1,721,098 research outputs found
Exposure and toxicity of mixtures of plant protection products (PPPs) in the environment under Norwegian conditions. Evaluation of a cumulative environmental risk assessment of PPPs
Get PDFThis project was performed to improve the environmental cumulative risk assessment (CRA) of mixtures of plant protection products detected by the Norwegian Agricultural Environmental Monitoring Programme (JOVA) in Norwegian surface waters. Existing ecotoxicity data were compiled and reduced the assessment uncertainty compared to previous risk assessments. Ecotoxicity tests verified that the cumulative toxicity of ecologically-relevant environmental mixtures was fairly well predicted for algae, daphnia and aquatic plants. The results from the ecotoxicity tests were used to evaluate the assessment factor used in the risk assessment, and the improved data used in the CRA of plant protection products in the JOVA monitoring performed in 2013. Three of the six investigated sites had risk quotients indicative of environmental risk. Mitigation measures based on the identification of the main risk drivers were discussed and include consideration of no-spray zones, grassed buffer strips, reduced doses and patch spraying, and pesticide risk maps.Mattilsynet
Norwegian Food Safety Authorit
Evaluation of the combined toxicity assessment and cumulative risk assessment of ecologically relevant mixtures of plant protection Products (PPPs) under Norwegian conditions
Get PDFThis project evaluated whether the principles of combined toxicity assessment (CTA) and cumulative risk assessment
(CRA) can be used to predict the toxicity of ecologically-relevant mixtures of plant protection products (PPPs) in
surface waters receiving run-off from Norwegian agricultural areas. A combination of testing solid phase extracts
(SPE), whole surface water and a synthetic mixture in an algal bioassay and predicting combined toxicity using CTA
models were conducted on selected samples from the Heia catchment (Råde, Norway). The results demonstrated that
designing and testing synthetic mixtures on the basis of measured concentrations of PPPs was the best method for the
accurate determination of combined toxicity due to confounding factors introduced by whole water and SPE testing.
Combined toxicity models based on Concentration Addition (CA) successfully predicted the toxicity of the complex
synthetic mixture and verified that a mixture of PPPs acted in an additive manner. Tiered assessment of the cumulative
risk of active PPP substances and PPP formulations proposed by the European Food Safety Authority (EFSA) were
considered applicable also for the CRA of complex environmental mixtures and could potentially aid the identification of relevant mixtures, risk drivers and susceptible species as input to the assessment and approval of PPPs.Mattilsynet; Norwegian Food Safety Authorit
Raw data and correlation analysis of physiological data sampled from Atlantic halibut (Hippoglossus hippoglossus) for the development of a PBPK model
No full text<p>Raw data sampled from Atlantic halibut <em>(Hippoglossus hippoglossus)</em> for the characterization of physiological parameters for the development of a species-specific physiology-based pharmacokinetic (PBPK) model. Additionally, the document containes imputed data for a PCA analysis and correlation coefficients and the related p-values from a correlation analysis. </p>
Characterization of pesticide hazard and risk to freshwater algae under ecologically relevant exposure conditions in Norway
Get PDFBalansen i det akvatiske økosystemet er under konstant press fra menneskelig påvirkning, og store mengder forurensende stoffer slippes ut i vannforekomster i hele verden. Blant disse er pesticider en stor kilde til utslipp, og dette skyldes i stor grad avrenning fra jordbruk og skogbruk. Et pesticid er ethvert stoff eller blandinger av stoffer produsert med det formål å forhindre, ødelegge eller begrense en skade eller sykdom på levende organismer.
I Norge er bruken av sprøytemidler hovedsakelig nedadgående, bortsett fra når det gjelder herbicider, som har hatt en svak økning de siste årene. Herbicider utgjør den største andelen av sprøytemiddelbruk i Norge, og utgjorde 69,5% av bruken i 2014. Individuell risikovurdering er gjort for stoffene som er godkjent for bruk i Norge, men det er en økende bekymring omkring blandinger av disse stoffene og de mulige negative effektene disse blandingene kan ha på det akvatiske miljøet rundt spesielt jordbruksområdene.
