Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2026
Authors
Trine Eggen Carl Einar Amundsen Robert Barneveld Aksel Bernhoft Barbara Alexandra Bukhvalova Gunnar Sundstøl Eriksen Belinda Flem Christiane Kruse Fæste Tron Øystein Gifstad Merete Grung Veronika Sele Kaja Helvik Skjærven Øystein Sæle Stefan Trapp Christian Vogelsang Håvard SteinshamnAbstract
This report presents a risk assessment of organic contaminants in sewage sludge and sewage-sludge-based products used on agricultural land in Norway, under current and alternative fertiliser regulations and management practices. It identifies a limited number of substances of concern for soil health, aquatic organisms, animal health, and human health, and provides a scientific basis for evaluating circular economy, organic fertilisers, and the safe recycling of bioresources in agriculture. Background and purpose The Norwegian fertiliser regulations was revised in 2025 to support reduced pollution, better utilisation of nutrients, fulfilment of international obligations, simplification, and facilitation of nutrient recycling. In Norway, 50 to 60 per cent of sewage sludge is used on agricultural land, compared with around 40 per cent in the EU. Norway has many small wastewater treatment plants and a long tradition of using treated sludge in agriculture. At the same time, incineration is less common in Norway than in many other European countries, partly because Norwegian wastewater treatment largely relies on chemical phosphorus precipitation (chemical separation of phosphorus). In recent years, new products based on sewage sludge have been developed, such as pellets, biochar and struvite (a fertiliser product recovered from wastewater that makes it possible to recycle phosphorus and nitrogen for agricultural use). At the same time, knowledge about organic contaminants in sewage sludge has increased. On this basis, the Norwegian Food Safety Authority asked VKM to assess the risks associated with organic contaminants in sewage sludge and sludge-based products. Terms of reference and scope VKM was tasked with identifying organic contaminants in sewage sludge and assessing which substances were relevant to include in the risk assessment. The assignment also covered products made from sludge, such as biochar, ash and struvite. Risks were to be assessed for the use of sludge on agricultural land over a period of up to 100 years. If current practice could lead to undesirable effects, alternative application rates and uses were also to be evaluated. In addition, less stringent rules for use in the cultivation of vegetables and on grassland used for mowing and grazing were to be assessed. The assessment covered possible effects on soil-dwelling organisms, aquatic organisms, livestock and humans. Combined effects of multiple substances were not assessed in detail. Methods and scenarios The risk assessment was based on data for more than 1,000 organic contaminants measured in Norwegian sewage sludge. For some pharmaceuticals that had not been analysed, levels were estimated using consumption data and modelling. Substances were prioritised based on occurrence, properties, degradation, mobility and toxicity. A model was developed to calculate how organic contaminants may accumulate and spread in soil, water and plants over time. The calculations were used to assess exposure for soil- and water-dwelling organisms, livestock and humans. The model accounted for climate and soil conditions in five regions in Norway. A wide range of scenarios for the use of sewage sludge and sludge-based products in the cultivation of cereals, potatoes, vegetables and grass were assessed. These included current practice, reduced application rates, use every ten years and annually, different intervals between application and cultivation or grazing, and the use of pellets, biochar, struvite and liquid digestate from sewage sludge. The effects of thermal hydrolysis were also assessed. Summary of main findings Norwegian monitoring data show that municipal sewage sludge contains many different organic contaminants, but levels vary widely between treatment plants and regions. The levels of several legacy pollutants, such as PCBs, PAHs and PBDEs, have decreased over time but are still present in sludge and remain relevant because they degrade slowly and can accumulate in the environment. PFAS are regularly detected, particularly PFOS and other long-chain PFAS. Pharmaceuticals and newer industrial chemicals often occur at low levels but with large variation. Several substances found at the highest concentrations are linked to cosmetics and personal care products. The different sludge-based products have different risk profiles. Pellets are expected to pose roughly the same or slightly lower risk than dewatered sludge. Struvite contains very low levels of organic contaminants and was consistently associated with low risk. Biochar is distinctive in that pyrolysis reduces many organic contaminants, but there is still uncertainty related to the possible formation of new compounds and how residues may be bound or released over time. For soil-dwelling organisms, the assessment showed that current practice may pose a long term risk for some substances. After quality assessment of the data, 19 organic substances showed potential risk, including certain pharmaceuticals, cosmetic-related substances, plastic related compounds, PAHs and PFOS. Lower application rates reduced risk but did not eliminate it. For some persistent substances, annual application could result in a higher cumulative load than application every