This dataset contains results on HELCOM Assessment unit level 4b for dissolved inorganic phosphorus. The information provided represents the data and results from the HELCOM HOLAS 3 indicator evaluation for eutrophication, covering the data period from 2016-2021. Data reported from national monitoring programmes to the HELCOM COMBINE database (hosted by ICES) is utilized for open sea assessment units. Open sea data extraction is carried out by ICES for in-situ (bottle) data creating the underlying assessment dataset [link ]. Coastal assessment units (WFD water types or water bodies) are assessed based on WFD result data reported by countries. Indicator analysis of both open sea and coastal areas is carried out using the HEAT assessment tool (https://github.com/ices-tools-prod/HEAT). This analysis provide the basis of the HELCOM indicator evaluations and are utilized in the HOLAS 3 thematic assessment of eutrophication. Attribute description: ES = Eutrophication Status ES_SD = Standard Deviation ES_N = Number of Observations ES_N_Min = Minimum Number of Observations any given year ES_SE = Standards Error ES_CI = Confidence Interval ET = Eutrophication Target / Threshold ER = Eutrophication Ratio ACDEV = Acceptable Deviation BEST = ET / (1 + ACDEV / 100) EQR = Ecological Quality Ratio EQR_HG = Ecological Quality Ratio High/Good Boundary EQR_GM = Ecological Quality Ratio Good/Moderate Boundary EQR_MP = Ecological Quality Ratio Moderate/Poor Boundary EQR_PB = Ecological Quality Ratio Poor/Bad Boundary EQRS = Ecological Quality Ratio Scaled GTC = General Temporal Confidence STC = Specific Temporal Confindence TTC = Total Temporal Confidence GSC = General Spatial Confidence SSC = Specific Spatial Confidence TSC = Total Spatial Confidence TC = Total Confidence

Concentration of phosphorus pressure layer is interpolated from annual seasonal average of total phosphorus measurements from surface waters (0-10 m) extracted from ICES’s oceanographic database, database of Swedish Meteorological and Hydrological Institute, EEA’s Eionet database and Data from Gulf of Finland year 2014. The points were interpolated to cover the entire Baltic Sea with Spline with barriers interpolation method. Values were log-transformed and normalised (more detailed description below).

This dataset contains results on HELCOM Assessment unit level 4b for total phosphorus. The information provided represents the data and results from the HELCOM HOLAS 3 indicator evaluation for eutrophication, covering the data period from 2016-2021. Data reported from national monitoring programmes to the HELCOM COMBINE database (hosted by ICES) is utilized for open sea assessment units. Open sea data extraction is carried out by ICES for in-situ (bottle) data creating the underlying assessment dataset [link ]. Coastal assessment units (WFD water types or water bodies) are assessed based on WFD result data reported by countries. Indicator analysis of both open sea and coastal areas is carried out using the HEAT assessment tool (https://github.com/ices-tools-prod/HEAT). This analysis provide the basis of the HELCOM indicator evaluations and are utilized in the HOLAS 3 thematic assessment of eutrophication. Attribute description: ES = Eutrophication Status ES_SD = Standard Deviation ES_N = Number of Observations ES_N_Min = Minimum Number of Observations any given year ES_SE = Standards Error ES_CI = Confidence Interval ET = Eutrophication Target / Threshold ER = Eutrophication Ratio ACDEV = Acceptable Deviation BEST = ET / (1 + ACDEV / 100) EQR = Ecological Quality Ratio EQR_HG = Ecological Quality Ratio High/Good Boundary EQR_GM = Ecological Quality Ratio Good/Moderate Boundary EQR_MP = Ecological Quality Ratio Moderate/Poor Boundary EQR_PB = Ecological Quality Ratio Poor/Bad Boundary EQRS = Ecological Quality Ratio Scaled GTC = General Temporal Confidence STC = Specific Temporal Confindence TTC = Total Temporal Confidence GSC = General Spatial Confidence SSC = Specific Spatial Confidence TSC = Total Spatial Confidence TC = Total Confidence

The layer depicts the pressure of eutrophication in the Baltic Sea, based on the data from the HOLAS 3 integrated eutrophication assessment. The methodology utilizes the Eutrophication Quality Ratios (EQRS) available for each HELCOM assessment unit on level 4b. The results of integrated eutrophication assessment combines the information of the three MSFD criteria groups (C1: Nutrient levels, C2: Direct effect, C3: Indirect effect) and use this value as an indication of pressure for each assessment unit. The Spatial Impact and Pressure Assessment is carried out using a 1x1km grid while the Integrated eutrophication status is assessed on vector based HELCOM assessment units, the vector data are rasterized. First, the vector data are rasterized to 100x100m resolution, and after that it is aggregated to a 10x10km grid using a mean value. A 10 km grid is used in order to make the gradients between assessment units slightly smoother and finally the values converted to 1x1 km resolution. The scale for the pressure values in the map (0.26-1) represents the scale in the original source data.

