Biodegradation and Characterization of Dissolved Organic Matter (DOM) along the Flowpath of a N-saturated Subtropical Forested Catchment in China

Excessive input of anthropogenic reactive nitrogen (Nr) to forested ecosystems is associated with increased rates of denitrification and possible emission of the potentially harmful greenhouse gas nitrous oxide (N 2 O). Denitrification is performed by heterotrophic bacteria, and Dissolved Organic Matter (DOM) is thus required for the process to proceed. Only a fraction of DOM is however assumed to be readily available for the bacteria. In a N- saturated subtropical forest in South China (Tie Shan Ping) potential denitrification rates and growth potential have been investigated in the framework of a study on N 2 O emissions. Spatial variations were found, displaying higher denitrification rates at the unsaturated hill slope (recharge zone) as compared to the more hydromorphic groundwater discharge zone. These findings were explained by the denitrifiers being C - limited, which was especially evident at the groundwater discharge zone. It was hypothesized that the reduced transport of DOM from the densely vegetated hill slope to the groundwater discharge zone was attributed to rapid mineralization along the flow pat h. This would result in only the more recalcitrant fraction of DOM remaining in solution for transportation to the groundwater discharge zone. The objective of this present study was to test this hypothesis by investigating differences in chemical characteristics and biodegradability of the DOM between the hill slope and the groundwater discharge zone. Soil-water samples collected along a topographic gradient, using suction lysimeters, were subject to both biological-, chemical-, and structural analyses. Measured biodegradability, using a batch experimental setup, suggested that the DOM from the groundwater discharge zone was far more biodegradable than the DOM from the hill slope. This was further corroborated with the structural characterization, using UV - Vis Absorbency and Fluorescence Spectroscopy, indicating small amount of more aromatic, and alow ratio of Humic to Fulvic acids in the DOM from the groundwater discharge zone as compared to the samples from the hill slope. This would imply that the attenuation of DOM along the flow path in Tie Shan Ping could not be attributed to mineralization. Instead, the loss of less biodegradable DOM is suggested to be explained by selective adsorption of the more aromatic, higher molecular weight, hydrophobic constituents of DOM to the clay-rich and organic-poor soils of the hill slope

Modelled Nitrosamine and Nitramine concentrations in Lake Elvåga following amine-based CO2 Capture at FOV Waste Incineration Plant at Klemetsrud

Project Manager Cathrine Brecke GundersenFuture levels of the carcinogenic- and potentially carcinogenic nitrosamines (NSAs) and nitramines (NAs), respectively, were modelled in the drinking water source, Lake Elvåga following the planned full-scale amine-based CO2 capture at the Oslo waste incineration plant. A high-resolution and dynamic catchment model (INCA-Contaminants) was combined with a lake model add-on. NSA and NA deposition rates (provided from COWI/Norsk Energi/CERC) were combined with site specific information (hydrology and climate), and literature values of NSA and NA bio- and photodegradation rates and physiochemical parameters. The three scenarios, “best”, “likely”, and “worst” cases were created to capture the uncertainty of key parameters. Three years of full-scale CO2 capture resulted in maximum annual average sums of NSAs and NAs in the lake water at 0.24, 3.3, and 4.4 ng L-1, for the three scenarios, respectively. For the NSAs, photodegradation was an efficient depletion pathway, nearly balancing out the input rates. Lake water levels of NAs increased with time due to the lack of an efficient depletion pathway. Seasonal variation was evident in both the NSA and NA concentrations and this should be considered for potential future monitoring programs.COWIpublishedVersio

Tålegrenser for forsuring og overskridelser for Høyangervassdraget i Vestland fylke

Prosjektleder: Cathrine Brecke GundersenDet har blitt beregnet tålegrenser for forsuring og overskridelse av disse for Høyangervassdraget og separat for delnedbørfeltene Håland, Gautingsdal og Eiriksdal. Overskridelser er beregnet for dagens (årene 2017-2021) og framtidige (år 2030 og 2050) avsetninger av svovel og nitrogen. Både SSWC- og FAB-modellene ble benyttet. Resultatene viser ingen overskridelse i nedbørfeltene for alle tidsperiodene. På grunn av forsinkelser i systemene kan det være forsuring selv om tålegrensene ikke er overskredet. Men så lenge det ikke er overskridelse, vil forsuringen gradvis avta, og de sure episodene vil bli mindre hyppigere og alvorlige.Statsforvalteren i VestlandpublishedVersio

Atmospheric deposition and lateral transport of mercury in Norwegian drainage basins: A mercury budget for Norway

Project manager Hans Fredrik Veiteberg BraatenReduced atmospheric loading of mercury (Hg) can improve the environmental status of freshwaters and coastal ecosystems. Sparse data limit impact assessments of changes in atmospheric Hg on aquatic ecosystems. Here, a Hg budget is calculated for Norway by estimating fluxes of Hg in the environment. Atmospheric inputs (ca. 3.3 tonnes annually) are a factor 10 higher than riverine export to coastal areas, indicating considerable retention in soils and lakes. Environmental loading of Hg to surface waters was separated into headwater (=catchment) export of Hg and atmospheric Hg loadings, which were of similar size (0.2 to 0.3 tonnes), where atmospheric loadings were considered of higher certainty than headwater fluxes. Robust methods for estimations of headwater Hg export at the regional scale are lacking. Hg budgets for small headwater catchments are more reliable and valuable to assess the fate of atmospheric Hg, and the role of aquatic Hg retention. Continued monitoring of Hg in deposition, catchments, and rivers are needed to reduce uncertainties in environmental assessments, in addition to international collaboration.Norwegian Environment AgencypublishedVersio

