WATER / WASTEWATER 13
CASE STUDY: CAITHNESS GENERAL HOSPITAL ACHIEVES THE AWS INTERNATIONAL STANDARD FOR WATER STEWARDSHIP
This pilot study was conducted to assess the effects of the Caithness General Hospital (CGH) on pharmaceutical pollution in Wick wastewater, and to monitor the changes in water quality as it travels from the drinking water source to the hospital and receives treatment at Wick WWTP (Niemi et al, 2020).
Image 2: A UN country survey on the number of pharmaceutical substances detected in surface waters, groundwater, or tap/drinking water (extracted from aus der Beek, 2015).
substances depend on prioritisation of substances for monitoring and resources available in each country. The 16 substances detected included: Diclofenac (anti-infl ammatory), Carbamazepine (epilepsy drug), Ibuprofen, Sulfamethoxazole (antibiotic), Naproxen (anti-infl ammatory), Estrone (oestrogen steroid/hormone), Estradiol (oestrogen steroid/hormone), Ethinylestradiol (synthetic oestrogen used in the pill for birth control), Trimethoprim (antibiotic), Paracetamol, Clofi bric acid (metabolite of a cholesterol lowering drug), Ciprofl oxacin (antibiotic), Ofl oxacin (antibiotic), Estriol (steroid/hormone used in hormone replacement therapy), Norfl oxacin (antibiotic) and Acetylsalicylic acid (aspirin).
What kind of concentrations of pharmaceuticals are found in the environment? A study in 2019 (Boxall and Wilkinson) found antibiotics present in river samples from 65% of sites in 72 countries. 111 of 711 sites had antibiotics above the safe threshold; in the worst cases at levels 300 times the limit set by the Antimicrobial Resistance Industry Alliance. Rout et al (2021) found emerging contaminants in wastewater treatment plant effl uent at up to 850 ng/l (Iopromide used as a contrast medium in radiography) and in sewage sludge at up to 4,800 ng/g (Ciprofl oxacin, an antibiotic). Even in a remote rural river in Scotland, the River Ugie, Carbamazepine and Ibuprofen were present at an average of 11.23 ng/l and 13.06 ng/l respectively (Zhang et al, 2018).
CAL PRODUCTION
Taking one example, the predicted no effect concentration for ecotoxicity for Ciprofl oxacin is 1200ng/l – the concentration found in sewage sludge (by Rout et al, 2021) was above this threshold; if the same concentrations were found in the
Human Pharmaceuticals
environment they would be expected to cause toxicological effects on aquatic ecology. Dr Zulin Zhang, Senior Environmental Scientist at the James Hutton Institute explained that reproductive effects caused by pharmaceuticals present in quantities as low as parts per billion (ppb). Therefore, highly sensitive technologies that can measure down to ppb or even parts per trillion (ppt) are needed. However, Dr Zhang says that pharmaceuticals are notably diffi cult to measure, despite concerns over their relatively signifi cant environmental impacts monitoring techniques need further advancement.
“The environmental occurrence and detection of emerging contaminants has really only been investigated over the last 20 years”, explains Richard Luxton, Director or the Institute of Biosensing Technology at the University of the West of England. Historically chromatography laboratory methods have been used to detect emerging contaminants, but there are now sensors and biosensors under development to detect these substances in the fi eld. The advantage of chromatography is that it can detect the presence of unknown substances, whereas sensors must be developed to recognise and detect specifi c substances. “The two methods can be used to complement each other”, says Professor Luxton, “with chromatography methods being used to confi rm the presence of target pharmaceuticals in water samples and the sensors being used to detect and monitor target substances of concern over time”.
A review of papers on new sensing technologies for emerging contaminants showed that about 25% are based on optical measurement whereas approximately 75% use electrochemical measurement (voltammetry, amperometry, impedance sensing and Field Effect Transistors) and around 1% are based on thermal sensors. Examples include a highly sensitive electrochemical graphene-based aptasensor developed to detect 17β-estradiol, using a unique, folded DNA molecule on the sensor surface to capture and detect estradiol, with a limit of detection (LOD) of 2.7 × 10-3
ng/l (Liu et al, 2019). Another new technology is a Molecular Imprinted Polymer (MIP) sensor to detect 17β-estradiol which is even more sensitive with an LOD of 1.7 x 10-3
ng/l. These
represent technologies which can detect substances at ppt but Professor Luxton questions whether this level of sensitivity is always needed “sometimes presence or absence of a substance is enough from a fi eld sensor and then lab analysis of a water sample can be used to confi rm the quantity” explains Professor Luxton.
Hospitals / Healthcare Facilities
Households
The next technological step is to link sensors for pharmaceuticals with a smartphone app to display results for in situ water quality monitoring. Integrated systems like this are under development, for example to measure a combination of acetaminophen (pain killer) and 17β-estradiol, and the heavy metal, lead using a potentiostat connected to three multiwalled carbon nanotubes and β-cyclodextrin screen printed electrodes (Alam et al, 2020).
