Microcystins (MCs) are a class of toxic secondary metabolites produced by some cyanobacteria strains that endanger aquatic and terrestrial organisms in various freshwater systems. Although patterns in MC occurrence are being recognized, divergences in the global data still hamper our ability to predict the toxicity of cyanobacterial blooms. This study aimed (i) to determine the dynamics of MCs and other cyanopeptides in a tropical reservoir, (ii) to investigate the correlation between peptides and potential cyanotoxin producers (iii) identifying the possible abiotic factors that influence the peptides. We analyzed, monthly, eight MC variants (MC-RR, -LA, -LF, -LR, -LW, -YR, [D-Asp3]-RR and [D-Asp3]-LR) and other peptides in 47 water samples collected monthly, all season long, from two sampling sites in a tropical eutrophic freshwater reservoir, in southeastern Brazil. The cyanopeptides were assessed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The biomass of potential cyanobacterial producers and water quality variables were measured. MCs were detected in both sampling sites year-round; the total MC concentration varied from 0.21 to 4.04 μg L−1, and three MC variants were identified and quantified (MC-RR, [D-Asp3]-RR, -LR). Additionally, we identified 28 compounds belonging to three other cyanopeptide classes: aeruginosin, microginin, and cyanopeptolin. As potential MC producers, Microcystis spp. and Dolichospermum circinalis were dominant during the study, representing up to 75% of the total phytoplankton. Correlational and redundancy analysis suggested positive effects of dissolved oxygen, nitrate, and total phosphorus on MC and microginins concentration, while water temperature appeared to favor aeruginosins. A comparison between our results and historical data showed a reduction in total phosphorus and cyanobacteria, suggesting increased water quality in the reservoir. However, the current MC concentrations indicate a rise in cyanobacterial toxicity over the last eight years. Moreover, our study underscores the pressing need to explore cyanopeptides other than MCs in tropical aquatic systems.

Nanoplastics (NPs) can adversely affect living organisms. However, the uptake of NPs by plants and the physiological and molecular mechanisms underlying NP-mediated plant growth remain unclear, particularly in the presence of iron minerals and humic acid (HA). In this study, we investigated NP accumulation in rice (Oryza sativa L.) and the physiological effects of exposure to polystyrene NPs (0, 20, and 100 mg L−1) in the presence of iron plaque (IP) and HA. NPs were absorbed on the root surface and entered cells, and confocal laser scanning microscopy confirmed NP uptake by the roots. NP treatments decreased root superoxide dismutase (SOD) activity (28.9–44.0%) and protein contents (31.2–38.6%). IP and HA (5 and 20 mg L−1) decreased the root protein content (20.44–58.3% and 44.2–45.2%, respectively) and increased the root lignin content (22.3–27.5% and 19.2–29.6%, respectively) under NP stress. IP inhibited the NP-induced decreasing trend of SOD activity (19.2–29.5%), while HA promoted this trend (48.7–50.3%). Transcriptomic and metabolomic analysis (Control, 100NPs, and IP-100NPs-20HA) showed that NPs inhibited arginine biosynthesis, and alanine, aspartate, and glutamate metabolism and activated phenylpropanoid biosynthesis related to lignin. The coexistence of IP and HA had positive effects on the amino acid metabolism and phenylpropanoid biosynthesis induced by NPs. Regulation of genes and metabolites involved in nitrogen metabolism and secondary metabolism significantly altered the levels of protein and lignin in rice roots. These findings provide a scientific basis for understanding the environmental risk of NPs under real environmental conditions.

The accumulation of potentially toxic elements (PTEs) in roadside soils and plant leaves due to vehicular emissions presents significant environmental and public health risks, particularly in densely populated urban areas. This study evaluated the concentrations of five PTEs—copper (Cu), lead (Pb), nickel (Ni), cadmium (Cd), and zinc (Zn)—in soils and leaves of three urban plant species (Pine, Cypress, and Mulberry) across six highways in Tehran, Iran, categorized into high, medium, and low-traffic zones. Soil samples were collected at a depth of 0–30 cm, and leaf samples were obtained from the canopy's outer sections. Samples were digested with aqua regia (soil) and nitric-hydrochloric acid (leaves) and analyzed using atomic absorption spectrophotometry. Pollution indices, including Pollution Load Index (PLI), Transfer Factor (TF), and Bioaccumulation Factor (BCF), were applied to assess contamination levels and metal mobility.The results showed moderate pollution levels across high-traffic zones (PLI = 3.94), with cadmium (Cd) contributing the most significant ecological risk (RI = 154.50). Transfer Factor (TF) analysis revealed high bioavailability for zinc (TF = 0.78) and lead (TF = 0.81), while cadmium exhibited limited uptake by plants (TF < 0.004). Bioaccumulation Factor (BCF) calculations indicated Pine and Cypress species had higher potential for metal uptake, with BCF values exceeding 1 for zinc and lead in high-traffic areas, whereas Mulberry demonstrated relatively lower accumulation. Despite a normalized NIPI index value of 1, the enrichment factor (EF) for zinc (EF = 98.04) underscores significant anthropogenic contributions, particularly from non-exhaust vehicular emissions. These findings highlight the need for ongoing monitoring, effective traffic management, and remediation strategies to address heavy metal pollution in urban environments.