Integrated Water Resources Management in Myanmar Ecology of Rivers, Lakes, and Reservoirs

Prosjektleder: Ingrid NesheimThis is the final report from output 1 of the IWRM project 2015-2024. The goal of the project was to implement a classification system for the ecological status of rivers and lakes in Myanmar like the EU Water Framework Directive. As the project was ended in 2021 due to the military coup in Myanmar, planned activities could not be finished. This report presents a summary of the ecological surveys and ecological status assessments in selected water bodies in Myanmar achieved within the project. The report should be read in conjunction with the other comprehensive publications from the project. Although the current political situation in Myanmar put a halt to our activities, the reports and scientific papers comprised in this project, in addition to transferred knowledge about freshwater ecology to selected staff and to one PhD student from Myanmar, have led to a set of recommendations that hopefully will be an impetus for future river and lake biomonitoring in Myanmar. As knowledge about the ecology of most of the many water bodies in Myanmar is still poor a much bigger number of freshwater ecologists need to be educated to achieve the goal of classifying their status and to find solutions for their improvement.The Norwegian embassy in Yangon, Myanmar Norwegian Ministry of Foreign Affairs, NorwaypublishedVersio

Elveovervåkningsprogrammet 2022 – vannkvalitetstilstand og ‐trender

Prosjektleder: Øyvind KasteIn the Norwegian River Monitoring Programme (in Norwegian: Elveovervåkingsprogrammet) 20 rivers along the Norwegian coast are monitored for physical and chemical parameters. This report presents the current status (2022) and long‐term (1990‐ 2022) trends in suspended particles, organic matter, nutrients, and metals. EU Water Framework Directive priority substances and river basin‐specific pollutants (trace metals and organic pollutants) from five rivers in south‐ and southwestern Norway are compared with annual average environmental quality standards (AA‐EQS). The report also presents light absorbance indices for characterisation of dissolved organic matter (DOM) quality in the rivers, and high‐frequency measurements of water temperature, pH, conductivity, turbidity and fluorescent DOM (FDOM) at four river stations.Norwegian Environment AgencypublishedVersio

The Norwegian river monitoring programme 2021 – water quality status and trends

Prosjektleder Øyvind KasteIn the Norwegian River Monitoring Programme (in Norwegian: Elveovervåkingsprogrammet) 20 rivers along the Norwegian coast are monitored for physical and chemical parameters. This report presents the current status (2021) and long-term (19902021) trends in suspended particles, organic matter, nutrients, and metals. EU Water Framework Directive priority substances and river basin-specific pollutants (trace metals and organic pollutants) from five rivers are compared with annual average environmental quality standards (AA-EQS). The report also presents light absorbance indices for characterisation of dissolved organic matter (DOM) quality in the rivers, and high-frequency measurements of water temperature, pH, conductivity, turbidity and fluorescent DOM (fDOM) in two rivers; Storelva (southern Norway) and Målselva (northern Norway).Norwegian Environment AgencypublishedVersio

Mercury in the Barents region – River fluxes, sources, and environmental concentrations

Arctic rivers are receiving increased attention for their contributing of mercury (Hg) to the Arctic Ocean. Despite this, the knowledge on both the terrestrial release sources and the levels of Hg in the rivers are limited. Within the Arctic, the Barents region has a high industrial development, including multiple potential Hg release sources. This study presents the first overview of potential Hg release sources on Norwegian and Russian mainland draining to the Barents Sea. Source categories cover mining and metallurgy industry; historical pulp and paper production; municipal and industrial solid waste handling; fossil fuel combustion; and past military activities. Available data on Hg in freshwater bodies near the identified potential release sources are reviewed. Levels of Hg were occasionally exceeding the national pollution control limits, thereby posing concern to the local human population and wildlife. However, the studies were sparse and often unsystematic. Finally, we present new data of Hg measured in five Barents rivers. These data reveal strong seasonality in the Hg levels, with a total annual flux constituting 2% of the panarctic total. With this new insight we aspire to contribute to the international efforts of reducing Hg pollution, such as through the effective implementation of the Minamata Convention. Future studies documenting Hg in exposed Barents freshwater bodies are warranted.publishedVersio

Trends and patterns in surface water chemistry in Europe and North America between 1990 and 2020, with a focus on calcium

Prosjektleder: Rolf David VogtThe report presents trends in major anions and cations, pH, TOC and bicarbonate in surface waters in Europe and North America from 1990 to 2020. Special attention is given to trends in calcium, which showed some unexpected increases. The trends in calcium are analysed in relation to changes in bicarbonates, organic anions, and deposition loads. The surface waters show strong signs of chemical recovery.Norwegian Ministry of Climate and Environment, United Nations Economic Commission for Europe (UNECE)publishedVersio

Screening Programme 2022. New environmental pollutants.

Prosjektleder: Cathrine Brecke GundersenThe 2022 Screening Programme followed up on some findings from the 2020 Screening Programme. This included further investigation of plastic-related substances, tyre-related substances, and disinfection agents. The 2022 Programme also included additional new PFAS, bisphenols, and new siloxanes.Norwegian Environment AgencypublishedVersio