scholarly journals Determination of leachate toxicity through acute toxicity using Daphnia pulex and Anaerobic Toxicity Assays

2017 ◽  
Vol 37 (1) ◽  
pp. 16 ◽  
Author(s):  
Patricia Torres Lozada ◽  
Yazmín Stefhany Carabalí Rivera ◽  
Luz Edith Barba Ho
Keyword(s):  
Acute Toxicity ◽  
Anaerobic Bacteria ◽  
Daphnia Pulex ◽  
Recovery Stage ◽  
Methanogenic Activity ◽  
Large Cities ◽  
Inorganic Matter ◽  
High Concentrations ◽  
Exposure Stage

The municipal solid waste (MSW) of large cities, in particular in developing countries, is mainly disposed of in landfills (LFs), whose inadequate management generates the emission of greenhouse gases and the production of leachates with high concentrations of organic and inorganic matter and occasionally heavy metals. In this study, the toxicity of the leachates from an intermediate-age municipal landfill was evaluated by ecotoxicity and anaerobic digestion tests. The acute toxicity assays with Daphnia pulex presented a toxic unit (TU) value of 49.5%, which indicates that these leachates should not be directly discharged into water sources or percolate into the soil because they would affect the ecosystems served by these waters. According to statistical analyses, the leachate toxicity is mainly associated with the inorganic fraction, with chlorides, calcium hardness and calcium having the greatest influence on the toxicity. The anaerobic toxicity assays showed that in the exposure stage, the methanogenic activity exceeded that of the control, which suggests that the anaerobic bacteria easily adapted to the leachate. Therefore, this treatment could be an alternative to mitigate the toxicity of the studied leachates. The inhibition presented in the recovery stage, represented by a reduction of the methanogenic activity, could arise because the amount of supplied substrate was not enough to fulfill the carbon and nutrient requirements of the bacterial population present.

scholarly journals Evaluation of toxicity from leachate lagoons sediments, using the toxicity leaching procedure - TCLP and acute toxicity tests

DYNA ◽  
2019 ◽  
Vol 86 (208) ◽  
pp. 192-198
Author(s):  
Patricia Torres Lozada ◽  
Yazmin Carabalí Rivera ◽  
Luz Edith Barba Ho
Keyword(s):  
Acute Toxicity ◽  
Poecilia Reticulata ◽  
Daphnia Pulex ◽  
Acid Soils ◽  
Biological Indicators ◽  
Toxicity Tests ◽  
Municipal Solid Wastes ◽  
Inorganic Matter ◽  
Acute Toxicity Tests ◽  
Agricultural Use

Landfills have been the most used alternative for final municipal solid wastes disposal, however, this system is the responsible of contamination problems associated with the generation of leachates, sediments and toxic gasses emissions. The sediments occur by the organic and inorganic matter precipitation from leachates dumped in retention lagoons, which can present toxic characteristics than affect the environment. The aim of this work was to evaluate the potential toxicity of leachates from a municipal landfill, using the TCLP procedure and acute toxicity assays with Daphnia pulex and Poecilia reticulata as biological indicators. The results showed that the sediment evaluated, did not exceed the stablished levels suggested by the EPA for the TCLP test, nor were they toxic to the organisms used. This results, suggests a potential agricultural use of this material in acid soils, since the nature of leachate sediments are pH alkaline and rich in nutrients and organic matter.

scholarly journals Determination of medium lethal dose (LD50) and acute toxicity of formulation Cytoreg®, an ionic mixture of strong and weak acids

2021 ◽  
Vol 3 (3) ◽  
pp. 1121-1126
Author(s):  
Rosa De Jesus ◽  
Nelson Vicuña- Fernández ◽  
Andrés Osorio ◽  
David Martucci ◽  
Lewis Pozo ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Active Compound ◽  
Lethal Dose ◽  
Liquid Form ◽  
Pharmacological Tests ◽  
High Concentrations ◽  
New Formulation ◽  
The University ◽  
Transport Complex

A series of toxicological and pharmacological tests were started in the bioterium of the University of Los Andes, in order to evaluate a new formulation for therapeutic purposes. The present work reports the results found regarding the LD50 and the acute toxicity of this formulation produced by Cytorex of Venezuela, S.A. The new formulation supplied in liquid form, containing a variety of acid atoms whose conjugated bases have different electrical charges. It constitutes an ion transport complex of positively charged cations and negatively charged anions in high concentrations that help regulate mitochondrial and cellular metabolism and utilizes the inorganic fluoride ion (HF) as the main active compound, as referred to by the supplier. All the concentrations described in this work are referred to hydrofluoric acid (HF), which is the active compound of the formulation. Conventional pharmacological methods were used and it was found that the average lethal dose in rats resulted in 44.83 mg/Kg, and of 0.82ml/Kg. At the concentration of minimum dose of 0,49 mL/Kg of weight, the surviving animals did not present apparent macroscopic lesions at necropsy.

Determination of acute toxicity of Tiacyclin solution for injection in laboratory animals

2019 ◽  
Vol 331 (8) ◽  
pp. 25-27
Author(s):  
N.Y. Morozov ◽  
◽  
S.I. Tchukina ◽  
E.I. Koveshnikova ◽  
◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Laboratory Animals

The bacterial numeration and an observation of a new syntrophic association for granular sludge

1997 ◽  
Vol 36 (6-7) ◽  
pp. 133-140 ◽  
Author(s):  
Zhu Jianrong ◽  
Hu Jicui ◽  
Gu Xiasheng
Keyword(s):  
Anaerobic Bacteria ◽  
Granular Sludge ◽  
Methanogenic Bacteria ◽  
Uasb Reactor ◽  
Two Phase ◽  
Methanogenic Activity ◽  
Syntrophic Association ◽  
Group I ◽  
Acetogenic Bacteria ◽  
Fermentative Bacteria

The bacterial numeration and microbial observation were made on granular sludge from laboratory single and two-phase UASB reactors. It was shown that the fermentative bacteria (group I), H2-producing acetogenic bacteria (group II) and methanogenic bacteria (group III) of granular sludge in single UASB reactor were 9.3 × 108−4.3 × 109, 4.3 × 107−4.3 × 108, 2.0−4.3 × 108, respectively, during the granulation process. The sludge of methanogenic reactor exhibited the similar results. That indicates there is no big difference between suspended and granular sludge, and bacterial population for three groups of anaerobic bacteria are similar. The formation of granular sludge depends mainly on the organization and arrangement of bacteria. An observation of granular sludge using electron microscope revealed that the fermentative bacteria and hydrogenotrophic methanogens existed on outer surface of granules, and aceticlastic methanogens and H2-producing acetogenic bacteria occupied the inner layer. A new syntrophic association between Methanosaeta sp. and Syntrophomonas sp. (even plus Methanobrevibacter sp.) was observed. Because Methanosaeta can effectively convert the acetate (the end product of propionate and butyrate) to methane, such a new syntrophic association is supposed to support the degradation of short fatty acids and high methanogenic activity of granular sludge. Based on structural pattern, a hypothesis on mechanism of granulation called “crystallized nuclei formation” is proposed.

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