Statistisk analyse av volum av forurenset sediment i Borg 1 og Flyndregrunnen, basert på samlet kjemisk analysemateriale fram til 2017

Prosjektleder Dag Øystein HjermannDet er foretatt statistiske beregninger av volummengden av forurenset sediment i området Røsvikrenna (nordligste del av leden til Borg havn, tiltaksområde Borg 1) samt Flyndregrunnen (den nordligste grunna i tiltaksområde Borg 2). Beregningene er basert på 620 prøver (seksjon av kjerneprøve eller overflateprøve) fra Røsvikrenna og 95 prøver fra Flyndregrunnen som er analysert kjemisk. Volumberegningen er gjort for ulike konfidensnivåer, der konfidens er definert ut fra andelen av sediment klassifisert som ikke-forurenset som i realiteten kan være forurenset. For Borg 1 er mengden forurenset sediment teoretisk beregnet til ca. 573 000 m3 (dersom en velger et konfidensnivå på 80 %) eller 757 000 m3 (dersom en velger et konfidensnivå 95 %). Beregninger fra Van ‘t Hoff Consultancy viser at de tilsvarende praktiske volumene, dvs. de massene som i praksis må behandles som forurenset, er estimert til 699 000 m3 (for konfidensnivå 80 %) eller 917 000 m3 (for konfidensnivå 95 %). For Flyndregrunnen er mengdene forurenset sediment beregnet til et teoretisk volum på ca. 39 000 m3 (for konfidensnivå 80 %) eller 42 000 m3 (konfidensnivå 95 %). Volumene med forurenset sediment er kartlagt og vises som konturer i kart laget for hver 10 cm dybde for begge konfidensnivåer.Rambøll Norge ASpublishedVersio

Do benthic algae provide important information over and above that provided by macrophytes and phytoplankton in lake status assessment? – Results from a case study in Norway

To test if phytobenthic algae provide additional important information to macrophytes and phytoplankton for lake monitoring, we sampled two large lakes in Norway. In each lake, we analyzed water chemistry and phytoplankton above the deepest site, recorded macrophytes and non-diatom phytobenthic algae at 20 sites around the shoreline and estimated site-specific nutrient input from land cover. Since no ready-to-use phytobenthos index exists for lakes in Norway, we tested the PIT index developed for rivers, commonly perceived signs of disturbance such as high algal cover, and taxon richness as well as similarity patterns. Both lakes were nutrient poor, but had potential local nutrient inputs (villages, agriculture). In neither of the lakes did phytobenthos indicate a worse overall ecological status than macrophytes and phytoplankton. Our data therefore, did not suggest that it would be useful to add phytobenthos into surveillance monitoring of lakes in Norway. There was a loose correlation between macrophyte and phytobenthic site-specific taxon richness and similarities. This means that macrophytes and phytobenthos do indeed give partly redundant information. High algal cover was found at sites with both high and low phosphorus input. Using algal cover as indicator of site-specific nutrient input is therefore overly simplistic. Urban and cultivated areas were associated with a more eutrophic PIT. This indicates that the PIT, despite being developed for lotic waters, may be used to detect site specific nutrient input in lakes.publishedVersio

Environmental effects of offshore produced water discharges: A review focused on the Norwegian continental shelf

Produced water (PW), a large byproduct of offshore oil and gas extraction, is reinjected to formations or discharged to the sea after treatment. The discharges contain dispersed crude oil, polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), metals, and many other constituents of environmental relevance. Risk-based regulation, greener offshore chemicals and improved cleaning systems have reduced environmental risks of PW discharges, but PW is still the largest operational source of oil pollution to the sea from the offshore petroleum industry. Monitoring surveys find detectable exposures in caged mussel and fish several km downstream from PW outfalls, but biomarkers indicate only mild acute effects in these sentinels. On the other hand, increased concentrations of DNA adducts are found repeatedly in benthic fish populations, especially in haddock. It is uncertain whether increased adducts could be a long-term effect of sediment contamination due to ongoing PW discharges, or earlier discharges of oil-containing drilling waste. Another concern is uncertainty regarding the possible effect of PW discharges in the sub-Arctic Southern Barents Sea. So far, research suggests that sub-arctic species are largely comparable to temperate species in their sensitivity to PW exposure. Larval deformities and cardiac toxicity in fish early life stages are among the biomarkers and adverse outcome pathways that currently receive much attention in PW effect research. Herein, we summarize the accumulated ecotoxicological knowledge of offshore PW discharges and highlight some key remaining knowledge needs.publishedVersio

