Dataset on geosynthetic material debris contamination of the South-East Baltic shore

The database gives information on the contamination of the shore of the South-Eastern Baltic with the debris of geosynthetic materials for the period 2018–2020. This new type of coastal pollution enters the natural environment due to the destruction of coastal protection structures and construction activities. The database contains sections: (1) a list of types of geosynthetic material residues, their photographic images and photographs illustrating examples of finds in natural conditions [1 List_geosynthetic_debris_SEB], (2) monitoring data on the contamination of the beach strip with the debris of geotextiles, braids from gabions, geocontainers (big bags), geocells and geogrids for the beaches of the South-Eastern Baltic for the period 2018–2020 [2 Monitoring_geosynthetic_debris_SEB]; (3) statistical distributions of the found geosynthetic debris by size [3 Scales_geosynthetic_debris_SEB] and (4) results of test surveys on the shores of Lithuania and Poland adjacent to Kaliningrad Oblast. All data refer to the beaches of the Kaliningrad Oblast (Russia), including the Russian parts of the Vistula and Curonian Spits, but also contains information on a one-time assessment of the pollution of the beaches of the adjacent territories: the Polish shore from the Poland-Russia border on the Vistula Spit to the mouth of the Vistula River, the Lithuanian shore from the border Lithuania-Russia on the Curonian Spit to the border of Latvia-Lithuania. Materials were collected during field surveys within the ERANET-RUS_Plus joint project EI-GEO, ID 212 (RFBR 18-55-76002 ERA_a, BMBF 01DJ18005).


a b s t r a c t
The database gives information on the contamination of the shore of the South-Eastern Baltic with the debris of geosynthetic materials for the period 2018-2020. This new type of coastal pollution enters the natural environment due to the destruction of coastal protection structures and construction activities. The database contains sections: (1) a list of types of geosynthetic material residues, their photographic images and photographs illustrating examples of finds in natural conditions [1 List_geosynthetic_debris_SEB], (2) monitoring data on the contamination of the beach strip with the debris of geotextiles, braids from gabions, geocontainers (big bags), geocells and geogrids for the beaches of the South-Eastern Baltic for the period 2018-2020 [2 Monitoring_geosynthetic_debris_SEB]; (3) statistical distributions of the found geosynthetic debris by size [3 Scales_geosynthetic_debris_SEB] and (4) results of test surveys on the shores of Lithuania and Poland adjacent to Kaliningrad Oblast. All data refer to the beaches of the Kaliningrad Oblast (Russia), including the Russian parts of the Vistula and Curonian Spits, but also contains information on a one-time assessment of the pollution of the beaches of the adjacent territories: the Polish shore from the Poland-Russia border on the Vistula Spit to the mouth of the Vistula River, the Lithuanian shore from the border Lithuania-Russia on the Curonian Spit to the border of Latvia-Lithuania. Materials were collected during field surveys within the ERANET -RUS_Plus joint project EI-GEO, ID 212 (RFBR 18-55- Value of the Data • The data are useful for policymakers to develop beach cleanup programs and programs to prevent possible coastal zone contamination. The data provided describe the level of contamination with the debris of geosynthetic materials on the beaches of the South-Eastern Baltic region (Kaliningrad Oblast, Russia and Polish and Lithuanian coasts adjacent to Kaliningrad Oblast), including the Curonian Spit UNESCO National Park. This new type of coastal contamination enters the natural environment due to the destruction of coastal protection structures and construction activities. The rate of contamination in surface beach sands is documented. • The data are useful for researchers comparing beach contamination status along the Baltic Sea (or European seas). Data are given for summer periods of 2018-2020 and show the interannual variability of contamination level. • The data are helpful for researchers to understand the general scheme of the transport by sea currents in the South-Eastern Baltic region. It can be used for hydrodynamic model calibration or validation.

Data Description
The database contains sections, which are presented in four separate files. The third file [3 Scales_geosynthetic_debris_SEB] demonstrates the statistical distributions of the found geosynthetic debris by spatial size. For geotextile (Fig. 3.1) and geo-container ( Fig.  3.2), variations of a sample area (cm 2 ) are presented, while for gabions (Fig. 3.3), the variations of a sample length (cm) are presented. The statistics on sample size are presented in the form of a box-and-whisker diagram for debris of geotextile, geo-container and gabion plastic coating for each monitoring year. On each box-and-whisker diagram, the label inside the box indicates the value of the median sample size. Upper and lower whiskers correspond to the maximum The position of the twelve test 1-km segments at the Lithuanian part of the shore of the Southeastern Baltic and seven test segments of various lengths at the Polish part of the neighbouring shore are illustrated on (Fig. 4.1). Information about test field surveys (coordinates, length of monitoring segments and time of the surveys) on the shore of the Lithuanian and Polish coasts are presented in (Table 4.1). The number of geosynthetic material debris of the various types which was found on the test segments on Lithuanian and Polish coasts are presented in (Table 4.2). All tables and figures mentioned in this paragraph is in the fourth file mentioned above.
Elena Esiukova took all photos.

