Biomedical Science and Research Journals | Pharmaceutical Residues in the Aquatic Environment: Recent Studies in Estonia
Pharmaceutical Residues in the Aquatic Environment: Recent Studies in Estonia
Introduction
Ecotoxicological impacts of pharmaceuticals in the environment
were first paid attention to in the 1990-ies, when a massive death
of the bird species Gyps africanus or white-backed vulture occurred
in Pakistan and India. This was found to be caused by accumulation
of diclofenac in their kidneys. These residues originated from
veterinary treatment of free-range livestock that the birds had been
eating Oaks et al. [1].
There are more than 3000 different active ingredients in use
for both veterinary and human medicine, including analgesics,
contraceptives, antibiotics, neuroactive compounds, beta blockers,
lipid regulators and their metabolites. Carlsson [2] who has assessed
the ecotoxicological effects of 27 different pharmaceuticals, has
assessed, that the most harmful for the environment are diclofenac,
ethinylestradiol, ibuprofen, metoprolol, norethisterone, oestriol
and oxazepam. Li [3] added sulfamethoxazole into this list. There
are various pathways for the medicine residues to fall into the
environment. Part of the consumed medicaments are excreted by
humans, discharged into wastewater treatment plants, accumulated
in the sludge and, if the latter is used in greening or even agriculture,
they may accumulate in plants, infiltrate into soil and ground water.
Table 1:Methods used to dispose unused pharmaceuticals Peake, et al. [13] cross-reference in the MSc thesis by Maiu Tiismus.
According to Oppel et al. [4] and Monteiro & Boxall [5] active
sludge binds over 99% of salicylic acid, and 85…99.7% of caffeine,
65-77% of ketoprofen, and less than 40% of carbamazepine
and celiprolol. Another pathway is by the incorrect handling of
pharmaceuticals by population, flushing those in toilets and sinks
or throwing those into garbage with other household waste from
where the next destination is landfill and landfill leachate. A recent
MSc study by Maiu Tiismus [6]
in Tallinn University of Technology
on the mindset and awareness of people, shows that the most
common way of disposal of unused and expired medications in
Estonia is still the garbage bin, although it is possible to take them
to either pharmacy or local hazardous waste reception station
free of charge. Discarded unused medicine should be mixed with
municipal waste in a ratio 1:1000 to avoid halogen evaporation and
incinerated in high temperature (>1200oC). Tiismus was awarded
the degree of MSc in June 2019 (Table 1).
Estonia (1.3 million inhabitants) has collected statistical
data on drugs (type and amount of medicines sold, sales value of
pharmacies and wholesalers) for more than 20 years. An excel
document on pharmaceuticals used in 2018 in defined daily dose
(DDD) of medication needed for 1000 inhabitants per day is
available on the webpage of the Estonian State Agency of Medicines
(SAM). In 2017 the Secretariat of the Baltic Sea Convention
(HELCOM) mentioned pharmaceutical pollution in the sea in their
status report of the sea Zandaryaa et al. [7] and in spring 2019 the
data of the first systematic screening of pharmaceutical residues in
the Baltic Sea were published Delfi [8].
Measurable concentrations of diclofenac, ibuprofen and
sulfamethoxazole were found in certain points of the Baltic Sea,
especially near the eastern shore of Sweden. In 2010 the effluents of
various wastewater treatment plants and their receiving waters in
Sweden were studied by a Swedish researcher Ericson. Diclofenac
was found ranging from 0.2to7.1 mg/l and ibuprofen between 0.1
and 0.2 mg/l. In Germany, 131 different pharmaceuticals have been
detected in surface and ground water sources Weber et al [9] (Table 2).
Table 2:Best sold pharmaceuticals in Estonia, Finland, Germany, and Sweden together and for Estonia and Sweden separately: Fent et al. [15,16]
cross-reference in the PhD thesis by Erki Lember [12].
Paracetamol, diclofenac and ibuprofen are common analgesics,
macrogol helps in case of constipation, mezalazine is used as an
anti-inflammatory pharmaceutical and metformin treats diabetes.
European Union has initiated and funded a thorough research
of the impact of the release of pharmaceuticals and veterinary
medicines on the state of the environment of the Baltic Sea. The
watch list includes diclofenac, 17 alpha ethinylestradiol (EE2) 17
beta estradiol (E2), estrone (E1) and macrolide with the maximum
permitted detection limits 10 ng/l, 0.035 ng/l, 0.4 ng/L and 90 ng/l
respectively [10].
Worldwide, ca 30 000 kg of synthetic contraceptives E1, E2 and
E3 are released into environment annually. In addition, 83 000 kg
of cattle estrogens (natural hormones) is believed to be released
in EU and USA Adeel et al. [11] affecting the living organisms. PhD
student of Tallinn University of Technology, Erki Lember [12]
analyzed the consumption rates of diclofenac and ibuprofen by
the inhabitants of 8 seaside cities in Estonia from 2006 to 2014
and found a decrease of 19.9% for diclofenac consumption and an
increase of 14,1% for ibuprofen. The European Medicines Agency
had declared that diclofenac could cause heart attack or stroke and
ibuprofen is as good analgesic as DFC. Lember modelled the fate of
these pharmaceuticals in human metabolism as well as the removal
of the residues of the partially modified and unmodified medicines
in the activated sludge process of wastewater treatment plants
(WWTPs). In the effluents of the WWTP, the theoretical model
showed an average decrease from 1 to 0.8 mg/l g for diclofenac and
increase from 11.4 to 13.4 mg/ for ibuprofen. Only a small part of
the residues is decomposed in the biological treatment process or
stays in the sediment. Such small concentrations are not harmful for
the environment, but one should also investigate the accumulative
impacts of different substances acting together.
Lember also measured the adsorption capacity (adsorbent
dose and residence time) of powdered activated carbon (PAC) for
removing three substances: diclofenac (DFC), sulfamethoxazole
(SMX) and levofloxacin (LFX) from the effluents. 77% of the LFX
could be removed in 5 minutes and 94% in 60 minutes, while only
68% of SMX was absorbed for 1 hour. An adsorption isotherm was
compiled for future dimensioning of treatment processes. While
the test was done in controlled conditions (using ultrapure ELGA
water), some supplementary experiments were done using actual
wastewater, measuring the decrease of total organic compounds
with the TOC sum parameter. PAC process had the adsorption
capacity per 1 g of PAC reaching 12096 mg/g, compared with APAC
process (PAC was dosed into aeration tank) where the relevant value
was 4060 mg/g. These results were first published in April 2017
in the 10th International Conference “Environmental Engineering“
held in Lithuania, Vilnius Gediminas Technical University and in the
fall 2018 Erki Lember was awarded the PhD degree.
To view fulltext of article:https://biomedgrid.com/fulltext/volume3/pharmaceutical-residues-in-the-aquatic-environment-recent-studies-in-estonia.000719.php
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