Remediating Agricultural Legacy Nutrient Loads in the Baltic Sea Region

Abstract

The Baltic Sea is considered the marine water body most severely affected by eutrophication within Europe. Due to its limited water exchange nutrients have a particularly long residence time in the sea. While several studies have analysed the costs of reducing current nutrient emissions, the costs for remediating legacy nutrient loads of past emissions remain unknown. Although the Baltic Sea is a comparatively well-monitored region, current data and knowledge is insufficient to provide a sound quantification of legacy nutrient loads and much less their abatement costs. A first rough estimation of agricultural legacy nutrient loads yields an accumulation of 0.5–4.0 Mt N and 0.3–1.2 Mt P in the Baltic Sea and 0.4–0.5 Mt P in agricultural soils within the catchment. The costs for removing or immobilising this amount of nutrients via deep water oxygenation, mussel farming and soil gypsum amendment are in the range of few tens to over 100 billion €. These preliminary results are meant as a basis for future studies and show that while requiring serious commitment to funding and implementation, remediating agricultural legacy loads is not infeasible and may even provide economic benefits to local communities in the long run.

Advancing Watershed Legacy Nitrogen Modeling to Improve Global Water Quality

“…Controlling surplus N in large river basins involves implementing conservation practices across broad spatial extents, e.g., ranging from the ∼11 600 km 2 Chesapeake Bay Watershed (United States) to the ∼2.13 million km 2 Baltic Sea drainage area . In these systems, N stores and fluxes vis-à-vis legacy N dynamics are important, , as is the capacity to project more realistic water quality targets based on inclusion of legacy N-related processes in the model.…”

Investigating phosphorus loads removed by chemical and biological methods in municipal wastewater treatment plants in Poland

“…However, P biogenic function has a serious drawback, reveled in the aquatic ecosystem in which it simulates algae growth what results in negative consequences as dissolved oxygen de cits, hypoxia, water taste and odor problems, limited photosynthesis and others leading to water eutrophication with harmful algal blooms (HABs) and water bodies degradation in the most severe cases (Ekholm and Krogerus 1998;Dodds et al 2009; Tang et al 2018). To mitigate eutrophication process which appeared in a growing number of water ecosystems such as Lake Michigan (Barbiero et al 2002), Lake Erie (Wilson et al 2018), Chesapeake Bay (Conley et al 2009), Constance Lake (AERZEN 2019), Taihu Lake (Wang et al 2019), the Baltic Sea (Tanzer et al 2021) and others, in many countries nutrients loads were limited in the nal e uent from wastewater treatment plants (WWTPs) (Preisner et al 2020). In the European Union (EU) Member States based on the Urban Wastewater Treatment Directive (91/271/EEC) (European Commission 1991) limits for P concentration in treated wastewater were established for 2 categories based on the agglomeration size set in population equivalent (PE).…”