| 1. |
- Kunce, Warren, et al.
(författare)
-
Combination effects of pyrethroids and neonicotinoids on development and survival of Chironomus riparius
- 2015
-
Ingår i: Ecotoxicology and Environmental Safety. - : Elsevier BV. - 0147-6513 .- 1090-2414. ; 122, s. 426-431
-
Tidskriftsartikel (refereegranskat)abstract
- Standard ecotoxicological risk assessments are conducted on individual substances, however monitoring of streams in agricultural areas has shown that pesticides are rarely present alone. In fact, brief but intense pulse events such as storm water runoff and spray drift during application subject freshwater environments to complex mixtures of pesticides at high concentrations. This study investigates the potential risks to non-target aquatic organisms exposed to a brief but intense mixture of the neonicotinoid pesticides imidacloprid and thiacloprid and the pyrethroid pesticides deltamethrin and esfenvalerate, compared to single substance exposure. All four of these pesticides have been detected in surface waters at concentrations higher than benchmark values and both classes of pesticides are known to exert adverse effects on non-target aquatic organisms under single substance exposure scenarios. First instar midge larvae of the non-target aquatic organism, Chironomus riparius, were exposed to combinations of these four pesticides at 50% of their LC50 (96 h) values in a 1 h pulse. They were then reared to adulthood in uncontaminated conditions and assessed for survival, development time and fecundity. Our results show that the risk of disruption to survival and development of non-target aquatic organisms under this scenario is not negligible on account of the significant increases in mortality of C. riparius found in the majority of the pesticide exposures and the delays in development after pyrethroid exposure. While none of the deleterious effects appear to be amplified by combination of the pesticides, there is some evidence for antagonism. No effects on fecundity by any of the pesticide treatments were observed.
|
|
| 2. |
- Kunce, Warren, et al.
(författare)
-
Combined effects of microplastics and a pyrethroid on the benthic invertebrate, Chironomus Riparius
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- There is growing evidence of widespread contamination of freshwater ecoystems with microplastics, plastic polymers that are < 5 mm. While a wide variety of organisms have been reported to ingest microplastics, the biological effects of chronic microplastic ingestion are not well understood. Microplastics can adsorb organic pollutants in aqueous environments which made lead to increased exposure to these chemicals if desorption occurs after ingestion. Alternatively, relatively clean microplastics may adsorb chemicals in the gut decreasing their bioavailability. This study investigates the effects of chronic sediment exposure to latex-based polystyrene microspheres alone and in combination with the pyrethroid pesticide, esfenvalerate, on the life-history traits of the benthic invertebrate, Chironomus riparius, under two scenarios: abundant food and limited food. We found that chronic sediment exposure to 1.0 and 10.0 µm latex-based polystyrene latex microspheres, a low concentration of esfenvalerate and a combination of the 1.0 µm microspheres and esfenvalerate led to no significant effects on survival, development time, emergence, or sex of C. riparius when food was abundant. However, effects of exposure did become apparent when food was insufficient indicating that these contaminants may be stressors with an energy cost to the organism.
|
|
| 3. |
- Kunce, Warren, et al.
(författare)
-
Effects of acute antihistamine exposure on thermal tolerance and behaviour in the freshwater snail, Planorbarius corneus
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Antihistamine pollutants have the potential to interfere with the normal functioning of aquatic organisms due to their intentionally bio-active nature. Histamine is a neurotransmitter present in multiple tissues in both vertebrates and invertebrates and histaminergic pathways have been identified in the thermoregulatory processes of invertebrates. Disruption of normal histamine functioning via exposure to the widespread antihistamine pollution observed in fresh waters may induce a range of sub-lethal effects on aquatic invertebrates including thermoregulatory and behavioural changes. We conducted three experiments exposing freshwater snails (Planorbarius corneus) to the antihistamine, diphenhydramine, for 24 hours then evaluating thermal tolerance, temperature preference and righting time. Diphenhydramine was found to increase thermal tolerance and righting time, but did not affect temperature preference. These results warrant further investigation into the biological effects of antihistamines on aquatic wildlife as well as altered thermal tolerance and thermoregulation as relevant toxicological endpoints in ecotoxicological risk assessment of pharmaceuticals.
|
|
| 4. |
- Kunce, Warren, et al.
