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The comet assay is one of the most popular tests for genotoxicity in cell cultures, non-animal species, animals and humans. It has high sensitivity to detect low levels of DNA damage, can be applied to non-proliferating cells, requires relatively few cells, is technically simple, and is low cost. The Organisation for Economic Co-operation and Development (OECD) adopted in 2016 the in vivo comet assay for measurement of DNA strand breaks in animal tissues. There is a desire to expand the comet assay to genotoxicity testing in cell cultures, including the detection of oxidatively damaged DNA by incubation of gel-embedded nucleoids with DNA repair enzymes, especially formamidopyrimidine DNA glycosylase (Fpg) which converts oxidised purines to DNA breaks. Based on available information in the literature, this review provides a retrospective evaluation of the validation status of this assay, focusing on accuracy and reliability in genotoxicity testing in vitro. Information on accuracy is scarce, although limited evidence suggests levels of Fpg-sensitive sites are similar to those obtained by Fpg-linked alkaline unwinding and alkaline elution assays. Several ring studies have shown that estimated background levels of DNA breaks vary within and between laboratories. However, ring studies indicate good intra- and inter-laboratory reproducibility of the standard assay on ionizing radiation-exposed and the Fpg-linked assay on potassium bromate exposed cells. Further studies are needed to assess the reproducibility in multiple laboratories using coded samples of non-genotoxins and genotoxins. Nevertheless, the available results indicate the comet assay is a reliable in vitro genotoxicity test.
2026
2011
2019
2019
2015
2025
Towards a remote-sensing-driven model of isoprene emissions from Alpine tundra
Abstract This study investigates isoprene emissions in a high-latitude Alpine tundra ecosystem, focusing on using near-field remote sensing of surface temperatures, the photochemical reflectance index (PRI) and normalized difference vegetation index (NDVI), and meteorological measurements to model these emissions. Isoprene is a key biogenic volatile organic compound (BVOC) emitted by select plants, which can impact atmospheric chemistry and climate. Increased temperatures, particularly in high latitudes, may enhance isoprene emissions due to extended growing seasons and heightened plant stress. The research was conducted in Finse, Norway, where isoprene and CO 2 fluxes were measured with eddy covariance alongside spectral and meteorological data, and surface temperature. A random forest (RF) model was developed to predict isoprene fluxes, considering the variable importance of different environmental factors. The results showed that surface temperature and CO 2 flux were consistently important predictors, across three differential temporal data aggregations (hourly, daily, weekly), while the PRI demonstrated low predictive power, possibly due to the heterogeneous vegetation and variable light conditions. The NDVI was more effective than anticipated, likely linked to phenological changes in vegetation. Model performance varied with temporal resolution, with weekly data achieving the highest predictive accuracy ( R 2 up to 0.76). The RF model accurately reflected seasonal emission patterns but underestimated short-term peaks, suggesting the potential to combine machine learning with process-based modelling. This research highlights the promise of proxy data from remote sensing for scaling BVOC emission models to regional levels, essential for understanding climate impacts in Arctic ecosystems.
2025
2024
2013
2013
2015
2017
Towards a modelling network in support of the new air quality directive. Powerpoint presentation. NILU F
2007
This report summaries the outcome of a workshop focused on standardizing monitoring strategies for Chemicals of Emerging Concern (CECs), including PFAS, flame retardants, chlorinated paraffins, siloxanes, and microplastics. Key recommendations include harmonised sampling methods, expanding the monitoring programs, conducting measurement campaigns, and enhancing analysis techniques.
NILU
2024
2007
2002
2002
2013
2008
Phosphorus is a building block for all life and therefore plays an essential role in food production. Currently, large amounts of phosphorus enter the Norwegian food system from abroad in the form of mineral fertilizer, feedstuff, food, as well as micro-ingredients for animal feed, mainly in salmon farming. However, only a small fraction of this phosphorus ends up as food for humans, while the largest part accumulates in soil and water systems. This inefficiency entails two challenges:
1. Phosphorus supply is critical. Phosphate rock, the primary source of phosphorus for fertilizer and micro-ingredient production, is a limited resource that is highly concentrated in a few countries. Over 80% of global phosphate rock reserves are found in only 5 countries, and ~70% are located in Morocco and Morocco-occupied Western Sahara. The high concentration renders many countries vulnerable to geopolitical and economic instabilities and threatens food safety. The EU has therefore included phosphate rock on its list of Critical Raw Materials.
2. The accumulation of phosphorus in water systems can lead to eutrophication and dead zones, threatening fish stocks and other aquatic life. The high phosphorus concentration in soils due to overfertilization over long periods of time increases the danger of losses to water systems by runoff, further exacerbating the eutrophication risk.
A more circular use of phosphorus could simultaneously reduce supply and pollution risks. This is particularly relevant in Norway, where the government has an ambition to increase salmon and trout production from currently 1,5 to 5 million tons by 2050.
Achieving a circular phosphorus economy is a complex task: (i) The land- and the sea-based food systems are increasingly interlinked, for example through agricultural production of fish feed or the application of fish sludge on agricultural land. (ii) The Norwegian phosphorus cycle is increasingly interlinked with that of other countries as trade flows along the entire food supply chain are growing. (iii) Phosphorus fertilizers, both primary and recycled, are often contaminated with heavy metals such as cadmium, uranium, and zinc, which tend to accumulate in soils. Cleaning the phosphorus cycle is therefore vital for soil fertility and human health.
This report is based on the MIND-P project, which studied the Norwegian phosphorus cycle for both agriculture and aquaculture at a farm-by-farm basis and explored options for increasing circularity. The project identified farm-level and structural barriers to managing phosphorus resources more effectively.
We propose four fundamental strategies to overcome these barriers:
1. Develop and maintain a national nutrient accounting.
2. Minimize phosphorus losses and accumulations at farm level.
3. Establish infrastructures for capturing, processing, trade, and use of manure and fish sludge to produce high-quality recycled fertilizers that are tailored to the needs of the users in Norway and abroad.
4. Adopt a regulatory framework to promote a market for recycled fertilizer.
The strategies proposed here were developed with the support of an Advisory Panel consisting of representatives from government, industry, industry associations, and NGOs in an online and two physical workshops conducted in 2022.
NTNU Open
2023