Ketil Hylland

Polycyclic aromatic hydrocarbon (PAH) ecotoxicology in marine ecosystems.

Low levels of oil and hence polycyclic aromatic hydrocarbons (PAHs) are naturally present in the marine environment, although levels have increased significantly following human extraction and use of oil and gas. Other major anthropogenic sources of PAHs include smelters, the use of fossil fuels in general, and various methods of waste disposal, especially incineration. There are two major sources for PAHs to marine ecosystems in Norway: the inshore smelter industry, and offshore oil and gas production activities. A distinction is generally made between petrogenic (oil-derived) and pyrogenic (combustion-derived) PAHs. Although petrogenic PAHs appear to be bioavailable to a large extent, pyrogenic PAHs are often associated with soot particles and less available for uptake into organisms. There is extensive evidence linking sediment-associated PAHs to induction of phase-I enzymes, development of DNA adducts, and eventually neoplastic lesions in fish. Most studies have focused on high-molecular-weight, carcinogenic PAHs such as benzo[a]pyrene. It is less clear how two- and three-ring PAHs affect fish, and there is even experimental evidence to indicate that these chemicals may inhibit some components of the phase I system rather than produce induction. There is a need for increased research efforts to clarify biological effects of two- and three-ring PAHs, PAH mixtures, and adaptation processes in marine ecosystems.

Characterization of the effluent from a nanosilver producing washing machine

The increasing number of nanomaterial based consumer products raises concerns about their possible impact on the environment. This study provides an assessment of the effluent from a commercially available silver nanowashing machine. The washing machine released silver in its effluent at an average concentration of 11μgL(-1), as determined by inductive coupled mass spectrometry (ICP-MS). The presence of silver nanoparticles (AgNPs) was confirmed by single particle ICP-MS as well as ion selective electrode measurements and filtration techniques. Size measurements showed particles to be in the defined nanosize range, with an average size of 10nm measured with transmission electron microscopy (TEM) and 60-100nm determined with nanoparticle tracking analysis (NTA). The effluent was shown to have negative effects on a natural bacterial community as its abundance was clearly reduced when exposed to the nanowash water. If washing machines capable of producing AgNPs become a common feature of households in the future, wastewater will contain significant loadings of AgNPs which might be released into the environment.

Contaminant accumulation and biomarker responses in flounder (Platichthys flesus L.) and Atlantic cod (Gadus morhua L.) exposed by caging to polluted sediments in Sørfjorden, Norway

Flounder (Platichthys flesus L.) and Atlantic cod (Gadus morhua L.) were subjected to caging at polluted sediments in a Norwegian fjord (Sorfjorden) for a period of 3 months. Three caging sites were located close to metal smelters, whereas a fourth site was located 30 km away as a reference. In sediment samples, polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and heavy metals were elevated at the innermost sites (1, 2 and 3) compared with the reference location (site 4). In fish, the biliary levels of fluorescent aromatic compounds (FACs) were elevated 5–20 fold in both species at the polluted sites. A two-fold difference in heavy metal levels was observed in cod (site 2 vs. 4), whereas no differences were seen in flounder. Pesticides bioaccumulated in a diffuse manner at all sites. In flounder at the innermost sites, plasma aspartate aminotransferase (AST) and hepatic cytochrome P450 1A (CYP1A) dependent 7-ethoxyresorufin O-deethylase (EROD) activity were elevated 4–5 and 5–10 fold, respectively, compared with the reference site. Both of these biomarkers were significantly correlated with FACs levels. For other biomarkers, the site effect was more marginal. The biomarkers seemed in general more responsive in flounder than in cod. The present study demonstrates biomarker measurements in caged fish as a promising approach for evaluating accumulation and effects of pollutants in marine teleosts.

Toxic levels of dietary copper in Atlantic salmon (Salmo salar L.) parr

Abstract Atlantic salmon ( Salmo salar ) parr were exposed for 4 weeks to dietary Cu concentrations of 5 (control), 35 and 700 mg Cu kg −1 dry feed to establish maximum tolerable levels of dietary Cu. Parr exposed to 35 and 700 mg Cu kg −1 dry feed had significantly increased ( P P >0.05). There were no significant changes in gill Cu, plasma Cu or liver MT levels at any of the dietary Cu concentrations, indicating that Cu homeostasis was maintained. A significant increase in liver Cu (1.6-fold relative to controls), but no significant change in liver MT, were observed only at the highest copper concentration. Cu-exposed Atlantic salmon parr showed an onset of adaptive responses (increase of intestinal PCNA, apoptosis, and MT levels) at concentrations of 35 and 700 mg Cu kg −1 dry feed, indicating that stress responses are induced at these dietary Cu concentrations.

