Effects of river water and salinity on the toxicity of deltamethrin to freshwater shrimp, cladoceran, and fish

Deltamethrin is a pyrethroid insecticide used extensively to control invertebrate pests on cotton and other crops. It is acutely toxic to nontarget aquatic organisms, but existing toxicity data are mostly from toxicity tests using purified laboratory water that differs greatly from the turbid, high-conductivity rivers in the cotton-growing regions of Australia. The aim of this study was to determine whether the water quality variables conductivity, suspended particles, and dissolved organic matter alter the toxicity of deltamethrin to freshwater crustaceans and a fish. We tested three Australian native species: a cladoceran (Ceriodaphnia cf. dubia), a freshwater shrimp (Paratya australiensis), and larvae of the eastern rainbow fish (Melanotaenia duboulayi). Conductivity of the test solutions ranged from 200 to 750 μS/cm, but such changes did not modify the toxicity of deltamethrin to any of the test species. However, the toxicity of deltamethrin to C. cf. dubia and P. australiensis in river water was significantly decreased (1.8-fold to 6.3-fold reduction) compared to that in laboratory water. Variability in the toxicity data limited our ability to detect differences between laboratory and river water for M. duboulayi. Despite reductions in toxicity in natural waters, deltamethrin remained highly toxic [all L(E)C50 values <0.26 μg/L] to all organisms tested; thus, further investigation of the hazard of deltamethrin is warranted. © 2008 Springer Science+Business Media, LLC

International Science Foresight Workshop: Global Challenges and Research Gaps. The Royaumont process.

How scientists might better contribute to SDGs in the land sector? At the invitation of INRAE, a group of high-level international experts delivers a comprehensive and systemic approach

Interspecific competition delays recovery of Daphnia spp. populations from pesticide stress

Xenobiotics alter the balance of competition between species and induce shifts in community composition. However, little is known about how these alterations affect the recovery of sensitive taxa. We exposed zooplankton communities to esfenvalerate (0.03, 0.3, and 3 μg/L) in outdoor microcosms and investigated the long-term effects on populations of Daphnia spp. To cover a broad and realistic range of environmental conditions, we established 96 microcosms with different treatments of shading and periodic harvesting. Populations of Daphnia spp. decreased in abundance for more than 8 weeks after contamination at 0.3 and 3 μg/L esfenvalerate. The period required for recovery at 0.3 and 3 μg/L was more than eight and three times longer, respectively, than the recovery period that was predicted on the basis of the life cycle of Daphnia spp. without considering the environmental context. We found that the recovery of sensitive Daphnia spp. populations depended on the initial pesticide survival and the related increase of less sensitive, competing taxa. We assert that this increase in the abundance of competing species, as well as sub-lethal effects of esfenvalerate, caused the unexpectedly prolonged effects of esfenvalerate on populations of Daphnia spp. We conclude that assessing biotic interactions is essential to understand and hence predict the effects and recovery from toxicant stress in communities

Environmental risk assessment of two mosquito control larvicides, Bacillus thuringiensis serovar israelensis and diflubenzuron : an experimental approach in field populations of Daphnia sp.

Environmental risk assessment of two mosquito control larvicides, Bacillus thuringiensis serovar israelensis and diflubenzuron : an experimental approach in field populations of Daphnia sp.. 15. European Society for Vector Ecology (SOVE) Conferenc

Influence of environmental factors on the response of a natural population of Daphnia magna (Crustacea: Cladocera) to spinosad and Bacillus thuringiensis israelensis in Mediterranean coastal wetlands