I løpet av sommeren 2015 (juni-august) ble det tatt vannprøver fra Heiabekken, Råde kommune, i forbindelse med overvåkningsprogrammet JOVA. I et samarbeid mellom Norsk institutt for vannforskning (NIVA) og NIBIO, ble det gjennomført ekstraksjon og kjemiske analyser av disse vannprøvene for blant annet å undersøke tilstedeværelsen av pesticider. Ved hjelp av en kumulativ toksisitetsvurdering basert på innsamlet litteratur, ble de største bidragsyterne for toksisitet i blandingen identifisert. Det ble gjennomført toksisitetstesting (72-timers veksthemming og 5-timers PSII-aktivitet) av en miljørelevant syntetisk pesticidblanding og de to viktigste herbicidene i blandingen, metribuzin og metamitron, på ferskvannsalgen Chlamydomonas reinhardtii.
Eksperimentene viste at den syntetiske blandingen måtte oppkonsentreres ~100 ganger i forhold til de målte miljøkonsentrasjonene for å gi en 50% veksthemming, men at både blandingen og enkeltstoffene hadde en tydelig redusert dose-responskurve ved økende konsentrasjoner. PSII-aktiviteten ble også tydelig påvirket, spesielt av metribuzin som er regnet som den mest potente risikodriveren for alger i blandingen.
Den kumulative toksisitetsvurderingen basert på CA-prediksjonsmodellen ble sammenliknet med de eksperimentelle toksisitetsstudiene gjort på C. reinhardtii. Giftigheten av blandingen ble relativt godt estimert, innenfor en faktor på 2, i forhold til de eksperimentelle studiene.The aquatic ecosystem balance is under constant pressure from human influence, and substantial amounts of pollutants are released to water bodies all over the world. Among these, pesticides are an important group, mainly due to runoff from agriculture and forestry. A pesticide is any compound or combinations of compounds produced with the aim to prevent, destroy or mitigate a pest.
In Norway, the use of pesticides is in general decrease, except for herbicide use, which has had a weak increase in recent years. Herbicides make up the largest proportion of pesticide use in Norway, constituting 69.5% of the use in 2014. Individual risk assessment is performed for the compounds approved for use in Norway, but there is an increasing concern regarding mixtures of these compounds and the possible adverse effects these mixtures may have on the aquatic environment around agricultural areas.
During the summer 2015 (June- August) water samples were collected from Heiabekken, Råde municipality, in conjunction with the monitoring programme JOVA. In a collaboration between NIVA and NIBIO, extractions and chemical analyses of these water samples were performed to investigate the presence of pesticides. By a cumulative toxicity assessment based on collected literature, the main contributors to toxicity in the mixture was identified. Toxicological testing (72 h growth inhibition and 5 h PSII-efficiency) was conducted on an environmentally relevant synthetic mixture of pesticides, and the two main herbicides in the mixture, metribuzin and metamitron, to the freshwater alga Chlamydomonas reinhardtii.
The experiments showed that the synthetic mixture had to be concentrated up to a factor of ~100 compared to the measured environmental concentrations, before a 50% growth inhibition could be seen. Still, both the synthetic mixture and the single compounds had a clear dose-response reduction with increasing concentrations. PSII-efficiency was also clearly affected, especially by metribuzin, which is regarded as the most potent risk driver for algae in the mixture.
