International audience | Due to its role in the crustacean moulting process, N-acetyl-beta-d-glucosaminidase (NAGase) is interesting to monitor the good proceeding of the moult cycle, as well as relevant in assessing changes in the moulting process caused by stressors. The present study aimed to measure the NAGase activity to monitor the moulting process of the freshwater amphipod Gammarus fossarum. Firstly, an optimised protocol measuring the NAGase activity was made, allowing a robustness and reproducibility of measurements. Then, intrinsic variability of NAGase response was checked under two physiological factors: the gammarid moult cycle and gender. For both genders, a significative increase of activity was observed during premoult, instead of a basal activity detected during postmoult and intermoult. However, the NAGase female profile was preconised to study since it was defined with more precision. Finally, a 16-day exposure of female gammarids to different levels of treated or non-treated wastewater effluents was made. If delays of tissue development appeared on effluent exposed specimens, NAGase activity was similar between the different conditions. This apparent desynchronization between tissue and molecular activities accentuates the diagnostic of moult impairment and raises the interest to use markers at different organisational levels.

The Zayandeh-Rood River (Isfahan Province, Iran) is of vital importance as a water source for various purposes, but it is facing adverse effects from human activities. This study focused on the surface sediment of 21 stations along the river to assess the concentration of potentially toxic elements (PTEs) and their environmental risk using the Geoaccumulation Index (Igeo), Enrichment Factor (EF), Pollution Load Index (PLI), and Potential Ecological Risk Index (RI). The mean concentration of the PTEs (mg/kg) was ranked as follows: Cd (0.34)< As (9.73)< Pb (10.95)< Co (11.91)< Cu (31.14)< Ni (31.90)< Zn (61.33)< Cr (96.95)< V (125.09)< Mn (707.76). Positive correlation coefficients were found among all the PTEs, while their relationships with the sediment physicochemical characteristics varied considerably, indicating that various interacting factors might influence the deposition and mobility of PTEs in the river. The river was classified as having moderate to low contamination (Igeo index) and minimal-to-moderate enrichment (EF index) except for Cd and As which exhibited extremely high enrichment and strong pollution in the upstream zone, where agricultural activities dominate. Therefore, managing agricultural practices and reducing the excessive use of PTE-containing pesticides and insecticides should be a primary focus to protect the Zayandeh-Rood River from further contamination.

The purpose of this study was to evaluate the environmental and health risk of PM2.5 microns in district 10 of Tehran. Initially, data related to the year 2019 were collected and analyzed through pollutant measurement at the regional level. Based on Kriging's interpolation the corresponding raster was produced and classified according to the minimum and maximum range. Finally, according to the air quality index, the level of importance of health safety was classified and the relevant map was prepared. Through the IO technique, the location layer of sensitive and vulnerable land uses and the carbon monoxide contaminant zoning layer were mapped. Results showed that District 10 of Tehran with the average concentration of 42µg/m3 is the most polluted area in terms of this contaminant in Tehran. Also, most of the PM2.5 pollutants belong to the northern, southern and western half of the region. Also, December was the most polluted month of the year with an average concentration of 56μg/m3. From the point of view of the air quality index based on the type of pollutants, the area had 104 days of unhealthy and unhealthy days for sensitive groups. Environmental and health risk assessment of these pollutants indicates that according to William Fine method, the risk number is 105, which indicates the average risk level. Therefore, it requires corrective and emergency risk control measures.

In this study systematic random sampling was conducted. To estimate the sample size, 100 households were selected based on the population of the city using Cochran's formula. Total generated municipal solid waste was consecutively collected, weighed and separated during a week. Then, after providing the required training through face-to-face manner and brochures regarding the economic, social, cultural and environmental importance of source separation to each of the households, once again the generated wastes were collected, weighed and separated. The difference in the composition and amount of waste generated before and after the training was compared by independent t-test. The effect of the demographic characteristics of the head of the household on reducing the amount of generated waste was determined by correlation test. The results highlighted the training as an effective intervention on the weight of produced waste from each household before and after the training (P=0.000). Education increases people's awareness about waste, recycling, harms of waste, definition of separation, benefits of separation, source separation and level of household education. The reduction in the amount of produced waste had no significant correlation with the age (P=0.89), occupation (P=0.16), income (P=0.95) and education level (P=0.36) of the heads of each household. The findings of this research showed that education, regardless of demographic characteristics, is an effective method to change specific behavior and create motivation to reduce the amount of waste at source, underlining the importance of training to improve waste recycling management.