The present study was undertaken to assess the impact of a candidate mosquito larvicide, spinosad (8, 17 and 33 μg L−1) on a field population of Daphnia magna under natural variations of water temperature and salinity, using Bti (0.16 and 0.50 μL L−1) as the reference larvicide. Microcosms (125 L) were placed in a shallow temporary marsh where D. magna was naturally present. The peak of salinity observed during the 21-day observation period may have been partly responsible for the decrease of daphnid population density in all the microcosms. It is also probably responsible for the absence of recovery in the microcosms treated with spinosad which caused a sharp decrease of D. magna abundance within the first two days following treatment whereas Bti had no effect. These results suggest that it may be difficult for a field population of daphnids to cope simultaneously with natural (water salinity and temperature) and anthropogenic (larvicides) stressors. Significant interaction between salinity and spinosad exposure impairs the recovery of a natural population of Daphnia magn

Effects of spinosad and Bacillus thuringiensis israelensis on a natural population of Daphnia pulex in field microcosms

Spinosad, a candidate biological larvicide for mosquito control, was evaluated for its effects on a field population of Daphnia pulex, using Bacillus thuringiensis serovar israelensis (Bti) as a reference larvicide. Microcosms (125 L enclosures) were placed in a shallow temporary oligohaline marsh where D. pulex was present. Three concentrations of spinosad (8, 17 and 33 μg L−1) and two concentrations of Bti (0.16 and 0.50 μL L−1) were applied (5 replicates per concentration, including the controls). Effects of larvicides on D. pulex were evaluated after 2, 4, 7, 14 and 21 d of exposure, through measurements of abundance and individual size. Dissipation of spinosad from the water phase was rapid. Four days after treatment, residue concentration represented 11.8%, 3.9% and 12.7% of the initial exposure level for the nominal concentrations of 8, 17 and 33 μg L−1, respectively. Spinosyns A and D dissipated at similar rates. Analysis of abundance and size structure of the D. pulex population showed an impact of spinosad. Both survival and size structure were affected. However, at the lowest concentration (8 μg L−1), population recovered after the first week. In microcosms treated with Bti, the abundance of D. pulex was not affected but the size structure of the population changed after 21 d. As compared to laboratory tests, the use of in situ microcosms improved the environmental risk assessment of larvicides, taking into account the influence of environmental factors (e.g., temperature, light, salinity) and intrinsic capacity of recovery of D. pulex under field conditions

Sustainable land-use transitions : moving beyond the 30x30 target and the land sparing/land sharing debates : policy brief

Policy Brief présenté pour discussion dans les COP Climat et Biodiversité, et Stockholm +50BACKGROUND The climate, biodiversity, water and health crises raise the crucial question of how we protect land while also producing food, fibre and biomass. Although this topic was addressed at the UN Food Systems Summit and at COP26 in 2021, the debate revolves around only two options presented as polar opposites: land sparing-high input, intensive farming that allows large portions of land to be "spared" for nature; and land sharing-biodiversity friendly low-input farming that shares land more equitably between nature and humans. In parallel, the Post-2020 Global Biodiversity Framework, to be discussed at the 15 th Conference of the Parties to the Convention on Biological Diversity (CBD), targets the protection of 30% of land and marine areas by 2030 (30 x 30 target). This target is fiercely debated because of: 1) its declarative nature, i.e., with no commitments on means and indicators; 2) its decoupling from the use of agricultural and forest areas, i.e., what is to be done with the remaining 70%? and 3) questions of State sovereignty, people' s land rights and environmental justice, i.e., in what geographic areas of the world and according to which forms of governance will the extension of protected areas be carried out? This policy brief reformulates the terms of the debate on land use within the framework of the Sustainable Development Goals. It shows that conservation policies are inseparable from the future of agriculture and food systems. It delivers four key messages

Sustainable land-use transitions : moving beyond the 30x30 target and the land sparing/land sharing debates : policy brief

