Attachment of APAM to mineral particles in seawater

Polymer injection is used in enhanced oil recovery (EOR) when an oil field ages and the pressure in the reservoir decreases, or for oil fields with heavy oil. By polymer injection, the viscosity of the water injected for pressure support is increased by mixing with a high concentration of a polymer solution. Polymers used in EOR operations are often high molecular weight polyacrylamides, including anionic polyacrylamide (APAM), which may subsequently enter the marine environment with produced water releases. Since seawater (SW) contains mineral particles (MPs) in low concentrations, and polymers like APAM are known to flocculate MPs, we investigated if APAM at different concentrations (0.5–10 mg/L) would attach and flocculate MPs, when these occurred in concentrations relevant for oceanic SW (1 mg/L). Two types of MPs, diatomaceous earth and kaolin, were exposed to fluorescence-tagged APAM (APAM-TAG). A low-energy carousel system with natural seawater (SW) was used for incubation of MPs and APAM-TAG at a temperature relevant for the Norwegian Continental Shelf (13 °C). Attachment to MPs and aggregates of these were analysed by fluorometry and fluorescence microscopy. Particle analyses showed that only minor fractions of the MPs aggregated. When samples were separated in steel filter with a mesh size of 20 μm, APAM-TAG was mainly measured in the flow-through fraction (<20 μm), and the results therefore showed that the polymer mainly remained in the water-phase, or was attached to small particles (<20 μm). For the small fraction of APAM attaching to aggregated MPs, attraction to kaolin was higher than to diatomaceous earth, and fluorescence microscopy analyses confirmed the presence of fluorescent particles at the higher APAM concentrations. MPs at concentrations relevant for oceanic SW are therefore not expected to significantly contribute to sedimentation of APAM dissolved in the water column.publishedVersio

Embryonic exposure to produced water can cause cardiac toxicity and deformations in Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) larvae

Regular discharges of produced water from the oil and gas industry represents the largest direct discharge of effluent into the marine environment worldwide. Organic compound classes typically reported in produced water include saturated hydrocarbons, monoaromatic and polyaromatic hydrocarbons (MAHs, PAHs) as well as oxygenated compounds, such as phenols, acids and ketones. This forms a cocktail of known and suspect toxicants, but limited knowledge is yet available on the sub-lethal toxicity of produced water to cold-water marine fish species. In the present work, we conducted a 4-day exposure of embryos of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) to produced water extracts equivalent to 1:50, 1:500 and 1:5000 times dilutions of raw effluent. No significant reduction in survival or hatching success was observed, however, for cod, hatching was initiated earlier for exposed embryos in a concentration-dependent manner. During recovery, significantly reduced embryonic heart rate was observed for both species. After hatch, larvae subjected to embryonic exposure to produced water extracts were smaller, and displayed signs of cardiotoxicity, jaw and craniofacial deformations. In order to improve risk assessment and regulation of produced water discharges, it is important to identify which produced water components contribute to these effects.acceptedVersio

The impact of exposure timing on embryo mortality and the partitioning of PAHs when cod eggs are exposed to dispersed and dissolved crude oil

During sub-sea oil spills to the marine environment, oil droplets will rise towards the sea surface at a rate determined by their density and diameter as well as the vertical turbulence in the water. Micro-droplets (< 50 µm) are expected to have prolonged residence times in the water column. If present, pelagic fish eggs may thus be exposed to dispersed oil from subsurface oil spills for days, and the contribution of these micro-droplets to toxicity is not well known. The purpose of this work was to investigate to what extent timing of exposure and the presence of oil micro droplets affects PAH uptake and survival of pelagic Atlantic cod eggs. A single batch of eggs was separated in two groups and exposed to dispersions and corresponding water-soluble fraction at 3–7 days (Early exposure) and 9–13 days (Late exposure) post fertilization. Partitioning of PAHs between crude oil microdroplets, water and eggs was estimated as well as the contribution of oil droplets to PAH body residue and acute and delayed mortality. Timing of oil exposure clearly affects both the mortality rate and the timing of mortality. Even though the body residue of PAHs were lower when embryos were exposed in the later embryonic stage, mortality rate increased relative to the early exposure indicating that critical body residue threshold is stage specific. Although our results suggest that the dissolved fraction is the dominating driver for toxicity in cod embryos exposed to oil dispersions, crude oil micro droplets contribute to increased mortality as well.publishedVersio

The β-oxidation pathway is downregulated during diapause termination in Calanus copepods