The cumulative toxicity assessment with the CA prediction model was compared to the experimental toxicity studies conducted on C. reinhardtii. The toxicity of the mixture was well estimated, within a factor of 2, compared to the experimental studies.The Norwegian Institute for Water Research (NIVA)submittedVersionM-MIN
Effekten av nanoplast i den marine organismen Tisbe battagliai
No full textPlastic is a material made out of polymer chains derived from oil and gas, and together with additives these polymers have numerous applications. Plastic is used in daily life as wrapping around food, in cosmetics and in clothes, and is inevitable nowadays. However, of all the 322 million metric tons of plastic that are produced annually, between 4.8 and 12.7 million metric tons are estimated to enter the oceans every year. In the oceans, plastic debris can be degraded by physical and chemical processes to micro- and nanoplastics (MP and NP). These small particles ( 1800nm). Whereas most particles displayed a negative surface charge, PS-NH2 was positively charged in both medias. To test acute mortality, copepods were exposed to different concentrations of NPs (0, 0.5, 1, 5, 10, 25, 50 and 100 g/mL) in NSW for 48 hours. PS-NH2 was shown to be the most toxic particle, with an EC50 value of 7.8 g/mL. This particle was therefore chosen for further studies to determine reactive oxygen species (ROS) formation and lipid peroxidation as markers for potential oxidative stress and damage. To detect ROS formation and lipid peroxidation within the copepods, in vivo tests using fluorescent probes were conducted. Copepods were exposed to PS-NH2 in several concentrations and three different fluorescent detecting probes (DHR123, H2DCFDA and C11-BODIPY) were added. All three probes showed a significant rise in fluorescence compared to the control for the highest concentration tested (100 g/mL), but the methods were not successfully optimised and need to be further developed to get more precise results. Suggestions for improvements in the method and future research are proposed to get an enhanced ecotoxicologial assessment of micro- and nanoplastics. Overall, results suggest that the NPs PMMA-COOH and PS-NH2, which do not agglomerate, have the greatest potential of entering the copepods through ingestion because of their small size. Results also suggest that the positive surface charge of PS-NH2 increased the toxicity of the polymer. Given the results from the acute test where PS-NH2 was the most lethal particle tested, and from the significant level of fluorescence measured in the probe test, it is possible that the mortality of copepods exposed to PS-NH2 is caused by oxidative stress formed inside the animals.Plast er et materiale bestående av lange polymerkjeder som er laget av olje og gass, og sammen med tilleggsstoffer som tilsettes under produksjonen får polymerene flerfoldige bruksområder. Plast brukes i dagliglivet til innpakning av matvarer, i kosmetikk og i klær, og er uunngåelig nå til dags. 322 millioner tonn plast produseres hvert år, og det anslås at mellom 4,8 og 12,7 millioner tonn av den plasten havner i havet. I havet kan plast brytes ned på grunn av fysiske og kjemiske prosesser, og bli til mikro- og nanoplast (MP og NP). Disse små partiklene (1800 nm). Mens de fleste partiklene hadde en negativ overflateladning, var PS-NH2 positivt ladd i begge de testede mediene. For å teste akutt dødelighet ble krepsdyrene eksponert for forskjellige konsentrasjoner av NP (0, 0,5, 1, 5, 10, 25, 50 og 100 g/ml) i NSW i 48 timer. PS-NH2 viste seg å være den mest giftige partikkelen, med en EC50-verdi på 7,8 g/ml. Denne plastpolymeren ble derfor valgt til videre testing for å bestemme dannelse av reaktive oksygenforbindelser (ROS) som markør for potensielt oksidativt stress og ødeleggelse i organismene. For å oppdage oksidativt stress (ROS-dannelse og lipidperoksidasjon) i krepsdyrene ble en in vivo-metode med fluorescerende prober gjennomført. Krepsdyr ble eksponert for PS-NH2-partikler i flere konsentrasjoner og tre forskjellige fluorescerende prober (DHR123, H2DCFDA og C11-BODIPY) ble tilsatt. Alle de tre probene viste en signifikant økning i fluorescens, sammenlignet med kontrollen, for den høyeste konsentrasjonen som ble testet (100 g/mL), men metoden ble ikke helt optimalisert, og testen må videreutvikles for å oppnå mer pålitelige resultater. Karakteriseringen av partiklene viste at PMMA-COOH og PS-NH2, de polymerene som ikke agglomererer, har størst potensiale til å komme inn i krepsdyrene gjennom inntak på grunn av den lille størrelsen. Det foreslås også at det er den positive overflateladningen til PS-NH2 som øker polymerens toksisitet. Gitt resultatene fra den akutte testen hvor PS-NH2 var den mest dødelige partikkelen som ble testet, og fra det betydelige nivået av fluorescens målt i probetesten, er det mulig at krepsdyr utsatt for PS-NH2 dør på grunn av oksidativt stress dannet inne i organismene.M-MIN
Effect of nanoplastics in the marine organism Tisbe battagliai
