Sucralose Induces Biochemical Responses in Daphnia magna

2014 | PLoS ONE | 9:4 (1-6)

The intense artificial sweetener sucralose has no bioconcentration properties, and no adverse acute toxic effects have been observed in standard ecotoxicity tests, suggesting negligible environmental risk. However, significant feeding and behavioural alterations have been reported in non-standard tests using aquatic crustaceans, indicating possible sublethal effects. We hypothesized that these effects are related to alterations in acetylcholinesterase (AChE) and oxidative status in the exposed animals and investigated changes in AChE and oxidative biomarkers (oxygen radical absorbing capacity, ORAC, and lipid peroxidation, TBARS) in the crustacean Daphnia magna exposed to sucralose (0.0001–5 mg L−1). The sucralose concentration was a significant positive predictor for ORAC, TBARS and AChE in the daphnids. Moreover, the AChE response was linked to both oxidative biomarkers, with positive and negative relationships for TBARS and ORAC, respectively. These joint responses support our hypothesis and suggest that exposure to sucralose may induce neurological and oxidative mechanisms with potentially important consequences for animal behaviour and physiology.

Effects of an oil spill in a harbor assessed using biomarkers of exposure in eelpout

Sturve, J.; Balk, L.; Liewenborg, B.; Adolfsson-Erici, M.; Förlin, L.; Carney Almroth, B.
2014 | Environ Sci Pollut Res | 21 (24) (13758-13768)

Oil spills occur commonly, and chemical compounds originating from oil spills are widespread in the aquatic environment. In order to monitor effects of a bunker oil spill on the aquatic environment, biomarker responses were measured in eelpout (Zoarces viviparus) sampled along a gradient in Göteborg harbor where the oil spill occurred and at a reference site, 2 weeks after the oil spill. Eelpout were also exposed to the bunker oil in a laboratory study to validate field data. The results show that eelpout from the Göteborg harbor are influenced by contaminants, especially polycyclic aromatic hydrocarbons (PAHs), also during “normal” conditions. The bunker oil spill strongly enhanced the biomarker responses. Results show elevated ethoxyresorufin-O-deethylase (EROD) activities in all exposed sites, but, closest to the oil spill, the EROD activity was partly inhibited, possibly by PAHs. Elevated DNA adduct levels were also observed after the bunker oil spill. Chemical analyses of bile revealed high concentrations of PAH metabolites in the eelpout exposed to the oil, and the same PAH metabolite profile was evident both in eelpout sampled in the harbor and in the eelpout exposed to the bunker oil in the laboratory study.

Tumor prevalence and biomarkers of genotoxicity in brown bullhead (Ameiurus nebulosus) in Chesapeake Bay tributaries

Pinkney, A.E.; Harshbarger, J.C.; Karouna-Renier, N.K.; Jenko, K.; Balk, L.; Skarphéðinsdóttir, H.; Liewenborg, B.; Rutter, M.A.
2011 | Sci. Total Environ. | 410-411 (248-257)

We surveyed four Chesapeake Bay tributaries for skin and liver tumors in brown bullhead (Ameiurus nebulosus). We focused on the South River, where the highest skin tumor prevalence (53%) in the Bay watershed had been reported. The objectives were to 1) compare tumor prevalence with nearby rivers (Severn and Rhode) and a more remote river (Choptank); 2) investigate associations between tumor prevalence and polynuclear aromatic hydrocarbons (PAHs) and alkylating agents; and 3) statistically analyze Chesapeake Bay bullhead tumor data from 1992 through 2008. All four South River collections exhibited high skin tumor prevalence (19% to 58%), whereas skin tumor prevalence was 2%, 10%, and 52% in the three Severn collections; 0% and 2% in the Choptank collections; and 5.6% in the Rhode collection. Liver tumor prevalence was 0% to 6% in all but one South River collection (20%) and 0% to 6% in the three other rivers. In a subset of samples, PAH-like biliary metabolites and 32P-DNA adducts were used as biomarkers of exposure and response to polycyclic aromatic compounds (PACs). Adducts from alkylating agents were detected as O6-methyl-2′-deoxyguanosine (O6Me-dG) and O6-ethyl-2′-deoxyguanosine (O6Et-dG) modified DNA. Bullheads from the contaminated Anacostia River were used as a positive control for DNA adducts. 32P-DNA adduct concentrationswere significantly higher in Anacostia bullhead livers compared with the other rivers. We identified alkyl DNA adducts in bullhead livers from the South and Anacostia, but not the Choptank. Neither the PAH-like bile metabolite data, sediment PAH data, nor the DNA adduct data suggest an association between liver or skin tumor prevalence and exposure to PACs or alkylating agents in the South, Choptank, Severn, or Rhode rivers. Logistic regression analysis of the Chesapeake Bay database revealed that sex and length were significant covariates for liver tumors and length was a significant covariate for skin tumors.

