Toxicity response of Poecilia reticulata Peters 1859 (Cyprinodontiformes: Poeciliidae) to some agricultural pesticides

Hedayati A, Tarkhani R, Shadi A. 2012. Mortality response of Poecilia reticulata Peters 1859 (Cyprinodontiformes: Poeciliidae) to some agricultural pesticides. Nusantara Bioscience 4: 6-10. This research was performed to determine and compare acute toxicity of diazinon and deltamethrin as potential dangerous organic pesticides to assess mortality effects of these chemicals to the freshwater guppy Poecilia reticulata. LC50 of 24 h, 48 h, 72 h, and 96 h was attained by probit analysis by Finney’s and using the maximum-likelihood procedure (SPSS). The 24-96 h LC50 for the diazinon were 40.9±0.98, 33.2±0.84, 23.2±0.74 and 16.8±0.57 ppm respectively. The 24-96 h LC50 for the deltamethrin were 0.297±0.13, 0.236±0.16, 0.204±0.47 and 0.195±0.06 ppm respectively. In the present study, LC50 values indicated that deltamethrin was more toxic than diazinon to this species. LC50 values obtained in the present study were different from the corresponding values that have been published in the literature for other species of fish

Sublethal effect of nanosilver on the structure of gill of Caspian roach (Rutilus rutilus caspicus) fingerlings

Widespread use of nanosilver can be led the contamination of aquatic environment and impact on living organisms such as fishes. We investigated histopathological changes in the gills tissue of Caspian roach fingerlings after two weeks exposure to sublethal concentrations of nanosilver. Following one and two weeks exposure, necrosis, shortening of secondary lamellae, edema, destruction of epithelial lamella, shortening of secondary lamellae, epithelial lifting and curling of secondary lamellae were observed in gill tissues. This observation showed that exposure to sub-lethal concentrations of nanosilver is caused damages in the gill tissues of Caspian roach. The results demonstrated direct correlation of gill tissue damage and toxin exposure i.e. increasing nanosilver concentration is caused more tissue damage. Hence, histopathological changes of gill can considered as a proper indicator for nanosilver contamination of aquatic environments

Acute toxicity effect of glyphosate on survival rate of common carp, Cyprinus carpio

Background: Herbicides are usually used to control weeds and some of them like glyphosate are nonselective herbicides. Aquatic environments are usually the last destinations of agricultural pesticides, which disrupt the metabolic processes of organisms. Thus, the aim of this study was to evaluate acute toxicity of glyphosate on the survival rate of common carp, Cyprinus carpio. Methods: A total of 135 common carp averaged 7 ± 0.8 g in weight were exposed to 0, 25, 50, 75, 100, 125, 150, 175 and 200 mL.L-1 glyphosate (15 fish in each treatment, with triplicates) for 96 hours. The aquariums capacity was 98 L in volume (80 × 35 × 35 cm) and physicochemical parameters were the same for all groups (pH 7.4-8, temperature = 26 ± 1ºC, DO = 7 mg.L-1 and total hardness of 190 mg CaCO3). LC10, LC20, LC30, LC40, LC50, LC60, LC70, LC80, LC90 and LC95 of glyphosate were calculated at 24, 48, 72 and 96 hours after adding glyphosate using probit test. Results: Mortality was observed in all treatments which exposed to higher than 50 mL.L-1 after 96 hours. The results showed that 96-hour LC50 of glyphosate for common carp was 92.71 mL.L-1. The fish exposed to different concentrations of glyphosate showed clinical signs such as increased mucus secretion, skin darkening and death with mouth open. Conclusion: Glyphosate disrupts the synthesis of amino acids in plants by inhibiting enzymatic activity of 5-enolpyruvylshikimate-3-phosphate synthase (EPSP). This enzyme is absent in animals. However, glyphosate is toxic for common carp. Keywords: Animals, Herbicides, Glyphosate, Carps, Excitatory postsynaptic potential