Dataset description: This dataset contains data on water flows, actual waterborne (riverine plus direct) inputs and atmospheric deposition of nutrients. Furthermore, it includes normalized total (atmospheric and waterborne) inputs of nitrogen and phosphorus into the Baltic Sea. The data are used in the HELCOM core indicator of nutrient inputs (nitrogen and phosphorus) to the Baltic Sea marine ecosystem (Inputs of nutrients - HELCOM indicators). The data is presented in the format of MS Excel workbook consisting of 3 sheets. Sheets of nitrogen inputs and phosphorus inputs integrate 4 tables each. These tables contain time series, starting from 1995, of assessed nutrient input values: waterborne actual (riverine+direct), atmospheric deposition (actual), total actual input (air+water), normalize total input (air+water). Nitrogen and phosphorus inputs are assessed for the following Baltic Sea sub-basins: Bothnian Bay (BOB), Bothnian Sea (BOS), Baltic Proper (BAP), the Gulf of Finland (GUF), the Gulf of Riga (GUR), Danish Straights (DS), Kattegat (KAT) and the whole Baltic Sea (BAS). All input data is given in tonnes per year (tonnes/year). The Flow sheet contains only one table with an annual water flow data time-series for each sub-basin of the Baltic Sea given in cubic meters per year (m3/s). The river input data is based on riverine monitoring data and estimation of loads from unmonitored areas by countries in the frame of national monitoring programs. Data on waterborne inputs and water flow is reported by Contracting Parties to the PLC-Water database. The data are verified and quality assured using the PLC water database verification tools and national expert quality assurance. Atmospheric deposition of nitrogen for all Baltic Sea sub-basins is computed using the latest version of EMEP MSC-W model and data on official emissions reported by EMEP Contracting Parties. Dataset content: Excel workbook contains the following sheets: Nitrogen inputs – time-series of waterborne actual (riverine+direct), atmospheric deposition (actual), total actual input (air+water), normalized total input (air+water) (tonnes/year) . Phosphorus inputs – time-series of waterborne actual (riverine+direct), atmospheric deposition (actual), total actual input (air+water), normalized total input (air+water) (tonnes/year). flow - annual water flow data time-series (m3/s). Visualization: MS Excel workbook. Data update: Metadata is updated by HELCOM Secretariat annually after adoption of indicator report. The dataset is updated by HELCOM Secretariat annually after adoption of indicator report.