Box 1: History of the development of chromatography methods for detecting emerging contaminants including pharmaceuticals (from Rout et al, 2021)
Solid Waste Disposal Wastewater Date methods were introduced or put into practice Landfi ll / Incineration
• 1965 Estrogen detection using UV absorbence • 1968 Gas Chromatography / Mass Spectrometry (GC/MS) introduced • 1970 Estrogen detection by colorimetric chromatography • 1975 Pharmaceuticals detected in wastewater by GC/MS • 1985 Electrospray ionisation Mass Spectrometry (ESI-MS) introduction • 1994 Quadrupole Time-of-Flight Mass Spectrometry (Q-TOF MS) introduction • 2002 US survey of organic contaminants in streams by GC/MS and LC/MS • 2005 Commercial orbitrap mass spectrometry introduction • 2005 onwards: non target (unknown ECs) analysis
Sampling was carried out every day (morning or afternoon) over four weeks at Loch Calder (drinking water source), the hospital (kitchen tap water and combined wastewater outfl ow) and Wick WWTP (raw infl uent and fi nal effl uent) to investigate temporal trends in pharmaceutical concentrations. Over the 28-day study, 20 sampling events were performed for the hospital wastewater, 19 for the Wick WWTP infl uent and effl uent and 4 for the Loch Calder source water and hospital tap water.
Water quality analysis was carried out following in-house procedures developed for research and commercial work. For pharmaceutical analysis, a solid phase extraction method and liquid chromatography-tandem mass spectrometry (LC/MS/MS) analysis technique were developed to monitor select compounds from four pharmaceutical classes: three analgesics and anti-infl ammatories (paracetamol, diclofenac and ibuprofen), two antibiotics (clarithromycin and trimethoprim), two psychiatric drugs (carbamazepine and fl uoxetine) and a synthetic hormone (17α-ethynylestradiol). Several of these compounds are controlled under UK and European water quality legislation due to their properties. Understanding the fate and transport of these compounds in wastewater and the receiving environment is therefore a priority.
NHS Highland worked in partnership with a number of agencies including the Scottish Environment Protection Agency, Scottish Water, Highland and Islands Enterprise and the University of the Highlands and Islands’ ERI in Thurso. The partnership, known as the One Breakthrough Partnership, is working to improve water quality, reduce the environmental impact of healthcare, reduce pharmaceutical wastage (e.g. through an educational campaign), reduce costs, and create integrated healthcare (green prescribing and lifestyle changes to reduce prescriptions). An early warning system is being investigated to link prescribing data with Scottish Water monitoring data so that the water company and environmental regulator could have advance warning of the quantity of medicines that will need treatment downstream and linking with SEPA to identify when extra environmental monitoring may be needed.
In 2020 Caithness Hospital was the fi rst hospital in the world to achieve the AWS water stewardship standard, and the only site in the UK to achieve this standard. The project hopes to achieve multiple benefi ts including reduction of water, energy and carbon footprints for water treatment and ultimately that the pill for every ill culture moves to a more preventative one.
Another approach is to remove pharmaceuticals from water by selectively adsorbing them to a surface. A European project (RECOPHARMA) is looking at removing cytostatic drugs (CDs) which are persistent in the environment and known to be present in effl uent from urban wastewater treatment plant and hospital effl uent across the world. CDs have been detected in wastewater effl uent in concentrations up to 146 ng/l for Cyclophosphamide and up to 200 ng/l for Tamoxifen for example. Certain CDs are diffi cult to remove from water using standard wastewater treatment methods and are transferred to surface water with unknown effects on the environment. MIPs (see above) have been developed to selectively adsorb and treat such CDs so that precious raw materials employed for their production can be recovered and actually reused to create a closed loop cycle.
“Going forward there is defi nitely an opportunity for innovation in sensors combined with digital healthcare to provide solutions to the issue of pharmaceuticals in the environment”, says Sharon Pfl eger. According to Ms Pfl eger, better management of pharmaceuticals in the water environment will require:
• Measurement of the occurrence, fate and impact of more medicines in the environment;
• A better understanding of the effects of a mixture of medicines compared with effects of a single medicine;
• Monitoring the effects of metabolites and transformation products; • A better understanding of different routes of exposure;
• The presence of pharmaceuticals in treated versus untreated waters (septic tanks); • Identifi cation of common indicator substances; • Standardisation of data collection, quality and storage; and
• Prioritisation of contaminants, water bodies and ecosystems for monitoring.
Individual Septic Sytems
Rosa Richards is an Independent Environmental Consultant specialising in water policy and monitoring. She is Programme Manager of the Sensors for Water Interest Group (SWIG), and a freelance writer of science and technology.
Author Contact Details Rosa Richards, Independent Environmental Consultant • Bristol • Tel: 01934 830658 • Email:
rosapmrichards@gmail.com • Web:
https://www.linkedin.com/in/rosa-richards-7a515936/
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WWW.ENVIROTECH-ONLINE.COM IET JANUARY / FEBRUARY 2021
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