Showing 8 results for Toxicity
K Naddafi, M.r Zare, M Younesian, M Alimohammadi, N Rastkari, N Mousavi,
Volume 4, Issue 2 (9-2011)
Abstract
Background and Objectives: This study was conducted to investigate the toxicity of Titanium Oxide (TiO2) and Zinc Oxide (ZnO) nanoparticles as two of most widely used nanoparticles. The result of this study can help to designing environmental standard and legislations for nanoparticles.
Materials and Methods: Different concentrations of nano ZnO and TiO2 nanoparticles were added to nutrient Agar culture media. Then, definite numbers of Escherichia coli and Staphylococcus aureus bacteria were added to culture media and inhibition of these bacteria growth was measured in comparison to controls. Obtained data were analyzed to determine nanoparticles' EC50 and NOEC (No Observed Effect Concentration) using SPSS ver.16 and Probit standard test.
Results: 24-hours EC50 of nano ZnO using E. coli and S. aureus determined to be 5.47 mg/L and 2.38 mg/L respectively. In addition, 24-hours EC50 of nano TiO2 using E. coli and S. aureus determined to be 5366 mg/L and 3471 mg/L respectively. In the case of ZnO nanoparticles, no observed effect concentration determined to be 1.15 and 3.28 mg/L for E. coli and S. aureus respectively and in the case of TiO2 nanoparticles no observed effect level determined to be 1937 and 1184 mg/L for E. coli and S. aureus respectively.
Conclusion: This study showed that acute toxicity of nano ZnO is by far more than that of nano TiO2. Regarding the EPA acute toxicity criteria, nano ZnO is categorized as moderately toxic and nano TiO2 is categorized as practically non toxic. Hence, regarding the acute toxicity, in recommending exposure criteria and environmental disposal standards, compared to nano TiO2, nano ZnO requires more attention.
Hamid Reza Salari-Joo, Mohammad Reza Kalbassi, Seyed Ali Johari,
Volume 5, Issue 1 (4-2012)
Abstract
MicrosoftInternetExplorer4
Background
and Objectives: Nanotechnology defined as understanding
and controlling of materials at dimension between 1-100 nm, which show unusual
physical and chemical properties. With Increasing development of
nanotechnology, concerns associated with release of materials containing
nanoparticles into the environment is rising. The purpose of this study is
investigation of salinity effect on the acute toxicity of silver nanoparticles
in rainbow trout fry (Oncorhynchusmykiss).
Materials
and Methods: In order to conduct the toxicity tests,
the Caspian Seawater(12±0.2 ppt) and (0.4 ppt) as sources of brackish water and
freshwater were used, respectively. Toxicity of silvernano particles were
evaluated in brackish water and freshwater at concentrations of1, 2, 4, 8, 16,
32and64ppm and 0.12, 0.25, 0.5, 1, 2, 4
and8 ppm, respectively. In addition, in order to investigate the quality of the
used silver nanoparticles the Zetasizer, ICP, and TEM method were applied.
Results: Results of 96-hour median lethal concentration(LC50 96h), showed that toxicity
of silver nanoparticles for rain bow trout fry in brackish water is 12 times
less than its toxicity in freshwater.
Conclusion: According to the toxicity categories, analysis of the results showed that, for
rainbow trout fry (1g), silver nanoparticles are classified as highly toxic
agent substances in fresh water, and little toxic in brackish water,
respectively.
Bijan Bina, Mohamadmahdi Amin, Mohamadreza Zare, Ali Fatehizadeh, Mohsen Mohseni, Mahdi Zare, Ali Toulabi,
Volume 6, Issue 2 (9-2013)
Abstract
Background and Objectives: Toxicity assessment of material related to nanotechnology is
necessary before excess development of this industry. On the other hand, specific
characteristic of nanomaterials can be used in disinfection of other material. In
this study toxicity and antibacterial properties of nano-TiO2 and nano-CuO
were investigated with four bacterial species in solid media.
Material and Methods: Stock
suspension of nanoparticles (10g-TSS/L) was diluted using Muller Hinton Agar to
achieve 5-6000mg-TSS/L concentration. We prepared three Petri dishes for each concentration
and refined bacteria were cultured on these Petri dishes. After culturing of these
bacteria on the media containing nanoparticles, growth inhibition was determined.
According to this data, 50% growth inhibition (EC50), no observed effect
concentration (NOEC) and 100% growth inhibition were determined.