ten years. For aquatic organisms, under current practice one substance exceeded the risk threshold, the pharmaceutical fenbendazole, but the assessment is uncertain. In scenarios with less stringent conditions or alternative uses, several substances were considered capable of posing a risk to the aquatic environment. For livestock, the calculations generally showed low levels of individual substances in feed rations. Risk was highest for grazing animals, as soil ingestion is an important exposure pathway, and with the use of liquid digestate from sewage sludge, direct intake may also contribute. Delayed grazing after application of products was found to reduce exposure. At the same time, some substances, particularly bisphenols and certain pharmaceuticals, are highlighted as relevant to animal health, and combined effects cannot be ruled out. For humans, current use of sewage sludge is generally assessed to pose relatively low risk to food safety for most of the substances examined. At the same time, an increase in organic contaminants in agricultural soil is undesirable. The report highlights PFAS, PCBs, dioxins, PAHs, PBDEs, siloxanes, bisphenol A, octocrylene and several pharmaceuticals as important for food safety, because dietary exposure to some of these substances is already considered undesirable or of concern. For individuals with high consumption of locally caught freshwater fish, exposure is generally assumed to be limited, but for some individuals it may be relevant. Main conclusion Norwegian data show that sewage sludge contains many organic contaminants, but levels vary widely. Most substances appear to pose low risk to soil-dwelling and aquatic organisms, and low health risk to livestock and humans. Some persistent substances may give rise to concern over time. Struvite was consistently associated with low risk, while pellets, biochar, sewage sludge and liquid digestate from sewage sludge have more complex risk profiles. For humans and livestock, risk is generally low under current practice, but certain groups of substances are undesirable because the overall burden is already high or of concern. The report concludes that some substances should be prioritised for further investigation and follow-up. In summary: VKM concludes that most organic contaminants in sewage sludge pose low risk, but that some organic contaminants may give rise to concern over time. This particularly applies to persistent substances that can accumulate in soil. The report therefore highlights the need for further investigation through the collection of more data and knowledge to support future risk assessments.
Abstract
No abstract has been registered
Abstract
The experiment aimed to investigate the effectiveness of a Monil virtual fence collar for small ruminants on mature Norwegian White ewes at the NIBIO Tjøtta station. The study aimed to evaluate the animals' learning ability and welfare, compare two auditory cues (Original vs. Modified; collar treatment), and examine the effects of wool (Shaved vs. Unshaved) on the efficacy of the virtual fence system. A total of 16 ewes were randomly assigned to two groups of 8, each equipped with one of the collars, and further divided based on wool treatment. Two mirrored training arenas were set up for the two groups. For two days, the collared animals had unrestricted access to graze the entire arena (VF-Off). This was followed by two days of restricted access to 2/3 of the arena using the virtual fence collars (VF-On). After the fourth day, the animals were switched to the other arena as a crossover design, and the sequence of VF-Off and VF-On was repeated. Data collected included position and cue logs from the virtual fence collars, heart rate monitors, and observation data gathered through three methods: Video Surveillance, Direct Observation Time Budget, and Pressure Marks Assessment. Our results indicate that the ewes were able to learn to avoid restricted zones effectively, relying more on auditory cues than on electrical cues. The virtual fence cueing imposed short-lived stress (acute stress), with both behavioral and physiological metrics returning to baseline levels within five minutes. Additionally, exclusively auditory cues resulted in less stress compared to cues associated with electrical stimulation. No indicators of chronic behavioral stress were observed. However, we found that the collars needed to move freely on the animals' necks to prevent pressure marks, suggesting that the ewes should be shaved around their necks before wearing the collars. While collar treatment showed no significant effects, wool treatment indicated that the shaved group was more compliant with the virtual fence system due to reduced insulation, which enhanced the effectiveness of electrical cues. During the deployment with the unshaved group, there were three instances in which the animals received an electrical cue that did not elicit the animal response, allowing for their “escape” over the virtual fence boundary. Therefore, equipping the virtual fence on shaved animals is paramount for enhancing the system's reliability. If the suggestion is followed, the system can effectively be used for sheep without compromising animal welfare.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
This animated short film shows how beneficial insects such as ladybirds and hoverflies can help control pests like aphids. By providing flower strips and suitable habitats in and around fields, farmers can support pollinators and natural enemies of pests — contributing to more resilient crop production over time.