No full textPlastic is a material made out of polymer chains derived from oil and gas, and together with additives these polymers have numerous applications. Plastic is used in daily life as wrapping around food, in cosmetics and in clothes, and is inevitable nowadays. However, of all the 322 million metric tons of plastic that are produced annually, between 4.8 and 12.7 million metric tons are estimated to enter the oceans every year. In the oceans, plastic debris can be degraded by physical and chemical processes to micro- and nanoplastics (MP and NP). These small particles ( 1800nm). Whereas most particles displayed a negative surface charge, PS-NH2 was positively charged in both medias. To test acute mortality, copepods were exposed to different concentrations of NPs (0, 0.5, 1, 5, 10, 25, 50 and 100 g/mL) in NSW for 48 hours. PS-NH2 was shown to be the most toxic particle, with an EC50 value of 7.8 g/mL. This particle was therefore chosen for further studies to determine reactive oxygen species (ROS) formation and lipid peroxidation as markers for potential oxidative stress and damage. To detect ROS formation and lipid peroxidation within the copepods, in vivo tests using fluorescent probes were conducted. Copepods were exposed to PS-NH2 in several concentrations and three different fluorescent detecting probes (DHR123, H2DCFDA and C11-BODIPY) were added. All three probes showed a significant rise in fluorescence compared to the control for the highest concentration tested (100 g/mL), but the methods were not successfully optimised and need to be further developed to get more precise results. Suggestions for improvements in the method and future research are proposed to get an enhanced ecotoxicologial assessment of micro- and nanoplastics. Overall, results suggest that the NPs PMMA-COOH and PS-NH2, which do not agglomerate, have the greatest potential of entering the copepods through ingestion because of their small size. Results also suggest that the positive surface charge of PS-NH2 increased the toxicity of the polymer. Given the results from the acute test where PS-NH2 was the most lethal particle tested, and from the significant level of fluorescence measured in the probe test, it is possible that the mortality of copepods exposed to PS-NH2 is caused by oxidative stress formed inside the animals
Developing a workflow for the multi-omics analysis of Daphnia
Get PDFIn the era of multi-omics, making reasonable statistical inferences through data integration is challenged by data heterogeneity, dimensionality constraints, and data harmonization. The biological system is presumed to function as a network where the physical relationships between genes (nodes) are represented by links (edges) connecting genes that interact. This thesis aims to develop a new and efficient workflow to analyse non-model organism multi-omics data for researchers who are entangled in the biology questions by using readily available software tools. The proposed approach was applied to the transcriptome and metabolome data of Daphnia magna under various dose rates of gamma radiation.
The first part of this workflow compares and contrasts the transcriptional regulation of short-and long-term gamma radiation exposure. A group of genes which share a similar expression across different samples under the same conditions are known as modules, because they are likely to be functionally relevant. Modules were identified using WGCNA but biologically meaningful modules (significant modules) were selected through a novel approach that associates genes with significantly altered expression levels as a result of radiation (i.e. differentially expressed genes) with these candidate modules. Dynamic transcriptional regulation was modelled using transcription factor (TF) DNA binding patterns to associate TFs with expression responses captured by the modules. The biological functions of significant modules and their TF regulators were verified with functional annotations and mapped into the proposed Adverse Outcome Pathways (AOP) of D. magna, which describes the key events which contribute to fecundity reduction. The findings demonstrate that short term radiation impacts are entirely different from long term and cannot be used for long term prediction.
The second part investigates the coordination of gene expression and metabolites with differential abundances induced by different gamma dose rates and the underlying mechanisms contributing to the varying extent of the reduction in fecundity. Significant modules which belong to the same design model of dose rates were combined and annotated with new functionality. The abundance of metabolites was also modelled with the same design model. Integrated pathway enrichment analysis was performed to discover and create pathway diagrams for visualising the multi-omics output. Finally, the performance of this workflow on explaining the reduction of fecundity of D. magna, which has not been described in previous studies, has been evaluated. Combining the information from the metabolome and transcriptome data, new insights suggest that the alteration to the cell cycle is the underlying mechanism contributing to the varying reduction of fecundity under the effect of different dose rates of radiation
Giftighet av biocider og blandinger av disse for algen Chlamydomonas reinhardtii
Get PDFAquatic organisms are exposed to several organic compounds including biocides. These
compounds are widely used, for instance as disinfectants, in antifouling paints, or as
material preservatives. Biocides can originate from different sources such as agricultural,
urban and industrial runoff. Their presence in the aquatic environment is cause of
concern, as they can be highly toxic, not only to target, but also to non-target organisms.
Each type of biocide has specific effects according to its mode of action (MoA).
Additionally, they may exist in complex mixtures and affect organisms through combined
toxicity. This study intended to characterise the single and combined effects of five
environmentally relevant biocides, aclonifen, bifenox, dichlofluanid, metribuzin and
triclosan on the unicellular algae Chlamydomonas reinhardtii.
