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Introduction: The health of the river basin is determined by the health of its ecosystem to provide important and valuable resources and services for human use and the basin itself. However, the changes in the land use pattern, which is an effective reflection of anthropic activities, have greatly disturbed the health of the river and are the main driver of water quality reduction. Examining the relationship between land use patterns and river water quality provides an important basis for water quality safety and effective land use management. Therefore, the aim of this study is to investigate the influence of land use patterns on surface water quality based on the water quality monitoring data and land use data from 38 sampling points in the sub-basin of the Maroon River. Material and Methods: In order to sample from the study area, first, the boundary of the sub-basin of the maroon river was determined, and then the sub-basin was divided into different smaller sub-basins using the hydrological analysis tool in ArcGIS software, and the map of waterways in the region was also prepared. Then, sampling stations were selected from the exit point of each of these sub-basins in the main sub-basin area. In order to measure the water quality parameters of the studied area, sampling was done from 38 monitoring stations in the sub-basins in triplicates in the spring of 2023. The land use map was prepared using Landsat satellite images to evaluate the changes and the impact of land use patterns on the water quality status of the Maroon River sub-basin. Then, using geographic information system and multivariate statistical techniques, the effects of land use on river water quality in the Maroon sub-basin were estimated. In addition, in order to evaluate the quality of river water in different sub-basins, water quality data was analyzed using the water quality index (WQI). Results and Discussion: The results of the evaluation of the distribution of land use patterns showed that the use of pasture is the dominant use in the sub-basin of the Maroon River and the water quality parameters exhibited significant changes in the stations covered by agricultural and forest use. The results of correlation analysis and linear regression of water quality parameters and land use patterns in the Maroon River sub-basin showed that agricultural land has a negative relationship with pH and DO parameters and a positive relationship with parameters , and Ca2+, forest land has a positive correlation with DO and a negative correlation with , and urban land also showed a negative correlation with DO. WQI values in different monitoring stations were estimated between 73.80 and 288.73 which showed that the health level of the river upstream of the sub-basin was better than downstream. In general, based on the WQI classification, 62.5% of the water quality of the Maroon River sub-basin was in the "poor" class, 25% in the "very poor" class, and 12.5% in the "good" class. Conclusion: The findings of the research showed that agricultural land was the key factor affecting the water quality parameters and as a result the decrease in water quality in the sub-basin of the Maroon River, so limiting the discharge of runoff from agricultural activities is critical for improving water quality in the study area. This study highlights the importance of LULC changes in water quality for making informed decisions on proper watershed planning and management.

Background: 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. Methods: 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 using cancer risk (CR) and hazard index (HI), respectively. Results: It was found that the average concentration of Fe and Zn had a statistically significant difference (P

Background: One of the most concerning pollutants in urban areas across the globe is particulate matter suspended in the Earth’s atmosphere. The main objective of the current investigation is to explore the spatial and temporal patterns of ambient air particles (PM10 and PM2.5) and PM2.5/PM10 ratio in different urban areas of Khuzestan Province. Methods: In this way, the required data were gathered from the environmental protection organization based on hourly mean concentrations of PM10 and PM2.5 of six air pollution-monitoring sites for 5 years. Results: Results indicated that the average concentrations of PM10, PM2.5, and PM2.5/PM10 are about 134.14±39.23 µg/m3, 44.51±13.44 µg/m3 and 0.33±0.07, respectively. The examinations revealed a reductive trend on annual values of PMs in terms of temporal variations. A detailed investigation of the annual mean concentrations of PMs and PM2.5/PM10 in terms of spatial variations demonstrated the largest values for Naderi-Ahvaz and Abadan stations. Furthermore, the measured AQI was larger than 100 and the Exceedance Factor (EF) values of PM10 and PM2.5 ranged between 1.51-2.73 and 0.77-1.41. The statistical analysis obtained from linear regression revealed a significant positive relation between AQI and PM2.5 and PM10 with correlation coefficients (R2) of 0.8259 and 0.7934, respectively. Conclusion: Although the analysis and measurement revealed a reductive trend in the annual mean concentrations of PM2.5 and PM10, the measured AQI and EF values are still far from the standards of good quality and low pollution. Therefore, it is highly necessary to follow the air pollution protocols to control PM air pollution in Khuzestan Province.

Background: Heavy metals due to their ecological risks and high toxicity to living organisms are considered as one of the most dangerous pollutants. Therefore, the present study was conducted to investigate the level of pollution, toxicity and the ecological risks of heavy metals in the coastal surface sediments of Bushehr province using systematic review. Methods: To conduct this review study, the concentration level of heavy metals in the surface sediments of Bushehr coastal was obtained by searching for published studies during the 9 years (2012-2020) through databases (Springer, Google Scholar, ProQuest, Web of Science, SID, Magiran). Finally, a comprehensive description of heavy metal pollution, toxicity and risks in coastal sediments was investigated using various indicators. Results: As a result of reviewing the extracted studies from the databases, 24 papers were selected. The survey results showed that the order of mean concentration of heavy metals in sediments was as Zn>Ni>Cr>Cu>Pb>Cd, and the amount of metals Pollution load index in different coastal sediments ranged from 0.15 to 1.99. The order of ecological risks for metals was observed as Cd>Pb>Ni>Cu>Cr>Zn, and the potential ecological risks for metals was obtained in the range of 3.76-257.38. In addition, the results of Toxic unit analysis and modified Hazard quotient of metals showed that the degree of toxicity and risk of contamination varies from very low to severely contaminated. Conclusion: Based on the findings from the perspective of toxicity control and ecological risks of metals, it is necessary to prevent the transfer of heavy metals, especially Cd, Pb and Ni due to dominant human activities in the coastal areas of Bushehr. Also, due to the maximum pollution load and ecological risks in Bidkhon (Assaluyeh) coasts, pollution sources should be determined to effectively control and manage the entry of pollutants in this area.

Background and Objective: Air quality and distribution of trace elements in the Tehran metropolis were evaluated using transplants of the epiphytic lichen Ramalina sinensis. Materials and Methods: 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. Results: 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. Conclusion: 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.

Background: The undesirable condition of air quality is one of the most important environmental problems that have challenged many of the world'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. Methods: 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. Results: 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. Conclusion: 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.