Water column monitoring of the biological effects of produced water from the Ekofisk offshore oil installation from 2006 to 2009

Brooks, S.J.; Harman, C.; Grung, M.; Farmen, E.; Ruus, A.; Vingen, S.; Godal, B.F.; Baršiene, J.; Andreikenaite, L.; Skarphéðinsdóttir, H.; Liewenborg, B.; Sundt, R.C.
2011 | J. Toxicol. Environ. Health Part A | 74 (582-604)

Tumor prevalence, biomarkers of exposure and response, and genetic flow in brown bullheads (Ameiurus nebulosus) in Chesapeake Bay tributaries

Pinkney, A.E.; Harshbarger, J.C.; Balk, L.; Skarphéðinsdóttir, H.; Liewenborg, B.; Karouna-Renier, N.K.; Bartron, M.L.; Rutter, M.A.
2010 | Society of Environmental Toxicology and Chemistry (SETAC) (414-415)

SETAC North America 31st Annual Meeting | September 19, 2019 | Portland, OR, USA

For many years, tumor prevalence in brown bullhead (Ameiurus nebulosus) has been used to evaluate and monitor habitat quality in the Laurentian Great Lakes and Chesapeake Bay. The evidence for an association between neoplasia and environmental contaminants is much stronger for liver compared with the skin. Here we report the results of tumor surveys conducted in tributaries on the western shore (South, Severn, and Rhode Rivers) and eastern shore (Choptank) of the Chesapeake from 2004 through 2008. At all locations, liver tumor prevalence was low (19%) in the South River, and low for most other locations. Data from these surveys were added to the Chesapeake Bay data base which began in 1992 and logistic regression was performed to identify significant covariates. For liver tumors, the best fit model contained hepatosomatic index, gender, and length as covariates. For skin tumors, length was the only covariate. We used two methods for analyzing DNA adducts—the 32P postlabelling assay which is frequently applied to polycyclic aromatic hydrocarbon adducts, and immuno-slot blot, used to detect alkylating agents. The selected adducts O6-methyl-2-deoxyguanosine and O6-ethyl-2-deoxyguanosine are specifically induced by alkylating agents and have been shown to be persistent in vivo, and have been consistently associated with mutations and carcinogenesis in vivo. For both assays, we used a 2009 bullhead collection from the Anacostia River as a “positive control.” Anacostia bullheads were previously reported to have high concentrations of adducts from 32P analysis and high prevalence of skin and liver tumors. The 32P results indicated 10 to 25-fold higher liver DNA adduct concentrations in Anacostia bullheads vs. those from the South and Choptank Rivers. There were also detectable adducts in 4 of 7 skin samples from the Anacostia vs. 0 of 3 from the South River. Immuno slotblot results indicated the presence of alkylating agent adducts in the liver of bullheads from the Anacostia and South Rivers but not the Choptank. We also used microsatellite markers to evaluate the genetic relationships between adjacent rivers to understand bullhead movements and gene flow between collection sites. It is likely that a salinity barrier between the South and Severn Rivers and Eastern and Western shores resulted in little mixing between these sites. We further evaluate the utility of thebrown bullhead as a habitat indicator in Chesapeake Bay and recommend research needs for assessing the role of contaminants.

