Laboratory Calibration and Field Deployment of the Polar Organic Chemical Integrative Sampler (POCIS)

for Pharmaceuticals and Personal Care Products

Sherri L. MacLeod and Charles S. Wong Department of Chemistry

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Pharmaceuticals as Pollutants

• numerous drugs

• intended biological effects in target organisms

• portions excreted unchanged

• sewage treatment removes pathogens

• continuous unregulated discharge

• non-target organisms chronically exposed

Daughton & Ternes Environ. Health Perspect. 107 (1999) 907. http://www.ehponline.org/members/2005/113-10/spheres.html.

http://www.ehponline.org/members/2005/113-10/spheres.html.

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Non-target Organisms

from a recent review (Fent et al. 2006 Aquatic Toxicology)

• acute effects – scenario unlikely unless a concentrated spill

• effluent/surface concentrations – generally 100× < chronic LOEC in lab organisms

Æ chronic effects not extensively studied

http://www.galab.de/laboratories/services/environment/pharmaceuticals.html

http://www.galab.de/laboratories/services/environment/pharmaceuticals.html

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Characterizing Exposure

• grab/composite water samples – laborious

– captures snapshot

– may miss important events

• passive sampling – low maintenance

– provides time weighted average

– characterizes chronic exposure

http://www.est-lab.com/img/spmd_onspider_250.jpg

SPMD for

nonpolar organics

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5Polar Organic Chemical

Integrative Sampler (POCIS)

• sequesters polar organics from water – pharmaceuticals & pesticides

• field usage mainly qualitative (ng/POCIS)

• requires calibration to be quantitative

Alvarez, Doctoral Thesis, University of Missouri Columbia, Columbia, MO, 1999.

U.S. Patent 6,478,961 – Petty, Huckins, Alvarez, November 12, 2002.

Alvarez et al. Environ. Toxicol. Chem. 23 (2004) 1640.

Jones-Lepp et al. Arch. Environ. Contam. Toxicol. 47 (2004) 247.

www.est-lab.com

Å single POCIS

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Polar Organic Chemical Integrative Sampler (POCIS)

• calibrated for uptake of 6 drugs

• aqueous boundary layer controlled uptake

• resistant to biofouling www.est-lab.com

Alvarez et al. Environ. Toxicol. Chem. 23 (2004) 1640.

Jones-Lepp et al. Arch. Environ. Contam. Toxicol. 47 (2004) 247.

Alvarez et al. Chemosphere 61 (2005) 610.

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Research Goals

1) to carry out lab based calibration of POCIS to characterize uptake of several common pharmaceuticals and personal care products (PPCPs)

2) to use field deployments for demonstration of the utility of the calibrated sampling rates

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Calibration Experiment

POCIS exposed to 33 common PPCPsA) flowing conditions (25 days, 4 renewals) B) quiescent conditions (29 days, 3 renewals)

setup: – 3L water per vessel (spiked at 1 ng/mL) – 3 separate vessels per condition – protected from light – regular water samples analyzed to monitor uptake

controls: 1. no drug (monitor for contamination) 2. no POCIS (monitor for dissipation)

Alvarez, Ph.D. Thesis, University of Missouri-Columbia, Columbia, MO, 1999.

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Measuring Uptake

assuming first order kinetics for uptake:

Cw(t) = Cw(o)e -kt

Cw(t) = aqueous concentration of PPCP at time,t Cw(o) = initial aqueous concentration of PPCP

uptake rate constants obtained for each renewal period averaged for each condition (flowing and quiescent)

dissipation rate constants similarly obtained for “no POCIS” control subtracted from uptake rate constants

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10 renew 1 renew 2 Calibration Data renew 3 control(no POCIS)

carbamazepine triclosan 1.25 1.25

1.00 1.00

0.25 0.25

0.00 0 50 100 150 0 50 100 150

time (hours) time (hours)

0.00

1.25 1.25

1.00 1.00

0.75

flowing 0.50

C(t

)/C

(o)

