نشریه مهندسی بهداشت محیط
سال دهم شماره 3 (پیاپی 40، بهار 1402)

Nowadays, due to the limited groundwater resources and increasing population, and growth of agriculture and industries, optimum operation of groundwater needs more attention. In this research, temporal and spatial changes in the quality of groundwater resources in Faradonbeh Plain located in Chaharmahal and Bakhtiari province have been investigated.

For this purpose, the time series of qualitative variables collected from 7 sampling stations (including 6 wells and one spring) in the Faradonbeh plain during a 29-year period (1991-2019) was used. The trend of changes in groundwater quality variables of this plain was investigated using the modified Mann-Kendall test (after completely removing the autocorrelation effect). Also, for each time series, the trend line slope was calculated using the Sen slope estimator. In order to draw the delineation maps of qualitative variables, Kriging method was used in the Arc GIS software. Finally, the usability of groundwater for agricultural use in Faradonbeh plain was investigated using USSL diagram.

Comparison of delineation maps of qualitative variables showed that the groundwater quality of this plain has decreased in recent years, especially in the central parts of the plain. Also, the results of he USSL diagram indicate a decrease in the quality of groundwater for agricultural uses.

Due to the expansion of agriculture lands in this plain, the overexploitation of groundwater resources and indiscriminate of fertilizers and chemical pesticides can pose a serious threat to the water resources in the region in terms of quantity and quality. Also, the use of industrial and municipal effluents for irrigation in the long-term can have adverse effects on the life cycle of this region due to undesirable changes in soil and the possibility of leakage of these pollutants into groundwater, especially in the central part of this plain.

Chemical industries are among the process industries and have many risks that can lead to catastrophic and irreparable consequences. The current research analyzed the health risk of chemicals in a company supplying chemicals to drilling rigs using WASPAS and SQRA methods in 2022.

The basic information of the materials used was collected based on intuitive methods, document review, MSDS of chemicals, processes, efficiency, and exposure to chemicals. In the SQRA risk assessment, hazard rate (HR) and exposure rate (ER) factors were calculated based on information related to acute toxicity, LD50, and LC50. The developed version of WASPAS-IVIF has been used to prioritize the health risk of chemicals. 10 process safety experts were used for scoring. Risk assessment calculations were done in the Excel2016 software environment, and the data fuzzification process was in Fuzzy Toolbox in the Matbal2019a software environment.

The results of the health risk assessment of chemicals using the SQRA method, out of 45 chemicals, 34 were evaluated as having no health risk potential. The health risk level for Acetone, Calcium Chloride, CITRIC ACID, Fuel Oil, and Naphthalene is low. For biocide, n-Butyl, ammonium nitrate, and xylenes are at medium level, toluene at a high level, and Benzene at a very high level. The results of the WASPAS-IVIF evaluation also show that Benzene is the most critical risk factor in the chemical storage of drilling fluids, with a coefficient of 0.828.

This research showed that the health effects caused by exposure to chemicals used in the drilling industry are worrying.

 Heavy metal pollutants in rivers are one of the serious environmental concerns in aquatic ecosystems. Sediments, as an environmental indicator, have an acceptable ability to express the degree of environmental pollution with heavy metals. Therefore, with the aim of evaluating the health of the water ecosystem of Zayandeh Rood, we investigated pollution using sediment indicators.

In this study, the sediments of Zayandeh Rood River were sampled at 17 stations. Metals lead, zinc, iron, cadmium, cobalt, nickel, copper and chromium were measured by acid digestion method with atomic absorption device. Also, land accumulation indices, Nemerow pollution index and ecological risk potential were calculated.

The average concentration of metals in sediments is 1762.92 iron, 201.52 nickel, 44.07 zinc, 23.36 cobalt, 28.67 copper, 11.51 lead, 10.09 chromium, and 0.87 cadmium mg/kg. According to the Igeo index, the average concentration of chromium, iron, copper, zinc and lead elements in all stations was lower than the average of the earth's crust, and the concentration of nickel and cadmium in all stations was higher than the background value. In all stations, the ecological risk potential index of cadmium was higher than other elements.

