| 1. |
- Woin, Per, 1958-, et al.
(författare)
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Effects of metsulfuron methyl and cypermethrin exposure on freshwater model ecosystems
- 2003
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Ingår i: Aquatic Toxicology. - Amsterdam : Elsevier. - 0166-445X .- 1879-1514. ; 63:3, s. 243-256
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the short-term (2 weeks) effects of the herbicide metsulfuron methyl alone and in combination with the insecticide cypermethrin in freshwater enclosures (80 l). We used a factorial design with four levels of herbicide (0, 1, 5, 20 mg/l) and two levels of insecticide (0 and 0.05 mg/l). The root growth of the macrophyte species Elodea canadensis and Myriophyllum spicatum decreased following exposure to the lowest concentration of metsulfuron methyl tested. Metsulfuron methyl exposure resulted in a decreased pH in the aquatic enclosure at the lowest concentration tested, which is most likely a further indication of decreased macrophyte primary production. The biomass of periphytic algae growing on the leaves of M. spicatum increased in the enclosures exposed to metsulfuron methyl. The species composition of the periphytic algae differed significantly from the controls in the enclosures exposed to 20 mg/l of the herbicide. The increased biomass of periphytic algae on the leaves of the macrophytes is probably an indirect effect of the herbicide exposure. The exposure to metsulfuron methyl possibly induced a leakage of nutrients from the macrophyte leaves, which promoted an increased algal growth. The exposure to metsulfuron methyl did not alter the biomass or the species composition of the phytoplankton community. The zooplankton communities in the enclosures were dominated by rotifers, which were not affected by the exposure to cypermethrin. However, a cypermethrin exposure of 0.05 mg/l initially decreased the abundance of copepod nauplii. Ten days after exposure, the abundance of nauplii was significantly higher in the insecticide-exposed enclosures compared with the non-exposed enclosures. This might be an indication of a sub-lethal stress response, which either increased the number of offspring produced or induced an increased hatching of copepod resting stages. No combined effects of the herbicide and insecticide exposure, either direct or indirect, were observed in the enclosure study. Significant effects on the macrophytes were observed following exposure to 1 mg metsulfuron methyl per litre in the enclosure study. Furthermore, a single species laboratory assay indicated that the shoot elongation of E. canadensis decreased following exposure to ]/0.1 mg metsulfuron methyl per litre. These concentrations are well within the range of expected environmental concentrations, thus this study shows that aquatic ecosystems, in particular those which are macrophyte- dominated, may be affected by metsulfuron methyl at concentrations that may well occur in water bodies adjacent to agricultural land.
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| 2. |
- Woin, Per, 1958-, et al.
(författare)
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Effects of the pyrethroid insecticide cypermethrin on a freshwater community studied under field conditions : II. Direct and indirect effects on the species composition
- 2003
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Ingår i: Aquatic Toxicology. - Amsterdam : Elsevier. - 0166-445X .- 1879-1514. ; 63:4, s. 373-389
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Tidskriftsartikel (refereegranskat)abstract
- The effects of cypermethrin, a commonly used pyrethroid insecticide, were studied in small in situ enclosures situatedin an eutrophic lake over an 11-day period. The experimental design used a regression principle that included threeuntreated controls and a gradient of six unreplicated cypermethrin concentrations, ranging from 0.01 to 6 mg/l. Thispaper is the second in a series of two and describes the effects on the species composition of the crustacean, rotifer,periphyton and phytoplankton communities. Multivariate ordination technique (redundancy analysis (RDA) combinedwith Monte Carlo permutation tests) showed that exposure to cypermethrin caused significant changes in the speciescomposition of the communities. Changes in the structure of the communities were observed following exposure to anominal concentration of 0.13 mg cypermethrin per litre above. The direct acute effect of exposure to cypermethrin wasa rapid decrease of many species of crustacean zooplankton. The alterations in crustacean species composition wereprobably due to variations in susceptibility to the direct toxic effects of cypermethrin. No effects concentration (NEC)for individual zooplankton species were calculated using inverse regression and revealed that copepod nauplii were themost sensitive (NEC /0.01 mg/l) of the crustacean groups examined. The observed alterations of the speciescomposition of the autotrophic communities as well as of the rotifers were most likely caused indirectly bycypermethrin, mediated through the direct negative effects of the insecticide on the crustacean grazers. The results ofthis experiment provide further knowledge about the direct and indirect effects of pesticide stress on the ecosystem level.They also show that there is a variation in sensitivity between different species of zooplankton under natural conditionsand thus exemplify the necessity of multispecies approaches in the risk assessment of pesticides.