Environmental Management Plan (EMP) is regarded as a guidance document to attain and measure compliance with the mitigation requirements and environmental protection of projects, which are normally requirements for project approvals. The study mainly aims to present an Environmental Management Plan for dams whose construction was suspended by opposing stakeholders for the harmful impacts on the environment in forested areas. As a case study, the Hyrcanian forests (Caspian forests) are located in western Asia and were inscribed on the United Nations Educational Scientific and Cultural Organization (UNESCO) World Heritage List in 2019. The construction of the hydropower Shafarood dam began in these forests in 1990. Because of budget deficits and the suspensions incurred by opposing activists in 2013, dam construction has only advanced by 23% ever since. To meet that aim, the research data was collected through analysis of documents, letters, articles, field visits to the construction site, and interviews. The semi-structured interviewing method was employed in holding interviews with governmental and environmental NGOs, local people, specialists, and academics because of their good cooperation. The results indicate that the most negative effects in the construction phase have been produced by deforestation and degradation of vegetation, source of material supply, settlement and livelihood of migrants impacted by dam impoundment, water, air and sound quality. Ultimately, an Environmental Management Plan was proposed for this dam and those under construction or suspended in forested areas to minimize the negative environmental effects of the Hydropower Shafarood dam, which technically concentrates on mitigating measures.

Remediation of residually contaminated soils remains a widespread problem. Biochar can immobilize polycyclic aromatic hydrocarbons (PAH). However, studies on its ability to immobilize PAH and N, S, and O substituted PAH (hetero-PAH) in real soils, and benchmarking with commercial activated carbon are missing. Here, we compared the ability of pristine biochar (BC), steam-activated biochar (SABC), and commercial activated carbon (AC) to immobilize PAH and hetero-PAH. The three carbons were tested on soils from four different contaminated sites in Austria. Different amendment rates (w/w) of the carbons were investigated (BC: 1.0, 2.5, and 5%; SABC: 0.5, 1.0, and 2.0%; AC: 1%) in batch experiments to cover meaningful ranges in relation to their performance. SABC performed better than AC, removing at least 80% PAH with the lowest application rate of 0.5%, and achieving a complete removal at an application rate of 1.0%. BC performed slightly worse but still acceptable in residually contaminated soils (40 and 100% removal at 1 and 5% amendment, respectively). The ability of BC and SABC to immobilize PAH decreased as the PAH-molar volume increased. PAH with three or more rings were preferentially removed by AC compared to SABC or BC. This can be explained by the difference in pore size distribution of the carbons which could limit the accessibility of PAH and hetero-PAH to reach sorption sites for π- π electron donor-acceptor interactions, which drive PAH and hetero-PAH sorption to carbons. Column percolation tests confirmed the results obtained in batch tests, indicating, that decisions for soil remediation can be derived from simpler batch experiments. In soil samples with 1% BC, a reduction of over 90% in the total concentration of PAH in the leached water was observed. Overall, BC and SABC were demonstrated to be valid substitutes for AC for stabilizing residually contaminated soils.

Oxidative coupling of thiols to the corresponding symmetrical disulfides were performed in the presence of silica gel supported tributylammonium fluorochromate(VI), (TriBAFC), and tributylammonium chlorochromate(VI), (TriBACC). Silica gel supported TriBAFC and TriBACC are versatile reagents for the effective and selective oxidation of organic substrates, in particular of thiol, under mild conditions. Disulfides are also key intermediates in a wide variety of organic synthetic routes. Considerable improvements are observed in the presence of the absorbent and making the work-up much more convenient. The nature of the solvent does not appear to be particularly critical. Hydrocarbons, benzene, ethers and chlorinated hydrocarbons are equally effective, the practical choice being oriented by the solubility of the products and the desired reaction temperature. The IR spectra of TriBAFC and TriBACC are similar to that of other fluoro and chlorochromates, TriBAFC and TriBACC are soluble in water, dimethylformamide, acetonitrile, acetone and dichloromethane; they are only sparingly soluble in benzene, carbon tetrachloride, chloroform and hexane.

