nasrin hassanzadeh

Soil erosion is one of the environmental problems that is a threat to natural resources, agriculture and environment, and in this regard, time and place information of soil erosion plays an effective role in management measures, erosion control and watershed management. Therefore, the aim of this research is to investigate the amount of soil erosion in Kozehh Topraghi watershed with the model (RUSLE) and its relationship with vegetation indicators. To achieve the goal of the research, the RUSLE experimental model, which includes R, K, LS, C and P factors, has been used. For this purpose, using the rain gauge data obtained from the Meteorological Organization, the soil texture layer 1:250000 of Iran, the digital model of 30 meters height of Aster and also the satellite image of Landsat 8 OLI have been prepared in the environment of the geographic information system (GIS) and after overlapping layers, the amount of annual soil erosion at the basin level was estimated. In the next step, the geomorphic and vegetation indices that are effective in the occurrence of soil erosion include topographic moisture index (TWI), waterway power index (SPI), domain curvature index (Curvatore), section curvature index (Profil Curvatore), surface curvature index (Plan) Curvatore) and Normal Vegetation Index (NDVI) were created in ArcMap environment and zoning maps were prepared. In line with this, GIS 10.8, ENVI 5.6, Excel, Word software were used to prepare maps as well as analysis. The results of this study showed that the amount of soil erosion for the whole basin was estimated between 0 and 26.63 tons per hectare per year. In another study, the relationship between geomorphic indices and vegetation cover with annual soil erosion rate was conducted, and the results showed that surface curvature indices and normal vegetation cover are the most influential with correlation coefficients of 0.39 and 0.26, respectively, compared to other indices. Also, Curvatore has the least effect with a value of 0.021. Therefore, it is concluded that based on the results obtained from the analysis of parameters related to erosion in the RUSLE model, as well as the indicators used in relation to soil erosion, finally, the surface curvature index and the vegetation index as an influencing factor compared to other parameters have the highest performance in the estimation of watershed soil erosion. The results of this research confirm the possibility of combining effective geomorphic and vegetation indicators on erosion, as well as the possibility of using other effective indicators and RS and GIS capabilities to quantitatively estimate soil erosion values. A

This study aimed to investigate the concentration of potentially toxic elements (PTEs) including iron (Fe), zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb) and determine their health risks, and evaluate the water quality of Abbas-Abad, Khako, Moradbeig Valley rivers and Ekbatan Dam inlets and bodies located in Hamadan, Iran.

In spring 2019, the concentrations of PTEs in water samples collected from 61 stations were quantified using an inductively coupled plasma optical emission spectrometry device. Water quality was evaluated using heavy metal pollution index (HPI), heavy metal evaluation index (HEI), contamination degree , heavy metal toxicity load (HMTL), and environmental water quality index (EWQI) indices. Carcinogenic and non-carcinogenic risks were calculated usingcancer risk (CR) and hazard index (HI), respectively.

It was found that the average concentration of Fe and Zn had a statistically significant difference (P < 0.05). By comparing the metal concentration to the World Health Organization’s standard, the concentrations of all elements were below the permissible limit, except for Fe and Cd, in 4 and 5 sampling stations. The quality of water sources revealed a low level of PTE contamination in the studied surface water. According to the HI results, there was no apparent threat to the residents’ health. Based on the CR assessment results, the dermal absorption of PTEs for both age groups was classified as low-risk. However, ingestion of these elements was categorized as high-risk.

Since Hamdan’s surface water sources are contaminated with PTEs, it is necessary to investigate effective management strategies for preserving the integrity and health of water resources.

Considering the role and importance of soil quality assessment in economic success and environmental sustainability, this study was conducted to evaluate the soil quality index (SQI) in different land use of Malayer province. For this purpose, 36 samples from 6 the land use were collected and 11 physical and chemical properties of soil were measured. The Soil quality index was determined based on criteria. Using the principal component analysis (PCA) method among 11 physical and chemical parameters of soil, two parameters of CaCO3 and K with a total variance justification of 63.08% as the most important parameters to evaluate the soil quality index were introduced using the Minimum Data Set (MDS) method. Finally, soil quality in different land uses was determined and compared. The results showed that the park and green spaces land use has the highest soil quality index in Malayer province, but irrigated farming and industrial land uses had the lowest soil quality, which requires management and increasing soil quality in these two land uses in order to prevent excessive soil degradation and erosion.  Considering that maintaining and increasing soil quality is one of the criteria for the sustainability of different ecosystems, the need to monitor this parameter in different land use and prone to damage in Malayer province is suggested.

