MONITORING PHARMACEUTICALS IN WATER
The majority of 4,000 odd pharmaceutical products on the market globally have not been assessed for their occurrence, environmental fate or environmental impacts. Studies around the world have found pharmaceuticals present in surface waters at concentrations of concern. This is perhaps not surprising as the use of medicines is increasing for various reasons in western countries. Indeed, the current Covid 19 pandemic has contributed a further increase in the use of medicines, particularly antibiotics. So which substances are present in water and at what kind of concentrations? What methods are available to monitor pharmaceuticals, their metabolites and other emerging contaminants at the limits of detection necessary to ensure that no biological effects are predicted? How do they enter surface waters? And how can they be better managed to prevent impacts on the environment and human health?
The presence of pharmaceuticals in the water environment is of concern as they are designed to produce a biological response at a very low dose. They are tailored to be stable (or ‘persistent’) to interact with target molecules. These qualities mean that pharmaceuticals therefore can have unintended impacts in the environment. The main effects are seen in aquatic life; for example, the well-publicised feminisation of fi sh from exposure to oestrogenic substances which can lead to population collapse, also Fluoxetine (Prozac) is also known to alter fi sh behaviour and affect their survival and reproduction success. Another signifi cant impact is an increase in antimicrobial resistance due to the widespread presence of antibiotics in the environment. There are already 700,000 deaths per year due to antimicrobial resistance, according to the World Health Organisation, but this is predicted to rise to 10 million deaths per year by 2050 if nothing is done. Another cause for concern is the lack of human risk assessment regarding long term and low levels of exposure to pharmaceuticals, especially in sensitive populations such as pregnant women, foetuses and children, stresses Sharon Pfl eger, Consultant in Pharmaceutical Public Health. According to the European Environment Agency, human exposure to pharmaceuticals is known to cause thyroid disease, increased cholesterol levels, liver damage, kidney cancer, testicular cancer, and developmental effects on the unborn child with other effects suspected but not yet proven.
“Medicine use is increasing for a number of reasons”, explains Sharon Pfl eger, “Such as growing and ageing populations, technological advances, and a ‘pill for every ill’ culture.” According to Ms Pfl eger, a typical 80-85 year old consumes 20 times as many medicines as a 20-25 year old.
In terms of regulation, drinking water quality standards in Europe have been established by the Drinking Water Directive (DWD) (98/83/
EC) which set out “to protect human health from adverse effects of any contamination of water intended for human consumption” by ensuring that it is “wholesome and clean”. Under the original DWD, a total of 48 microbiological, chemical and indicator parameters had to be monitored and tested regularly. This Directive has been revised and a new DWD was ratifi ed in October 2020, to be transposed into member state legislation within 2 years. Amongst the changes are stronger catchment risk assessments (linked with the Water Framework Directive requirements), longer lists of parameters for measurement (bisphenol A must now be monitored) and new ‘watch lists’ for potential emerging contaminants such as endocrine disrupting chemicals, pharmaceuticals, plastics and new chemicals in the supply chain. ”The fi rst watch list will be published in 2021 and will include 17β-estradiol and nonyl phenol,” explains Moira Malcolm, Drinking Water Specialist at the Drinking Water Quality Regulator, Scotland, “Watch lists will be produced regularly as emerging chemicals are identifi ed and measurement techniques become available, so there will be a greater need for monitoring”. (Scotland has committed to keep pace with changes in EU Directives after Brexit.) Ms Malcolm points out that according to Drinking Water Inspectorate research, pharmaceuticals were not present in 2011 in concentrations of concern in drinking water.
The key sources of pharmaceuticals and their metabolites in the environment are consumption and excretion into the wastewater system, inappropriate disposal down sinks and toilets, and from the manufacturing industry (image 1). After passing through the human or animal body, medicines are excreted either in an unchanged active form or as metabolites, which may be active or inactive, and have the potential for further breakdown into numerous transformation products in wastewater treatment plants (WWTPs) or in the environment.
However, conventional WWTPs are not 100% effective in removing CASE STUDY: MONITORING COMMONLY OCCURRING PHARMACEUTICALS IN THE RIVER UGIE
The River Ugie is categorised as a priority catchment to achieve ‘Good Ecological Status’ under the Water Framework Directive, and is used by Scottish Water as a drinking water source for Aberdeen. Zhang et al (2018) selected 6 pharmaceuticals and personal care products (PPCPs) from a list of PPCPs commonly present in the aquatic environment around the world (Diclofenac, Ibuprofen, Paracetamol, Tramadol, Carbamazepine, Triclosan).
PPCPs were monitored monthly over a year using a combination of spot sampling (and laboratory analysis using GC-MS after derivatisation) to validate results from passive sampling using a Polar Organic Chemicals Integrated Sampler (POCIS). The cumulative passive sample collected from the POCIS was subjected to solvent extraction and chemical recovery and then chemical analysis also using
GC/MS after derivatisation. Overall, results from passive sampling were in good agreement with spot sampling results.
In this remote rural river, all 6 of the PPCPs were detected; Carbamazepine and Ibuprofen were on average the dominant contaminants. The highest recorded concentrations were 192.7 ng/l for Carbazamepine and 119.4 ng/l for Paracetamol. In general the highest concentrations of the 6 determinands were found at a site closest to a wastewater treatment plant and near the largest village in the catchment, which is likely due to wastewater effl uent and use of pharmaceuticals. The levels detected were similar to those observed in other European countries.
An ecological risk assessment was undertaken by Zhang et al by calculating a risk quotient for each substance, by dividing the quantity present by
IET JANUARY / FEBRUARY 2021
WWW.ENVIROTECH-ONLINE.COM
the toxicity of each (using the predicted no effect concentration). For the 6 substances, Triclosan was deemed to be of medium risk, the others were low or minimal risk to the aquatic environment due to the quantities present and toxicity of each.
Monthly and annual outfl ows of the 6 substances into the Ugie Estuary and the North Sea were also estimated. The total annual outfl ows were estimated to be 4.6 kg. Following this, the researchers wondered what quantity of these 6 substances must be discharged globally into the sea? Their ballpark calculations suggest this could be as much as 1,383 tonnes per year globally, a staggering amount just for these 6 substances, without taking into account other pharmaceuticals and chemicals being leached into the sea. Toxicological research is only just starting to consider the combined effects of exposure by organisms to multiple substances simultaneously.
Manure / Slurry / Biosolids Wastewater Spreading
emerging contaminants including pharmaceuticals and their metabolites (image 1). Studies around the world have found pharmaceuticals present in water bodies (image 2). Globally 631 pharmaceuticals and metabolites were found in the environment in a combined study by aus der Beek in 2015. Residues of 16 pharmaceutical substances were detected in the surface, drinking, and groundwater of all the UN regions. These substances do not necessarily refl ect the most commonly present pharmaceuticals as the reasons for the detection of these
PHARMACEUTICA
Veterinary pharmaceuticals
Aquaculture
Companion Animals
Livestock
Wastewater Treatment Plants
R
Image 1: Major pathways for the release of human and veterinary pharmaceuticals into the environment
O U N
F R
E S H
W A
T E R (
S U R
F A C E
W A T
E R A
N D G
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48
