Norwegian Institute for Water Research

About: Norwegian Institute for Water Research is a nonprofit organization based out in Oslo, Norway. It is known for research contribution in the topics: Population & Eutrophication. The organization has 730 authors who have published 2443 publications receiving 99199 citations. The organization is also known as: Norsk Institutt for Vannforskning & NIVA.

Dissolved organic carbon trends resulting from changes in atmospheric deposition chemistry.

Abstract: Several hypotheses have been proposed to explain recent, widespread increases in concentrations of dissolved organic carbon (DOC) in the surface waters of glaciated landscapes across eastern North America and northern and central Europe. Some invoke anthropogenic forcing through mechanisms related to climate change, nitrogen deposition or changes in land use, and by implication suggest that current concentrations and fluxes are without precedent. All of these hypotheses imply that DOC levels will continue to rise, with unpredictable consequences for the global carbon cycle. Alternatively, it has been proposed that DOC concentrations are returning toward pre-industrial levels as a result of a gradual decline in the sulphate content of atmospheric deposition. Here we show, through the assessment of time series data from 522 remote lakes and streams in North America and northern Europe, that rising trends in DOC between 1990 and 2004 can be concisely explained by a simple model based solely on changes in deposition chemistry and catchment acid-sensitivity. We demonstrate that DOC concentrations have increased in proportion to the rates at which atmospherically deposited anthropogenic sulphur and sea salt have declined. We conclude that acid deposition to these ecosystems has been partially buffered by changes in organic acidity and that the rise in DOC is integral to recovery from acidification. Over recent decades, deposition-driven increases in organic matter solubility may have increased the export of DOC to the oceans, a potentially important component of regional carbon balances. The increase in DOC concentrations in these regions appears unrelated to other climatic factors.

Are We Speaking the Same Language? Recommendations for a Definition and Categorization Framework for Plastic Debris.

Abstract: The accumulation of plastic litter in natural environments is a global issue. Concerns over potential negative impacts on the economy, wildlife, and human health provide strong incentives for improving the sustainable use of plastics. Despite the many voices raised on the issue, we lack a consensus on how to define and categorize plastic debris. This is evident for microplastics, where inconsistent size classes are used and where the materials to be included are under debate. While this is inherent in an emerging research field, an ambiguous terminology results in confusion and miscommunication that may compromise progress in research and mitigation measures. Therefore, we need to be explicit on what exactly we consider plastic debris. Thus, we critically discuss the advantages and disadvantages of a unified terminology, propose a definition and categorization framework, and highlight areas of uncertainty. Going beyond size classes, our framework includes physicochemical properties (polymer composition, solid state, solubility) as defining criteria and size, shape, color, and origin as classifiers for categorization. Acknowledging the rapid evolution of our knowledge on plastic pollution, our framework will promote consensus building within the scientific and regulatory community based on a solid scientific foundation.

