Estimation of domestic and industrial emissions to the European fresh and marine waters is needed for assessing current ecological status of water bodies and providing inputs to conceptual models of pollutant transport and fate. Regulatory efforts of the European Commission, particularly Urban Waste Water Directive (UWWTD) and Water Framework Directive (WFD) prompted investments in waste treatment, and as a result point source emissions to water bodies have declined. In order to account for these improvements, domestic and industrial emission assessments were to be updated for conditions valid in the 2010s. The aim of this study was to assess the quantity and location of domestic and industrial waste emissions of pollutants in European waters for the 2010s. Specifically, the pollutants considered in this study were total Nitrogen (N), total Phosphorous (P), and organic pollution as measured by 5-days Biochemical Oxygen Demand (BOD). The spatial resolution and extent of the analysis corresponded to the CCM2 River and Catchment Database for Europe. Pollutants were estimated in terms of mean annual average load (t/y) released in the CCM2 catchments. The reference period for the assessment was set to 2014- 2015, although in some cases a longer time period was considered. The assessment of pollutant loads to waters from domestic and industrial emissions made full use of available European databases created in response to EU regulations. A method was developed to exploit the European datasets and fill in content gaps through alternative sources of information (REP approach). The European datasets allowed pinpointing waste emissions to a much higher spatial and conceptual resolution than before, although some knowledge gaps remained, affecting especially emissions from domestic waste of isolated dwellings, small agglomerations, and industries. Outside EU28, Switzerland and Norway, domestic and industrial emissions were assessed based on population density and national statistics of shares of population served by sewerage treatment and per WWTP treatment level (POP approach). The comparison between Population Equivalent generated in agglomerations and reported in the UWWTD database with country resident population allowed estimating an equivalence of 1.23 PE per inhabitant, meaning that on average in Europe the contribution of small industries, commercial activities and tourism can be considered about 23% of waste load generated in agglomerations. This information was used to assess population unreported in the UWWTD database because belonging to small, isolated dwellings. Estimates of total emissions due to domestic waste with REP approach with those from POP approach for 30 countries covered by both methods were in good agreement, with Pearson’s correlation coefficient of 0.95 for Nitrogen, 0.94 for Phosphorous and 0.71 for BOD. Yet, important differences emerged when separating emissions by treatment type or pathway, e.g. looking at disconnected, connected not treated or connected and treated shares of domestic waste. The comparison highlighted inconsistencies between the European database and national statistics and it was noted that for some countries national statistics were scant or inconsistent. Thus, while total emissions are comparable, care should be taken when considering each population share independently. Finally, total pollutant emissions for Europe in 2010s were obtained by merging all available data, using the REP approach and the POP approach estimates to fill in knowledge gaps. In EU28, annual emissions to water from domestic and industrial waste for the 2010s were estimated at 777.6 kt/y of Nitrogen, 126.6 kt/y of Phosphorous and 2,190 kt/y of BOD. The majority of domestic waste is treated in WWTPs, with high adoption rates of tertiary treatment and Phosphorus removal technology, lowering emissions of domestic waste per capita. EU28 IND emissions accounted for 11.3% of N, 6.7% of P and 33.7% of BOD emissions. Waste from population disconnected to sewerage systems or treated with Individual Appropriate Systems (for which only primary treatment was assumed) accounted for 11.2% of Nitrogen, 14.6% of Phosphorous and 19.5% BOD emissions to the environment. However only a part of these emissions would eventually reach freshwater systems, as environmental abatement (not considered in this study) would further reduce them. Conversely, connected not treated population contributed 6.2% of Nitrogen, 7.2% of Phosphorous, and 14.4% of BOD directly discharged to freshwater bodies. Tackling these sources of domestic waste and upgrading primary treatment facilities may further reduce pollution loads discharged in fresh and marine waters.