Results: Our results showed
that toxicity of TiO2 is more than CuO in solid media. In this regard,
nano-TiO2 EC50 for Escherichia coli, Bacillus subtilis, Staphylococcus
aureus, and Pseudomonas aeruginosa was calculated 181, 571, 93 and 933mg-TSS/L respectively.
These figures for nano-TiO2 were 2550, 1609, 946, and 1231mg-TSS/L respectively.
Conclusion: This study
showed that compared with other bacteria studied, E. aureus due to high sensitivity
and E. coli due to high resistance to both TiO2 and CuO nanoparticles
are more proper as bioindicator in toxicity test and antibacterial test respectively.
M Kermani, M Farzadkia, A Esrafili, Y Dadban Shahamat, S Fallah Jokandan,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Discharge of industrial wastewater containing Catechol has adverse effects on human and environmental health. Purpose of this study was to determine the effects of catechol toxicity before and after advanced oxidation process (ozonation process) by bioassay test with Daphnia Magna.
Materials and Methods: This study is an applied research in which the toxicity of catechol was determined by Daphnia Magna bioassay test during the ozonation process. First, Catechol stock solution was prepared at a concentration of 250 mg/L. Then, 10 samples were prepared that each contained 0 (control), 0.5, 1, 3, 6, 12, 25, 50, 75 and 100% of volume of primary solution. Initial samples were prepared from reactor effluent in the same volume as those of the samples. According to standard method, 10 Daphnia infants were added to each sample. The samples were observed after 24, 48, 72 and 96 hours. Finally, lethal concentration (LC50) and toxicity unit (TU) were calculated using Probit analysis.
Results: According to the results, Daphnia magna was affected by the toxicity of catechol. LC50 (24-hour) for raw effluent was increased from 13.30 mL/100 mL to 30.4 mL/100 mL after 60 minutes Treatment. The toxicity unit was decreased from 7.51 TU to 3.29 TU accordingly, showing reduction of 56% in toxicity. The toxicity of the treated effluent decreased during ozonation process of catechol.
Conclusion: Based on the bioassay test, ozonation process was able to reduce the toxicity of catechol. Therefore, this process can be used as an option to treat wastewater that contains catechol.
S Mortazavi, M Hatami-Manesh, F Joudaki,
Volume 11, Issue 4 (3-2019)
Abstract
Background and Objective: Considering the toxicity, health and ecological hazards of heavy metals in the environment and the impact on organisms, it looks essential to measure and evaluate their concentrations at the various levels in indigineous ecological strctures. The present study evaluated the concentration of Lead, Nickel, Copper and Zinc and their ecological risk assessment in surface sediments of Sezar River in Lorestan province.
Materials and Methods: 16 stations along the Sezar River were selected for sampling. After preparation and acid digestion of the samples, the concentrations of these metals were determined by Atomic absorbtion.
Results: The average total concentration of the detected metals Ni, Zn, Cu and Pb in the sediment was 71.84 > 40.56> 7.75 > 5.61 mg/kg, respectively. In addition, the evaluation of the Potential acute toxicity, ecological risk, and Pollution Load Index represented a low pollution in the sediments. The environmental risk of the metals in the sediment was evaluated as: Ni> Pb> Cu> Zn. The findings showed that among metals, the contamination factor and modified hazard quotient (mHQ) for nickel was moderate and in the mediun to severe pollution level to the contamination, respectively.
Conclusion: According to the results, it can be concluded that Potential acute toxicity, pollution and ecological risk in the region for investigated metals were low. However, a rapid expansion of various human activities in the area and the pollution of nickel in the river along with the probability of its biological effects require continuous monitoring of the river in order to assess the health risk and its ecological risk.
Sadegh Hosseinniaee, Mohammad Jafary, Ali Tavili, Salman Zare,
Volume 16, Issue 4 (3-2024)
Abstract
Background and Objective: The toxicity of heavy metals is one of the most important environmental issues in the current century. This research aimed to investigate the effect of municipal solid waste compost on the absorption of nutrients and lead and zinc metals in M. cuneatum and V. speciosum plants.
