IVL - Swedish Environmental Research Institute

Abstract Reactive nitrogen compounds are responsible for multiple negative impacts while they remain in the environment, changing their state and chemical form. Here we develop a methodology to trace these compounds throughout the environment using a stringent concept to describe their fate consistently and comprehensively. Using an individual country as the system scale, the individual flows of reactive nitrogen compounds are characterized between and within eight pools reflecting human society, economic sectors and environmental spheres, also accounting for transboundary flows, to create a national nitrogen budget. The methodology has been devised for implementation by national agencies in conjunction with greenhouse gas or air pollution emission inventories, hence it links closely with the structures and data derived in these contexts. The guiding methodological principle is the mass conservation of reactive nitrogen, implemented as a material flow analysis that systematically describes all flows and stock changes. Embedding results obtained from five European countries demonstrates the feasibility of the approach. The major environmental pathways of reactive nitrogen compounds can be traced from industrial processes and agricultural production, including the agri-food chain, indicating levers for policy interventions. Spatial and temporal benchmarking of the results demonstrates comparisons between countries or over time. While further results of practical implementation are needed to assess overall robustness, the budget approach allows for multiple opportunities of data checks and verification to visualize the uncertainty associated to many input data, such as lacking information on nitrogen contents and specific flows, or the relevance of so-far unaccounted-for stocks of reactive nitrogen. Useful applications have been identified that link nitrogen budgets to impacts on human health as well as on ecosystems and the climate, indicating that developing and using national nitrogen budgets may shape improved and information-led policies.

Quantifying the environmental benefits of designing buildings for disassembly and flexibility (DfD/DfF) remains challenging within current life cycle assessment (LCA) frameworks. This study assesses the climate impact of a two-story Swedish timber multifamily building (377 m2) designed for future transformation and reuse. An LCA covering modules A–D was performed for one linear scenario (S0: demolition without reuse) and three circular scenarios (S1: layout change, S2: relocation, S3: vertical extension), applying three allocation methods: 100:0, 50:50, and system expansion. All circular scenarios reduced climate impact compared to the linear reference, though to varying degrees. Reductions ranged from 8–50% within the system boundary (A–C), depending on scenario and allocation method. While the 50:50 approach attributed significant reductions within A–C, the 100:0 method emphasized benefits primarily in module D. The 50:50 method yielded the lowest impacts within the system boundary, whereas system expansion showed the largest overall reductions but relied on uncertain assumptions. The study concludes that including future scenarios in LCA is more effective in promoting circularity than the specific choice of allocation method. It emphasizes the need for standardized frameworks that account for multiple use cycles and support fair comparisons in policy and procurement.

ABSTRACT Attaining net-zero emissions globally requires counterbalancing residual emissions with carbon dioxide removal (CDR), such as bio-energy with carbon capture and storage (BECCS). BECCS potential is unevenly distributed, meaning that regions may have a ‘surplus’ or ‘deficit’ potential relative to the regional need for counterbalancing. Market mechanisms can be used to transfer BECCS outcomes from one region with surplus BECCS potential to another with deficit potential. We analyse the potential for such trade within the Nordic countries. We show that Sweden has a significant theoretical surplus BECCS potential of at least 19 MtCO2/year compared to what is needed to achieve its net-zero target, which could be realized and transferred to other countries based on e.g. Article 6 of the Paris Agreement. Within the Nordics, Denmark and Iceland could be possible buyers of such outcomes due to their relatively low BECCS potential compared to the prospective need for CDR to achieve long-term climate targets. Norway also has a small BECCS potential, but it likely suffices to reach its ‘low emission society’ target. Finland has a large BECCS potential but will likely need any domestic BECCS towards its net-zero target due to unforeseen changes in forest sinks. The residual emissions in need of counterbalancing estimated in this paper, and, thus, the potential for collaboration for BECCS outcomes, is subject to uncertainty due to vaguely formulated mitigation targets. We recommend that policy makers (i) adopt separate quantified targets for emission reductions and counterbalancing measures, (ii) evaluate whether there is a surplus or deficit domestic CDR potential to reach the targets, and (iii) seek collaborations with other countries as sellers or buyers of CDR, to facilitate net-zero.