Biocide toxicity was examined by analysing their effects in the freshwater microalgae
through three different toxic endpoints: inhibition of growth, Photosystem II (PSII)
efficiency and formation of Reactive Oxygen Species (ROS). The combined toxicity
assessment was conducted using the concentration (CA) and independent action (IA)
prediction models to analyse if the compounds in a mixture caused toxicity by similar or
dissimilar MoA, respectively. For the compounds/mixtures which MoA and adverse
outcomes were understood, preliminary Adverse Outcome Pathways (AOPs) were
developed to collect, organize and evaluate all the relevant information. The results were
also used to assess the potential environmental risk of the biocides to algae when present
as single chemicals and in mixtures, by using a Risk Quotients (RQs) and Toxic Units
(TUs) approach.
The growth inhibition test allowed verifying the general toxicity of each biocide and of
the mixture with all the compounds. The order of toxic potency was: bifenox>
metribuzin> dichlofluanid> aclonifen> triclosan. The IA model best predicted the
mixture involving all the biocides at 48 h and 72 h, thus suggesting that the compounds
had different MoA. A potential antagonism was observed particularly at 24 h for low to
median effect levels, possible due to the fact that the different compounds required longer
time to propagate the effects to the apical level (growth). In this study, metribuzin,
dichlofluanid, bifenox and triclosan showed a potential risk to algae, although the risk by
dichlofluanid might be overestimated due to lack of adequate exposure information. The
mixture with all the compounds presented a potential environmental risk for algae.
From the 5 tested compounds (aclonifen, bifenox, dichlofluanid, metribuzin and
triclosan), only aclonifen and metribuzin showed effects on the PSII efficiency, with the
first being the most toxic. This effect was correlated with the inhibition of growth,
showing that the inhibition of PSII was the main toxic MoA for these compounds. The
effects of the binary mixture were best described by the IA model, consistent with these
herbicides displaying additive effects by dissimilar MoA. For the growth, IA best fitted
the data in the beginning of exposure, whereas the data was best predicted by CA at
longer exposures. A concentration-dependent deviation from additivity, interpreted as
synergy, was observed for medium to high concentrations of this mixture. While the
single compounds did not present a risk at environmentally relevant concentrations, the
effects of the binary mixture were higher than expected and a potential environmental
risk was identified.
The formation of ROS was a potential MoA for aclonifen and metribuzin; therefore, a
high-throughput assay for ROS detection was used to analyse the 5 compounds
(aclonifen, bifenox, dichlofluanid, metribuzin and triclosan). Among these, only
aclonifen, metribuzin and bifenox induced ROS in a significant and concentrationdependent
manner. The combined effects of the three herbicides were also studied in
binary and ternary mixtures. The best predictions were achieved by the CA model when
testing the ternary mixture and the binary mixture of aclonifen and bifenox at low to
median effect levels, whereas synergism was observed at higher effects levels. The binary
mixture of aclonifen and metribuzin was best predicted by the IA model, while the binary
mixture of bifenox and metribuzin was equally well predicted by the two models. The
combination of ROS formation and inhibition of photosynthesis was proposed to explain
the observed combined effects. The present work demonstrated that C. reinhardtii is a suitable model organism to
evaluate the toxicity of biocides and their mixtures. The applied methods were able to
determine both sublethal and lethal effects of the studied compounds and provided a
better understanding on their MoA. The CA and IA models provided good predictions for
the observed effects of the mixtures of biocides with similar and dissimilar MoA. The
cumulative risk assessment using TUs and RQs based approaches were shown to be an
applicable way for predicting the risk of the biocides mixtures to algae.
The present work has contributed to advance the field of ecotoxicology by providing a
better understanding of the MoA of commonly used biocides, deciphering the combined
toxicity of simple mixtures of these and identifying whether these biocides and their
mixtures represent a risk to algae under ecological relevant exposure scenarios. Given the
limited data available on the studied biocides, the knowledge gathered in the present
work contributed to the characterization of their MoA and ecotoxicological effects in C.
reinhardtii. This information can be integrated to further develop risk assessment tools
for a better understanding and protection of the aquatic environment.Vannlevende organismer er utsatt for en rekke organiske forbindelser, inkludert biocider.