Experimental Design, Materials and Methods
The study area ( Fig. 1 ) in the South-Eastern Baltic included the beaches of the Kaliningrad Oblast (Russia) and also contains the beach segments on the adjacent territories: the Polish shore from the Poland-Russia border on the Vistula Spit to the mouth of the Vistula River, the Lithuanian shore from the border Lithuania-Russia on the Curonian Spit to the border of Latvia-Lithuania. Therefore, the transboundary shores of the sandy barrier, the Vistula and Curonian spits were studied as a whole.
The main activity was applied to the shore of the Kaliningrad Oblast, which was divided into 13 monitoring segments of nearly equal length. The length of such a specific monitoring segment was approximately 10 km ( ± 1.5 km), making it possible to efficiently carry out work on it in one expedition day. The average time spent on one monitoring segment is about 6-8 hours. In addition, the monitoring segments were assigned to reach the starting and ending points of the section by road.
The segments were numbered in the direction from south to north (from west to east), starting from the state border with the Republic of Poland (on the Vistula Spit) and ending at the state border with the Republic of Lithuania (on the Curonian Spit).
There are two sections (No. 1-2) on the Russian side of the Vistula Spit; 3 sections on the western shore of the Sambia Peninsula (No. 3-5); 4 sections on the northern shore (No. 6-9) of the Sambia Peninsula; 4 sections (No. 10-13) on the Russian part of the Curonian Spit. This numbering was used for logistic purposes during the organisation of monitoring activity.
The monitoring network of the State Organization of the Kaliningrad oblast "Baltberegozaschita'' (BBZ), the local coastal protection authority, was used for more detailed grounding of the found geosynthetic debris. This monitoring network includes reference points with the step of 500 m and covers the whole coastline within the Kaliningrad Oblast. The reference points started at the Polish-Russian border on the Vistula Spit (the point No1 is 500 m north from the Polish-Russian border) and ended at the Lithuanian-Russian border on the Curonian Spit (the point No 289 is just before the Lithuanian-Russian border). All geosynthetic remnants found during the 500 m subsegment were referred to this subsegment (to avoid unnecessary detailing). The subsegments were numbered by the last monitoring reference point of the BBZ monitoring network included in this subsegment.
A preliminary survey [1] showed that fragments of geosynthetic materials are unevenly distributed on the beach. The use of an area-selective technique, such as for anthropogenic debris [2] and microplastics [3,4] , is not resultative in such a case.
The technique of continuous visual scanning [1] has been applied to find the fragments of geosynthetic materials not smaller than meso-forms t(approximately 1 cm in scale). This technique assumes a continuous passage along the entire coastline, covering the entire width of the beach from the edge to the foredune (or cliff), in a group of several observers. The average width of the beaches of the Kaliningrad Oblast is 30 m (up to 190 m in extreme), and the group of observers usually included three people ( Fig. 2 ). The beach (from the coastline to the foredune or cliff) was divided into three control zones; each member of the group controlled the strip of 'his'' zone to capture the edge of the neighbouring zone -for a complete scan of the entire beach.
The monitoring has been carried out for three years. In 2018, 29 monitoring visits were carried out in the period from June to November. In 2019, the scope of work amounted to 18 monitoring visits from March to December. The field campaign in 2020 included 13 monitoring visits.
When registering each detected geosynthetic sample, the following parameters were recorded: the type of geosynthetic sample, geometrical dimensions (length and area), number of the subsection where this sample was found, position on the beach (in % of the distance from the waterline, 100% is at the beach back). Next, photographs were taken, and this sample was collected for further laboratory analysis. The proposed monitoring design helps to assess the beach contamination by geosynthetic debris only superficially. It is impossible to notice all the geosynthetic fragments during a visual inspection of the beach because the fragments: -can be covered with sand or hidden in a heap of pebbles/boulders/algae; -can be smeared or covered with algae or dirt; -do not belong to the types of geosynthetic materials known in advance in the area; -can be severely degraded (destroyed) up to the impossibility of identification; -can be in an inaccessible place (underwater). Finally, the inattention or fatigue of observers cannot be disregarded. Various household waste, of which there is a large amount on the beaches, was not considered in this work and was not taken into account. Also, the counts did not take into account tens and hundreds of threads from big bags, which were unevenly distributed along the line of the current splash.
It should be noted that the work was not carried out immediately after the storms passed, and, accordingly, some of the fragments were probably already buried under a layer of sand. Sometimes, the parts of the big bags were partially or almost completely buried in the thickness of the beach, and it did not allow them to be removed from the natural environment and accurately record their sizes.

Ethics Statement
It is not relevant to this study.

CRediT author statement
Boris Chubarenko: Conceptualisation, Monitoring design development, Methodology development, Organisation of the fieldwork, Reviewing and editing of dataset presentation. Writing