Acute toxicity of toluene, hexane, xylene, and benzene to the rotifers Brachionus calyciflorus and Brachionus plicatilis

1992 ◽  
Vol 49 (2) ◽  
Author(s):  
M.D. Ferrando ◽  
E. Andreu-Moliner
Keyword(s):  
Acute Toxicity ◽  
Brachionus Plicatilis ◽  
Brachionus Calyciflorus

Effect of salinity and food concentration on competition between Brachionus plicatilis Müller, 1786 and Brachionus calyciflorus Pallas, 1776 (Rotifera)

2020 ◽  
Vol 71 (4) ◽  
pp. 493
Author(s):  
N. S. Ferrando ◽  
S. Nandini ◽  
M. C. Claps ◽  
S. S. S. Sarma
Keyword(s):  
Brachionus Plicatilis ◽  
Natural Populations ◽  
Food Concentration ◽  
Brachionus Calyciflorus ◽  
Food Density ◽  
Food Concentrations ◽  
Salinity Levels ◽  
Planktonic Rotifers ◽  
Salado River ◽  
Pampean Shallow Lakes

Natural populations of planktonic rotifers are affected by salinity and food density, among other stressors. Moreover, competition among congeneric species limits the abundance of certain rotifers in ecosystems without spatial heterogeneity and environmental fluctuations. We isolated Brachionus plicatilis and Brachionus calyciflorus from Salado River basin waterbodies and studied the demographic characteristics and competition between them at three salinity levels (0.75, 1.75 and 2.75gL–1 NaCl) and at two food concentrations (0.1×106 and 0.5×106 cells mL–1 Chlorella vulgaris). The lowest salinity level proved to be unfavourable for the population growth of B. plicatilis, but at higher salinity levels the growth was similar to that of controls (without competition), even in the presence of the competitor and at either food concentration. By contrast, the competitor almost always decreased the density of B. calyciflorus. Salinity greatly affected the peak density of B. plicatilis, whereas the effects of salinity and competition on B. calyciflorus were similar. Biomass was inversely related to salinity for both species, and was significantly affected by competition in B. plicatilis. These results show that B. calyciflorus is more adversely affected than B. plicatilis by competition and high salinity, and explain why both species can coexist in eutrophic saline lowland rivers and pampean shallow lakes.

Cyst-Based Toxicity Tests. IV. The Potential of Ecotoxicological Tests for the Prediction of Acute Toxicity in Man as Evaluated on the First Ten Chemicals of the MEIC Programme

1992 ◽  
Vol 20 (3) ◽  
pp. 396-405 ◽  
Author(s):  
Mabel C. Calleja ◽  
Guido Persoone
Keyword(s):  
Acute Toxicity ◽  
Brachionus Plicatilis ◽  
Artemia Salina ◽  
In Vitro Cytotoxicity ◽  
Aquatic Invertebrate ◽  
Toxicity Tests ◽  
Acute Oral Toxicity ◽  
Oral Toxicity ◽  
Aquatic Test Systems

In the framework of the multicentre evaluation of in vitro cytotoxicity (MEIC) programme, the first ten chemicals of the prescribed list were tested for acute toxicity in four standardised cyst-based aquatic invertebrate tests, consisting of two rotifer species (the estuarine Brachionus plicatilis and the freshwater Brachionus calyciflorus) and two crustacean species (the halophilic anostracan Artemia salina and the freshwater anostracan Streptocephalus proboscideus). Mortality was the test criterion and toxic effects, expressed as 24-hour LC50 values, were correlated with rodent and human acute oral toxicity data. Generally, a good correlation was obtained between any of the invertebrate tests and the rodent data. Likewise, the predictive screening potential of the aquatic invertebrate tests for acute oral toxicity in man was slightly better than the rat test for eight (excluding diazepam and digoxin) and nine (including diazepam, excluding digoxin) of the ten substances. The aquatic test systems, however, appear to be more suitable for compounds soluble in water.

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