As the world entered the industrial era, the nature of environmental threats and dangers posed by technology also have gone through fundamental changes. One of these environmental pollutants is the propagation of waves with different wavelengths in the environment. In this study, we aimed to investigate the effect of 2.45 GHz microwaves on blood biomarkers of mice. In this study, 80 immature male BALB/c mice were used. According to the inclusion criteria, 72 mice were included in the study. Mice were divided into two groups (control group=24 mice, exposed group=48 mice). Exposed groups were divided into two subgroups of 24 (groups A and B). Subgroup A was exposed to a simple modem without antenna and subgroup B was exposed to a modem with two antennas. In the first phase of the study, mice were exposed daily for 60 minutes for 90 days and in the second phase for 8 hours daily for 90 days. Blood samples were taken on days 90 and 180. Data analysis was done by SPSS software version 25 (P value<0.05). This study shows that blood cells are affected by long-term exposure to Wi-Fi waves by decrease in number and volume. Furthermore, no significant difference was observed between the blood parameters of the two groups exposed to different modems which vary in the number of antennas. The results showed that the highest effect of Wi-Fi waves was on the following blood factors, respectively PLT, RBC, HCT, HGB, and WBC.

The aim of this study was to assess the noise pollution of sports facilities in multi-purpose halls in Lahijan city, Iran. This research was of applied type. Through networking, 16 halls were randomly selected in four zones of the city and data were collected in the field. The sound level in the clubs was measured at level A and as an equivalent level by a portable device and Decibel X 2019 and compared with the sound standard (OSHA-90 dBA). The measurements were performed in triplicate and repeated three times. The calculated parameters included sound pressure level (SPL), average sound level ((LP) ̅), continuous sound equivalent level (Leq) and individual daily dose LAEp,d. The results showed that the lowest sound pressure level was 73.9 dB in the northern zone and in the first turn. The highest sound pressure level in the western zone was 97.7 dB. As the time changed from early morning to night, the average sound pressure level increased, highlighting the direct relationship between the sound pressure level and the measurement time. The average sound level in the western zone was higher than in other zones, and the average sound level in the southern zone was lower than in other zones. In both zones, the gyms were of the shed type, which could not establish a relationship between the structural form and the sound level. All the studied halls had levels higher than the standards for recreation centers and parks, as well as the standards of the United States Environmental Protection Agency (EPA). However, all of the gyms met other standards such as ACGIH, NIOSH and OSHA standards related to occupational health. Finally, there was a relationship between the urban location of sports halls and the sound level, such that halls located in the northern and western zones (the more affluent part of the city) had higher sound levels; in contrast, those located in the southern and eastern zones (poorer areas of the city) had lower sound levels.

Land use change shapes landscapes and is crucial for effective natural resource management, requiring a deep understanding of its trends for informed land management. The study utilized Landsat TM and Sentinel-2 satellite images spanning 1994 to 2023 to generate a 30-year land use change map of Erzurum. After processing of satellite images in ENVI, the Maximum Likelihood Algorithm used for classification and the Kappa coefficient used for reliability of results. Single and dynamic land use change indices used to assss the changes in LULC classes. The results indicated appropriate accuracy in the classified maps with a Kappa coefficient exceeding 0.75. The results revealed that the most significant land use changes in the Erzurum region were related to the conversion of rangeland to agricultural land. Over the period from 1994 to 2023, there was a notable increase in agricultural land use in Erzurum, contrasting with negative trends in waterbodies and garden areas. Rangeland experienced the most significant decline, decreasing by 19.22%, while agricultural land increased by 18%. indicating the highest growth among land use categories. According to the Single Dynamic Index, Bare Ground exhibited a change of +0.32%, while tree lands displayed a notably high dynamic degree of +0.31%. The significant expansion of agricultural land in Erzurum is primarily driven by agriculture being the main livelihood for local communities. This shift from rangelands highlights the strain on natural resources, necessitating careful management planning to balance agricultural expansion with environmental conservation concerns.