Are Agricultural Soils Dumps for Microplastics of Urban Origin

Abstract: D to their ubiquitous distribution and chemical composition, microplastics (MPs) are increasingly being recognized as a global concern. While it is widely acknowledged thatMPs in the ocean are a serious issue with potentially negative effects onmarine organisms, information aboutMPs in terrestrial and freshwater environments is fragmentary. Based on new MP emission estimates in industrialized countries, we suggest that widespread application of sewage sludge frommunicipal wastewater treatment plants (WWTPs) to farmlands is likely to represent a major input of MPs to agricultural soils, with unknown consequences for sustainability and food security. Terrestrial emissions are the dominant source of MPs, including those conveyed to receiving waters by WWTP outfalls. Recent reports based on product life cycle data offer the first quantitative insights into national MP emission inventories. MPs originate predominantly from automobile tire wear, household and laundry dust, industrial processes (e.g., blasting and deflashing of plastics), and through deterioration of surfaces made of or coated with plastic, for example, artificial turf and polymeric paint. Most of these emissions occur in urban and residential areas. In developed regions, municipal/industrial effluents and even diffuse urban runoff are eventually conveyed to WWTPs. During wastewater treatment, over 90% of MPs are retained in sewage sludge. Effectiveness of MP retention is dependent on particle density and size. MPs with a density greater than water are almost completely retained in sewage sludge during primary and secondary treatment. Tertiary filtration treatment effectively removes larger floating particles, while smaller and lighter particles, expectedly, are released with wastewater effluents. The use of sewage sludge as fertilizer for agricultural applications is often economically advantageous and is common in many developed regions. In Europe and North America about 50% of sewage sludge is processed for agricultural use. Using national data on farm areas, population and sewage sludge fate (http://ec.europa.eu/eurostat), with estimates of MP emissions and applying broad but conservative uncertainty ranges, we estimate that between 125 and 850 tons MP/million inhabitants are added annually to European agricultural soils either through direct application of sewage sludge or as processed biosolids. This is at least equal to, and probably much higher than our estimate of 110 to 180 tons MP/million inhabitants emitted annually to surface waters based on refs 1−3. In Europe, in fact, between 1270 and 2130 tons MPs/million inhabitants are released to urban environments, annually. Conservatively assuming that 10−90% of MPs produced from road wear and debris from building coating are collected by sewers, between 360 and 1980 tons MPs are expected to reach municipal WWTPs. Here, an uncertain fraction of MPs from car tire debris (conservatively, 20−80%) and >90% of MPs from personal care products are likely to be retained in sludge, giving a total input of between 250 and 1700 tons/million inhabitants each year. Sludge application to agricultural land was calculated as the sum of direct application and application of processed biosolids, excluding the fraction of wastewater sludge incinerated, disposed in landfills or subject to other nonagricultural uses. These figures are highly conservative as sludge is only ever applied to a small percentage of agricultural land. There is a broad range of sludge application rates and intensities to European agricultural land (Figure 1). Application rates (estimated as compost plus direct application) range from 0 to 91%, with an average of 43%. This equates to average and maximum areal per-capita loadings of 0.2 and 8 mg MP/ha/yr. MPs inputs estimated here possibly reflect the situation in other countries with similar socioeconomic conditions and/or similar use of plastics (e.g., in Asia and the Americas). A rough extrapolation from data in refs 1−3 produces a total yearly input of 63 000−430 000 and 44 000−300 000 tons MPs to European and North American farmlands, respectively. This would be an alarmingly high input. Comprehensively, this exceeds the total accumulated burden of 93 000−236 000 tons MPs currently estimated to be present in surface water in the global oceans.

Regional trends in aquatic recovery from acidification in North America and Europe

Abstract: Rates of acidic deposition from the atmosphere (‘acid rain’) have decreased throughout the 1980s and 1990s across large portions of North America and Europe1,2. Many recent studies have attributed observed reversals in surface-water acidification at national3 and regional4 scales to the declining deposition. To test whether emissions regulations have led to widespread recovery in surface-water chemistry, we analysed regional trends between 1980 and 1995 in indicators of acidification (sulphate, nitrate and base-cation concentrations, and measured (Gran) alkalinity) for 205 lakes and streams in eight regions of North America and Europe. Dramatic differences in trend direction and strength for the two decades are apparent. In concordance with general temporal trends in acidic deposition, lake and stream sulphate concentrations decreased in all regions with the exception of Great Britain; all but one of these regions exhibited stronger downward trends in the 1990s than in the 1980s. In contrast, regional declines in lake and stream nitrate concentrations were rare and, when detected, were very small. Recovery in alkalinity, expected wherever strong regional declines in sulphate concentrations have occurred, was observed in all regions of Europe, especially in the 1990s, but in only one region (of five) in North America. We attribute the lack of recovery in three regions (south/central Ontario, the Adirondack/Catskill mountains and midwestern North America) to strong regional declines in base-cation concentrations that exceed the decreases in sulphate concentrations.