Calanus copepods are keystone species in marine ecosystems, mainly due to their high lipid content, which is a nutritious food source for e.g. juvenile fish. Accumulated lipids are catabolized to meet energy requirements during dormancy (diapause), which occurs during the last copepodite stage (C5). The current knowledge of lipid degradation pathways during diapause termination is limited. We characterized changes in lipid fullness and generated transcriptional profiles in C5s during termination of diapause and progression towards adulthood. Lipid fullness of C5s declined linearly during developmental progression, but more β-oxidation genes were upregulated in early C5s compared to late C5s and adults. We identified four possible master regulators of energy metabolism, which all were generally upregulated in early C5s, compared to late C5s and adults. We discovered that one of two enzymes in the carnitine shuttle is absent from the calanoid copepod lineage. Based on the geographical location of the sampling site, the field-samples were initially presumed to consist of C. finmarchicus. However, the identification of C. glacialis in some samples underlines the need for performing molecular analyses to reliably identify Calanus species. Our findings contributes to a better understanding of molecular events occurring during diapause and diapause termination in calanoid copepods.publishedVersio

Effects of marine mine tailing exposure on the development, growth, and lipid accumulation in Calanus finmarchicus

Marine tailing disposal (MTD) is sometimes practiced as an alternative to traditional mine tailing deposition on land. Environmental challenges connected to MTD include spreading of fine particulate matter in the water column and the potential release of metals and processing chemicals. This study investigated if tailing exposure affects the marine copepod Calanus finmarchicus, and whether effects are related to exposure to mineral particles or the presence of metals and/or processing chemicals in the tailings. We investigated the impacts of three different tailing compositions: calcium carbonate particles with and without processing chemicals and fine-grained tailings from a copper ore. Early life stages of C. finmarchicus were exposed over several developmental stages to low and high suspension concentrations for 15 days, and their development, oxygen consumption and biometry determined. The data was fitted in a dynamic energy budget (DEB) model to determine mechanisms underlying responses and to understand the primary modes of action related to mine tailing exposure. Results show that copepods exposed to tailings generally exhibited slower growth and accumulated less lipids. The presence of metals and processing chemicals did not influence these responses, suggesting that uptake of mineral particles was responsible for the observed effects. This was further supported by the applied DEB model, confirming that ingestion of tailing particles while feeding can result in less energy being available for growth and development.publishedVersio

Effects of produced water on pelagic marine organisms - Focus on the copepod Calanus finmarchicus

The main aim of this project was to provide a basis for assessing the potential health effects of produced water (PW) on the marine pelagic zooplankton Calanus finmarchicus in the field. This report describes three experiments assessing the impact of reconstituted PW extracts on copepod PAH body residue, stress gene expression and metabolic profiles. The project established relationships between produced water exposure, PAH uptake and biological responses in a laboratory settings, in order to be used as a basis for sampling and analyses of copepods exposed to environmentally realistic scenarios in the field. A selection of endpoints are suggested for analyses of field-collected copepods in the water column monitoring in 2017.publishedVersio

KNM "Helge Ingstad" ‐ Miljøundersøkelse - Forvitringsegenskaper, kjemi og toksisitet

Flere drivstoffprøver fra havaristen Helge lngstad har blitt analysert mhp fysikalske egenskaper og kjemisk sammensetning: Diesel både fra nødlossing og tatt opp på sjø, samt en helikopter­fuel som var samlet opp på sjøen. I tillegg mottok SINTEF to vannprøver: En med fritt vann fra oppsamlingen som også inneholdt spor av diesel og en blandingsprøve med vann og helikopter­fuel. Vanninnholdet i dieselprøvene var lavt, mindre enn 0.2%, og vil derfor ikke ha betydning for oljeregnskapet. Tetthet og viskositet var som forventet for diesel. To av dieselprøvene ble toppet til 250 °C+ og kokepunktskurven viste at det var mer lette komponenter i dieselen fra nødlossingen enn den som var tatt opp på sjøen, med et fordampningstap på hhv 26 og 17%. Akutt toksisitet (Skeletonema costatum og Calanus finmarchicus) og kjemiske sammensetning av den vannløselige fraksjonen (WAF) av fersk og forvitret diesel fra nødlossingen, samt prøven med fritt vann ble undersøkt. Det viste seg at vannprøven inneholdt en del oljedråper som kan ha bidratt til toksisiteten sammen med mulig oksygenmangel. Spesifikk toksisitet var den samme for WAF fra fersk og forvitret diesel fra nødlossingen, både for Skeletonema og Calanus. Ved sammenligning med testingen av MGO fra 2014, viste resultatene at den akutte toksisiteten av dieselen fra Helge lngstad lå om lag i samme område. Teoretisk toksisitet, TU, for de to WAF­prøvene fra nødlossingen var mindre enn 1, noe som indikerer en forholdsvis lav teoretisk toksisitet. For vannprøven var TU (5.6) høyere enn WAF, trolig pga bidrag for de mindre vannløselige komponentene som kom fra oljedråpene.publishedVersio