Metallothionein protein and acetylcholinesterase enzyme are among the most important biomarkers in evaluating the health of aquatic ecosystems and have been introduced as one of the defense mechanisms of aquatic organisms in the face of various pollutants. Therefore, the aim of this study was to evaluate and biologically monitor the organic and mineral pollution of Gamasyab River using the biomarkers of acetylcholinesterase enzyme and metallothionein protein in two species of rainbow (Onchorhynchus mykiss) and common carp (Cyprinus carpio). Sampling was done from five rainbow trout farms and eight common carp farms along the Gamasiab River, and the samples were quickly frozen in liquid nitrogen and transported to the laboratory. The amount of metallothionein (MT) was measured based on spectrophotometric method and the analysis of cholinesterase enzyme (AchE) in fish brain was performed based on Elman's method. The findings showed that there was a statistically significant difference between different sampling locations in terms of the average values and effects of AchE and MT in two fish species (P<0.05). In addition, the average values of total AchE and MT in carp fish are equal to 3.42 µm/min/g and 707.75 µg/g, respectively, and in rainbow trout it is equal to 1.33 µm/min/g and µg, respectively. /g were 3105.7 and the comparison of the average amount of AchE and MT between two species of carp and rainbow trout showed that the amount of MT in rainbow salmon is higher than that of carp, And the amount of AchE activity in carp was higher than that of rainbow trout. The differences in the level of MT and AchE biomarkers can be caused by exposure of fish species exposed to different levels of pollutants due to differences in their feeding habits and behavior as well as differences in sampling points with environmental conditions and the entry of polluting sources are different. In this study, the application of 2 specific biomarkers to investigate the presence and effects of two groups of organic and inorganic pollutants in the Gamasiab River were determined without conducting any type of chemical analysis. directly exposed to the simultaneous entry of organic and mineral pollutants due to the extent and dispersion of different human uses on its margins, which can be detected by tracking specific biomarkers in indicator species (including rainbow trout and carp) to be a basis for monitoring the pollution of ecosystems.

Sustainable quality of rivers water has become one of the main concerns in developing countries, so monitoring the water quality of these resources for various uses is essential to formulate a public health and environmental management policy. The purpose of this study is to evaluate the water quality of Karun and Dez river systems in Khuzestan province and to analyze the suitability of their water quality for drinking and agricultural purposes. To this end, various techniques, indicators and statistical analyzes are used to evaluate spatio-temporal changes in the interpretation of large and complex datasets of 12 water quality parameters collected from the Karun and Dez river basins over a period of 17 years (2003-2019).Evaluation of the trend of water quality changes in the study period also showed that according to WQI, the water quality of Karun and Dez rivers from 2003 to 2007 are in the category of "very poor"and "poor", and from 2008 to 2018 in the "unsuitable" and "very poor"category, respectively. Regarding irrigation parameters, the lack of a clear trend in their values can indicate the lack of effect of river water quality from natural factors and their obedience with human factors. Overall, this study highlights the importance of using water quality indicators that provide a simple interpretation of monitoring data to help improve water quality, because based on these indicators and PCA, it can be concluded that related human activities along the banks of the Karun and Dez rivers, especially in recent years, affect their water quality.