Lightweight expanded clay aggregate due to its physical and chemical properties; it can increase the process of adsorption and ion exchange. In this study, the efficiency 2 types of Lightweight Expanded Clay Aggregate in reducing the amount of COD, BOD, TSS, nitrate and phosphate in dairy industry wastewater were investigated and the impact of different factors such as adsorbent dosage, mixing speed and mixing time were studied. The results showed that the efficiency of COD reduction of wastewater after touch with the granular type after 20 h is 65.9%. TSS and BOD have also been greatly reduced. Also the use of powder type, the highest removal efficiency was 31.81%, mixing speed 100 rpm, mixing time 20h, and adsorbent dosage 10 gr/l in addition; increasing the rate of mixing speed increases the amount of nitrate absorption. The most effective nitrate removal is 63.87% which was at mixed speed 200 rpm and absorbent dose 4 g/l. Results show that, the mixing speed has little effect on the absorption of phosphate. So, after 30 minutes, even with increasing mixing speed for doses 2 & 4 g/l, the reduction efficiency also decreases the change in absorbent dose from 1 g/l to 4 g/l was virtually unaffected. Increased mixing speed is due to better distribution of nitrate and phosphate molecules in the solution and their contact with adsorbent increased the absorption rate. According to the results, the LECA granular has more ability to remove the COD.

ABSTRACT: The preset study investigated heavy metals located on the leaves of street side trees in crowded areas of Tehran in order to evaluate the metal pollution caused by cars. Contamination factor, Index of geo-accumulation, enrichment factor, modified degree of contamination, and Pollution load index were used to describe the pollution of the environment and probable sources of metal emissions. The potential ecological risk of exposure to metals in the areas was measured. Leaves are useful and low-cost collectors of aerosols which are produced by transportation. According to the results of the present study, Pb, Cu, Cd, Co, Ni and Zn elements are the main pollutants within the study area; Cr and Hg, also, turned out to produce pollution in the environment. Pb and Cr have probably been emitted from depreciation of vehicles and corrosion of parts and industries; probable origins of Zn and Cu are the industrial combustion sources and alloys of automobile parts. Mn is emitted from anthropogenic sources and further studies are required to identify its emission sources. Mo and V are probably the result of natural sources. The origin of Al, Co and Hg is a combination of natural and man-made sources, with high proportion for man-made activities. Due to high concentrations of Hg and Cr in areas outside and inside the city, further studies are required to find the source of origin of Hg and Cr elements. The ecologic risk of Pb, Cd and Cu was higher in different study areas. The risk of exposure to heavy metals in high density areas, and especially in Geisha, turned out to be high. Traffic of old cars and the traffic flow are effective in the pollution changes in different areas, and decrease in wind speed and direction causes pollution escalation in central areas of Tehran, compared to Western and Northern areas.

Tehran is the most affected town by light pollution in Iran. In this study, the role of the regional topography in the distribution of light pollution in Tehran was evaluated using digital images recording and analyzing the obtained images from Tehran sky-glow by East and South in standard image-processing Software. The scale of Tehran's glowing =dome as measured by 17 mag/arc sec2 or 0.017 cd/m2 by South, and 18.7 (mag/arc sec2) or 0.0035 cd/m2 by East. Considering the approximately equal distance of the two viewpoints from the center of Tehran city, the calculated scale by South is 1.36 times larger than the amount from the East point.

This study aims to evaluate efficiency of saponin, a bio-surfactant, in removal of heavy metals like nickel and vanadium from the soils which are smeared by crude oil and it was conducted according to properties of soils locating within Shahid Chamran oil Pump Station in 2016. For this purpose, after conducting primary studies and in order to determine pilot conditions of test, soil properties were initially studied in this zone and then 5 sampling stations were selected. Parameters of nickel and vanadium were measured along with the TPHs and pH. The studied phases included three variables of temperatures within ranges of (15, 25, 35°C), pH range (6, 7, 8) and concentration of oil compounds within ranges of 10000 and 30000ppm. The findings from assessment on efficiency of removal of heavy metals showed that the conditions with variables of temperature (35°C) and pH (about 9) included the best efficiency of removal of nickel and vanadium. Under concentration 10000ppm, the efficiency for removal of nickel shows rate of 42.98% at constrained mode for removal of nickel and 32.46% to efficiency for removal vanadium. In concentration 30000ppm, rate of efficiency for removal of nickel was 44.34% and also yield of 35.24% for removal of vanadium. This indicates by rising of concentration in oil compounds, the rate of efficiency increased in efficiency of soil washing.