(författare)
-
Single and mixture impacts of two pyrethroids on damselfly predatory behavior and physiological biomarkers
- 2017
-
Ingår i: Aquatic Toxicology. - : Elsevier. - 0166-445X .- 1879-1514. ; 190, s. 70-77
-
Tidskriftsartikel (refereegranskat)abstract
- Direct mortality due to toxicity of single pesticide exposure along a concentration gradient, while the most common, is only one important parameter for assessing the effects of pesticide contamination on aquatic ecosystems. Sub-lethal toxicity can induce changes in an organism's behavior and physiology that may have population -level ramifications and consequences for ecosystem health. Additionally, the simultaneous detection of multiple contaminants in monitored watersheds stresses the importance of gaining a greater understanding of the toxicities of combined exposures, particularly at low, environmentally relevant concentrations. Using larvae of the Azure Damselfly (Coenagrion paella), we conducted a combined exposure investigation of two widely-used pyrethroid insecticides presumed to share the same neurotoxic mechanism of action, and estimated their effect on predatory ability, mobility and three physiological biomarkers (Glutathione S-transferase; GST, respiratory electron transport system; ETS, and malondialdehyde; MDA). Deltamethrin exposure (0.065 mu g/L and 0.13 mu g/L) was found to reduce the predatory ability, but it did not affect the larvae's mobility. Esfenvalerate exposure (0.069 mu g/L and 0.13 mu g/L), on the other hand, induced no significant changes in predatory ability or mobility. The decrease in predatory ability after the combination exposure (0.067 mu g/L deltamethrin and 0.12 mu g/L. esfenvalerate) did not significantly differ from the impact of the single deltamethrin exposures. Glutathione-S-transferase was induced after single esfenvalerate exposure and the lower deltamethrin concentration exposure, but seemingly inhibited after exposure to the higher concentration of deltamethrin as well as the combination of both pyrethroids. Our data indicate that sub-lethal exposure to deltamethrin reduces predatory ability and suggest that sub-lethal combined exposure to deltamethrin and esfenvalerate inhibits the GST detoxification pathway. These effects can eventually result in a lower emergence of adults from contaminated ponds.
|
|
| 5. |
- Kunce, Warren
(författare)
-
Sub-lethal Effects of Anthropogenic Contaminants on Aquatic Invertebrates
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Anthropogenic contaminants are considered to play a substantial role in the decline of freshwater invertebrate diversity. Sub-lethal effects of many of these contaminants on behaviour and life-history traits of aquatic invertebrates may contribute to their decline. As contaminants are rarely present in the environment alone, the effects of mixture exposures are highly relevant in assessing the risk these substances pose to the biota. This thesis focuses on sub-lethal effects of exposure to aquatic pollutants, separately and in combination, on fresh-water invertebrates. To investigate the single and combined effects of pesticides, larvae of the midge, Chironomus riparius were exposed to a 1 hour pulse of two neonicotinoids and two pyrethroids. This short exposure to environmentally relevant concentrations of pesticides decreased the survival and delayed development in C. riparius. The combination of neonicotinoids and pyrethroids did not produce synergistic effects; however, there was some indication of antagonism. Additionally, larvae of the damselfly, Coenagrion puella, were exposed for 14 hours to two environmentally relevant concentrations of pyrethroid pesticides, alone and in combination. Exposure to the pyrethroid, deltamethrin, reduced the larvae’s predatory ability. Combined exposure to both deltamethrin and esfenvalerate inhibited the Glutathione S-transferase detoxification pathway and may have additive toxic effects on the larvae’s predatory ability. Microplastics are increasingly gaining attention as an aquatic pollutant of major concern with respect to the toxicity of the microplastics themselves as well as their capacity to adsorb persistent organic pollutants like pesticides. To investigate the effects of microplastics and a pyrethroid, alone and in combination, C. riparius larvae were raised in sediment spiked with two sizes of polystyrene-based latex microbeads and an environmentally relevant concentration of esfenvalerate under normal and food-restricted conditions. Exposure to both sizes of microplastics and esfenvalerate lead to equally decreased emergence under food-restricted conditions. Additionally, exposure to esfenvalerate led to decreases in survival when food was scarce that did not occur when microplastics were co-present. Antishistamines are also an emerging aquatic contaminant of concern with very little known about their biological effects on aquatic wildlife. Antihistamines could potentially interfere with the histaminergic pathways and thus affect thermal tolerance and temperature preference in aquatic invertebrates. The freshwater snail, Planorbarius corneus, was exposed for 24 hours to the antihistamine, diphenhydramine. This exposure increased thermal tolerance and righting time, but did not affect temperature preference. The results of the investigation suggest that anthropogenic contaminates alone and/or in combination have sub-lethal effects on life history, behavior and physiology of aquatic invertebrates. Such sub-lethal effects have the potential to affect populations and community structure in the aquatic and terrestrial environment.