The purpose of this research is to analyze the risk of ammonia release in the cold storage of one of the large food companies in Mashhad. This is an applied research that was done using FTA technique and fuzzy logic. Fuzzy logic was used to weight experts' opinions (Delphi panel). In this study, to model the consequences and calculate the collective risk using the DNV PHAST 7.2 software, the most critical conditions that have the greatest possible contribution to the release of ammonia were, respectively: lack of proper and planned maintenance; Pressure increase and failure and defects in gaskets. Also, the results showed that the rate of death, toxicity and explosion is directly related to the distance. On the other hand, the maximum amount of possible losses in the event of an explosion will be in the winter season and at a distance of 14.26 meters, and finally, 95% of the losses due to the blast wave will occur at a distance of 13.54 meters and 99% of deaths of people up to a radius of 38.89 meters, also 50% of the deaths of people from the radius of 38.89 meters to the radius of 124.93 meters, and 10% of the deaths of people from the radius of 124.93 meters to the radius of 178.53 meters, also 1 percent of deaths from the radius of 178.53 meters to the radius of 234.05 meters.

This study provides a practical solution to manage non-hazardous waste and aid the environment. The largest group of non-hazardous waste is called municipal solid waste (MSW) which can be effectively used as an alternative material in civil projects. In this research, as an alternative to traditional modification methods of soil which causes global warming, the soft clay (Clay) was chemically modified by four different percentages of MSW in soil dimensions (15%, 25%, 35%, 45%) in 28 and 120 days. The optimum percentage of MSW addition (15%) to the Clay at the curing age of 28 days increased the unconfined compressive strength (UCS) and California bearing ratio (CBR) by 1.28 and 3.34 times, respectively. Given that higher percentages of MSW reduce the UCS and CBR in the specimens, four percentages of Nano-MgO, i.e., 0.25, 0.5, 0.75, and 1% were used for stabilization. The specimens containing optimum percentages of MSW (15%, 25%) and stabilized with 1% Nano-MgO could improve UCS and CBR 2.34 and 5.59 times, respectively that results had better durability over 120-days which can be attributed to the CBR testing condition. The cause of the increase in UCS and CBR was investigated using microstructural analysis for 120 days of curing. The specimen with high durability approved the cement bond formation with Anorthite & Dolomite minerals. In conclusion, using optimum MSW and Nano-MgO effectively solved the Clay problems in suitable conditions and allowed higher percentages of MSW to be removed from the environment.

The present descriptive cross-sectional study was conducted by altering the type of blowers in the wastewater treatment system of Abuzar hospital in Ahvaz during the first and second quarters (6 months). In every month, inlet raw wastewater, aeration tank one, and effluent were sampled in one week (Saturday-Friday), which resulted in harvesting a total of 42 samples. Then, they were assessed based on the techniques provided in the book entitled "standard methods for evaluating water and wastewater", and data were evaluated through employing statistical analyses. The average removal efficiency of total and organic phosphorus, phosphate, and ammonia in the effluent was respectively determined 46.47, 34.45, 18.14, and 68.49 before starting up a new aeration system, which reached 69.36, 76.21, 65.09, and 96.53 during the second period, respectively. In addition, the average concentration of nitrate varied from 21.79 to 44.11 mg/l, while that of nitrite changed from 0.04 to 0.03 mg/l. Further, an increase (39.19 to 67.19%) was observed in the average nitrogen removal efficiency in effluent. Based on the results, EAAS process was efficient in eliminating nitrogen and phosphorus by using the helicoidal pumps of aeration blowers and regulating aeration rate. Thus, aeration plays an effective role in activated sludge systems despite the microorganism diversity in aeration tank sludge. The produced effluent was consistent with Iran national standards in terms of the parameters under study, especially phosphorus and nitrogen, and can be discharged into the environment.