Policy Brief présenté pour discussion dans les COP Climat et Biodiversité, et Stockholm +50BACKGROUND The climate, biodiversity, water and health crises raise the crucial question of how we protect land while also producing food, fibre and biomass. Although this topic was addressed at the UN Food Systems Summit and at COP26 in 2021, the debate revolves around only two options presented as polar opposites: land sparing-high input, intensive farming that allows large portions of land to be "spared" for nature; and land sharing-biodiversity friendly low-input farming that shares land more equitably between nature and humans. In parallel, the Post-2020 Global Biodiversity Framework, to be discussed at the 15 th Conference of the Parties to the Convention on Biological Diversity (CBD), targets the protection of 30% of land and marine areas by 2030 (30 x 30 target). This target is fiercely debated because of: 1) its declarative nature, i.e., with no commitments on means and indicators; 2) its decoupling from the use of agricultural and forest areas, i.e., what is to be done with the remaining 70%? and 3) questions of State sovereignty, people' s land rights and environmental justice, i.e., in what geographic areas of the world and according to which forms of governance will the extension of protected areas be carried out? This policy brief reformulates the terms of the debate on land use within the framework of the Sustainable Development Goals. It shows that conservation policies are inseparable from the future of agriculture and food systems. It delivers four key messages

Sustainable land-use transitions : moving beyond the 30x30 target and the land sparing/land sharing debates : policy brief

Policy Brief présenté pour discussion dans les COP Climat et Biodiversité, et Stockholm +50BACKGROUND The climate, biodiversity, water and health crises raise the crucial question of how we protect land while also producing food, fibre and biomass. Although this topic was addressed at the UN Food Systems Summit and at COP26 in 2021, the debate revolves around only two options presented as polar opposites: land sparing-high input, intensive farming that allows large portions of land to be "spared" for nature; and land sharing-biodiversity friendly low-input farming that shares land more equitably between nature and humans. In parallel, the Post-2020 Global Biodiversity Framework, to be discussed at the 15 th Conference of the Parties to the Convention on Biological Diversity (CBD), targets the protection of 30% of land and marine areas by 2030 (30 x 30 target). This target is fiercely debated because of: 1) its declarative nature, i.e., with no commitments on means and indicators; 2) its decoupling from the use of agricultural and forest areas, i.e., what is to be done with the remaining 70%? and 3) questions of State sovereignty, people' s land rights and environmental justice, i.e., in what geographic areas of the world and according to which forms of governance will the extension of protected areas be carried out? This policy brief reformulates the terms of the debate on land use within the framework of the Sustainable Development Goals. It shows that conservation policies are inseparable from the future of agriculture and food systems. It delivers four key messages

L'évaluation du risque écotoxique d'herbicides et de biocides le long du continuum de l'estuaire de la baie de Vilaine (Bretagne, France)

International audienceEstuarine areas represent complex and highly changing environments at the interface between freshwater and marine aquatic ecosystems. Therefore, the aquatic organisms living in estuaries have to face highly variable environmental conditions. The aimof this work was to study the influence of environmental changes from either natural or anthropogenic origins on the physiological responses of Mytilus edulis. Mussels were collected in theVilaine estuary during early summer because this season represents a critical period of active reproduction in mussels and of increased anthropogenic inputs from agricultural and boating activities into the estuary. The physiological status of the mussel M. edulis was evaluated through measurements of a suite of biomarkers related to: oxidative stress (catalase, malondialdehyde), detoxication (benzopyrene hydroxylase, carboxylesterase), neurotoxicity (acetylcholinesterase), reproductive cycle (vitelline, condition index, maturation stages), immunotoxicity (hemocyte concentration, granulocyte percentage, phagocytosis, reactive oxygen species production, oxidative burst), and general physiological stress (lysosomal stability). A selection of relevant organic contaminant (pesticides, (polycyclic aromatic hydrocarbons, polychlorobiphenyls) was measured as well as environmental parameters (water temperature, salinity, total suspended solids, turbidity, chlorophyll a, pheopigments) and mussel phycotoxin contamination. Two locations differently exposed to the plume of the Vilaine River were compared. Both temporal and inter-site variations of these biomarkers were studied. Our results show that reproduction cycle and environmental parameters such as temperature, organic ontaminants, and algal blooms could strongly influence the biomarker responses. These observations highlight the necessity to conduct integrated environmental approaches in order to better understand the causes of biomarker variations