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| 3. |
- Woin, Per, 1958-, et al.
(författare)
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Effects of the pyrethroid insecticide, cypermethrin, on a freshwater community studied under field conditions : I. Direct and indirect effects on abundance measures of organisms at different trophic levels.
- 2003
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Ingår i: Aquatic Toxicology. - Amsterdam : Elsevier. - 0166-445X .- 1879-1514. ; 63:4, s. 357-371
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Tidskriftsartikel (refereegranskat)abstract
- The effects of the pyrethroid insecticide cypermethrin on a natural freshwater community were studied in small in situenclosures over an 11-day period. The experiment was conducted in a eutrophic lake using a regression design thatincluded three untreated controls and a gradient of six unreplicated cypermethrin concentrations, ranging from 0.01 to6.1 mg/l. This paper is the first in a series of two, and describes the fate of cypermethrin and its effects on the abundanceof crustaceans, rotifers, protozoans (cilliates and heterotrophic nanoflagellates (HNF)) and bacteria and the biomass ofperiphytic and planktonic algae. The concentration of cypermethrin decreased quickly during the experiment, with ahalf-life of 48 h for the total and 25 h for the dissolved fractions of cypermethrin, respectively. Cypermethrin proved tobe acutely toxic to crustaceans in enclosures receiving nominal cypermethrin concentrations of ]/0.13 mg/l. No EffectConcentration (NEC) and median Effect Concentration (EC50) for the total crustacean community and cladoceran andcopepod subgroups ranged between 0.02 /0.07 and 0.04 /0.17 mg/l, respectively, with copepods being less sensitive thancladocerans. The abundance of rotifers, protozoans and bacteria and the chlorophyll-a concentration of planktonic andperiphytic algae was significantly related to the concentration of cypermethrin. All groups proliferated within 2 /7 daysafter the cypermethrin application in those enclosures where the abundance of crustaceans was seriously affected bycypermethrin (i.e. ]/0.13 mg/l). We hypothesise that the proliferation of rotifers, protozoans, bacteria and algae was dueto a reduced grazer control from crustaceans and thereby mediated indirectly by cypermethrin. The results of thisexperiment provide knowledge on how an entire microplankton community may respond to pyrethroids in nature, andthe indirect effects observed on the community clearly demonstrates the necessity of multispecies field experiments inecotoxicological risk assessment
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| 4. |
- Bjerselius, R, et al.
(författare)
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Male goldfish reproductive and physiology are severely affected by exogenous exposure to 17b-estradiol
- 2001
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Ingår i: Aquatic Toxicology. - 0166-445X .- 1879-1514. ; 53:2, s. 139-152
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Tidskriftsartikel (refereegranskat)abstract
- Mature male goldfish were exposed to different concentrations of the natural hormone 17beta-estradiol (E2). Two methods of exposure were employed, via ingestion at 0, 1, 10 and 100 microg/g food and via the water at 0, 1 and 10 microg/l. The fish were exposed for 24-28 days during the spawning period. The males were then paired with an artificially induced, spawning female and their sexual behaviour was observed during a 15 min period. The physiological status of the fish was also examined with respect to GSI, presence of milt and spawning tubercles and the blood plasma concentration of E2. Despite the relatively short exposure period, exposure to physiological levels of E2 was shown to severely affect the male goldfish reproductive behaviour and physiology. In conclusion, the results from this study and the ability to interpret the effects on this well-studied species, show that the effects of E2, and possibly other estrogenic EDCs, have severe effects at several vital levels of male goldfish reproduction. The results also suggests that the hormone E2 can act as an endocrine disrupting chemical (EDC) in the environment.PMID: 11311390 [PubMed - indexed for MEDLINE]
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| 5. |
- Bjerselius, Rickard, et al.