Dataset description: This spatial dataset displays catchment areas of the Baltic Sea sub-basins for which the nutrient input to the marine environment and the fulfilment of the maximum allowable inputs of nutrients (MAI) are assessed. Attributes to the polygonal features reflect results of the latest assessment of total normalized input of total nitrogen (TN) and total phosphorus (TP) to the sub-basin from all pathways (riverine, direct, airborne), which are used as HELCOM Core indicator to assess progress towards maximum allowable input (MAI) of nutrients to the Baltic Sea Inputs of nutrients - HELCOM indicators. The assessment takes into account statistical uncertainty which is added to the computed input value. Thus, the fulfilment of MAI means that the nutrient input after adding the statistical uncertainty is below the agreed maximum allowable input value. Attributes TN status and TP status indicate whether MAI is fulfilled or not which is visualized in a simple traffic light colour scheme. The green colour of a catchment indicates that input plus statistical uncertainty was lower than MAI, red colour - input (without statistical uncertainty) was higher, and yellow indicates that input value was lower than MAI but statistical uncertainty does not allow to determine whether MAI was fulfilled. The assessment is performed in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (HELCOM PLC-Water Guideline). Dataset content: Polygonal feature class contains the following attributes: Sub-basin code (subb_code): Code of the Baltic Sea sub-basin (used for PLC assessment) MAI of total nitrogen (MAI_TN): Maximum allowable input of total nitrogen to respective sub-basin (tons/year) MAI of total phosphorus (MAI_TP): Maximum allowable input of total phosphorus to respective sub-basin (tons/year) Total nitrogen (TN): assessed input of total nitrogen to respective sub-basin (tonnes/year) Total phosphorus (TP): assessed input of total phosphorus to respective subbasin (tonnes /year Total nitrogen uncertainty (TN_uncert): statistical uncertainty of the assessment (tonnes /year) Total phosphorus uncertainty (TP_uncert): statistical uncertainty of the assessment (tonnes /year) Total nitrogen status (TN_status): fulfilment of MAI for TN (fulfilled, not fulfilled, undefined). Total phosphorus status (TP_status): fulfilment of MAI for TP (fulfilled, not fulfilled, undefined). Catchment area (Area): in square kilometres. Year (Year). The following Baltic Sea sub-basin codes are used in the dataset: BAP-BALTIC PROPER; BOB-BOTHNIAN BAY; BOS-BOTHNIAN SEA; GUF-GULF OF FINLAND; GUR-GULF OF RIGA; KAT-KATTEGAT; DS-Danish Straights. Visualization: Map of fulfilment of MAI for nitrogen input to the Baltic Sea - visualizes catchment areas of the Baltic Sea sub-basins in relation to fulfilment of maximum allowable inputs of total nitrogen. Map of fulfilment of MAI for phosphorus input to the Baltic Sea - visualizes catchment areas of the Baltic Sea sub-basins in relation to fulfilment of maximum allowable inputs of total phosphorus. Data update: Metadata is updated by HELCOM Secretariat annually after adoption of indicator report. The dataset is updated by HELCOM Secretariat annually after adoption of indicator report.

