Scottish Water provides 1.34 billion liters of drinking water every day and takes away 847 million liters of waste water daily. Answerable to both the Scottish Parliament and the people of Scotland, Scottish Water recognizes that innovation is a key enabler for them to deliver sustainable, high-quality water treatment services.
One of the many compounds they monitor for is the drug class of estrogens. Estrogens are routinely used either as contraceptive medicines or in hormone replacement therapy and can enter aquatic environments via the discharge of final effluent waters. Once waste water is released into the environment, these synthetic hormones can have negative effects on wildlife. Estrogens are believed to have a negative effect on aquatic environments by disrupting the hormonal systems of fish; for example, they may contribute to intersex changes in fish.
In the EU directive 2013/39/EU, 15 additional priority substances were added to the water framework directive (WFD, 2000/60/EC). In this latest update, 17α-ethinyl-estradiol (EE2) and 17β-estradiol were not included in this list, but were instead added to a watch list in order to gather further data regarding the presence of these compounds in aquatic environments and the risks they pose.
“Even low concentrations of EE2 have an impact on fish – both their behaviour and their genetics. We have seen a change in the genetic balance in fish, and that they have a harder time catching food. Previous studies have shown that the fish also develop problems with procreation. This can lead to the complete disappearance of an entire fish population, and consequences for entire ecosystems,” said Lina Nikoleris at Lund University in Sweden in a 2016 paper.
Waters partnered with Scottish Waters to develop and validate an analytical method for the analysis of 17β-estradiol, estrone and 17α-ethinyl estradiol in surface water, crude influent, and final effluent from a waste water treatment plant utilizing off-line solid phase extraction followed by analysis on an ACQUITY UPLC System with 2D LC Technology, coupled to a Xevo TQ-S Mass Spectrometer.
The combination of off-line SPE followed by analysis on the ACQUITY UPLC System with 2D LC Technology and Xevo TQ-S for MS/MS quantification allows for ultra-sensitive detection of natural and synthetic estrogens in surface and treated water.
Concentration with sample prep
Surface water samples were initially extracted utilizing an optimized method on an off-line Oasis HLB Solid Phase Extraction (SPE) Cartridge. Crude influent and final effluent samples were first filtered, and then underwent the same Oasis HLB offline extraction step. This was followed by a second SPE step utilizing Sep-Pak Silica Cartridges.
These off-line SPE steps are critical to achieving lower limits of detection by providing the initial concentration step and cleaner extracts; thus reducing ion suppression on the tandem quadrupole mass spectrometer.