Abstract
The decline of soil organic carbon (SOC) content is a major concern in agricultural soils, and reduction of tillage frequency is proposed as a measure to counteract this tendency. Here, we assessed the effect of tillage and renewal frequency on grassland SOC content based on a long–term experiment at Fureneset, Western Norway. The objective was to compare permanent and unrenewed grassland treatments with treatments ploughed and renewed 6 to 15 times from 1974 to 2016. Mean SOC content of the permanent grassland was 64 ± 9 g kg−1 (one standard deviation) at 0 to 40 cm depth and soil contained 210 Mg C ha−1, compared to 60 ± 6 g kg−1 and 190 Mg C ha−1 for grassland renewed with ploughing. Higher SOC contents were associated with reduced forage dry matter yields (DMY) of the permanent grassland, but not in frequently renewed grasslands. High SOC contents correlate with high porosity and water content, as soil properties approach those of organic soils. This may cause a wetter soil and reduced plant growth and increase soil compaction. In areas with generally high SOC contents in agricultural soils, increased carbon content due to no tillage may thus make the soils more agronomically challenging to manage
Authors
Johannes Kollmann Larissa Uhe Marcello D’Amico Jan C. Habel Tina Heger Svenja B. Kroeger Tommy Lennartsson Hans Martin HanslinAbstract
Roadside habitats have abiotic and biotic conditions that deviate from natural habitats and thus constitute “novel ecosystems” with insufficient adaptation of native biota. In roadsides, the net effect of positive and negative impacts determines population viability. This situation constitutes an “ecological trap,” when attractive habitats become demographic sinks due to locally reduced reproduction or increased mortality. The impact could be exacerbated by novel ecological factors. To investigate to what extent, for which species, and under which conditions ecological traps are actually occurring, we reviewed the effects of roadsides on plant and animal performance and population dynamics. We identified 390 relevant publications with 470 different effect cases based on a standardized literature review (2008–2018). Overall, 30% of these cases reported positive effects of roadsides on plant and animal populations, 31% of cases reported negative effects, and 39% showed no effects at all. In only 18 cases, negative effects were combined with positive ones, most often due to attractive but unsuitable habitats that constituted ecological traps. Ecological novelty was not used to interpret these effects. We conclude that there is abundant literature on ecological effects of roadsides, while specific research is needed on ecological traps, including potential effects of ecological novelty.
Authors
Tommy Lennartsson Marcello D’Amico Weronika Axelsson Linkowski Hans Martin Hanslin Johannes Kollmann Svenja B. Kroeger Larissa Uhe Anna Westin Jörgen WissmanAbstract
Roads impose several types of negative impact on landscapes and biodiversity, but may also favor some organisms by providing habitats and dispersal corridors. To prioritize, plan, design, and perform activities for promoting biodiversity in road verges, it is essential to understand which key environmental factors contribute to forming different types of roadside habitats. In this chapter, we explore relationships between biodiversity and environmental factors in road verges based on a literature review with a primary focus of vascular plants and arthropods. Roadside literature indicates a number of interacting ecological factors, which together form the roadside habitat and determine community composition. These key factors can be assigned to three groups: (1) ecological conditions such as soil, topography, and microclimate, (2) ecological processes such as vegetation succession and disturbance or management of ground and vegetation, and (3) the surrounding landscape. Based on the identified key factors, we suggest an ecological classification of roadside habitats into four major groups, namely successional roadsides, dry roadsides, tallgrass roadsides, and meadow roadsides. Trees and shrubs can occur in all groups, for example as tree avenues or hedgerows, resulting in a cross-cutting subgroup: successional/dry/tallgrass/meadow roadsides with trees and shrubs.