This dataset reflects the spatial distribution of area specific inputs to the sea of total nitrogen and total phosphorus from different land-based sources. Area specific inputs to the sea are calculated for each sub-catchment designated for the HELCOM PLC assessment. The sub-catchments are the smallest areas for which loads of nutrients and hazardous substances are assessed. Sub-catchments are always located within borders of a single country and drain into one Baltic Sea sub-basin. Sub-catchments may correspond to either monitored or unmonitored areas. Unmonitored sub-catchments may represent either unmonitored parts of river catchments or aggregated unmonitored areas (depending on the reporting format of each Contracting Party). Area specific inputs to the sea are calculated applying the load-oriented approach (see PLC-Water Guideline, http://www.helcom.fi/Lists/Publications/PLC-Water%20Guidelines.pdf). It means that computed values reflect nutrient inputs from identified sources into respective Baltic Sea sub-basins, considering also retention in downstream sub-catchments. The data on sources of nutrients is obtained through national monitoring programmes and periodically reported by Contracting Parties to the HELCOM Pollution Loads Compilation (PLC-water) database as an integral part of HELCOM Pollution Loades Compilation process. The data is produced, compiled and quality assured in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (PLC-Water Guideline, http://www.helcom.fi/Lists/Publications/PLC-Water%20Guidelines.pdf). Dataset content: Polygonal feature class contains the following attributes: 1. Source_Code: Unique code for sub-catchment 2. Name: Name of river catchment or unmonitored area 3. SubBasin: Sub-basin of the Baltic Sea the sub-catchment drains to. 4. Country: Country on which territory the sub-catchment is located. 5. Polygon area in sq.km. 6. Retention of nitrogen (%) 7. Retention of phosphorus (%) 8. Area specific inputs of Nitrogen to the sea (kg/km2) 9. Area specific inputs of Phosphorus to the sea (kg/km2) 10. NBL_TN: Area specific background inputs of Nitrogen to the sea (kg/km2) 11. NBL_TP: Area specific background inputs of Phosphorus to the sea (kg/km2) 12. Diffuse_TN: Area specific total diffuse inputs of Nitrogen to the sea (kg/km2) 13. Diffuse_TP: Area specific total diffuse inputs of Phosphorus to the sea (kg/km2) 14. AGL_TN: Area specific agricultural inputs of Nitrogen to the sea (kg/km2) 15. AGL_TP: Area specific agricultural inputs of Phosphorus to the sea (kg/km2) 16. Dif_other_TN: Area specific diffuse nitrogen inputs to the sea from sources other than agriculture (kg/km2) 17. Dif_other_TP: Area specific diffuse phosphorus inputs to the sea from sources other than agriculture (kg/km2) 18. Trans_TN: Area specific transboundary nitrogen inputs to the sea (kg/km2). 19. Trans_TP: Area specific transboundary phosphorus inputs to the sea (kg/km2). Visualization: The following maps visualize the data on area specific loads of nutrients from various sources: • Retention of Nitrogen (%) • Retention of Phosphorus (%) • Area specific total inputs of Nitrogen to the sea (kg/km2) • Area specific total inputs to the sea of Phosphorus to the sea (kg/km2) • Area specific background inputs of Nitrogen to the sea (kg/km2) • Area specific background inputs of Phosphorus to the sea (kg/km2) • Area specific total diffuse inputs of Nitrogen to the sea (kg/km2) • Area specific total diffuse inputs of Phosphorus to the sea (kg/km2) • Area specific agricultural inputs of Nitrogen to the sea (kg/km2) • Area specific agricultural inputs of Phosphorus to the sea (kg/km2) • Area specific diffuse Nitrogen inputs to the sea from sources other than agriculture (kg/km2) • Area specific diffuse Phosphorus inputs to the sea from sources other than agriculture (kg/km2) • Area specific transboundary inputs of Nitrogen load to the sea (kg/km2). • Area specific transboundary input of Phosphorus load to the sea (kg/km2).