Disse forbindelsene er mye brukt blant annet som desinfeksjonsmidler, i bunnstoff, eller
som konserveringsmidler. Biocider kan stamme fra ulike kilder som landbruk, urban og
industriell avrenning. Deres tilstedeværelse i det akvatiske miljøet er bekymringsverdig
da de kan være svært giftige til målorganismer, men også arter de ikke er utviklet for å
påvirke. Hver type biocid har spesifikke effekter i henhold til sin virkningsmekanisme
(MoA). I tillegg eksisterer disse stoffene i komplekse blandinger og påvirke organismer
gjennom kombinasjonsgiftighet. Dette studiet hadde til hensikt å karakterisere effekten av
enkeltstoffer og blandinger av de fem miljørelevante biocidene aclonifen, bifenox,
diklofluanid, metribuzin og triklosan på den encellede algen Chlamydomonas reinhardtii.
Giftigheten av biocidene ble undersøkt ved å analysere deres effekter på ferskvannsalgen
gjennom tre forskjellige giftighetsmekanismer: hemming av vekst, hemming av
fotosystem II (PSII) effektivitet og dannelse av reaktive oksygenarter (ROS).
Vurderingen av kombinasjonseffekter ble utført ved bruk av prediksjonsmodeller basert
på konsentrasjonaddisjon (CA) og uavhengig samvirkeinteraksjon (IA) for å analysere
om forbindelsene i en blanding skyldes effekten av samme eller ulik
virkningsmekanisme. For forbindelsene/blandinger der MoA og skadeeffekter ble
kartlagt, ble såkalte Adverse Outcome Pathways (AOP) utviklet for å samle, organisere
og vurdere relevant informasjon. Resultatene ble også brukt til å vurdere den potensielle
risikoen av biocidene på alger når tilstede som enkeltstoffer og i blandinger ved hjelp av
beregning av risikokvotienter (RQ) og toksiske enheter (TU).
Testen for veksthemming i alger verifiserte den generelle toksisitet av hvert biocid og
blanding av disse. Giftighetspotensialet til de ulike stoffene var: bifenox> metribuzin>
diklofluanid> aclonifen> triklosan. Modellen for uavhengig samvirkeinteraksjon
predikerte effekten av alle biocidene ved 48 og 72 timer, og antydet at forbindelsene
hadde ulike MoA. En potensiell antagonisme ble observert etter 24 timer eksponering for
lave til intermediære effektnivåer, trolig på grunn av at forbindelsene hadde ulik evne til å gi effekter på organismenivå (vekst hemming). I dette studiet ble det påvist at
metribuzin, diklofluanid, bifenox og triklosan hadde en potensiell risiko i forhold til
alger, selv om risikoen av diklofluanid muligens var overestimert pga. mangel på
tilstrekkelig eksponerings-informasjon. Blandingen med alle forbindelser viste seg å
representere en potensiell miljørisiko for alger.
Av de 5 testede forbindelsene (aclonifen, bifenox, diklofluanid, metribuzin og triklosan)
var det bare aclonifen og metribuzin som ga effekter på PSII effektivitet, der aclonifen
var den mest giftige. Denne effekten viste godt samsvar med veksthemming, som viser at
inhiberingen av PSII var den viktigste MoA for disse forbindelsene. Virkningene av den
binære blandingen ble best beskrevet av IA, noe som var i samsvar med at disse
herbicidene ga additive effekter og hadde ulik MoA. For veksthemming ga IA best
tilpasning til de eksperimentelle data i begynnelsen av eksponeringen, mens CA ga best
tilpasning til effektdataene ved lengre eksponering. Et konsentrasjonsavhengig avvik fra
additivitet, tolket som synergi, ble observert for middels til høye konsentrasjoner av
denne blandingen. Mens de enkelte forbindelser ikke utgjorde en risiko for alger ved
miljørelevante konsentrasjoner, var effekten av den binære blanding høyere enn forventet
og representerte en potensiell miljørisiko for algene.