Pharmaceutically active compounds (PhACs) in wastewater pose significant environmental risks due to their persistence and potential to disrupt aquatic ecosystems. Onsite wastewater treatment systems (OWTS) often fail to adequately remove PhACs. This study investigated the efficiency of a multi-module biochar filter (MmBF) system as secondary treatment in OWTS for removing PhACs. Two parallel MmBF systems, each comprising six sequential modules filled with biochar, were evaluated for their removal of 25 detected PhACs across multiple pharmaceutical classes. The MmBFs were operated with municipal wastewater as influent for over one year, after which wastewater samples were collected and analysed from the influent and effluent of each module. The MmBFs showed consistent reduction in the aggregated PhACs concentrations by >99% over several sampling occasions, with only six PhACs having less than 95% removal. The first aerobic module M1 contributed to more than 92% of the total removal. The subsequent aerobic modules (M2-M3) provided additional reduction, resulting in over 98% of PhACs removal in the aerobic modules. In contrast, the anoxic modules (M4-M5) had a lower overall contribution, but the removal of specific compounds was observed, suggesting potential anaerobic degradation. This study demonstrates the potential of biochar-based systems as a sustainable option for OWTSs.

The circumstances under which species diversify to genetically distinct lineages is a fundamental question in biology. Atlantic herring (Clupea harengus) is an extremely abundant zooplanktivorous species that is subdivided into multiple ecotypes that differ regarding spawning time and genetic adaption to local environmental conditions such as temperature, salinity, and light conditions. Here we show using whole genome analysis that multiple populations of piscivorous (fish-eating) herring have evolved sympatrically after the colonization of the brackish Baltic Sea within the last 8000 years postglaciation. The piscivorous ecotype grows faster, and is much larger and less abundant than the zooplanktivorous Baltic herring. Lesions of the gill rakers in the piscivorous ecotype indicated incomplete adaptation to a fish diet. This niche expansion of herring in the young Baltic Sea, with its paucity of piscivorous species, suggests that empty niche space is more important than geographic isolation for the evolution of biodiversity.

ABSTRACTOstrea edulis, the European flat oyster, was once a widespread economically and ecologically important marine species, but has suffered dramatic declines over the past two centuries. Consequently, there has been a surge in European restoration efforts, many of which focus on restocking as a conservation measure. In this study, we used whole‐genome sequencing (WGS) data to investigate the population structure, demographic history, and patterns of local adaptation of O. edulis across its natural distribution with increased sampling densities at Scandinavian localities. Results revealed seven distinct genetic clusters, including previously undescribed complex population structure in Norway, and evidence for introgression between genetic clusters in Scandinavia. We detected large structural variants (SVs) on three pseudo‐chromosomes. These megabase long regions were characterised by strong linkage disequilibrium and clear geographical differentiation, suggestive of chromosomal inversions potentially associated with local adaptation. The results indicated that genomic traces of past translocations of non‐native O. edulis were still present in some individuals, but overall, we found limited evidence of major impacts of translocations on the scale of contemporary population structure. Our findings highlight the importance of considering population structure and signatures of selection in the design of effective conservation strategies to preserve and restore wild native European flat oyster populations, and we provide direct knowledge safeguarding sustainable mitigation actions in this important species.

District heating (DH) is an efficient urban heating solution. Numerous external factors (energy efficiency, fuel-price increases, heat -pump competition and policy changes) are challenging. It is relevant to explore long-term cost-competitiveness of DH. A model has been developed testing three, future DH pathways: (i) phase out of biomass (aligned to the cascading principle of the EU Taxonomy), (ii) including waste heat in the fuel supply mix (aligned to the updated Energy Efficiency Directive) and (iii) lower system temperatures (aligned to the idea of more renewables and waste heat).The model considers the long-term development of the supply and demand sides together and simultaneously. This allows the model to determine the most cost-efficient heating solution for different building types in different points in time.The results confirm that a phaseout of biomass would erode -but that developments rendering lower system temperatures and increased waste heat utilization would strengthen-the DH business case. Additionally, it is confirmed that heat pumps constitute the main competition to DH. Hence, to remain a cost-efficient heating alternative in the future, DH systems need to revisit the tradition of centralized heat supply resorting to combustion for decentralized heat supply resorting to heat supply on demand.

