NILU - The Norwegian Institute for Air Research

Pharmaceutical residues in the northern Norwegian environment

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Courtesy of Courtesy of NILU - The Norwegian Institute for Air Research

Surprisingly high concentrations of pharmaceutical residues are found in sewage water and sea water in the Arctic environment of Northern Norway. That’s one of the conclusions in a joint science project under the leadership of NILU.

All pills and drugs we take will come out eventually. In principle all pharmaceutical drugs produced and applied will sooner or later end up in the environment. The most common way goes through the sewer system.

The presence of selected pharmaceuticals in different environmental compartments was reported for the first time by Richardson and Bowron (1985). Since than, many international scientific studies have reported pharmaceuticals in the environment.

The here presented study was designed to elucidate levels and discharges of selected pharamceuticals in the environment in the marine environment around Tromsø, a middle size city in Northern Norway. The amount of pharmaceutical residues found in Tromsø is equally high as similar measurements done for European cities with three times the inhabitants as Tromsø.

Pharmaceutical residues in the northern Norwegian environment

Some highlights from the conclusions

Some key factors can be extracted from the examination:

  • Pharmaceutical residues in the Northern Norwegian Environment is proven.
  • The day-to-day variations can vary considerably for the selected compounds.
  • Caffeine was the predominant compound found.
  • The dilution effect was lower than expected.
  • The effect on the environment is uncertain.


Ibuprofen was detected in all samples in concentrations ranging from ~ 10 to 400 ng/L while its main metabolites hydroxy-ibuprofen (Ibu-OH) and carboxy-ibuprofen (Ibu-CX) were present at significantly higher concentrations (up to ~ 3 µg/L).

Diclofenac was only detected in samples related to the psychiatric hospital (3 ng/L) and the University general hospital (2,4 µg/L) in Tromsø.

The antiepileptic carbamazepine and the antidepressants paroxetine and sertraline were found in sewage affected by the psychiatric hospital.

Caffeine was determined at high concentrations (20 - 280 µg/L) in all samples. It correlates well with the levels of other compounds of concern (e.g., Ibu-OH).

Pharmaceutical residues in the northern Norwegian environment


Only caffeine, ibuprofen and its metabolites were detectable in significant amounts in Tromsø sound seawater.

Caffeine-concentrations were found in the same order of magnitude throughout all sea water samples, ranging from 20 to 80 ng/L.

Ibuprofen and its major metabolites were present in most seawater samples at concentrations up to 2 ng/L. Concentration levels seemed appeared slightly elevated in Samples close to the effluent of the General hospital, where the contributing sewer contained high levels of these contaminants.

Carboxy-ibuprofen was the dominant compound in most samples. This result is in contrast to other findings from other, where the ratio Ibu-CX/Ibu-OH strongly decreases after sewage treatment and subsequent release into the aquatic environment.

Conclusions and perspectives

Human activities result usually in locally restricted elevated concentrations of hydrophilic contaminants. Also in our study, elevated levels for caffeine, ibuprofen and its metabolites were found. Due to specific discharge pattern, the presence of hospital related release of other pharmaceuticals (e.g., b-blockers, antidepressants etc) were confirmed in municipal sewage.

Due to the special northern weather conditions in the Norwegian Arctic, degradation processes are expected to be hindered by climate factors [e.g., temperature, light conditions]. As a consequence, higher compound stability and residence time for contaminants compared to lower latitudes regions can be expected.

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