Materials and Methods: In a greenhouse experiment, compost at four levels (0, 1, 3 and 5% w/w) was completely mixed with natural soil contaminated with heavy metals (Pb and Zn). After six months of harvesting the plants, the shoot and root biomass was determined. Also, the concentration of macronutrients and micronutrients, Pb and Zn in the roots and aerial parts of plants and available Pb and Zn in the soil were measured using the ICP-OES. In order to investigate the correlation between the measured plant and soil parameters, principal component analysis (PCA) was performed
Results: Compost significantly improved the shoot dry weight of M. cuneatum and V. speciosum by 13 and 19%, respectively. 5% compost significantly reduced shoot lead by 64 and 34.4% in M. cuneatum and V. speciosum, respectively, compared to the control. Compost was more effective in increasing potassium, phosphorus, copper, and nickel than magnesium, manganese, and calcium, and increased shoot potassium by 22 and 32%, respectively, in M. cuneatum and V. speciosum compared to the control; this increase was 30 and 14% for copper and 19 and 21% for phosphorus, respectively. PCA analysis showed that, among the investigated elements, potassium, phosphorus and copper were most affected by composting and had the maximum role in improving plant growth and reducing lead toxicity.
Conclusion: Municipal solid waste compost improved the growth of M. cuneatum and V. speciosum and reduced phytotoxicity by immobilizing lead in the soil.
Seyedeh Sholeh Hosseini, Bahareh Lorestani, Soheil Sobhanardakani, Mehrdad Cheraghi, Sahar Rezaian,
Volume 17, Issue 4 (3-2025)
Abstract
Background and Objective: Street dust, as both a source and sink of pollutants, is considered a reliable indicator for assessing atmospheric pollution. Therefore, this study aimed to evaluate the pollution levels and environmental toxicity of arsenic (As), zinc (Zn), lead (Pb), cadmium (Cd), and copper (Cu) in street dust in the city of Hamedan in 2023.
Materials and Methods: A total of 108 street dust samples were collected from 12 sampling sites, including residential, commercial, and industrial regions, during the spring, summer, and fall seasons. The concentrations of the analyzed elements were determined using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Additionally, pollution indices (PI), integrated pollution index (IPI), and mean effects range median quotient (mERM-Q) were calculated.
Results: The highest average concentrations of the analyzed elements in street dust were observed in the industrial regions and the fall season for As (5.79 mg/kg), Zn (405 mg/kg), Cd (0.758 mg/kg), and Cu (84.8 mg/kg). For Pb, the highest average concentration (110 mg/kg) was found in commercial regions during the fall season. PI values indicated pollution levels for As, Zn, Pb, Cd, and Cu ranging from "moderate" to "very high." The average IPI values varied between 2.52 and 3.90, reflecting "high" pollution conditions across all sampling sites and seasons. Furthermore, the average mERM-Q values suggested a 21% probability of elemental toxicity in the analyzed street dust samples.
Conclusion: The findings highlight the influence of human activities, seasonal variations, and emission source fluctuations on street dust pollution. To mitigate pollution, it is recommended to identify and control the release sources of these elements, particularly in regions with higher pollution levels.
Naseh Babakhani, Soheil Sobhanardakani, Borhan Mansouri, Mehrdad Cheraghi, Bahareh Lorestani,
Volume 18, Issue 1 (5-2025)
Abstract
Background and Objective: Growing concerns exist regarding the impact of nanoparticles on organisms and environmental health. This study aimed to investigate the effects of silver and graphene oxide nanoparticles on the gill and intestinal tissues of guppy fish (Poecilia reticulata) during acute toxicity exposure.
Materials and Methods: The acute toxicity (LC50) for both nanoparticles was calculated over a 96-hour period using Probit software. Histopathological examination of the gill and intestinal tissues exposed to the nanoparticles was performed using the hematoxylin-eosin staining method. A semi-quantitative approach was employed to assess the severity of tissue damage.
Results: The LC50 values for silver nanoparticles, graphene oxide nanoparticles, and their combination were determined to be 2.6 mg/L, 65.2 mg/L, and 1.8 mg/L, respectively. Simultaneous exposure to these nanoparticles exhibited a cumulative acute toxicity effect on fish tissues, with the severity increasing progressively from 24 to 96 hours. Notable injuries included hyperplasia, fusion, and adhesion of secondary lamellae in the gill tissue, as well as villi fusion, structural expansion of villi, increased blood cell count, and erosion in the intestinal tissue of the fish.
Conclusion: Simultaneous exposure to silver and graphene oxide nanoparticles significantly increases the acute toxicity in guppy fish. This study highlights the need for further research to fully understand the implications of nanoparticle exposure across the food chain.