C(t

)/C

(o)

C(t

)/C

(o)

C(t

)/C

(o)

0.75

0.50

0.75 0.75

quiescent0.50 0.50

0.25 0.25

0.00 0 100 200 0 100 200

time (hours) time (hours)

0.00

carbamazepine, a commonly used anti-epileptic drug, poorly eliminated in WWTP thus frequently found in surface waters

AND

triclosan, a commonly used antimicrobial agent, also commonly found in surface waters

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Sampling Rates

sampling rate = Rs = kV where V = 3L water in vessel

• rate = effective L water sampled per day

• 3 flow rates investigated – inconclusive for RS dependence on flow rate

• POCIS calibrated for 25 of 33 drugs – reliable data over course of experiment – reproducible uptake curves – 13 of 25 show boundary layer controlled uptake

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* * * *

* *

* * *

*

* *

*

(significant differences between flowing and quiescent Rs

indicated by star)

Sampling Rates

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Undetermined Sampling Rates

caffeine – only 3% dose sequestered

– uptake data scattered

– POCIS not suitable based on this data set

omeprazole, paroxetine, sulfisoxazole – dissipation comparable to quiescent uptake

– reliable sampling rate could be determined for quiescent water conditions

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• indicates portion of experimental dose accounted for

• most ~100% – reliable accounting

– no dissipation once sequestered on POCIS

Mass Balance

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Sampling Rates & PPCP Properties

• no correlation with molecular weight

• correlations with log Kow if classified

• example: cations

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www.ratsinc.net

Gold Bar WWTP

Town of Lac La Biche

City of Edmonton

www.larry-bolch.com www.edmonton.ca

Field Deployments

Lac La Biche WWTP

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• grab samples taken at deployment/retrieval – range of PPCP concentrations

POCIS in the Field

1) POCIS captures information that grab samples may miss.

example: carbamazepine upstream of Edmonton – grab samples: 1 L – POCIS: 11±3 L (30 days)

grab (ng/L) POCIS (ng/L) grab (ng/L) POCIS (ng/L) grab (ng/L)

0.55 ±0.08 0.12 ±0.04 <0.06 0.14 ±0.15 <0.04

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18 2) TWA concentration is generally similar to

that derived from grab samples. Sampling rates make sense: downstream of Edmonton

temazepam

naproxen

metoprolol

gemfibrozil

diclofenac

carbamazepine

Aug. (grab) Summer POCIS Sept. (grab) Autumn POCIS Oct. (grab)

0 25 50 75 100 125

Concentration (ng/L)

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193) Does biofouling have an impact?

Not sure: Lac La Biche WWTP treated effluent

temazepam

naproxen

metoprolol

gemfibrozil

diclofenac

carbamazepine

Aug. (grab) Summer POCIS Sept. (grab) Autumn POCIS Oct. (grab)

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

Concentration (ng/L)

EXTRA INFO

potential biofouling

potential uptake curve not linear for part of the sampling period

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4) Is there a flow rate dependence on 20

sampling rate? Not sure: Field Lake

temazepam

gemfibrozil

codeine

carbamazepine

1 10 100 1000

<1.2

<8

<16

Concentration (ng/L)

Aug. (grab) Summer POCIS Sept. (grab) Autumn POCIS Oct. (grab)

via quiescent sampling rate: 20% < grab

via flowing sampling rate: 40% > grab

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Conclusions & Future Work

• POCIS calibration completed for 25 PPCPs – some are boundary layer controlled

– potential dependence on log Kow

• reasonable for TWA determinations

• unanswered questions – dependence on analyte properties?

– dependence on environmental variables?

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Acknowledgements

Wong Group Members & Machine Shop (University of Alberta)

Brian Jackson & Mike Bilyk (Alberta Environment)

Gary Siebold & Maurice Brulhart (Lakeland County & Lac La Biche)

SETAC Early Career Award for Applied Ecological Research sponsored by ACC (CSW)

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thank you

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