This study was conducted to investigate the concentration, ecological, and health risk assessment of linear alkylbenzene sulfonate (LAS(, as the most common anionic surfactant in detergent formulations, in the Khako and Dare-Moradbaig Rivers in Hamadan Province. 13 stations accordingly were selected for water sampling, and some water quality parameters were measured at the sampling site. The samples were then transferred to the laboratory, the LAS absorption was read by spectrophotometer (UV-VIS-NIR) at 650 nm, and the final LAS concentration was calculated using the calibration curve equation. The results showed the LAS concentration was in a range of 0.2-1.66 mg/L. The Pearson correlation test did not show a significant linear relationship between LAS and water quality factors. The results of the ecological risk assessment in 9 stations were high risk, medium risk in 2 stations, and low risk in the 2 other stations. The results of the health risk assessment of LAS also showed no risk at different age groups. The comparison of LAS concentration with standard surfactant discharge (in surface water, irrigation, and agricultural applications in Iran) showed that the mean concentration of LAS in terms of discharge into surface waters is less than the allowable limit. By contrast, in terms of use for agriculture and irrigation, the mean LAS concentration is higher than the allowable limit. Given the importance of these rivers in terms of drinking water and agriculture supply and the need to maintain the health of the environment and society, it is necessary to take effective measures to control the entry of untreated wastewater into the Khako and the Dare-Moradbaig Rivers.

Air quality and distribution of trace elements in the Tehran metropolis were evaluated using transplants of the epiphytic lichen Ramalina sinensis.

Thalli of R. sinensis were collected from a non-contaminated area and transplanted in the six urban sites of Tehran for six months. After the end of the exposure period, the content of twelve elements in lichen was determined by ICP-MS method and the obtained data were evalusted using statistical analysis and various indicators.

Based on the results, the order of mean concentration of the trace elements in the R. sinensis lichen samples was determined as: Ca > K > Fe > Mg > Na > Mn > Zn > Pb > Cr > Cu > Ni > Co and the highest amount of bioaccumulation was found for the essential elements. For sevelar elements, significant differences were observed in various sampling sites. Based on the pollution load indexes (PLIs), two sites at Sharif university and Setad Bohran were more polluted than other areas. Exposed-to-control (EC) ratio values for Pb, Zn, Cr, Fe, Mn, Ni, Mg, and Co were also found in the range of 1.25-1.75. Based on the relative accumulation factor (RAF), the accumulation preference of elements by R. sinensis lichen was observed as Na > Cr > Cu > Fe > Mg > Ni > Zn > Mn > Co > Pb > Ca > K, respectively, which represents the significant ability of this species in the accumulation of elements such as Na, Cr, Cu and Fe. PCA and EF analysis indicated that trace elements adsorbed by lichen were mainly sourced from vehicle transportation.

This study demonstrates the application and importance of R. sinensis lichen in biomonitoring of air pollutants elements in urban areas. This approach can justify the suitability, accuracy and cost-effectiveness of lichen compared to other biomonitors for air pollutants and more importantly highlights its capability to the determination of wide levels of air pollution in large scales.

The benzene, toluene, ethylbenzene, and xylene (BTEX) compounds are the most abundant volatile organic compounds in the urban atmosphere. This study aimed to investigate and monitor the ambient BTEX compounds in Ahvaz, Iran.

The atmospheric concentrations of the BTEX were measured using the Air Quality Monitoring Station in the center of Ahvaz. Hourly mean concentration data of the BTEX compounds from March 21, 2017, until November 21, 2017, were obtained from the environmental protection organization of Khuzestan province.

Mean concentrations of the BTEX compounds were 0.80±0.04, 2.55±0.10, 0.54±0.03, and 1.26±0.07 µg/m3, respectively, and these concentrations were lower in the summer, compared to other seasons. A significant relationship between benzene and other BTEX compounds indicates that BTEX release from certain sources, such as gasoline vehicles. Moreover, the mean toluene/benzene ratio was estimated at 3.29±0.84, and this ratio shows that the highest concentrations of pollutant emissions were emitted from the activity traffic. Carcinogen risk assessment of Ahvazi people exposure to benzene showed that the mean cancer risk value for benzene exposure was 0.89×10−6, which was lower than the unit cancer risk value (i.e., 1×10-6). Hazard quotient's calculation showed that the mean non-carcinogenic risk values for exposure to BTEX compounds were 3.84, 0.074, 0.077, and 1.76, respectively. The mean hazard index (HI) for exposure to BTEX compounds was 5.75, which was considerably higher than the unit value of 1.

Based on the findings, the necessity of controlling BTEX emissions, especially benzene and identifying the sources of these compounds can be a useful tool for the management of connected control strategies.

Given the increasing use of detergents and the problems of water pollution caused by the release of wastewater containing large amounts of detergents in recent decades, this study aimed to investigate the concentration and health and ecological risk assessment of linear alkylbenzene sulfonate (LAS) as the most important detergent composition in Ekbatan Dam is Hamedan.

