Environ Sci Pollut Res 
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perfluoroalkyl carboxylic acids (PFCAs), 7 PPCPs, and 32 
herbicides covering the classes phenylureas (6), 
phenoxycarboxilic acids (4), triazines (9), and others (13) 
(Tab. SI). The observations ofthe German routine monitoring 
program performed in the North were the base for the selected 
micropollutants. The median concentration ofthe most detect 
ed compounds in all 133 samples ranged from < LOD to 3.2 
ng/L, and are displayed in Fig. 2. In Tab. S6, more statistical 
details of all measured compounds are summarized. 
Compounds that were measured in small concentrations (me 
dian <0.15 ng/L) or in few samples (Fig. 2, displayed in gray) 
were excluded from further discussion (see Tab. S6). As met- 
oprolol was found below its LOQ and was only analyzed since 
2013, it is also excluded from further description. The com 
pounds carbendazim (CARBEND), benzotriazole 
(BENZTRI), and PFASs were analyzed since 2009 (Tab. 
SI2). Compounds of each class, measured with the highest 
median concentrations are further discussed in this paper (Fig. 
2, displayed in color). 
Among the herbicides, chloridazon (CHL) showed the 
highest median concentration (3.2 ng/L) followed by simazine 
(SIM) and atrazine (ATR) (2.7 ng/L and 2.5 ng/L, respective 
ly), 2,4-dichlorophenoxyacetic acid (2,4-D), diuron (DIU), 
terbuthylazine (TERB), MCPA, and isoproturon (ISO) (0.3 
to 1.8 ng/L). From the PFASs, perfluorooctanoic acid 
(PFOA) and perfluoroctylsulfonic acid (PFOS) exhibited the 
highest values (0.4 ng/L and 0.2 ng/L, respectively). The phar 
maceuticals carbamazepine (CARB) and primidone 
(PRIMID) were detected with concentrations of 2.4 ng/L 
and 2.2 ng/L respectively, as well as the complex-forming 
agent BENZTRI (2.3 ng/L). Many of the compounds (Fig. 
2) showed low variation coefficients of 15 to 100%, which 
is an indication for a low variance in space and time. Flowever, 
compounds of low concentrations exhibit higher variabilities 
of up to 393% (Tab. S6). 
Spatial distribution and input sources in the western 
part of the Baltic Sea 
The main survey area is the German exclusive economic zone 
(EEZ) in the western Baltic Sea, where 12 surveys from 2001 
to 2014 were carried out (Tab. S2, S3). In addition, one sur 
vey, covering the whole Baltic Sea area up to the Bothnian Sea 
and the Gulf of Finland, was done in summer 2008 (Tab. S2, 
S3). 
In order to get a first spatial and temporal overview of the 
distribution of the ten, most frequently sampled stations, the 
total concentrations were calculated for each year from 2001 
to 2014 (Fig. 3, data Tab. S7). The different stations show 
similar total concentration medians over time, which was in 
dicated from the low overall variation coefficients. When the 
sampling campaigns are subdivided into two periods (2001— 
2007 and 2009-2014), the general trend shows a slight in 
crease in the median concentration by about 6 ng/L, from first 
to second period (2001-2007, 18.1 ng/L, n = 22; 2009-2014, 
24.5 ng/L, n = 47; excluding station PB1-3). Furthermore, the 
detected total concentration range until 2007 (13.2-33.7 ng/L, 
2001-2007) is smaller than the range from 2009 to 2014 
(TO.1-50.2 ng/L), reflecting the slight increased median con 
centration. The station which can easily be identified by its 
high concentrations is the station PB1-3, which is situated 
close to the Odra mouth (Fig. lb). The concentrations are 
higher at this station than at any other sampled stations. As 
Fig. 2 Median concentrations 
(2001-2014) ofthe most 
frequently detected compounds of 
the total data set. Compounds 
displayed in color will be further 
discussed. *’ corrosion inhibitor, 
* 2 pyridazinone herbicide; Data: 
see Tab. S6, S7