bioassay - Poster @ ChemCYS 2018Guo, Wei; Van Langenhove, Kersten; Elskens, Marc; Baeyens, Willy; Gao, Yue

Publication date:2018

Document Version:Final published version

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Citation for published version (APA):Guo, W., Van Langenhove, K., Elskens, M., Baeyens, W., & Gao, Y. (2018). Novel passive sampling for steroidhormones in aquatic environments using DGT and the ERE-CALUX bioassay - Poster @ ChemCYS 2018.Poster session presented at ChemCYS 2018, Blankenberge, Belgium.

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Download date: 19. Aug. 2020

Novel passive sampling for steroid hormones in water using Diffusive Gradients in Thin films and the ERE-CALUX bioassay

W. Guo1,2, K. Van Langenhove1, M. Elskens1, W. Baeyens1, Y. Gao1

1Vrije Universiteit Brussel (University of Brussels), Department of Analytical, Environmental and Geo-Chemistry (AMGC), Pleinlaan 2, 1050 Brussels, Belgium. 2School of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China

Framework Water Framework Directive consisting of 33 priority (hazardous) pollutants and 8

other chemicals under Annex II (2008/105/EC) in water quality assessment

Stringent detection limits for AA-EQS of watchlist chemicals (2013/39/EU)

Hormones at 0.035 ng/L and 0.4 ng/L for, respectively, EE2 and E2

• Classic spot sampling and sample pretreatment requires high volumes with

current chemical detection methods (GC/LC-MS-MS) in the range of 0,1-7ng/L

Objectives Development of a time-integrated passive sampler for in-situ determination of

estrogens in water using diffusive gradients in thin films (DGT) and having E2 as

a model contaminant

Independence of flow properties of the sampling environment requiring no post-

calibration for uptake and binding characteristics

Combined DGT approach with in vitro effect directed analysis for assessment of

mixture activity otherwise missed by conventional methods during field work

Results & Discussion Uptake capacity of XAD18 resin and experimental De

Adsorption to DGT components is minimal (less than 5%)

The XAD18 resin accumulates linearly and with an efficiency close to 100%

A theoretical diffusion coefficients Dt, 25°C for E2 (5.17-6 cm-2 s-1) in diffusive gel is

in close agreement to an experimental value for De, 25°C of (4.65 ± 0.37)-6 cm-2 s-1

and is comparable to the literature value in water Dw of 4.88-6 cm-2 s-1

Effect of pH, Ionic strength and DOM on DGT performance

The pH and Ionic strength range do not influence DGT uptake, while DOM is

retained on the filter membrane without reaching the diffusive layer (time: 24hrs)

The method detection limit (MDL) is based on the instrumental detection limit of

CALUX (0.024 pg E2) and applied dilutions. Over a deployment time of 1 day the

MDL reaches 0.026 ± 0.003 ng E2-eq./L

Field application and DBL (δ) measurement

Effluents of three sewage plants in Beijing, China were sampled by DGT and grab

sampling (sampling time: 6hrs)

DBL (δ) measurements in the lab (δ: 0.021cm) and field (δ: 0.022cm) justify the use

of a combined De of 5.16-6 cm-2 s-1 for estrogens

Spot sampling (mix of samples t:0 and t:6) is not different from DGT sampling for

Gaobeidian (GBD), Qinghe (QG), and Liangxiang (LX) stations

Conclusion Development of a novel passive sampling DGT device capable of measuring low

levels of estrogens (MDL of 0.026 ng E2-eq./L) and independent of river flows

Effective diffusive coefficient De, 25°C of (4.65 ± 0.37)-6 cm-2 s-1 for E2 in agarose and

δ determination of 0.022cm (field) that is non-negligible compared to Δg (0.092cm)

Future applications with multiple DGTs in combination with hyphenated MS

techniques for EU WFD compliance monitoring

Acknowledgements INNOVIRIS in financing the Prospective Research For Brussels project. Belspo FOD18 and NewSTEHPS programme and

FWO for travel opportunities. The CALUX bioassay VM7Luc4E2 cell line was developed with funding from the National

Institute of Environmental Health Sciences Superfund Research grant (ES04699) to Prof. M.S. Denison (UC Davis), cells were

kindly provided by Prof. M.S. Denison.