Spatiotemporal assessment of some heavy metals in the Anzali International Wetland during 2007-2014

Background: Todays, water resources are affected by various factors such as organic materials, pathogens (bacterial and microbial agents), and minerals (including heavy metals). For this reason, continuously examining the spatiotemporal changes in environmental pollutants is one of the most critical components of water quality studies. Methods: The sampling of some heavy metals (Ni, Cd, Zn, Pb) took place from 8 different stations in four seasons of 2014. After the preparation of the samples, they were used to measure the elements based on the technique proposed in Standard Methods. Results: Among the studied stations, the highest concentrations of metals were measured at the Pirbazar Station. The concentration of these metals was higher in the spring and summer than in the rest of the seasons. The results showed that the concentration of metals in water at different stations in the four seasons was Ni 0.05), but the results of the paired-sample t-test showed a significant increase in heavy metals(Ni, Cd, Zn, Pb) in comparison with the results obtained in 2007 (p<0.05). Conclusion: Adoption of appropriate management approaches for comprehensive environmental assessment and control of anthropogenic pollutants reducing the organic load from industrial, urban and agriculture waste, continuous quality surveillence around the year and finally environmentaly upgrading the wetland is suggested

Assessing nitrogen dynamics model and the role of artificial lagoon in effluent loading of shrimp farms in Gomishan wetland, southern Caspian Sea

Shrimp farming increases the nutrients, especially nitrogen in the water resources reducing water quality. This study was conducted to evaluate the nitrogen dynamics in white shrimp (Litopenaeus vannamei) farms and the role of artificial lagoon (24 ha) in reducing nitrogen levels in Gomishan coastal wetland, the eastern Caspian Sea. The results indicated that at the end of the 4-month breeding period, the amounts of nitrogen and phosphorus introduced into Gomishan wetland were calculated as to 220.157 and 39 tons, respectively in a breeding area covering 830 hectares. Nitrogen values (based on nitrate) calculated based on the relationship between the basin and the discharge of the outlet channel of the site at the time of complete emptying of the farms, were calculated to be approximately 121.8 tons per breeding time that it had an important role in eliminating about 45% of nutrient pollution and reducing the concentration of dissolved nitrogen. Moreover, nitrogen isotopic trace was observed in shrimp samples, in similar levels in the samples of both shrimp pond and lagoon, which emphasizes the role of feeding from natural food, especially benthic fauna. Overall, due to the decline of Caspian Sea water level, Gomishan coastal wetland is drying, and the output of shrimp farms is currenly the only source supplying water for the wetland. Hence, appropriate management strategies could minimize the amounts of nutrients into the natural water whilst aiding wetland's survaival

Acute toxicity of two pesticides Diazinon and Deltamethrin on Tench (Tinca tinca) larvae and fingerling

Diazinon and deltamethrin are common useful agricultural pesticides in the world. The present research compared the acute toxicity of diazinon and deltamethrin to tench larvae and fingerling. LC50 of 24 h, 48-h, 72 h and 96 h were determined using a probit. Fish samples (21 fish in each test group) were exposed to different concentrations of diazinon and deltamethrin (diazinon: for fingerling between1-20 ppm and larvae 0.25-2 ppm, deltamethrin: for fingerling between 0.01-0.2 ppm and larvae 0.0025-0.02) for 96 h and mortality were recorded. The LC50 96 h of diazinon for fingerlings and larvae were 6.77 and 0.63, respectively. The LC50 96 h of deltamethrin for fingerlings and larvae were 0.07 and 0.005 ppm, respectively. According to the results, larvae are more sensitive than fingerlings, LC50 values indicated that deltamethrin is more toxic than diazinon to Tinca tinca, so we suggest to use diazinon instead of deltamethrin in agriculture

Long-term dynamic analysis based on Landsat imagery in the Gorgan Bay- Gomishan Wetland, Iran