Dataset description: The dataset contains annually reported data on water flow, input of nutrients and selected hazardous substances to the Baltic Sea from monitored rivers and unmonitored areas within its catchment area. The data, obtained through national monitoring programmes, is reported by all Contracting Parties to the HELCOM (PLC-water) database as part of HELCOM Pollution Load Compilation (PLC) process. The input from transboundary rivers reflects the whole river catchment including its transboundary parts.. All data is quality assured and approved by Contracting Parties to HELCOM in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (HELCOM PLC-Water Guideline). Dataset content: The dataset contains the following information: Source name. Name of monitored river or unmonitored area. Source code. The source code refers to the code used in the PLC-water database for the monitored or unmonitored sub-catchments. Country code. The country code indicates the country within the Baltic Sea drainage area (DK; EE; FI; DE; LV; LT; PL; RU; SE;). Sub-basin code. The sub-basin code refers to the Baltic Sea sub-basin used in HELCOM assessment of inputs of nutrients and hazardous substances (ARC; BAP; BOB; BOS; GUF; GUR; KAT; SOU; WEB). Parameter. Parameters reported by the contracting parties to the Helsinki Convention to assess riverine inputs of nutrients and selected hazardous substances. : AOX; BOD5; BOD7; Cd*; COD-Cr; COD-Mn; Cr; Cu; FLOW; Hg*; Ni; NNH4*; NNO2*; NNO3*; NNO3; NTOT*; Oil; Pb*; PPO4;* PTOT*; SPM; TOC; Zn. (tonnes/year or flow in m3/s). Year. Year of observation. *Mandatory parameters for annually reported riverine data. Other parameters are voluntary. Country codes used in the dataset correspond to: DK-DENMARK; EE-ESTONIA; FI-FINLAND; DE-GERMANY; LV-LATVIA; LT-LITHUANIA; PL-POLAND; RU-RUSSIA; SE-SWEDEN; The Baltic Sea sub-basin codes used in the dataset are: ARC-ARCHIPELAGO SEA; BAP-BALTIC PROPER; BOB-BOTHNIAN BAY; BOS-BOTHNIAN SEA; GUF-GULF OF FINLAND; GUR-GULF OF RIGA; KAT-KATTEGAT; SOU-SOUND; WEB-WESTERN BALTIC. Visualization: The dataset can be retrieved from the HELCOM PLC-Water database and visualized utilizing an online user interface. The following filters are available to generate the dataset: Source of input: monitored river, unmonitored area. Multiple selection possible Country: DENMARK; ESTONIA; FINLAND; GERMANY; LATVIA; LITHUANIA; POLAND; RUSSIA; SWEDEN. Multiple selection possible. Baltic Sea sub-basin: ARCHIPELAGO SEA; BALTIC PROPER; BOTHNIAN BAY; BOTHNIAN SEA; GULF OF FINLAND; GULF OF RIGA; KATTEGAT; SOUND; WESTERN BALTIC. Multiple selection possible. Year: the first and the last year of the data request (1995-20…) Parameter: AOX; BOD5; BOD7; Cd; COD-Cr; COD-Mn; Cr; Cu; FLOW; Hg; Ni; NNH4; NNO2; NNO23; NNO3; NTOT; Oil; Pb; PPO4; PTOT; SPM; TOC; Zn. Only one parameter can be selected. Data update: Metadata is updated by the HELCOM Secretariat annually by 1 April. The dataset is updated annually and becomes publicly available in accordance with PLC-Water Guidelines, which details the procedures for reporting data to the HELCOM pollution load compilation (PLC) and the release of PLC products based on reported data.

Dataset description: The dataset contains data on locations of river monitoring stations of nutrients and hazardous substances inputs to the Baltic Sea reported to the HELCOM Pollution Load Compilation (PLC-water) database. The stations are categorized as hydrological (only flow monitoring) and chemical (monitoring of chemical components). The data is reported to the HELCOM database and quality assured by Contracting Parties to HELCOM in accordance with the HELCOM Guidelines for the annual and periodical compilation and reporting of waterborne pollution inputs to the Baltic Sea (PLC-Water Guidelines). Dataset content: Station code (st_code): unique HELCOM PLC code Station name (st_name). River code (r_code): unique HELCOM PLC code. Sub catchment code (subc_code): unique HELCOM PLC code Country code (c_code): DK; EE; FI; DE; LV; LT; PL; RU; SE. Sub-basin code (subb_code): ARC; BAP; BOB; BOS; GUF; GUR; KAT; SOU; WEB. Station category (st_cat): hydrological (H) and chemical (C). Latitude (st_lat). Longitude (st_lon). Reporting year (year). Country codes used in the dataset correspond to: DK-DENMARK; EE-ESTONIA; FI-FINLAND; DE-GERMANY; LV-LATVIA; LT-LITHUANIA; PL-POLAND; RU-RUSSIA; SE-SWEDEN. The Baltic Sea sub-basin codes used in the dataset are: ARC-ARCHIPELAGO SEA; BAP-BALTIC PROPER; BOB-BOTHNIAN BAY; BOS-BOTHNIAN SEA; GUF-GULF OF FINLAND; GUR-GULF OF RIGA; KAT-KATTEGAT; SOU-SOUND; WEB-WESTERN BALTIC. Visualization: Map - point feature class. Legend visualizes two categories of monitoring station: hydrological, chemical. Data update: Metadata is updated by HELCOM Secretariat annually by 1 April. The dataset is updated by HELCOM Secretariat annually by 1 April.