Tissue metallothionein, apoptosis and cell proliferation responses in Atlantic salmon (Salmo salar L.) parr fed elevated dietary cadmium.

Atlantic salmon parr were reared for 4 months on experimental diets supplemented with 0 (control), 0.5, 5, 25, 125, or 250 mg Cd x kg(-1) feed to establish a threshold concentration for dietary cadmium exposure by assessing early adaptive cellular responses. At the end of the experiment, the lowest dietary Cd concentration that caused significant accumulation in the gut, kidney and muscle was 5 mg Cd x kg(-1) compared to the control group. Over time, dietary Cd accumulated first in the gut (after 1 month), followed by the kidney (2 months), and later by muscle (4 months). Highest Cd accumulation (100-fold) was found in the gut. A significant increase in regulated cell death and proliferation in salmon fed 125 mg Cd x kg(-1) compared to control fish appeared efficient in preventing gross histopathological damage in the intestine. The highest increase in metallothionein levels was found in the kidney, and metallothionein (MT) levels increased disproportionally to Cd accumulation at increased exposure concentrations. It was concluded that MT was not directly associated with long-term Cd accumulation. Atlantic salmon showed increased metallothionein levels in the kidney at a median effective concentration (concentration of dietary Cd giving 50% of the maximum increase in metallothionein, EC50) of 7 mg Cd x kg(-1), indicating toxic exposure at this concentration.

Differential gene expression and biomarkers in zebrafish (Danio rerio) following exposure to produced water components

The main effluent from oil and gas production is produced water (PW), a waste that contains low to moderate concentrations of oil-derived substances such as polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APs). PW components may be present in seawater at low concentrations over large areas in the vicinity of oil and gas production facilities. In this study, zebrafish (Danio rerio) were exposed to control and three treatments (high-, pulsed-, low-dose) of a synthetic PW mixture for 1, 7 and 13 weeks. The aim was to investigate the development of transcriptome and biomarker responses as well as relationships between early responses and population-relevant effects. The synthetic PW contained a mixture of low-molecular-weight PAHs (<5 ring) and short-chain APs (C1-C4). The water-borne exposure levels (sum PAH) ranged from 0.54 ppb (low dose) to 5.4 ppb (high dose). Bile pyrene metabolites ranged from 17-133 ng g(-1) bile in the control group to 23-1081 ng g(-1) bile in the high exposure group. Similar levels have been observed in wild fish, confirming an environmentally relevant exposure. The expression of mRNAs of hepatic genes was investigated in the high exposure group using the Zebrafish OligoLibrary from Compugen. Functional clustering analysis revealed effects in the reproductive system, the nervous system, the respiratory system, the immune system, lipid metabolism, connective tissue and in a range of functional categories related to cell cycle and cancer. The majority of differentially expressed mRNAs of genes were down-regulated, suggesting reduction in gene transcription to be as relevant as up-regulation or induction when assessing biological responses to PW exposure. Biomarkers for effects of PAHs (cytochrome P450 1A) and environmental estrogens (vitellogenin) did not appear to be affected by the chronic exposure to low concentration of PW components. Effects at the population level included a reduction in condition factor in male fish from all exposed groups and spinal column deformations in the F1 generation of exposed groups. The different exposure regimes did not produce any significant differences in reproduction or recruitment. The results from this study demonstrate that environmentally relevant concentrations of PW affect gene expression and population-relevant endpoints in zebrafish, although links between the two were not obvious.

Biomarkers in flounder (Platichthys flesus): an evaluation of their use in pollution monitoring

Flounder (Platichthys flesus) is among the most common fish-species in Norwegian and European estuaries. It lives in or on sediments from which it also finds most of its food. The aim of the present work was to evaluate biomarkers in flounder for possible future use in monitoring programmes. There were clear biomarker responses in flounder following injection of model contaminants benzo[a]pyrene (B[a]P), PCB #156 and Cd, singly or in sequence. Cytochrome P4501A responded following injection of the organic contaminants and metallothionein (MT) following Cd injection. All groups receiving B[a]P, either singly or in combination with other contaminants, accumulated high levels of B[a]P-metabolites in bile. There was little change in glutathione-S-transferase activity (measured using CDNB as substrate) following the treatments. Starvation appeared to affect the response of hepatic MT to Cd, but none of the other biomarkers. PAH in sediments elicited strong biomarker responses in caged flounder, whereas sediment-associated metals appeared to be largely unavailable to flounder in this study.