ESPIAL - Data review and evaluation of historical data (WP1)

Prosjektleder Ailbhe MackenThe present report details the outcome of work package 1 of ESPIAL, with the aim of compiling the historical data from previous surveys at the aluminium sites in a common database and further to analyse the data. A graphical data displaying tool was developed as a custom interactive tool for data visualisations and was designed to be intuitive and user friendly. The main outcomes and findings of this work package can be summarized as follows: Polycyclic aromatic hydrocarbons (PAHs) constitute most data in the database; There is a decent amount of data on sediment samples in the data base, however these do not form time series; Most time series available in the data base are on blue mussel from Sunndal and northern horsemussel from Årdal; Most time series show a declining tendency; All statistically significant PAH time trends show declining concentrations; The database is likely not complete, and more data could be available; The graphical data displaying tool is a promising aid for instant insight in concentrations and time series of different analytes in environmental samples, historically collected in the vicinity of the smelters; The graphical data displaying tool makes it possible to view concentrations and trends in relation to the EQSs, giving insight in chemical status and sites of interest, in terms of possible need of remedial action or natural recovery.Aluminiumindustriens Miljøsekretariat (AMS)publishedVersio

Non-cooperative exploitation of multi-cohort fisheries — the role of gear selectivity in the North-East Arctic cod fishery

North-East Arctic cod is shared by Russia and Norway. Taking its multi-cohort structure into account, how would optimal management look like? How would non-cooperative exploitation limit the obtainable profits? To which extent could the strategic situation explain today’s over- harvesting? Simulation of a detailed bio-economic model reveals that the mesh size should be significantly increased, resulting not only in a doubling of economic gains, but also in a biologi- cally healthier age-structure of the stock. The Nash Equilibrium is close to the current regime. Even when effort is fixed to its optimal level, the non-cooperative choice of gear selectivity leads to a large dissipation of rents

Tiltaksorientert overvåking av sjøområdet utenfor Elkem Carbon og REC Solar i Kristiansand i 2022

Prosjektleder: Sigurd ØxnevadNIVA har gjennomført tiltaksorientert overvåking av sjøområdet utenfor Elkem Carbon og REC Solar i Kristiansand i 2022. I overvåkingen er det gjort analyser av blåskjell fra fem stasjoner og konsentrasjonen av polysykliske aromatiske hydrokarboner (PAH-forbindelser), tungmetaller (arsen, bly, kadmium, kobber, krom, kvikksølv, nikkel og sink), silisium og kalsium er bestemt. Det var høyest konsentrasjoner av PAH-forbindelser i blåskjellene fra Lumber. Blåskjellene som var samlet inn ved Lumber, Fiskå, Timlingen og Svensholmen hadde konsentrasjoner av PAH-forbindelsen benzo(a)pyren som oversteg grenseverdien for dette prioriterte stoffet. Blåskjellene fra Lumber og Timlingen hadde også konsentrasjoner av fluoranten som var høyere enn grenseverdien. Kjemisk tilstand for stasjonene Lumber, Fiskå, Timlingen og Svensholmen klassifiseres derfor til «ikke god». Blåskjellene fra Flekkerøygapet hadde ingen konsentrasjoner som var høyere enn grenseverdiene for de prioriterte stoffene, og stasjonen klassifiseres til «god» kjemisk tilstand. De to siste årene har det vært høyere konsentrasjoner av PAH-forbindelser i blåskjellene enn i de tre foregående årene. I forbindelse med oppstart av nytt renseanlegg for PAH og tilkobling av prosessvannsutslippet til dette renseanlegget hadde Elkem Carbon et uhellsutslipp i mars 2022. Dette kan ha bidratt til de økte konsentrasjonene av PAH-forbindelser i blåskjell i 2022.Elkem Carbon og REC SolarpublishedVersio