Dataset description: The assessment dataset contains data on water flow and annual nutrient inputs (total nitrogen and phosphorous loads) from catchments and from point sources (municipal, industrial and aquaculture) directly discharging to the Baltic Sea sub-basins. The dataset is produced by regional experts (PLC implementation group) through statistical analysis and filling data gaps in the data reported by national experts to the HELCOM PLC-water database. The dataset includes actual (non-normalized), and water flow normalized annual inputs of total nitrogen (TN) and total phosphorus (TP) from monitored and unmonitored areas per Balic Sea sub-basin. It also contains data on total nitrogen (TN) and total phosphorus (TP) annual inputs from point sources (industrial, municipal and aquaculture) aggregated per country and per sub-basin discharging directly into the Baltic Sea sub-basins. The dataset is published as MS Excel workbook, consisting of several sheets. The sheets provide assessment data for flow, total nitrogen and total phosphorus, as well as background information on data treatment and aggregation. Spatial delineation of catchments is provided in the catchment dataset accessed through HELCOM Metadata Catalogue - (PLC) Assessment catchments (spatial data). Datasets can be related using Source_Code field. The dataset is used in HELCOM Baltic Sea Environmental Fact Sheet (BSEFS) on Waterborne nitrogen and phosphorus inputs and water flow to the Baltic Sea published annually. Dataset content: Excel workbook contains the following tables: AggregationsOfIncompleteRiverTi – the table enlists aggregation of monitored areas of sub-catchments with incomplete time-series with unmonitored areas (country specific), UnmonitoredAreasMergedInMonitor – the table enlists aggregation of unmonitored and monitored areas into unified catchments (country specific). OriginalRivers_Flow, OriginalRivers_TN, OriginalRivers_TP – time series of flows (m3/s) and total N and P (tonnes/year) inputs as reported to PLC-Water database for monitored rivers OriginalUnmonitored_Flow, OriginalUnmonitored_TN, OriginalUnmonitored_TP - time series of flows (m3/s) and total N and P inputs (tonnes/year) as reported to PLC-Water database for unmonitored areas Rivers_Flow (m3/s), Rivers_TN (tonnes/year), Rivers_TP (tonnes/year) - non-normalized inputs from rivers and unmonitored areas, Rivers_NormTN (tonnes/year), Rivers_NormTP (tonnes/year) - normalized inputs from rivers and unmonitored areas, Industry_TN (tonnes/year); Industry_TP (tonnes/year) – aggregated input from industrial point sources discharging directly into the Baltic Sea, Municipal_TN (tonnes/year); Municipal_TP (tonnes/year) – aggregated input from municipal WWTPs discharging directly into the Baltic Sea, Aquaculture_TN (tonnes/year); Aquaculture_TP (tonnes/year) – aggregated input from aquaculture discharging directly into the Baltic Sea. Tables under items 3-6 contain the following fields: Source_Code, Name, Country code, Basin code, 1995, …, 20XX Where water flow is given in m3s-1 and TN/TP tonnes year-1 for each year. Tables under items 7-9 contain the following fields: Country code, Basin code, 1995, …., 20XX Where TN/TP is given in tonnes year-1 for each year. Visualization: MS Excel table. PowerBI visualization tool Data update: Metadata is updated by HELCOM Secretariat annually by 1 July. The dataset is updated by HELCOM Secretariat annually by 1 July.