31 sampling stations from Ekbatan dam reservoir and Inlet Rivers to Ekbatan dam and overflow dam (Abshineh dam) selected for water sampling. Parameters such as water temperature, pH, EC, TDS, DO and ORP was measured at the sampling site. LAS adsorption was reading through a spectrophotometer (WTW 660) at 650 nm. The pollutant concentration was calculated through the equation of the calibration curve.

The results showed the measured LAS concentration in the range of 0.01-1.4 mg / L. The results of the Spearman correlation test between LAS and water quality factors showed a positive significant relationship between LAS with salinity, TDS and EC at 0.01 level and a negative relationship between LAS and DO at 0.05 levels. The results of the health risk assessment of LAS showed no risk in different age groups. The results of the comparison of LAS concentration with surfactant discharge standard in surface water and irrigation and agricultural applications in Iran showed that the concentration of LAS is below the permissible level (1.5 mg / L) for discharge into surface water. However, in terms of use for agricultural and irrigation purposes, the LAS value at 7 stations was higher than the permissible level (0.5 mg / L).

The results of this study showed that Ekbatan dam and rivers entering the dam are exposed to mild wastewater as a result of human activities. Therefore, it is necessary to take effective and preventive activities to control and reduce pollutants entering this valuable dam.

The aim of this study was to investigate the linear alkyl benzene sulphonates (LASs) as molecular markers to detect contaminants associated with municipal wastewater in Abbasabad River. Sampling was done in 17 stations from Abbasabad River in spring 2019. water temperature, (pH), (EC), (TDS), (DO) and(ORP) were measured at the sampling site. the LAS concentration was read using a spectrophotometer at 650 nm and the LAS concentration was calculated using the calibration curve and absorbed wavelength. Ecological risk assessment was performed by calculating RQ index. The results showed LAS concentration ranged from 0.11 to 2.65 mg/L with a mean of 1.25 mg/L. The entry of untreated wastewater into the Abbasabad River was the main cause of the high concentration of LAS. Ecological risk assessment results showed high risk in the studied basin. The results of Spearman correlation test between LAS and water quality factors showed positive relationship between LAS with salinity, TDS, EC and temperature. Comparison of LAS concentration according to Iranian standard for discharge to groundwater resources and agricultural and irrigation purposes showed that LAS concentration in 14 stations was higher than permitted for agricultural, irrigation and discharge into wells and at four stations above the permitted level of discharges to surface water sources. The concentration of LAS at 15 stations was above the permissible level of detergents in drinking water according to the Iranian and WHO standards. This study demonstrated the usefulness of investigating LASs as powerful indicators for tracking contaminants associated with urban wastewater discharge.

 of the Study: The current study was designed to determine the quality of sediments in Karun in Ahvaz, Iran, according to aquatic pollution indices.

The sediment samples were obtained from six river stations in summer and winter. The sediment samples were air-dried, sifted, homogenized, and stored in plastic bags, and the concentrations of metals were determined in the laboratory.

The obtained findings revealed that the mean concentrations of lead, zinc, chrome, and cadmium were 26.27, 72.36, 53.47, and 3.85 mg/kg dw in summer and 13.41, 59.54, 30.28, and 0.42 mg/kg dw in winter, respectively. According to the mean scores of the potential ecological risk index (PERI), in two seasons, the sediment enrichment with metals was observed in the order of Cd > Pb > Cr > Zn; however, according to biological toxicity test (the effects range-median quotient), the sequences of the metals during summer and winter were Cd > Cr > Zn > Pb and Zn > Cr > Pb > Cd, respectively. The comparison of indices between stations showed that in summer, stations 3 and 4 were medium-low priority side according to the mean effects range-median quotient (mERM-Q) and were reported with moderate ecological risk based on the PERI. In winter, stations 2 and 4 had a medium-low priority side and moderate ecological risk according to mERM-Q and PERI, respectively. The results of hazard quotient (HQ) and modified hazard quotient also showed that the HQ values of Pb and Zn (0.1<hq</hq

Based on all the indices, station 4 was the most contaminated site, and Cd was reported with the highest risk. Therefore, entering the wastewater canal and input contaminants, especially cadmium into Karun can be regarded as a major concern.