The global plasticizer market is projected to increase from $17 billion in 2022 to $22.5 billion in 2027. Various emerging/alternative plasticizers entered the market following the ban on several phthalate plasticizers because of their harmful effects. However, there is limited data (especially peer-reviewed) on emerging plasticizers’ toxicity and environmental impact. This review compiles available data on toxicity, exposure, environmental effects, and safe production of emerging plasticizers. It identifies gaps in scientific research and provides evidence that emerging plasticizers are potential cases of regrettable substitution. Several alternative plasticizers, such as acetyl tributyl citrate (ATBC), diisononyl cyclohexane-1,2 dicarboxylate (DINCH), tris-2-ethylhexyl phosphate (TEHP), tricresyl phosphate (TCP), tris-2-ethylhexyl phosphate (TPHP), bis-2-ethylhexyl terephthalate (DEHT), and tris-2-ethylhexyl trimellitate (TOTM), show potential as endocrine disrupting properties and other toxic characteristics. Some chemicals like bis-2-ethylhexyl adipate (DEHA), diisobutyl adipate (DIBA), ATBC, DINCH, bis-2-ethylhexyl sebacate (DOS), diethylene glycol dibenzoate (DEGDB), DEHT, and phosphate esters showed the potential to cause toxicity in aquatic species. Plus, there is great lack of information on compounds like diisononyl adipate (DINA), dibutyl adipate (DBA), diisodecyl adipate (DIDA), dipropylene glycol dibenzoate (DPGDB), dibutyl sebacate (DBS), alkylsulfonic phenyl ester (ASE), trimethyl pentanyl diisobutyrate (TXIB), DEGDB and bis-2-ethylhexyl sebacate (DOS). Some compounds like epoxidized soybean oil (ESBO), castor-oil-mono-hydrogenated acetate (COMGHA), and glycerin triacetate (GTA) are potentially safer or less toxic. Alternative plasticizers such as adipates (LogKow 4.3–10.1), cyclohexane dicarboxylic acids (LogKow 10), phosphate esters (LogKow 2.7–9.5), sebacates (LogKow 6.3–10.1), terephthalates (LogKow 8.4), and vegetable oil derivatives (LogKow 6.4–14.8) have logKow values that are comparable to phthalate plasticizers (LogKow 7.5–10.4), indicating potential bioaccumulation and health consequences. Field studies have demonstrated that phosphate esters can undergo bioaccumulation and biomagnification, but there is a lack of bioaccumulation studies for other compounds. We also discuss the metabolism of emerging plasticizers, though data is limited. Our article highlights that numerous alternative compounds display potential health and ecological risks, indicating they might not be suitable substitutes for legacy plasticizers. There is also a lack of scientific data on most emerging plasticizers. This way, we call for increased research and timely regulatory action to prevent global contamination and health risks. Finally, this study presents a scientifically robust protocol to avoid harmful substitutions and ensure the production of safer chemicals.

Excess heat is generated from different industrial processes and from urban infrastructure (sewage water, transport, datacentres and buildings). Thirty-five percent of the European energy demand for heating and cooling could be met by excess heat. Today, however, this energy reserve is barely exploited. There are known barriers to excess heat recovery but limited information on stakeholder interactions in the early stages of excess heat collaborations and on successful collaborations. Sweden is world champion in terms of excess heat recovery into district heating systems, and the country has a long tradition in this field (dating back to the 1970 s). By studying two cases, we shed light on success factors in the early stages and in successful collaborations. We identify that the main success factors for excess heat recovery are (i) trust between the collaborating partners, (ii) the involvement of as many stakeholders across the DH (District Heating) value chain as possible (in the decision-making process), (iii) the establishment of joint goals, and (iv) the identification of a business model allowing for a win-win solution that prioritizes excess heat recovery and secures funding for the necessary investments. Excess heat recovery investments have features similar to those of other investments in climate change mitigation, making the success factors relevant to applications beyond the case of excess heat recovery.