In situ calibration of three passive samplers for the monitoring of steroid hormones in wastewater

• Three passive samplers were calibrated for steroid monitoring in wastewater.
• Sample cleanup and derivatisation with dansyl chloride improved method limits.
• Sorbent/water distribution of steroids limited the sampler uptake capacity.
• Sampling rates of steroids ranged from 0.04 to 0.18 l of water extracted per day.
• Uptake of steroids was sped up under turbulent water conditions.

In situ extraction of steroid hormones from waste water using adsorption-based integrative passive samplers represents a promising approach for their monitoring in water at ultra-trace concentrations. Three passive samplers, namely a POCIS, a Chemcatcher fitted with an Empore SDB-RPS disk, and an Empore SDB-RPS disk-based sampler with enhanced water flow, were calibrated in situ in treated municipal wastewater for the purpose of monitoring five estrogens (17-β-estradiol, 17-α-estradiol, 17-α-ethinylestradiol, estrone and estriol) at sub ng per litre concentrations. Uptake of steroids to samplers during 14-day exposure in wastewater was compared with steroid concentrations in daily collected composite water samples. Sampling rates were obtained from a numerical solution of first order uptake kinetics equations describing the uptake of compounds into a passive sampler over time. Mass transfer of steroids in the Chemcatcher fitted with naked Empore disks was more than two times faster than in the POCIS sampler. The uptake capacity of the applied Empore disk was not sufficient for integrative uptake of all tested steroids during the entire 14-day exposure. Time-weighted average concentrations of steroids estimated at concentrations in units of ng L−1 using the in situ-calibrated samplers were within a factor of two from values obtained using composite water samples.

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