Coastal ecosystems are very dynamic and their changes occur relatively quickly due to the collision of two dynamic environments of land and sea. Gorgan Bay and Gomishan Wetland are unique ecosystems in the south-eastern part of the Caspian Sea. In this study periodic changes in the ecosystems of Gomishan Wetland and Gorgan Bay were evaluated over a period of 40 years using Landsat satellite imagery from 1978-2018. MSS, TM and OLI imagery along with NDWI index were used. The results show that the fluctuations in both ecosystems were consistent and the coastline changes were greater in the near-land areas. Based on the results, the highest area of ​​water in both ecosystems was obtained in 1997 (210.43 and 528.97 km2 for Gomishan Wetland and Gorgan Bay, respectively). These ecosystems also exhibited the lowest water area in 1978. In general, it can be conclude that remote sensing was an efficient tool in monitoring and managing coastal ecosystems

Morphological comparison of western and eastern populations of Caspian kutum, Rutilus kutum (Kamensky, 1901) (Cyprinidae) in the southern Caspian Sea

This study aimed to investigate morphological differences of western and eastern populations of Caspian kutum Rutilus kutum in the southern Caspian Sea and its providing length-weight relationships and condition factor (CF). A 13-landmark based morphometric truss network system was used to investigate the hypothesis of population fragmentation of western and eastern populations of this species. The studied populations were differentmorphologically based on pre anal, body height, distance from pectoral fin to ventral fin, distance from pectoral fin to anal fin, caudal peduncle length, head length, pre orbital, pre ventral, and dorsal length. The results also revealed a negative allometry (b<3) of length-weight relationships for both sexes. Maximum condition factors was found in March. The results suggest distinct stocks in the western and eastern of Caspian Sea for fisheries management

Acute toxicity of Diazinon to the Caspian vimba, Vimba vimba persa (Cypriniformes: Cyprinidae)

The present research was performed to determine lethal concentrations of diazinon for the Caspian vimba, Vimba vimba persa. Fish samples (50 ± 5 g) collected from Sefidroud river were acclimatized for 5 days and exposed to 5 concentrations of diazinon, 0.07, 0.08, 0.1, 0.13 and 0.16 mg/l (with three replicates) and lethal concentrations (LC) LC1, LC10, LC30, LC50, LC70, LC90 and LC99 for 24, 48, 72 and 96 h were determined using a probit analysis. The results indicated that the 96 h LC50 value of diazinon for Caspian Vimba was 0.08 mg/l

Comparison of temporal and spatial patterns of water quality parameters in Anzali Wetland (southwest of the Caspian Sea) using Support vector machine model

Urgent is growing to have reliable information from the country's water resources. In recent years, data mining models such as artificial neural network (ANN), gene expression programming, Bayesian network, machine algorithms, such as a support vector machine (SVM), and Random Forest have found widespread use in the field of simulation and prediction of components in aquatic ecosystems. Variables vary greatly on water quality parameters (due to nonlinear and complex relationships). Therefore, conventional methods are not eligible to solve water resource quality management problems. The aim of this study was to investigate the possibility of simulating the spatial and temporal alterations in water quality parameters during the period 1985-2014 in Anzali Wetland using a SVM model. Based on principal components analysis (PCA), the parameters EC, TDS, pH and BOD5 were selected for analysis in this study. Spearman correlation was calculated to determine the inputs of the model and the correlation coefficient(CC) between the water quality parameters. According to the results of the correlation table analysis, 8 types of structures including different inputs were used to predict the parameters with machine vector. In the next stage, 70% of the data were used to train, while the rest were used for analyzing the models. Criteria for determination coefficient (R2) and root mean square error (RMSE) were used for evaluation and model performance. The results revealed that in verification stage among different used models, the pH had the highest accuracy (0.95), while the lowest RMSE (0.20). Trend of alterations for optimal model of each parameter on a time scale, indicated an adequate estimation at most points. In general, the results exhibited the appropriate accuracy and acceptable performance of the SVM model in simulating water parameters