Dannelsen av ROS er en potensiell MoA for aclonifen og metribuzin og medførte at et
høy-kapasitetsassay for deteksjon av ROS ble brukt for å analysere effekten av de 5
forbindelsene (aclonifen, bifenox, diklofluanid, metribuzin og triklosan). Av disse
biocidene var det bare aclonifen, bifenox og metribuzin som indusert ROS på en
signifikant og konsentrasjonsavhengig måte. Samvirkeeffekten av de tre herbicidene ble
også undersøkt i binære og ternære blandinger. De beste prediksjonene ble oppnådd ved
bruk av CA modellen for den ternære (alle tre stoffene) og binære blandingen av
aclonifen og bifenox med lav til intermediære effektnivåer, mens synergisme ble
observert ved høyere effekternivåer. Den binære blanding av aclonifen og metribuzin ble
beste predikert av IA-modellen, mens den binære blanding av bifenox og metribuzin var
predikert like godt av de to modellene. Ble foreslått at en kombinasjon av ROS dannelse
og inhibering av fotosyntesen kunne forklare de observerte blandingseffektene. Dette arbeidet viste at C. reinhardtii er en velegnet modellorganisme for å vurdere
giftigheten av biocider og deres blandinger. De anvendte metodene var i stand til å
bestemme både subletale og letale effekter av forbindelsene testet og ga en bedre
forståelse av deres MoA. CA og IA-modellene ga gode prediksjoner av de observerte
blendingseffektene med lik og ulik MoA. Den kumulative risikovurdering ved bruk av
TUs og RQs baserte tilnærminger viste seg å være en relevant måte å forutsi
miljørisikovurdering av biocidblandinger.
Dette arbeidet har bidratt til å utvikle økotoksikologisk forskning ved å gi en bedre
innsikt i MoA til vanlig anvendte biocider, avdekke sammenhengen om
kombinasjonseffekter av enkle blandinger av disse, og identifisere hvorvidt disse
biocidene og deres blandinger utgjør en risiko for alger under økologisk relevante
eksponeringssituasjoner. Gitt den begrensede datatilgjengeligheten for disse biocidene
har kunnskap samlet i dette arbeidet bidratt til karakterisere deres MoA og undersøke
økotoksikologiske effekter i C. reinhardtii. Denne informasjonen kan samlet benyttes til
å videreutvikle risikovurderingsverktøy og dermed bedre både kunnskapen om risiko og
vern av organismer i det akvatiske miljøet
Metal mixtures, assessing speciation models to predict uptake in Brown Trout (Salmo trutta)
Get PDFAlum shale is an organic-rich rock which contains high concentrations of U, Ni, V, Mo, Co, Cu, Zn, As and other metals. These metals are released into the environment by human actives and rock weathering. Many different metals can be found in water as a mixture that can be taken up by aquatic organisms and cause adverse effects and harm.
Uptake of metal mixtures by fish is a complex process that depends on several factors such as pH, temperature, water hardness, element species, the presence of dissolved organic carbon and others. To predict the uptake of metals by fish, computer models like WHAM 7 and Visual Minteq 3.1 are used. These computer models attempt to describe the complex behavior of metals in water, while considering their chemical speciation, charge, amount and complexation with organic matter. The simulated amount of bounded metals to the fish gill was compared to other prediction methods such as free-ion concentration and total metal concentration.
In this project WHAM 7 and Visual Minteq 3.1, developed to predict metal binding to fulvic acid and humic acid, were used to predict metal binding to a fish gill from the assumption that a gill has similar metal binding properties as humic acid. The input data used in both models was obtained from leeched alum shale samples taken from a tunnel and road construction site in Norway as part of the NORWAT research.
This master thesis has focused on U, Sr, Cd, Ni and V. From the results we see that the metal mixture approach from these models adjusts better to reality than the freeion concentration or the total metal concentration approaches. WHAM predicted better for Cd, Ni and V, meanwhile Minteq gave better results for U and Sr. Both WHAM and Minteq predicted more than 50% lower ratios, compared to the free-ion concentration and the total metal concentration. Further model development and model adjustments are needed to improve the predicted metal uptake by fish. Both models performed good, considering that they were not designed as an estimation tool for metal uptake to aquatic organisms.acceptedVersionM-RA
Innvirkning av tilstandsform og opptak på giftighet av metaller enkeltvis og i blandinger på den marine kopeboden Tisbe battagliai
Get PDFIn coastal waters a wide variety of metals are present in different physicochemical forms (low molecular mass species, colloids, aggregates, or particulate metal), usually as mixtures of different metals. High risk of pollution in estuarine/brackish water makes the studies of coastal ecosystem very important. In coastal areas, metal speciation can change with salinity that further influences the exposure and uptake of metals to aquatic organisms. Ionic metal species are known to be more bioavailable than metals existing as colloids and particulates. Both metal ions and high molecular metal species can enter coastal water with freshwater.