Genotoxicity of Environmentally Relevant Concentrations of Water-Soluble Oil Components in Cod (Gadus morhua)

Holth, T.F.; Beylich, B.A.; Skarphéðinsdóttir, H.; Liewenborg, B.; Grung, M.; Hylland, K.
2009 | Environ. Sci. Technol. | 43 (9) (3329-3334)

Large discharges from oil and gas production platforms (produced water) have led to concerns for adverse biological effects in marine areas. The aim of this study was to investigate the development of DNA adduct formation and related biomarkers in fish after chronic exposure to water-soluble components of oil. Atlantic cod (Gadus morhua) were exposed for up to 44 weeks to three treatments (low, pulsed, high) containing environmentally relevant concentrations of low-molecular-weight polycyclic aromatic hydrocarbons (PAHs) and short-chained alkylphenols (APs). A time- and dose-related pattern of DNA adduct formation (measured using P-32-postlabeling) was observed. The results suggested that an extended exposure period (more than 16 weeks) would be required for the formation of DNA adduct levels above background. Interestingly, fish receiving pulsed high exposure did not develop elevated concentrations of DNA adducts, possibly due to DNA repair processes. No obvious relationship between DNA adduct concentration and cytochrome P4501A activity (EROD) was observed. This study has demonstrated the genotoxic potential of water-soluble oil components, relevant for operational discharges (produced water) and chronic oil spills. The quantification of PAH metabolites in bile and hepatic DNA adduct formation appear to be suitable for environmental monitoring of chronic oil pollution.

Condition monitoring in the water column 2008: Oil hydrocarbons in fish from Norwegian waters

Grøsvik, B.E.; Meier, S.; Liewenborg, B.; Nesje, G.; Westrheim, K.; Fonn, M.; Kjesbu, O.; Skarphéðinsdóttir, H.; Klungsøyr, J.
2009 (1-61) | Report No: 2

Undersökning av tånglake i Göta älvs mynning, Stenungsund, Brofjorden och Fjällbacka

Förlin, L.; Fagerholm, B.; Andersson, J.; Adolfsson-Erici, M.; Liewenborg, B.; Balk, L.; Parkkonen, J.; Holmqvist, I.; Sturve, J.
2008 | Mimeo (1-13)

Vi har undersökt fisk från tre förorenade områden, Göta älvs mynning, Stenungsund och Brofjorden. Ett område utanför Fjällbacka där inga direkta utsläpp sker undersöktes också. Undersökningen gjordes under 2006 på tånglake som är en rekommenderad fiskart i svenska miljökontrollprogram. Vi har använt oss av en undersökningstyp där tånglaken studeras med hjälp av ett batteri av olika metoder. En liknande undersökning i samma områden gjordes hösten 1999.

En mycket kortfattad sammanfattning av den föreliggande undersökningen är att vi finner ungefar samma påverkan hos fisken i de undersökta områden 2006 som 1999.

Störningar hos tånglakens yngel är fortsatt tydliga i Stenungsunds- och Brofjordenlokalerna. Vi ser således likartade yngelstörningar 2006 och 1999. Dessutom har man känt till att tånglakeyngel är skadade i Stenungsundsområdet i 20 års tid. Det är väsentligt att ta reda vad som orsakar dessa yngelskador och hur stora områden som är påverkade, och om möjligt ta fram en åtgärdsplan.

Vi ser återigen en uppreglering av avgiftningsenzymer hos fisken från Göta älvs mynning. Detta indikerar att fisken är belastad av polycykliska kolväten (PAH) eller PAH-Iiknande ämnen. En liknande men svagare respons ser vi även hos fiskarna från Brofjordenlokalen. PAH är produkter som finns i olja eller bildas vid förbränning (finns t.ex. i bilavgaser). Oljehanteringen med transporter, lagring och raffinering av olja nära Brofjorenlokalen och i Göteborgs hamn är sannolik källa för PAH. Andra källor är sannolikt t.ex. dagvatten och regnvatten med PAH från flera olika diffusa källor såsom vägdamm, rökavgaser och däckgummi.