Authors
Ascensão, Fernando Barrientos, Rafael Araya-Gamboa, Daniela Bannock, Carol Baxter-Gilbert, James Bhardwaj, Manisha Biasotto, Larissa D. Boyle, Sean P. Camacho, Carlos Carmona, Guillermo Celi, Jorge E. Chiles, Sarah Clevenger, Anthony P. Colino Rabanal, Victor J. Collinson-Jonker, Wendy J. Corlett, Richard T. Darryl, Jones N. Deacon, Charl Engert, Jayden E. Ford, Adam Goldfarb, Benjamin Grilo, Clara Haider, Sylvia Hans Martin Hanslin Hernandez-Hernandez, Javier Hughes, Alice C. Huijser, Marcel P. Jaeger, Jochen A. G. Jakes, Andrew F. Januchowski-Hartley, Stephanie R. Jones, Paul F. Kindel, Andreas Kollmann, Johannes Svenja B. Kroeger Lamb, Clayton Langen, Tom A. Laurance, William F. Leal, Cecilia G. Lennartsson, Tommy Lourenço, Rui Mahmoud, Mahmoud Ibrahim Malo, Juan E. Maslo, Brooke McClure, Christopher J. W. Medrano-Vizcaíno, Pablo Megía-Palma, Rodrigo Mestre, Frederico Millán, Javier Milton, Suzanne J. Moreira, Francisco Morelli, Federico Mulero-Pázmány, Margarita Navarro, Laetitia M. Paige, L. Christine Petrovan, Silviu Phillips, Benjamin B. Popp, Jesse N. Quiles, Pablo Raiter, Keren Gila Rodriguez, Airam Román, Jacinto Rytwinski, Trina Samways, Michael J. Santoro, Simone Santos, Sara M. Schlacher, Thomas A. Seidler, Renee G. Selva, Nuria Shilling, Fraser M. Soanes, Kylie Stokes, Josie Sánchez de Miguel, Alejandro Teixeira, Fernanda Zimmermann Thompson, Cassie J. Varela, Diego Wang, Yun Weston, Michael A. van der Grift, Edgar A. van der Ree, Rodney D’Amico, MarcelloAbstract
Road Ecology has experienced rapid growth as a field, yet significant knowledge and research gaps remain, particularly regarding underexplored impacts of roads on fauna and flora, ecosystems and landscapes, as mitigation methods and management solutions to avoid or reduce negative impacts. Here, we synthesize the key research needs identified throughout the book and emphasize topics that have received limited attention, highlighting the growing need for interdisciplinary and technologically advanced studies, and innovative statistical methodologies to assess infrastructure impacts and the combined effects of different types of infrastructures (such as roads and powerlines) on biodiversity. We highlight the need for more comprehensive studies on ecosystem functioning, evolutionary effects, and the role of roadside habitats, while calling for improvements in the cost-effectiveness of mitigation measures and large-scale assessments of road impacts. Emerging research priorities for Road Ecology include a growing emphasis on interdisciplinary and technologically advanced studies, and innovative statistical methodologies to assess infrastructure impacts and the combined effects of multiple infrastructures (such as roads and powerlines) on biodiversity. The impact of new infrastructure in areas supporting multiple migratory species is also becoming a priority issue, especially in regions where there is significant growth in infrastructure projects. Interdisciplinary efforts should prioritize strategies that balance infrastructure development with biodiversity conservation, especially in rapidly developing regions.