|
|
| 6. |
- Varg, Javier Edo, 1988-, et al.
(författare)
-
Microplastic exposure across trophic levels : effects on the host microbiota of freshwater organisms
- 2022
-
Ingår i: Environmental Microbiome. - : Springer Nature. - 2524-6372. ; 17:1
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundMicroplastics are a pervasive pollutant widespread in the sea and freshwater from anthropogenic sources, and together with the presence of pesticides, they can have physical and chemical effects on aquatic organisms and on their microbiota. Few studies have explored the combined effects of microplastics and pesticides on the host–microbiome, and more importantly, the effects across multiple trophic levels. In this work, we studied the effects of exposure to microplastics and the pesticide deltamethrin on the diversity and abundance of the host–microbiome across a three-level food chain: daphnids–damselfly–dragonflies. Daphnids were the only organism exposed to 1 µm microplastic beads, and they were fed to damselfly larvae. Those damselfly larvae were exposed to deltamethrin and then fed to the dragonfly larvae. The microbiotas of the daphnids, damselflies, and dragonflies were analyzed.ResultsExposure to microplastics and deltamethrin had a direct effect on the microbiome of the species exposed to these pollutants. An indirect effect was also found since exposure to the pollutants at lower trophic levels showed carry over effects on the diversity and abundance of the microbiome on higher trophic levels, even though the organisms at these levels where not directly exposed to the pollutants. Moreover, the exposure to deltamethrin on the damselflies negatively affected their survival rate in the presence of the dragonfly predator, but no such effects were found on damselflies fed with daphnids that had been exposed to microplastics.ConclusionsOur study highlights the importance of evaluating ecotoxicological effects at the community level. Importantly, the indirect exposure to microplastics and pesticides through diet can potentially have bottom-up effects on the trophic webs.
|
|
| 7. |
- Varg, Javier Edo, 1988-, et al.
(författare)
-
Single and combined effects of microplastics, pyrethroid and food resources on the life-history traits and microbiome of Chironomus riparius
- 2021
-
Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 289
-
Tidskriftsartikel (refereegranskat)abstract
- There is growing evidence of widespread contamination of freshwater ecosystems with microplastics. However, the effects of chronic microplastic ingestion and its interaction with other pollutants and stress factors on the life history traits and the host-microbiome of aquatic invertebrates are not well understood. This study investigates the effects of exposure to sediment spiked with 1 mu m polystyrene-based latex microplastic spheres, an environmentally realistic concentration of a pyrethroid pesticide (esfenvalerate), and a combination of both treatments on the life-history traits of the benthic-dwelling invertebrate, Chironomus riparius and its microbial community. The chironomid larvae were also exposed to two food conditions: abundant or limited food in the sediment, monitored for 28 and 34 days respectively. The microplastics and esfenvalerate had negative effects on adult emergence and survival, and these effects differed between the food level treatments. The microbiome diversity was negatively affected by the exposure to microplastics, while the relative abundances of the four top phyla were significantly affected only in the high food level treatment. Although the combined exposure to microplastics and esfenvalerate showed some negative effects on survival and emergence, there was little evidence for synergistic effects when compared to the single exposure. The food level affected all life-history traits and the microbiota, and lower food levels intensified the negative effects of the exposure to microplastics, esfenvalerate and their combination. We argue that these pollutants can affect crucial life-history traits such as successful metamorphosis and the host-microbiome. Therefore, it should be taken into consideration for toxicological assessment of pollutant acceptability. Our study highlights the importance of investigating possible additive and synergic activities between stressors to understand the effects of pollutants in the life story traits and host-microbiome.
|
|