Fisken i Göta älvs mynning innehöll alkylfenoler (nonylfenol och oktylfenol) som är restprodukter från t.ex. rengörings- och emulgeringsmedel. Proverna innehöll också förhöjda halter av bisfenol A (mjukgörare i plaster) och triclosan. Halterna är generellt lägre i 2006 års undersökning jämfört med 1999. Man hittar dessa ämnen i utgående vatten från reningsverk där de således inte bryts ner fullständigt utan följer med ut i vattnet. När det gäller oktylfenol hittade vi även höga halter i fisken från Stenungsundsområdet.

Vår undersökning 1999 var bland de första som spårade kraftigt upptag av triclosan i fisk i miljön. Då liksom nu var halterna högst i Göteborgsområdet. Halterna har dock sjunkit vilket troligtvis speglar en mindre användning av denna onödiga tillsats till några vardagsprodukter såsom vissa tandkrämer och deodoranter.

Vi ser ingen påverkan som tyder på att fiskarna är oxidativt stressade eller som tyder på hormonella förändringar. Det gjorde vi inte heller 1999. En anmärkningsvärd skillnad från vår tidigare undersökning (1999) är att tånglakarna har högre halter av vita blodceller. Det gäller samtliga lokaler. Vad orsaken är till denna förändring är inte känt. En möjlig förklaring, som bör undersökas närmare, är att vita blodcellsbilden kan påverkas av eutrofiering och algblomningar längs våra kuster, eller att de stigande kadmiumnivåerna man konstaterat hos tånglake ger upphov till denna förändring.

DNA adducts in hepatic and extrahepatic tissues of cod (Gadus morhua) and haddock (Melanogrammus aeglifinus): Comparison of Icelandic waters with the one from Tampen oil field in the North Sea

Skarphéðinsdóttir, H.; Liewenborg, B.; Balk, L.
2007 | ITM, SU (1-34) | ISBN: ISSN: 1103-341X | Report No: 162

DNA adducts were analyzed in fish sampled in the Tampen area in the North Sea, an active oil field consisting of numerous oil platforms with large releases of oil contaminated produced water. The fish species studied were cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). Special effort was made to study DNA adducts in the liver as well as in extrahepatic tissues, and to also include low molecular weight aromatic hydrocarbons in the analytical protocol. The liver of marine fish may not be the optimal tissue to work with for biomarker analysis/response since it is in many cases extremely rich in lipids which complicates the analytical work. Therefore it is highly motivated to investigate if other tissues could better serve the purpose of a target organ for biomarker investigations of DNA adducts. Recent studies on other fish species have shown high levels of DNA adduct in extrahepatic tissues, and the aim was to investigate if cod and haddock were affected in a corresponding way. The tissues studied in this investigation were: liver, whole blood, trunk kidney, head kidney, gills, spleen, intestinal mucosa, and brain. Reference fish for background values were collected south-west of Iceland. The results revealed that highest DNA adduct levels were found in liver of haddock from Tampen with an average of 6.52±1.62 nmol adducts/mol normal nucleotides (n=6). Liver of Icelandic haddock had 0.76±0.42 nmol adducts/mol normal nucleotides (n=6).
Extrahepatic tissues of haddock had all lower DNA adduct levels than the liver. The highest extrahepatic DNA adduct levels in haddock were found in the intestinal mucosa; 1.23±0.6 nmol adducts/mol normal nucleotides in Tampen haddock. The extrahepatic results do indicate that the liver tissue in haddock is suitable as the target organ for DNA adduct formation, and by that fact also suitable for regular monitoring. Cod from Tampen area had comparatively low DNA adduct levels in all tissues, including the liver, with average adduct levels ranging from 0.49-2.15 nmol adducts/mol normal nuc1eotides, where the highest level in some individual fish were found in the trunk kidney. An alternative/additional target tissue for DNA adduct analysis for this species could possibly be the trunk kidney. That haddock shows higher DNA adduct levels in liver than cod is in agreement with previous investigations from this area (Balk et al., manuscript) and may reflect a different distribution of genotoxic contaminants in the species habitat and diets and/or a different metabolism. DNA adduct levels observed in haddock from this study are lower than those found in previous investigation (18.8 nmol adducts/mol normal nuc1eotides; Klungsoyr et al. 2003) for unknown reasons.
A general pattern, including both haddock and cod, was that when the DNA adducts were evident in various tissues the occurrence of DNA adducts were much more common in the Tampen area than in the Icelandic waters.
Standards for 1 aromatic ring DNA adducts (styrene oxide DNA adducts) were run parallel with the samples, and confirmed that also at least some small DNA adducts can be retained in our analytical system. We are however not yet capable of distinguishing between smaller and larger adducts.

