Published online: 23 March 2021 
£) Springer 
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Environmental Science and Pollution Research 
https://doi.org/10.1007/s11356-021-13254-5 
RESEARCH ARTICLE 
Seasonal variability, long-term distribution (2001-2014), and risk 
assessment of polar organic micropollutants in the Baltic Sea 
Kathrin Fisch o • Bent Brockmeyer 2 • Wolfgang Gerwinski 2 • Detlef E. Schulz-Bull 1 • Norbert Theobald 2 
Received: 2 October 2020 /Accepted: 1 March 2021 
(C) The Author(s) 2021 
Abstract 
From 2001 to 2014, 13 surveys were conducted in the Baltic Sea, to determine its pollution of 50 micropollutants. The 
investigations focused mostly on the German western Baltic Sea; in 2008, one survey covered the entire Baltic Sea. Various 
groups of herbicides (such as triazines, phenoxyacetic acid, phenylurea), perfluoroalkyl substances, pharmaceuticals, and indus 
trial products were analyzed during these surveys. The highest concentrations (median 1 to 4 ng/L) were observed for atrazine, 
simazine, chloridazone, 2,4-dichlorophenoxyacetic acid, benzotriazole, primidone, and carbamazepine. Most micropollutants 
exhibited a relatively homogenous spatial distribution, though some herbicides show elevated concentrations in certain regions 
(e.g., Odra estuary), indicating a riverine input. The data set was analyzed, both for seasonal influences and long-time trends. 
Some herbicides exhibited higher concentrations during summertime. Both upward- and downward-directed time trends could be 
identified for some herbicides and perfluorinated compounds. For most of the detected compounds, a low-risk quotient was 
calculated. Only the occurrence of carbendazim could potentially pose a higher risk to the Baltic Sea. 
Keywords Herbicides ■ Perfluorinated compounds Pharmaceuticals ■ Polar micropollutants Baltic Sea ■ Long-term trend. Risk 
assessment 
Introduction 
While long-lasting monitoring programs quite well-document 
information about the burden of the marine environment by 
classical non-polar pollutants such as chlorinated hydrocarbons 
(CHs) or polycyclic aromatic hydrocarbons (PAHs), the knowl 
edge of the contamination by polar organic micropollutants is by 
far less described and evaluated (HELCOM 2010; Theobald 
2011; Abraham et al. 2017; HELCOM 2018; Lang et al. 
2018). The term micropollutant assembles many diverse com 
pounds that are of anthropogenic origin in the environment. 
Compounds such as herbicides (e.g., triazines, phenoxyacetic 
acid, phenylurea, and miscellaneous), perfluoroalkyl substances 
Responsible Editor: Roland Peter Kallenborn 
G3 Kathrin Fisch 
kathrin.fisch@io-warnemuende.de 
Leibniz-Institute for Baltic Sea Research, Warnemünde, Seestr. 15, 
18119 Rostock, Germany 
2 Federal Maritime and Hydrographic Agency, Bemhard-Nocht Str. 
78, 20359 Hamburg, Germany 
(PFASs), pharmaceuticals and personal care products (PPCPs), 
and industrial products are regarded as polar micropollutants 
(Hollender et al. 2008; Loos et al. 2009; Nodler et al. 2014). 
Due to their polar character, most of them are water-soluble and 
can be detected in the aquatic phase and transported with the 
river water into the marine environment (Reemtsma and Jekel 
2006; Loos et al. 2009). In terms of PFASs, as they are volatile, 
they can also be transported through the atmosphere into the 
marine environment (Prevedouros et al. 2006). For 
perfluorooctane sulfonic acids (PFOSs), the riverine input into 
the sea is more important source than the atmospheric deposi 
tion, e.g., Baltic Proper 172 kg/year atmospheric deposition ver 
sus 602 kg/year estuarine export (Lindim et al. 2016). Whereas 
for the perfluorooctanoic acid (PFOA), the atmospheric deposi 
tion is of greater relevance, e.g., Baltic Proper 689 kg/year at 
mospheric deposition versus 386 kg/year estuarine export 
(Lindim et al. 2016). As some of the PFOSs are known for their 
toxicity, bioaccumulation, and persistence in the environment, 
they have been regulated by the European Union, and were 
added to the Annex B list of “persistent organic pollutants” by 
the Stockholm Convention in 2009 (European Commission 
2005a, b, c , 2006, 2007; Convention 2009). Many other polar 
micropollutants are not regulated yet.