The undesirable condition of air quality is one of the most important environmental problems that have challenged many of the worldchr('39')s cities. In this study, considering the importance of particle matter as one of the most important atmospheric pollutants in Ahwaz, the main objective is the air quality assessment of this city in terms of PM2.5 and PM10 in 2016-2017.

The air pollution data were obtained from the Ahwaz Air Quality monitoring network. To check the status of suspended particles and determination of the contribution of each pollutant to air quality decline and also determine the responsible pollutant, USEPA-AQI and IND-AQI methods and Exceedance Factor were used.

The mean annual concentrations of PM10 and PM2.5 were 165.35 µg/m3 and 58.26 µg/m3, respectively. According to the results of the Ahwaz air quality index during this period, in terms of the PM10 pollutant concentration, 27 days and based on the concentration of PM2.5 pollutant in the total days, the condition were unhealthy. Comparison of seasonal concentrations of pollutants with NAAQS showed that the pollutants were higher than the NAAQS limit in all seasons. The air quality classification based on IND-AQI showed that the air quality level was poor in all seasons, and based on the USEPA-AQI, this condition of Ahwaz air has been created unhealthy air quality and Unhealthy for Sensitive Groups. Comparison of two methods showed that IND-AQI in the region was 273/90 and the responsible pollutant is PM10 but according to USEPA-AQI method, the responsible pollutant was PM2.5 with 136.93 AQI value. The EF factor also confirmed the results of the IND-AQI method and showed that the responsible pollutant in reducing air quality to poor and critical condition during these two years is PM10 contaminant.

Therefore, based on the findings continuous monitoring of air quality, especially in terms of PM10 pollutant, is one of the main strategies for controlling air pollution in this city.

Evaluation of concentration and degree of heavy metal contamination in rivers based on sediment contamination indices is one of the important issues in ecotoxicology research. Therefore, the purpose of this study was to measure the heavy metal concentrations in the sediments of the Siahrood River and to assess the health risk of these pollutants. Another purpose was to determine the status of the river in terms of contamination and non-contamination for ecotoxicology studies.

Acid digestion method was used to prepare the samples. Then the concentrations of Cr, Fe, Zn, As, Se, Ni, Co, Al and Mn were measured using ICP-OES. Pollution and ecological risk indices were also calculated.

The mean concentrations of chromium, iron, zinc, arsenic, selenium, nickel, cobalt, aluminum and manganese were 33.02, 7309.82, 42.61, 13.15, 13.36, 12.88, 6.58, 159.28 and 384.51 µg/g dw, respectively. Most of the studied elements were in the first category of pollution assessment indices.

The results based on contamination indices and comparison with sediment quality guidelines showed that concentrations of Cr, Se and As are of concern and could potentially be a threat to the health of organisms. For ecotoxicology studies, this river is considered to be relatively contaminated in terms of Cr, Se and As and non-contaminated for other studied elements. However, further studies and monitoring of pollutants in this ecosystem are essential for making proper and effective management decisions.

There are several methods for determining the water supply system safety, including the WSP program that recommended by the World Health Organization (WHO). So, The aim of this study was assessment the water supply system of Hamadan city based on the Water Safety Plan (WSP) guideline introduced by the world health organization in 2018. This investigation employed the WSP-QA Tool and the WSP manual of the WHO and the AWI in 2017. For this purpose, software checklists were prepared and, after confirmation of content and face validity, completed based on Hamadan water and wastewater company records and interview with company’s experts. Data was analyzed using WSP-QA Tool and then system hazards were identified and risk assessment and prioritized hazards were performed by use of semi-quantitative risk matrix approach presented by the WHO guideline. The results showed that from the total score of 440 complete implementations of WSP and according to the 384 score related investigation different phases of this study, the 220 score was achieved that 50 % was coordinated with WSP. The Results of risk assessment showed that discharge wastewater from a village and agriculture in the catchment, blocked filter and algae in treatment, old pipe and excavation and installation facilities in the distribution and pressure drop and constructing wells at home in point of use are the most important hazards in water supply system of Hamadan. Overall, The results showed that the implementation WSP in Hamadan city is in a moderate situation.

