gholamreza darvishi

Ammonia accumulation in warm-water fish pond can lead to mortality or reduction in growth and body immune indices.

The present study aimed to investigate the effects of chronic sub-lethal unionized ammonia (NH3) on growth indices and gill and kidney histopathology l, after a 30 – day trial in common carp (Cyprinus carpio).

Herein, 180 fish with an average weight of 4.5±0.5 g were divided into six tanks. Two groups, including one control group and one treatment group (with three replicates for each one), were considered. The treatment fish were exposed to 0.1 mg/l on un-ionized ammonia (NH3) for 30 consecutive days. Following one -month, ammonia exposure growth indices and histological analysis of gill and kidney were investigated.

The results showed that exposure to 0.1 mg/l of NH3 led to a significant reduction in growth indices. Additionally, edema and epithelial lifting with hyperplasia in the second lamella were detected in the gill of the treatment group. The kidney was characterized by focal renal tubules degeneration and necrosis, congestion, and increase in the melano-macrophage centers.

Although chronic exposure to 0.1 mg/l of unionized ammonia was not found to cause mortality in common carp, it could have some side effects, such as a decline in growth indices and histopathological effects in kidney and gill tissues. Thus, for higher production, sublethal levels of ammonia should also be taken into account in common carp ponds.

Today, plastics have a special place among the various issues that are considered as sources of pollution. Most of these plastics are in the dimensions of Micro and Nano. One of the most important sources of Microplastics transfer is wastewater treatment plants, where a large amount of these particles, which are not removed in the treatment process, enter the receiving environment. The purpose of this study is to first determine the optimal method of identifying and extracting particles from wastewater for counting and then to investigate the amount of removal and also to determine the amount of particles leaving the treatment plant.Sampling of inlet and outlet of wastewater treatment plant located in Mazandaran province was done seasonally in three seasons of spring, summer and autumn to determine in which season of the year, the amount of microplastics in wastewater increases or decreases. Also, the extraction and identification method is based on acid washing operation and based on creating a density difference, which has resulted in a favorable result with optimization and innovation.Using this method, the amount of Microparticles and microfibers along with the size and shape of the particle was determined and it was determined to what extent the normal treatment process is able to separate Microplastics from wastewater. The treatment plant can remove an average of 95% of the particles, which means that the remaining 5% of the particles are removed with the effluent and enter the aqueous environment.Finally, it was found that the determined laboratory method can identify and extract Microplastics in very small sizes to a very desirable extent. Also, determining the appropriate parameters of liquid volume, salt consumption and the use of dual capacity iron increased the efficiency compared to other methods and led to the identification of smaller particles than previous research.

Rivers are one of the primary water resources for agricultural, drinking, industrial and environmental applications; thus, assessment of the river water quality has a great significance. This study aims to evaluate the self-purification capacity of the Haraz river and identify critical areas with the lack of dissolved oxygen along the river. Also, the QUAL2K model, IRWQI and NSFWQI indexes were applied for the determination of water quality. In this study, primary pollutant sources including urban areas, industrial centers, farmlands and multiple cold-water fish farms that their water usage and discharge have severe consequences on the quality and quantity of the river's stream were identified and located. This model was built and calibrated for four seasons with data from six sampling stations of Haraz river. Based on this study, upstream of Haraz river has adequate self-purification capacity in comparison to its midstream and downstream, especially in the Amol city area, lack of dissolved oxygen was observed and self-purification capacity considerably reduced. The critical areas of Haraz river in spring and winter seasons are downstream and the estuary region, while in summer and autumn, critical areas are increased in Amol city. In general, as the elevation decreases, the water quality decreases. Only in upstream areas (near the Poloor village and before the Chelav station), water quality is in the average condition, but near the Caspian sea, the condition of Haraz river is worrying due to the existence of contamination sources.

Nowadays, traffic-induced air pollution factors are classified as destructive to the environment. Due to the increase in urbanization and the increasing growth of cars and transportation and movement of passengers and citizens between cities, scientific and practical studies on transportation systems with the intervention of mathematical science and intelligent systems, should move towards sustainable development and having a healthy air and transportation. The purpose of this article is to investigate the effect of traffic parameters on air pollution of suburban roads in the Sari-Qaemshahr road in Mazandaran province with respect to atmospheric variables and ozone pollution.

In this study, ozone pollutant concentrations were analyzed and modeled the Sari-Qaemshahr road. The study was conducted to determine the factors affecting the concentration of pollutants based on traffic and climate statistics and the relationship between traffic variables, average speed, rainfall, temperature, humidity, wind speed and finally their relationship with air pollution. Then, by using SPSS 16 software and based on the regression method, a model was presented that will be able to estimate the concentration of ozone pollutant on suburban roads with appropriate accuracy for the coming years.

According to the proposed model for ozone pollutants, among the available variables, temperature, traffic volume and wind speed have the greatest impact on ozone pollutants. Also, the results obtained from the validation show the success rate of the model in estimating pollution. In this study, the level of regression significance was above 95%. Also, the 90% data contribution rate for ozone pollutants in the model has been very favorable.

According to the results, modeling by regression method and using Spss software is a suitable method for estimating ozone pollutants. The proposed model can control and manage pollution emissions in road design and construction.