(författare)
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Male goldfish reproductive behaviour and physiology are severely affected by exogenous exposure to 17 beta-estradiol
- 2001
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Ingår i: Aquatic Toxicology. - 0166-445X .- 1879-1514. ; 53:2, s. 139-152
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Tidskriftsartikel (refereegranskat)abstract
- Mature male goldfish were exposed to different concentrations of the natural hormone 17 beta -estradiol (El). Two methods of exposure were employed, via ingestion at 0, 1, 10 and 100 ug/g food and via the water at 0, 1 and 10 mug/l. The fish were exposed fur 74-28 days during the spawning period. The males were then paired with an artificially induced, spawning female and their sexual behaviour was observed during a 15 min period. The physiological status of the fish was also examined with respect to GSI. presence of milt and spawning tubercles and the blood plasma concentration of E-2. Despite the relatively short exposure period. exposure to physiological levels of E-2 was shown to severely affect the male goldfish reproductive behaviour and physiology. In conclusion, the results from this study and the ability to interpret the effects on this well-studied species, show that the effects of E-2, and possibly other estrogenic EDCs have severe effects at several vital levels of male goldfish reproduction. The results also suggests that the hormone E-2 can act as an endocrine disrupting chemical (EDC) in the environment.
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| 6. |
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| 7. |
- Skarpheoinsdottir, H, et al.
(författare)
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Tissue differences, dose-response relationship and persistence of DNA adducts in blue mussels (Mytilus edulis L.) exposed to benzo[a]pyrene
- 2003
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Ingår i: Aquatic Toxicology. - 0166-445X .- 1879-1514. ; 62:2, s. 165-177
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Tidskriftsartikel (refereegranskat)abstract
- Baltic Sea blue mussels Mytilus edulis) were experimentally exposed to the genotoxic model substance benzo[a]pyrene (B[a]P) to study DNA adduct formation. The specific aims were (a) to examine where in the mussels the DNA adducts were formed, in gills or digestive glands (b) to study the dose-response relationship between B[a]P exposure and DNA adduct formations and (c) to examine the persistence of the formed adducts. A Scope for growth (SFG) study was also run to compare physiological responses of the mussels with the degree of DNA adduct formation. In an initial dose-response experiment, the mussels were exposed to 0.5, 50, and 100 mug/l of tritium labelled B[a]P under semi-static conditions for 4 days, and thereafter the bioaccumulation of B[a]P and DNA adduct formation in different tissues was determined using liquid scintillation counting and P-32-postlabelling analysis. respectively. In a following exposure-depuration experiment, mussels were exposed to 17 mug/l of radiolabelled B[a]P under semi-static conditions for 6 days. B[a]P accumulation and DNA adduct formation were determined during the exposure, and B[a]P elimination and persistence of DNA adducts were studied during 28 days of depuration in uncontaminated water, The results revealed large tissue differences in DNA adduct formation. DNA adduct levels were not elevated in the digestive gland of the mussels at any exposure concentration (0-100 mug/l). even though the highest B[a]P tissue concentrations were found in the digestive gland (1.0+/-0.1 mg B[a]P/g tissue dry wt at 100 mug/l, mean+/-SE. n = 12). DNA adducts were on the other hand formed in the gills, with the highest levels found in mussels exposed to 50 and 100 mug B[a]P/l. and a dose dependent increase in adduct levels (from 1.6 to 5.9 nmol adducts/mol nucleotides) from 0 to 50 mug B[a]P/l, In gills, DNA adduct levels increased with time during the 6-day exposure period in the exposure-depuration experiment, and then persisted for at least 2 weeks after exposure cessation while B[a]P tissue levels exhibited a rapid decrease (half-life of 8 days). No significant differences were observed in SFG between the control and exposed groups. Since DNA adducts exhibited a relatively high persistence in gills compared to B[a]P tissue concentrations, they seem to be a more integrated measure of genotoxic exposure than only chemical analysis of the contaminant bioaccumulation. The results also suggest that if using analysis of DNA adducts in H. edulis for monitoring purposes. analysis of gills in addition to the more commonly used digestive gland should be taken into consideration.