Di(2-ethylhexyl)phthalate (DEHP) is a plasticizer in a variety of consumer products. Given the adverse toxicity effects of DEHP on living organisms, its high consumption and dispersal has been caused a serious concern. . Nowedays, the Fish Embryo Test (FET) method is widely used among the conventional methods of toxicology .The aim of the this study was to determine the acute toxicity of Di(2-ethylhexyl)phthalate on zebrafish (Danio rerio) embryo using FET method to assess both lethal and sublethal endpoints and anomalies effects over 5 days . Zebrafish embryos (3 hours post-fertilization) were exposed to different concentrations of DEHP (0.05, 5, 20, 35, 50 and 100 µg/l) for 120 h, then, lethal and sub-letahl endpoints of embryos evaluated and data were analized using Probit software. The LC50, NOEC and LOEC values obtained for DEHP were 46.14, 12.08 and 22.06 µg/l, respectively. Also, There were abnormalities including coagulation of the embryo, lack of somite formation, non-detachment of the tail bud from the yolk sac, malformation of tail and lack of heartbeat in the embryos. This study showed that DEHP is a teratogenic pollutants and the application of FET method is / an alternative method for developmental toxicity tests to predict effects of emerging pollutants on aquatic organisms.

Background & Aims of the Study: Grape, a crucial agriculture crop of Malayer city, is affected by Vine cicada, Psalmocharias alhageos. Imidacloprid, a neonicotinoid insecticide, provides a good management of this insect. The aim of this research is residue persistence study of imidacloprid on grapes, to estimate its residue deposit, the half-life of degradation and safe pre-harvest consumption time. Residues of imidacloprid were estimated in grape following two recommended types of spraying (80.0 g a.i. ha-1) and duplicates the application rate (160.0 g a.i. ha-1). Samples were collected at 1 h to 21 days after spraying of imidacloprid. The analyses were done by the QuECHERS technique, using HPLC-UV. The average initial concentration of imidacloprid on grapes found to be 10.58 and 17.56 mg kg-1 at single and double dosages, respectively. These residues of imidacloprid decreased to 97.8% and 98.0%, respectively, at single and double dosages in 15 days, with a half-life period of 2.21 and 2.94 days. Residues of imidacloprid on grapes were less than its MRL value after 7 and 10 days of recommended and double dosage of spraying. Residues of imidacloprid in grape berries at harvest were discovered to below the determination limit. Consequently, a waiting time of 7 and 10 days is usually recommended for safe consumption of grapes once imidacloprid spraying. Acceptable daily intake (ADI) of imidacloprid is 0.06 mg kg-1 body weight day-1. According to the results of this study, the employment of imidacloprid on the grape looks to be toxicologically acceptable.

This study aimed to investigatethe changes in Gonad Somatic Index (GSI), vitellogenin induction and ovarian histopathology in zebrafish (Danio rerio) adult female, as an ecological model in toxicology, after exposure to 0.002, 0.02, 0.2, 2 and 20 µg/L cadmium chloride for 21 days under sub-lethal condition. The results showed that 0.002 to 20 µg/L cadmium chloride had no significant effect on the survival, But GSI and vitellogenin concentrations in whole body homogenate (WBH) decreased in a dose- dependent manner in all treatments. Gonad histology showed increased proportion of atretic follicles, reduced proportion of vitellogenic oocytes, haemorrhage, hyperemia, membrane folding in some oocytes, hypertrophy of granulosa cells, proteinaceous fluid and decreased yolk formation in vitellogenic oocytes. These changes indicate a disturbed reproductive output. The results of this study showed that an increase in atretic follicles and decreased vitellogenin have negative effects on zebrafish fertility. Moreover,continuous exposure to subacute sublethal concentrations of cadmium chloride had anti-estrogenic and irreversible effects on zebrafish reproduction.