As toxic effects of metals depend strongly upon bioaccumulation, there is a need to assess the bioavailability of different metal species, including particulates. Filtering organisms such as copepods are small crustaceans that are an important part of the zooplankton and important grazers for other marine species such as fish. Due to their coastal ecology, they are continuously exposed to different concentrations and size fractions of trace metals at different salinities. Despite their high relevance in the marine ecosystem, studies with filter-feeders have concentrated mainly on acute lethal responses of metal ions without taking into account other metal species and their possible bioaccumulation.
Thus, the main objective of the present PhD project was to obtain the knowledge about speciation (size distribution), bioavailability (body burden) and toxic effects of common marine metal pollutants: Cu, Al, Zn and Ni as single stressors and in their binary mixtures to the marine copepod Tisbe battagliai. This was achieved experimentally by i) identifying the impact of particulate and ionic metal species on bioavailability and uptake to the filter feeding copepod, ii) comparing the toxicity of selected trace metals, iii) linking the determined whole-body concentration to toxic effects. Moreover, observed toxic effects of binary mixtures were compared with additivity-based models: concentration addition (CA) and independent action (IA). The linkage between speciation, uptake and toxicity of metals and impact of salinity were studied and assessed in Paper 1, whereas size distribution, uptake and combined toxicity of metals in binary mixtures were studied in Paper 2 and 3.I kystvann er metaller til stede i forskjellige fysisk - kjemiske tilstandsformer, som lavmolekylære, kolloider, partikler etc., ofte i blandinger av flere metaller som påvirker metall tilstandsformene. Marine kystnære økosystemer er spesielt utsatt på grunn av høy risiko for metall forurensning i estuarier og brakkvannsområder. I vann kan metall tilstandsformene påvirkes av saltholdighet som igjen påvirker eksponeringen og opptaket av metaller i vannlevende organismer. Metall ioner er generelt antatt å være mer biotilgjengelig enn kolloidale og partikulære tilstandsformer av metall. Både metall ioner og høymolekylære metall tilstandsformer kan transporteres med ferskvann til kystvann.
Ettersom gifteffekten av metaller er sterkt avhengig av bioakkumulering, er det nødvendig å ha kunnskap om biotilgjengeligheten til ulike metal tilstandsformer, inkludert partikulære metall tilstandsformer. Filtrerende organismer som kopepoder er små krepsdyr som er en viktig del av dyreplanktonet og viktige beitedyr for andre marine arter som fisk. Kopepoder er vanlig forekommende i kystnære økosystem hvor de blir kontinuerlig eksponert for metaller i ulike konsentrasjoner og tilstandsformer ved varierende saltholdighet. Til tross for at filterorganismer har en sentral rolle i det marine økosystemet, har økotoksikologiske studier hovedsakelig fokusert på akutte effekter av metall ioner i vannet uten å ta hensyn til andre metall tilstandsformer og bioakkumulering.
Det overordnede målet med dette doktorgradsprosjektet var å få kunnskap om tilstandsformer (metallstørrelsesfordeling), biotilgjengelighet (kroppskonsentrasjon) og gifteffekten av vanlig forekommende metall forurensninger: Cu, Al, Zn og Ni enkeltvis og i binære kombinasjoner i eksponeringsløsninger for den marine kopepoden Tisbe battagliai. Dette ble oppnådd eksperimentelt ved å: i) identifisere biotilgjengeligheten og opptak av LMM og partikulære metall tilstandsformer i den filtrende kopepoden, ii) sammenligne gifteffekten av de utvalgte spormetallene og iii) bestemme og knytte helkropps konsentrasjonen til gifteffekt. I tillegg, ble kombinasjonseffekter av binære metall blandinger sammenlignet med additive interaksjonsmodeller: konsentrasjonsaddisjon (CA) og uavhengig respons addisjon (IA). Sammenhengen mellom tilstandsformer, opptak og gift effekt av metaller, og betydning av saltholdighet på dette var studert og vurdert i Paper 1, mens tilstandsform, opptak og blandingsgiftighet av metaller i binære blandinger var studert i Paper 2 og 3.NIVA ; CERA
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