Spatial diastereomer patterns of hexabromocyclododecane (HBCD) in a Norwegian fjord

Hexabromocyclododecane (HBCD) is the third most used brominated flame retardant globally, and has been found widely distributed in the environment. The present study reports concentrations and spatial patterns of alpha, beta and gamma-HBCD in a contaminated Norwegian fjord. Intertidal surface sediment and selected species from the marine food web were sampled at five locations in increasing distance from a known point source of HBCD. All sediment and biota samples were analyzed for the three HBCD diastereomers by liquid chromatography and mass spectrometry (LC/MS). The results demonstrated a HBCD gradient with decreasing concentrations at increasing distance from the point source in sediment and sedentary species, but less so in the species with large feeding ranges. Mean concentrations of Sigma HBCD at the closest/most remote locations relative to the point source were 9000/300 ng g(-1) TOC in sediment and 150/90 ng g(-1) lw in the species with largest feeding range (great black-backed gull). The HBCD diastereomer patterns were similar for each of the matrices (sediment, organisms) independent of distance from the source, indicating no difference in environmental partitioning between the diastereomers. However, the concentration ratio of diastereomers in each matrix ranged from 3:1:10 (alpha:beta:gamma) in the sediments to 55:1 (alpha:gamma) in the highest trophic level species, suggesting diastereomer-specific bioaccumulation in the organisms.

Detection of DNA damage in haemocytes of Mytilus galloprovincialis in the coastal ecosystems of Kastela and Trogir bays, Croatia.

Coastal waters are burdened with different contaminants of anthropogenic origin due to intensive urbanisation and economical development. Bays, semi-enclosed areas with limited water renewal ability, are particularly endangered by contaminant inputs. Kastela Bay (Dalmatia, Eastern Adriatic) has earlier been identified as an area loaded with diffuse sources of pollution, including genotoxic agents. However, there is lack of data on the effects of these contaminants on the local marine fauna. The aim of this study was to assess genotoxic impacts in Kastela Bay and the neighbouring Trogir Bay using the micronucleus test and Comet assay with mussel (Mytilus galloprovincialis) haemocytes. Native and caged mussels were included in the studies. Our results confirmed that mussels in Kastela and Trogir Bays are affected by genotoxic contaminants. In addition to mussels from the most known polluted site (Vranjic), there was evidence for genotoxic effects in mussels collected at other locations. The response in the micronucleus test and the Comet assay differed somewhat between sites, the latter apparently being more sensitive, but the two methods complement each other and it is therefore desirable to use them both in monitoring the impacts of genotoxic pollution in coastal waters.

Biomarkers in Natural Fish Populations Indicate Adverse Biological Effects of Offshore Oil Production

Background Despite the growing awareness of the necessity of a sustainable development, the global economy continues to depend largely on the consumption of non-renewable energy resources. One such energy resource is fossil oil extracted from the seabed at offshore oil platforms. This type of oil production causes continuous environmental pollution from drilling waste, discharge of large amounts of produced water, and accidental spills. Methods and principal findings Samples from natural populations of haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua) in two North Sea areas with extensive oil production were investigated. Exposure to and uptake of polycyclic aromatic hydrocarbons (PAHs) were demonstrated, and biomarker analyses revealed adverse biological effects, including induction of biotransformation enzymes, oxidative stress, altered fatty acid composition, and genotoxicity. Genotoxicity was reflected by a hepatic DNA adduct pattern typical for exposure to a mixture of PAHs. Control material was collected from a North Sea area without oil production and from remote Icelandic waters. The difference between the two control areas indicates significant background pollution in the North Sea. Conclusion It is most remarkable to obtain biomarker responses in natural fish populations in the open sea that are similar to the biomarker responses in fish from highly polluted areas close to a point source. Risk assessment of various threats to the marine fish populations in the North Sea, such as overfishing, global warming, and eutrophication, should also take into account the ecologically relevant impact of offshore oil production.