Dredging associated effects: Maternally transferred pollutants and DNA adducts in feral fish

Sundberg, H.; Hanson, M.; Liewenborg, B.; Zebühr, Y.; Broman, D.; Balk, L.
2007 | Environ. Sci. Technol. | 41 (2972-2977)

This study reports on the bioavailability, maternal transfer, and genotoxicity in feral fish of organic sediment pollutants. Northern pike (Esox lucius) and perch (Perca fluviatilis) were caught in a polluted bay before and during dredging activities and from reference areas. Polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were analyzed in ovulating eggs to investigate if the bay sediment posed a threat to early life-stages of fish. On the basis of previous investigations in this area, the level of exposure via maternal transfer and diffusive uptake of water-borne pollutants after hatch is likely sufficient to cause abnormalities in early life-stages of fish. During dredging, hepatic DNA adducts were elevated in adult fish, demonstrating an increased release of genotoxic compounds, which may contribute to adverse effects in aquatic organisms for several years. Although no substantial increase of maternally transferred pollutants were observed during dredging, this is the first time a correlation between hepatic DNA adducts in fish and pollutant burden in their eggs is demonstrated. Our findings underline the importance of combining chemical and toxicological methods as well as a need for greater emphasis on other polycyclic aromatic compounds in environmental risk evaluations.

Genotoxic effects of pollutants in herring gulls (Larus argentatus) in south Sweden and Iceland

Skarphedinsdottir, H.; Hallgrimsson, G.; Hansson, T.; Hägerroth, P.-Å.; Tjärnlund, U.; Åkerman, G.; Liewenborg, B.; Balk, L.
2007 | Society of Environmental Toxicology and Chemistry (SETAC) (329-330)

SETAC Europe 17th Annual Meeting | September 19, 2019 | Porto, Portugal

Genotoxic effects were studied in herring gulls (Larus argentatus) from different areas in South Sweden affected with high unexplained bird mortality and in herring
gulls from Iceland for reference. DNA adducts were analysed in hepatic and extrahepatic tissues of the birds with the 32P postlabelling method, and micronuclei will be analysed in erythrocytes by microscope examination. DNA adduct levels were highest in liver of Swedish herring gulls, ranging from 5,5 - 72,6 nmol adducts/ mol normal nucleotides, with an average of 24,9 17,5 stdev (n=22). DNA adduct levels in Icelandic herring gulls ranged from 0 49,8 nmol add/mol norm. nuclt., with an average of 16,5 12,5 stdev (n=18). Six herring gulls from each country with the highest hepatic DNA adducts were also studied for levels of DNA adducts in extrahepatic tissues. For the six Swedish herring gulls, average DNA adduct levels were 44,7; 29.8; 5,73; 3,51 nmol add/mol norm. nuclt. in liver, kidneys, intestinal epithelium and blood respectively.

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