Materials and Methods Diffusive Gradients in Thin Films

The total mass of analyte (M) accumulated on a resin over time (t) after passing

through a well-defined area (A) with a known gradient (De) can be modeled

according to Fick’s first law to determine the bulk water (Cw) concentration:

𝐷e =𝑀 ∆𝑔+𝛿

𝐶w𝐴𝑡

Whereby De is the effective diffusion

coefficient of organics in the diffusive

gel which can be calculated from lab

experiments and corrected for

temperature variations in the field

DGT sampler:

Teflon base (2.5cm)

HVLP Durapore filter membrane

(PVDF 0.45μm; 0.017cm thick)

Agarose diffusive gel

(0.025-0.125cm thick)

XAD18 Resin gel (0.05cm thick)

Resin layers are fabricated in pre-heated casts and stored in 0.03M NaCl until use

After sampling, resins gels are collected and extracted using an ASE 200 (Dionex)

Spiked water samples are extracted using Oasis HLB (6cc; 200mg) cartridges

Bioanalytical estrogen activity measurements using CALUX

Chemically Activated Lucifere gene eXpression for ER binding

VM7Luc4E2 (variant breast cancer MCF7) recombinant luciferase reporter assay

Measure total endocrine activity as opposed to individual compound conc.

Determine biological equivalence to E2 reference compound by calculating a BEQ or EEQ expressed as ng E2-eq./L (ng EEQ/L)

Experiments carried out according to optimized XDS LUMI-CELL® and OECD TG455 protocols and guidelines

Dif

fuu

siv

e B

ou

nd

ary l

ayer

Fil

ter

m

emb

ran

e

Co

nce

ntr

ati

on

Distance

Resin

gel

Diffusive

gel

Bulk

solution

Cb

C0

δ

∆g

Cell exposure to extracts Light quantitation after 24h BEQ calculation

y = 0,0376x - 0,0132 R² = 0,9997

0

0,5

1

1,5

2

2,5

3

0 10 20 30 40 50 60 70

Mas

s o

f E2

on

re

sin

(n

g E2

)

Water concentration (ng E2/L)

Experimental

Theoretical

Linear (Experimental)

y = 0,0025x - 0,0126 R² = 0,9752

0

0,01

0,02

0,03

0,04

0,05

0,06

5 10 15 20 25

Diffusive gel 1/Δg (1/cm)

Effective diffusioncoefficient

Linear (Effectivediffusion coefficient )

Table 1. Physicochemical properties of E1, E2, E3 and EE2 and their theoretical diffusion coefficients in diffusive gel at 25 °C.

Chemical Molecular

weight(Mw)

Log

Kowa

Molecular volume

(V)

Calculated diffusion

coefficient (Dt)

g mol-1 Ǻ3 cm2 s-1

Estrone (E1) 270.4 3.43 387.1 5.17×10-6

17β-estradiol (E2) 272.4 3.94 386.4 5.17×10-6

Estriol (E3) 288.4 2.81 380.1 5.20×10-6

17α-ethinylestradiol (EE2) 296.4 4.15 406.8 5.08×10-6

a Octanol-water partition coefficient.

0,00

0,20

0,40

0,60

0,80

1,00

1,20

5,09 6,01 7,01 8,09

CD

GT/

CSo

luti

on

pH

pH (5-8)

0,001 0,01 0,1 0,5

Ionic strength (M NaCl)

Ionic strength (0.001-0.5M NaCl)

0,02 2 6 15 31

Dissolved organic matter (mg/L)

DOM (0.02-30 mg/L)

0

10

20

30

40

50

60

GBD-1 GBD-2 QH-1 QH-2 LX-1 LX-2

End

ocr

ine

act

ivit

y (n

g E2

-eq

./L)

Sewage stations (1: sink outlet; 2: filtration outlet)

Spot sampling

DGT sampling

0,00

0,02

0,04

0,06

0,08

0,10

0,12

0,04 0,06 0,08 0,10 0,12 0,14

Inve

rse

mas

s o

n r

esi

n (

1/n

g E2

)

Diffusive gel thickness Δg (cm)

Lab experiments

Field experiments

1

𝑀=

Δ𝑔

𝐶w𝐴𝑡𝐷e+

𝛿

𝐶w𝐴𝑡𝐷w