The share of Poland in the phosphorus pollution status of Baltic Sea in the light of HELCOM PLC research

Abstract The aim of the study was to analyse the results of the current research in the HELCOM PLC project on Poland’s share in the phosphorus pollution of the Baltic Sea waters. The analysis considers annual update of the HELCOM Core Pressure Indicator, which monitors the implementation of maximum allowable nutrient loads (MAI), covering data from 1997 to 2022, assessment of progress in achieving national nutrient input limits (NIC assessment) in the years 1995–2020, sources and pathways of nutrients to the Baltic Sea environment by 2020 and comparative analysis at the level of source data from 1995–2018 for Poland. In 2022 total phosphorus TP inputs to the entire Baltic Sea have been reduced by 32% since the reference period 1997–2003, and about 65% of this reduction was due to reduced phosphorus inputs to the Gulf of Finland and Baltic Proper. The Polish 4,766 t of TP loads to be reduced makes 58% of the estimated loads in 2020. More than half (68%), i.e. almost 5554 t of the loads, come from other dispersed water sources. Point sources (from sewage treatment plants, industrial plants with separate discharges and aquaculture plants) discharging loads to inland fresh waters and directly to the sea, and atmospheric sediments at sea, account for 27% each, i.e. approx. 2205 t each. Main loads of total phosphorus from Poland to the Baltic Sea are delivered via inland waters (indirect sources) and come from agriculture (60%), municipal sewage (23%) and natural background (5.1%).