Modeling the concentration–response function of the herbicide dinoseb on Daphnia magna (survival time, reproduction) and Pseudokirchneriella subcapitata (growth rate)

2005 ◽  
Vol 62 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Nathalie Chèvre ◽  
Alessandra R. Brazzale ◽  
Kristin Becker-van Slooten ◽  
Renata Behra ◽  
Joseph Tarradellas ◽  
...  
Keyword(s):  
Growth Rate ◽  
Survival Time ◽  
Daphnia Magna ◽  
Response Function ◽  
Pseudokirchneriella Subcapitata ◽  
Time Reproduction

Silver nanoparticles and silver nitrate induce high toxicity to Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio

2014 ◽  
Vol 466-467 ◽  
pp. 232-241 ◽  
Author(s):  
Fabianne Ribeiro ◽  
Julián Alberto Gallego-Urrea ◽  
Kerstin Jurkschat ◽  
Alison Crossley ◽  
Martin Hassellöv ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Daphnia Magna ◽  
Danio Rerio ◽  
Pseudokirchneriella Subcapitata ◽  
High Toxicity

The toxicity of cadmium-copper mixtures on daphnids and microalgae analysed using the Biotic Ligand Model

2021 ◽  
Author(s):  
Bernard CLEMENT ◽  
Vincent FELIX ◽  
Valentin BERTRAND
Keyword(s):  
Growth Inhibition ◽  
Water Chemistry ◽  
Daphnia Magna ◽  
Mixture Toxicity ◽  
Pseudokirchneriella Subcapitata ◽  
Major Cations ◽  
Biotic Ligand ◽  
Accumulation Of Metals ◽  
Parameter Values ◽  
Ligand Model

Abstract For the prediction of metals mixture ecotoxicity, the BLM approach is promising since it evaluates the amount of metals accumulated on the biotic ligand on the basis of water chemistry, i.e. species (major cations) competing with metals, and related toxicity. Based on previous work by Farley et al. 2015 (MMME research project), this study aimed at modelling toxicity of Cd:Cu mixtures (0:1–1:1–1:0–1:2 − 1:3 − 2:1–3:1–4:1–5:1–6:1) to the crustacean Daphnia magna (48h immobilization tests) and the microalga Pseudokirchneriella subcapitata (72h growth inhibition tests). The USGS model was chosen, assuming additivity of effects and accumulation of metals on a single site. The assumption that EDTA could contribute to toxicity through metals complexing was also tested, and potential effects due to reduction of ions Ca2+ absorption by metals were considered. Modelling started with parameter values of Farley et al. 2015 and some of these parameters were adjusted to fit modelled data on observed data. The results show that toxicity can be correctly predicted for the microalgae and that the hypothesis of additivity is verified. For daphnids, the prediction was roughly correct, but taking into account CuEDTA led to more realistic parameter values close to that reported by Farley et al. 2015. However, It seems that, for daphnids responses, metals interact either antagonistically or synergistically depending on the Cu:Cd ratio. Furthermore, synergy could not be explained by additional effects linked to a reduction of Ca absorption since this reduction, mainly due to Cd, increased inversely to synergy. Finally, the USGS model applied to our data was able to predict Cu:Cd mixture toxicity to microalgae and daphnids, giving rise to estimated EC50s roughly reflecting EC50s calculated from observed toxicity.

scholarly journals Investigating The Sub-Acute Responses Of Lemna Minor, Pseudokirchneriella Subcapitata, Euglena Gracilis And Anodonta Grandis To Tributyltin-Hydride And Atrazine In Freshwater

2021 ◽  
Author(s):  
Christopher J.E. Pearce
Keyword(s):  
Growth Rate ◽  
Euglena Gracilis ◽  
Lemna Minor ◽  
Aquatic Toxicity ◽  
Normal Growth ◽  
Pseudokirchneriella Subcapitata ◽  
Cell Counts ◽  
Realistic Representation ◽  
Antifouling Agent ◽  
Anodonta Grandis

Freshwater resources exist in limited quantities and are subject to increasing demands due to the consumption by residential, commercial and industrial uses. There are concerns that the widely used chemical analysis of drinking water does not deliver timely results. This study examines the efficacy of developing a holistic, multi-organism early-warning biomonitoring technology to assess aquatic toxicity. Sensitive indicator species such as Lemna minor, Pseudokirchneriella subcapitata, Euglena gracilis, and Anodonta grandis have been selected due to their specific behavioural and short-term biochemical responses in the identification of classes of contaminants in aquatic environments. Tributyltin, an antifouling agent in paints used on boats and atrazine, an herbicide widely used on agricultural crops, are evaluated in increasing concentrations to identify behavioural changes in these organisms. These graded responses, upon implementation in models, will warn water treatment operators of incoming contaminants and help identify the nature of the stressor. All organisms displayed some sensitivity to selected concentrations of the two test chemicals. The normal growth rate of L. minor dramatically declined with exposure to TBT (100.0 mg/L) and atrazine (500.0 g/L). Monitoring the biochemical changes, dissolved oxygen production, and also the growth rate, cell counts, of P. subcapitata showed significant effects to similar concentrations of TBT (100.00 g/L) and atrazine (500.00 g/L). The aquatic protest, E. gracilis, alters its cell morphology in the presence of low concentrations of TBT (10.0 g/L) and atrazine (50.0 g/L). Respiration patters of the bivalve, A. grandis, was directly influenced by the two chemicals, TBT (1.0 mg/L) and atrazine (50.0 mg/L). This study demonstrates that biological assessments of water samples deliver a rapid, realistic representation of the surrounding aquatic environment conditions.

