Iranian Journal of

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.
 

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.