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| 8. |
- Tedengren, Michael, et al.
(författare)
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Heat pretreatment increase cadmium resistance and HSP 70 levels in Baltic Sea mussels
- 2000
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Ingår i: Aquatic Toxicology. - 0166-445X .- 1879-1514. ; 48:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- The effects of heat treatment and cadmium exposure on the synthesis of a major stress inducible protein (hsp 70) and on the metabolism of the blue mussel Mytilus edulis L. from the Baltic Sea, were studied in a laboratory experiment. The mussels were kept in sea water of ambient salinity (6.3‰) and temperature (4°C). The effects of cadmium (20 μg l−1), measured as changes in physiological rates (oxygen consumption, ammonia excretion, clearance rates and scope for growth) and hsp 70 expression were studied at 4°C and in combination with a rapid rise in temperature to 20°C. Relatively low levels of hsp 70 were detected but the negative effect was reflected in a reduction of scope for growth of the exposed mussels compared to controls. This effect was more pronounced at 20°C. Mussels not exposed to cadmium in the first experiment were used in a second set of experiments. Heat shocked mussels were allowed to reacclimatise to 4°C for 5 days and then, along with the mussels already at 4°C, exposed to cadmium (20 μg l−1). The results clearly indicated that the mussels exposed to 20°C in the first experiment more rapidly induced synthesis of hsp 70 after cadmium exposure in the second experiment. Also the reacclimatised mussels exposed to heat shock but not to cadmium in the first experiment, induced some hsp 70 in the second experiment. This suggests that the rate of induction of heat shock or stress proteins in Baltic mussels is slower than what has been described for mussels from more marine environments. The mussels kept at 4°C throughout the experiment and exposed to cadmium showed low levels of hsp 70, again indicating a low rate of induction. The increasing levels of hsp 70 correlated well with a maintained level of physiological fitness, in terms of scope for growth, although the mussels showed increasing body burdens of cadmium.
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| 9. |
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| 10. |
- Arrhenius, Åsa, 1973, et al.
(författare)
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Predictability of the mixture toxicity of 12 similarly acting congeneric inhibitors of photosystem II in marine periphyton and epipsammon communities
- 2004
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X. ; 68:4, s. 351-367
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Tidskriftsartikel (refereegranskat)abstract
- Testing of single chemicals with single species is common ecotoxicological practice in contrast to contaminated environments where highly diverse biological communities are exposed to highly diverse mixtures of chemical compounds. We, therefore, investigated whether mixture toxicity approaches that have been used successfully for single species, might also be applied on a community level of biological complexity. Twelve inhibitors of photosystem II, selected by QSAR and chemometrical approaches as the structurally most similar from a congeneric group of phenylurea herbicides, were tested singly and as mixtures on two types of marine microalgal communities, periphyton and epipsammon. Inhibition of photosynthesis was measured in short-term tests using incorporation of radiolabelled carbon (14C) to estimate photosynthetic rates. Two basic concepts, concentration addition (CA) and independent action (IA), were used to predict the toxicities of the mixtures. Congeneric and similar-acting substances such as the phenylureas are expected to comply with CA rather than IA. The aim of the present study was to evaluate whether these concepts can be used to predict mixture toxicity also to periphyton and epipsammon photosynthesis, i.e. at the level of natural communities. We found that deviations between observed and predicted mixture toxicity were relatively small but that CA predictions were the more accurate ones. The predictions proved to be robust, when based on single substance information even from different seasons, years, and sites. We conclude that the concept of CA for predicting mixture toxicity applies also at the community level of algal testing; at least when a physiological short-term effect indicator is used that matches the mechanism of action of the substances
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