Cadmium (Cd) is one of the most toxic environmental heavy metals to organisms. The prominent toxic effects of Cd on reproductive organs are very well known. Gonad histopathology is a valuable tool for the assessment of endocrine disruption compounds EDCs effects on fish. The aim of this study was to evaluate the reproductive toxicity of cadmium chloride (CdCl2) on histopathology of Zebrafish (Danio rerio) testis under sub-lethal conditions. Male Zebrafish were exposed to four concentrations of CdCl2 (0.002,0.02, 2, and 20 mg/L) for 21 days in semi-static conditions. Histopathological changes in testis and Gonad Somatic Index (GSI) were studied. Treatment at 0.002 to 20 mg/L cadmium had no significant effect on the survival and condition factor. GSI decreased in a dose- dependent manner and the decrease was significant (P

Methyl paraben (MP) is widely used as a preservative in various products. It frequently enters into aquatic environment and renders potential threat to fish. The aim of this study was to evaluate reproductive toxicity of MP on zebrafish (Danio rerio) under laboratory conditions. Male zebrafish were exposed to four concentrations of MP (0.001, 0.01, 1, and 10 mg L-1) for 21 days in semi-static condition. Changes in mean length, mean weight, gonadosomatic index (GSI) and histology of testis were studied. Treatment at 0.001 to 10 mg L-1 MP had no significant effect on the survival, mean length and mean weight of fish. But, GSI decreased in a dose dependent manner and the decrease was significant in the group that received the highest dose. Histological alteration of testis consisted of general testicular atrophy, multi-nucleated gonocytes (MNGs), impaired germ cell, spermatogonial proliferation, Leydig cell hyperplasia, interstitial fibrosis and apoptosis of Sertoli cells. It was concluded that sub-chronic exposures of MP could adversely affect GSI, disrupt the histology of testis and produce estrogenic and antispermatogenic activity in male zebra fish.

Paraben compounds are used widely as preservatives to inhibit microbial growth and extend used in pharmaceuticals, hygienic, cosmetics, care products. They pose the potential for reproductive toxicity for users. This paper provides an overview of the applications of histopathological biomarkers in reproductive toxicity in zebrafish caused by methylparaben. The present study investigated the changes in ovarian histopathology and Gonad Somatic Index (GSI) in zebrafish (Danio rerio</em>) adult female after exposure to 0.001, 0.01, 1 and 10 mg/L methylparaben for 3 weeks in semi-static condition. Histological preparations were stained with Hematoxylin & Eosin. The results showed that Treatment at 0.001 to 10 mg/L of methylparaben had no significant effect on the survival, and condition factor. But in all treatments, GSI decreased and ovarian complications include wrinkled ooplasm, impaired yolk production, granulomatous inflammation and proteinaceous fluid were observed in the interstitial space of treated zebrafish ovaries. Also, atresia of vitellogenic oocytes was determined. These data show that an increase in atretic follicles has negative effects on zebrafish fertility and continuous exposure to subacute sublethal concentrations of methylparaben increase estrogenic and irreversible effects on the reproductive in female zebrafish.

Background and Today، environmental pollution، especially pollution of aquatic ecosystems، has caused serious problems for humans and other organisms. Endocrine disrupting chemicals are a group of chemical compounds that have serious adverse effects on humans and animals reproduction system. Phthalate acid esters (PAEs) are used as plasticizers which are easily released and transferred from plastics to the environment. To our knowledge، so far، no studies have been done in Iran on contamination levels of 2 PAEs، therefore، this study aimed to determine the concentration of di (2- ethylhexylphtalate) (DEHP) and di-n-butyl phthalate (DnBP) in the surface water of Anzali wetland. Water samples were taken from stations and prepared using dispersive liquid–liquid microextraction (DLLME) method. Then، they were injected into the Gas Chromatographymass Spectrometry (GC-MS). The concentration ranges of DEHP and DnBP in water samples were 0. 41-31. 15 and 0. 03-21. 84 (in μg/l)، respectively. Among 30 samples analyzed، no sample was found to be free of DEHP and DBP، which indicates these two phthalate esters were ubiquitous in this wetland. The concentrations of DEHP and DnBP in eastern part of Anzali wetland were higher than those of the western part. Results showed that the concentrations of DEHP and DnBP in the water of Anzali wetland were higher than the environmental risk limit (ERL). DEHP and DnBP are potentially hazardous to the aquatic organisms and humans and could cause serious infertility problems in male species. So، an effective PAE management and control strategy must be implemented in order to reduce the problems caused by PAEs in the environment.