scholarly journals Short-Term Projection of COVID 19 Cases in Kenya using an Exponential Model

2020 ◽  
Author(s):  
Samuel Kiruri Kirichu
Keyword(s):  
Growth Rate ◽  
Real Time ◽  
Case Fatality Rate ◽  
Reproduction Number ◽  
Case Fatality ◽  
Daily Growth Rate ◽  
Daily Growth ◽  
The Real ◽  
Time Reproduction ◽  
First Case

Abstract Introduction: The COVID-19 disease has spread to over 200 countries and territories since the first case was recorded in Wuhan, China in December 2019. In Kenya, the first case of COVID-19 was recorded on 13th March 2020 and since then over five thousand cases have been confirmed as of 26th June 2020. In the same period, one hundred and forty four mortality cases had been recorded in the country. With the rapid changing situation, timely and reliable data is required for monitoring, planning and rapid decision making with an aim of reversing the already deteriorating situation (economic, health, learning among others) in the country. Methods: The study used the exponential growth model to estimate the daily growth rate and the real-time-effective reproduction number. The study also estimated the naïve and the adjusted Case Fatality Rates. Results: The naïve-Case Fatality Rate of 26th June 2020 which was the 106 day after the first case was confirmed in Kenya was estimated as 2.5% while the adjusted Case Fatality Rate with a lag of 2 days was estimated as 2.6%. The daily exponential growth rate was estimated as 0.22 while the real-time reproduction number as of 26th June 2020 was estimated as 1.28 [95% CI: 1.27 – 1.29]. Conclusion: The daily growth rate and the real-time reproduction number indicated that the outbreak was still growing as of the time of analysis.

scholarly journals Characterization of different microalgae cultivated in open ponds

2019 ◽  
Vol 41 (1) ◽  
pp. 37723 ◽  
Author(s):  
Dagon Manoel Ribeiro ◽  
Alessandro Minillo ◽  
Cinthia Aparecida De Andrade Silva ◽  
Gustavo Graciano Fonseca
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Dry Mass ◽  
Maximum Specific Growth Rate ◽  
Pseudokirchneriella Subcapitata ◽  
Western Region ◽  
Lipid Contents ◽  
The World ◽  
Main Fatty Acid

 Microalga is one of the main sources of biomasses for the production of biofuels in the 21st century. Many labs and industries around the world are seeking for more productive strains and better cultivation models. The aim of this work was to evaluate the growth and kinetic parameters of six microalgae, and the moisture and lipid contents and fatty acids profiles of the biomasses harvested at the end of each cultivation. The microalgae were isolated in the Mid-Western Region of Brazil cultivated in open pond systems. It was observed that among the six microalgae used in this work, Pseudokirchneriella subcapitata presented the higher maximum specific growth rate (μmax) (0.12 day-1). The microalgae Coelastrum sp. and P. subcapitata were the ones with the highest lipid contents, with approximately 20% of dry mass. The main fatty acid accumulated in these conditions was palmitic acid, with percentages of 59 to 69% for all microalgae evaluated. Other factors that had influenced results from cultivations in open ponds were discussed here. 

scholarly journals Assessment of acrylamide toxicity using a battery of standardised bioassays / Procjena toksičnosti akrilamida pomoću standardiziranih biotestova

2015 ◽  
Vol 66 (4) ◽  
pp. 315-321 ◽  
Author(s):  
Mira Zovko ◽  
Željka Vidaković-Cifrek ◽  
Želimira Cvetković ◽  
Jasna Bošnir ◽  
Sandra Šikić
Keyword(s):  
Daphnia Magna ◽  
Lemna Minor ◽  
Low Cost ◽  
Drinking Water Treatment ◽  
Pseudokirchneriella Subcapitata ◽  
Laboratory Animals ◽  
Freshwater Organisms ◽  
Desmodesmus Subspicatus ◽  
Class 1 ◽  
Increased Sensitivity

Acrylamide is a monomer widely used as an intermediate in the production of organic chemicals, e.g. polyacrylamides (PAMs). Since PAMs are low cost chemicals with applications in various industries and waste- and drinking water treatment, a certain amount of non-polymerised acrylamide is expected to end up in waterways. PAMs are non-toxic but acrylamide induces neurotoxic effects in humans and genotoxic, reproductive, and carcinogenic effects in laboratory animals. In order to evaluate the effect of acrylamide on freshwater organisms, bioassays were conducted on four species: algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata, duckweed Lemna minor and water flea Daphnia magna according to ISO (International Organization for Standardisation) standardised methods. This approach ensures the evaluation of acrylamide toxicity on organisms with different levels of organisation and the comparability of results, and it examines the value of using a battery of low-cost standardised bioassays in the monitoring of pollution and contamination of aquatic ecosystems. These results showed that EC50 values were lower for Desmodesmus subspicatus and Pseudokirchneriella subcapitata than for Daphnia magna and Lemna minor, which suggests an increased sensitivity of algae to acrylamide. According to the toxic unit approach, the values estimated by the Lemna minor and Daphnia magna bioassays, classify acrylamide as slightly toxic (TU=0-1; Class 1). The results obtained from algal bioassays (Desmodesmus subspicatus and Pseudokirchneriella subcapitata) revealed the toxic effect of acrylamide (TU=1-10; Class 2) on these organisms.

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