Climatic effects filtered through the food web affect the dynamics of Arcto-Norwegian cod

The world's largest cod stock, the Arcto-Norwegian cod (a.k.a. North-East Arctic cod), is heavily influenced by temperature in two ways: First, cod recruitment tends to be high when Barents Sea temperature in the spawning year is high. Secondly, there is a more indirect effect of climate via herring and capelin: Warm conditions increase the chance of high recruitment of Norwegian Spring-spawning herring; 1-2 year old herring eat 0-year old capelin; and cod cannibalism increases when the biomass of 1-4 year old capelin is low. While these relationships have been shown separately and for the later years, we develop and parameterize models for the effects of herring (via capelin) and temperature on cod recruitment at age 3, using data from 1973 until present. Using data on cod, herring and temperature back to 1921 to verify the model,we find a significant relationship between predictions and data back to the 1950s, but before this, the predicted time-series pattern is not observed in the data

Tiltaksorientert overvåking i henhold til vannforskriften for Glencore Nikkelverk AS i Kristiansandsfjorden. Undersøkelse av blåskjell i 2022.

Prosjektleder: Merete SchøyenNIVA har gjennomført tiltaksorientert overvåking i sjøområdet utenfor Glencore Nikkelverk AS i Kristiansandsfjorden i 2022 i henhold til vannforskriften. Ved fem blåskjellstasjoner har det blitt analysert for et utslippsrelevant utvalg av de prioriterte stoffene dioksiner, dioksinliknende PCB, bly (Pb) og nikkel (Ni). Det har også blitt analysert for de vannregionspesifikke stoffene arsen (As), kobber (Cu) og sink (Zn). I tillegg ble det analysert for sølv (Ag), kobolt (Co), jern (Fe), palladium (Pd), selen (Se), thorium (Th) og uran (U). Et utvalg triklor-trimetylbenzener (KAB) ble også analysert. For de prioriterte stoffene i blåskjell ble det ikke målt konsentrasjoner som overskred miljøkvalitetsstandarder (Environmental Quality Standard, EQS), og alle de fem blåskjellstasjonene var derfor i «god kjemisk tilstand». For de vannregionspesifikke stoffene er det ikke oppgitt EQS-verdier i biota i Veileder 02:2018. Det var signifikante oppadgående tidstrender for Co i blåskjell ved Glencore kai, og for As ved Dvergsøya. Det var signifikante nedadgående tidstrender for Cu i blåskjell ved Glencore kai og Hanneviksbukta, for Ni, Pb, Zn, Co og Fe ved Hanneviksbukta, og for dioksiner og dioksinliknende PCB ved Myrodden. Det ble påvist triklor-trimetylbenzener (sum KAB) på fire av de fem blåskjellstasjonene.Glencore Nikkelverk ASpublishedVersio

Possible adverse impact of contaminants on Atlantic cod population dynamics in coastal ecosystems

While many in-laboratory ecotoxicological studies have shown the adverse impact of pollutants to the fitness of an individual, direct evidence from the field on the population dynamics of wildlife animals has been lacking. Here, we provide empirical support for a negative effect of pollution on Atlantic cod (Gadus morhua) population dynamics in coastal waters of Norway by combining unique time series of juvenile cod abundance, body size, environmental concentration of toxic contaminants and a spatially structured population dynamics model. The study shows that mercury concentration might have decreased the reproductive potential of cod in the region despite the general decline in the environmental concentration of mercury, cadmium and hexachlorobenzene since the implementation of national environmental laws. However, some cod populations appeared to be more resistant to mercury pollution than others, and the strength and shape of mercury effect on cod reproductive potential was fjord-specific. Additionally, cod growth rate changed at scales smaller than fjords with a gradient related to the exposure to the open ocean and offshore cod. These spatial differences in life-history traits emphasize the importance of local adaptation in shaping the dynamics of local wildlife populations. Finally, this study highlights the possibility to mitigate pollution effects on natural populations by reducing the overall pollution level, but also reveals that pollution reduction alone is not enough to rebuild local cod populations. Cod population recovery probably requires complementary efforts on fishing regulation and habitat restoration.acceptedVersio