Sorption of PAHs to microplastic and their bioavailability and toxicity to marine copepods under co-exposure conditions

Organic chemical pollutants associated with microplastic (MP) may represent an alternative exposure route for these chemicals to marine biota. However, the bioavailability of MP-sorbed organic pollutants under conditions where co-exposure occurs from the same compounds dissolved in the water phase has rarely been studied experimentally, especially where pollutant concentrations in the two phases are well characterized. Importantly, higher concentrations of organic pollutants on ingested MP may be less bioavailable to aquatic organisms than the same chemicals present in dissolved form in the surrounding water. In the current study, the sorption kinetics of two model polycyclic aromatic hydrocarbons (PAHs; fluoranthene and phenanthrene) to MP particles in natural seawater at 10 and 20 °C were studied and the bioavailability of MP-sorbed PAHs to marine copepods investigated. Polyethylene (PE) and polystyrene (PS) microbeads with mean diameters ranging from 10-200 µm were used to identify the role of MP polymer type and size on sorption mechanisms. Additionally, temperature dependence of sorption was investigated. Results indicated that adsorption dominated at lower temperatures and for smaller MP (10 µm), while absorption was the prevailing process for larger MP (100 µm). Monolayer sorption dominated at lower PAH concentrations, while multilayer sorption dominated at higher concentrations. PE particles representing ingestible (10 µm) and non-ingestible (100 µm) MP for the marine copepod species Acartia tonsa and Calanus finmarchicus were used to investigate the availability and toxicity of MP-sorbed PAHs. Studies were conducted under co-exposure conditions where the PAHs were also present in the dissolved phase (Cfree), thereby representing more environmentally relevant exposure scenarios. Cfree reduction through MP sorption was reflected in a corresponding reduction of lethality and bioaccumulation, with no difference observed between ingestible and non-ingestible MP. This indicates that only free dissolved PAHs are significantly bioavailable to copepods under co-exposure conditions with MP-sorbed PAHs.publishedVersio

Microplastic dispersal behavior in a novel overhead stirring aqueous exposure system

Using nominal dose metrics to describe exposure conditions in laboratory-based microplastic uptake and effects studies may not adequately represent the true exposure to the organisms in the test system, making data interpretation challenging. In the current study, a novel overhead stirring method using flocculators was assessed for maintaining polystyrene (PS) microbeads (Ø10.4 μm; 1.05 g cm−3) in suspension in seawater during 24 h and then compared with static and rotational exposure setups. Under optimized conditions, the system was able to maintain 59% of the initial PS microbeads in suspension after 24 h, compared to 6% using a static system and 100% using a rotating plankton wheel. Our findings document for the first time that overhead stirring as well as other, commonly used exposure systems (static) are unable to maintain constant microplastic exposure conditions in laboratory setups whereas rotation is very effective. This suggests toxicological studies employing either static or overhead stirring systems may be greatly overestimating the true microplastic exposure conditions.publishedVersio

Potential oil product leakages from World War II shipwrecks - Assessment of possible environmental risk

The water accommodated fractions (WAFs) of oils from the British sloop HMS "Bittern", the British carrier tanker RFA "Boardale", the German destroyer "Erich Giese", and the German cargo ship MS "Nordvard" have been studied with special emphasis on chemistry and taxicity. A limited study of the weathering properties of three of these oils (not "Nordvard") was also performed to predict the behaviour of oil at sea in order to optimize the effectiveness of potential response operations. The results from taxicity studies show that the more "synthetic" oils from German WWII shipwrecks "Erich Giese" and "Nordvard" seem to have higher taxicity to marine organisms than the "mineral" oils from the British shipwrecks "Bittern" and Boardale". There will be no risk for fire hazard during a response operation (flash points >60°C for all oils). Solidification on the sea surface is not expected for any of the oils. Ause of weir skimmer could be an option for oil spill recovery for "Erich Giese" and "Boardale", but reduced efficiency is expected for "Bittern" under certain winter conditions. Boom leakage is expected for "Erich Giese" due to low emulsion viscosities. There is a potential for use of dispersants for all three oils in a spill operation. This has become the basic methodology for assessment on of the potential environmental risk of oil leakage from shipwrecks, and has given valuable input to the decision maker's recommendations of how to deal with the shipwrecks. It has resulted in an altering of the priority list for future oil recovery from WWII wrecks due to the potential for higher impact on the marine environment of coal based oilsThe Norwegian Coastal AdministrationpublishedVersio