Natural and human factors have always threatened the health of Qanats, valuable water sources for arid and semi-arid regions. The present study decided to qualitatively classify eight selected Qanats of East Tehran, Iran, using two multivariate statistical methods, cluster analysis (CA) and principal component analysis (PCA) based on parameters includind pH, TDS, EC, Na2+, Ca2+, Mg2+, K+, Cl-, NO3 and SO42- according to standard methods during the summer of 2020. Data were analyzed by CA and PCA methods, the results of which based on the degree of pollution divided the studied stations into three groups, high pollution (anthropogenic origin), moderate pollution (natural and anthropogenic origin) and low pollution (natural origin). The stations close to each other for quality status were placed in the same group. The eigenvalues obtained from PCA based on the evaluated parameters showed that the first and second components explained more than 58% of changes between the stations. Analyzing the coefficients of each parameter (eigenvectors) for the first and second components revealed that the main causes for the difference between the stations were Cl-, Na2+, Mg2+ and SO42-, TDS and NO3. The two-dimensional display of the stations based on the first two main components confirmed the grouping resulting from the cluster analysis and was able to separate the investigated stations from each other like cluster analysis. The findings of this research highlighted the usefulness and efficiency of two multivariate statistical techniques, CA and PCA, to effectively manage Qanat water quality. Manuscript profile

Fire can destroy forest areas along with air pollution and health hazards. The forest parks of the southern slopes of Alborz, Iran, are amazing tourist destinations for people in surrounding cities. Therefore, we determined the capabilities and limitations and formulated the best strategies to prevent and control fires using SWOT-AHP (A'SWOT) combined method. First, SWOT technique detected internal factors (strengths, or S, weaknesses, or W) and external factors (opportunities, or O, threats, or T) based on open-ended questions from local communities and experts. Then, AHP analysis model and Likert scale were performed to prioritize the best strategies as SO, WO, ST, WT solutions. The results showed that the most important factors in fire risk management, in order of the highest relative weight, were "easy access to forest park" (0.77), "lack of budget" (0.459), "existence of road networks" (0.76), "decrease in motivation and interest of volunteer and public forces" (0.417) in the strength, weakness, opportunity and threat groups, respectively. Further, the most important fire risk management strategies from the SWOT matrix and AHP method and scoring with a Likert scale, respectively, were "planning in accordance with the degree of fire risk for each part of the forest park" (0.715), "deploying quick reaction force and firefighting equipment at the appropriate point of the forest park" (0.685) and "updating knowledge in the field of fire risk management" (0.635). The A'SWOT technique was found to be appropriate in identifying the effective factors and providing operational strategies to prevent and control forest fires. Manuscript profile

Today, accidents, explosions, environmental damages and any defects in chemical industry are inevitable events. The ever-increasing of such industries makes effective risk management of these projects necessary to prevent environmental and health pollution and damage. The present study aimed to identify the possible risks caused by chemical industries in the south of Tehran (Iran) by examining the documents available in the health, safety and environment (HSE) units, interviewing experts, and using the Delphi technique and questionnaire. FMEA method was used to prioritize potential risks based on the risk priority number. Data analysis identified 17 risks in four environmental (n=6), health (n=5), safety (n=3) and occupational (n=3) categories. Based on the results of both Delphi and FMEA methods, the highest level of risk was related to three environmental aspects of "air pollution and air quality change", "surface water and groundwater pollution" and "soil pollution". According to the results of the FMEA method, in addition to the three environmental risks mentioned, the occupational risks including "failure to use personal protective equipment by personnel and lack of warning signs for personnel" and "human and operational errors, inappropriate equipment, and failure to comply with workplace safety instructions" were also detected as high-level risks. The findings of the current study revealed that despite the applicability of the FMEA technique in determining the risk factors caused by the activity of the chemical industry, preliminary hazard analysis is also suggested for a more accurate and complete assessment of this process. Manuscript profile