Considering the condition of river sediments in terms of cadmium and nickel pollution and their very high ecological risk, it is necessary to comprehensively monitor the river and its living organisms. Also, in order to evaluate its health and ecological risk with the approach of examining the trend of spatial and temporal changes, heavy metal pollution in water and river sediments should be taken into consideration.

Bread is the main source of nutrition and provides most of the daily energy of people. In order to have healthy and suitable bread, it is necessary to pay attention to the environmental health indicators in bakeries. The current research was conducted with the aim of determining the environmental health status of bakeries in Sanandaj City in 2023.

In this cross-sectional descriptive survey, 30 bakery units in Sanandaj city were investigated through a health inspection checklist of bakery that is approved by the Ministry of Health and Education. This checklist has four sections which include personal health, food, tools and equipment, and building hygiene. The collected data were analyzed by Excel software.

In the present study, the highest level of desirability was reported in the health sector of the building with a frequency of 73.96% and the lowest degree of desirability was reported in the section of personal health and hygiene of tools and equipment with a frequency of 70.48%.

The state of the environmental health in the bakeries of Sanandaj city is not completely in accordance with the bakery health regulations, and in order to improve the conditions, it is necessary for the environmental health inspectors to be more careful and serious in terms of personal health indicators and the hygiene of tools and equipment. It is suggested that the health officials provide the necessary platforms to implement the process of self-control and self-declaration of health in order to further monitor the studied bakeries.

The use of Spirulina platensis has been expanded in various fields. The main goal of this research is to optimize the growth conditions of this microalgae to reduce costs and increase the benefits of its mass production in seawater. It is also feasible to lessen environmental pollution by producing more spirulina by discovering the best growing conditions for it through the enrichment of Persian Gulf water.

First, the growth conditions of Spirulina platensis were optimized based on three factors: temperature, light, and pH. The temperature factor included four treatments, the light factor included four treatments, and the PH factor included five treatments. Also, Spirulina platensis microalgae were cultured in optimal growth conditions in Persian Gulf water, seawater enriched with 5% Zarrouk, 10% Zarrouk, with urea, and pure Zarrouk culture medium.

The best temperature range for the growth of Spirulina platensis was 27–32 degrees Celsius. Also, the best growth was achieved in 16 hours of light and 8 hours of darkness; for the PH factor, the most appropriate value was determined between 10.72 and 11.47. Also, in the cultivation of Spirulina platensis, optimal conditions for the growth of Spirulina microalgae were obtained in the medium of Zarrouk, urea, 10% Zarrouk, 5% Zarrouk, and seawater, respectively.

Therefore, the growth of Spirulina platensis in Persian Gulf water is slow and shows little performance, and by enriching this water with the mentioned factors, the microalgae enter the logarithmic phase faster and show better performance.

The abundance of humic substances in nature and their entry into water resources cause changes in color, taste and smell in water. which makes a huge amount of water in the world useless, Recently various methods have been presented to remove natural organic substances from water. But surface adsorption has a high removal capacity compared to the other methods. In this research the performance of modified watermelon skin in adsorption of humic acid from aqueous solutions on a continuous scale have been investigated.

In this study, the effect of different parameters such as contact time, activation temperature,pH, adsorbent dose, initial concentration and ionic strength and thermodynamics on humic acid removal efficiency were investigated.Using SEM spectrum (scanning electron microscope) the appearance characteristics of the adsorbent were done. Humic acid concentration was determined using spectrophotometer in 254 nm wavelength.

Results of the research showed that the highest amount of removal occurs in acidic environment, By increasing time and adsorbent dose and decreasing the initial concentration, the removal efficiency of humic acid increased for example:in time(45 minutes) and PH=4 and amount of adsorbent(0.1 g.L-1) with concentration removal is (50 mg.L-1) and the maximum removal of humic acid reached (90.98%) and the humic acid adsorption thermodynamically is an endothermic process.

Activated carbon produced from watermelon skin as a new adsorbent from agricultural wastes is very effective in removing humic organic substances due to its abundance, low price and high efficiency.

Nowadays, the growing population has increased the demand for food especially for protein triggering the aquaculture industry's expansion. However, unplanned and unregulated farm will caused be at the subsequent yield failure and cost of environmental stress in the aquaculture farm. Accordingly, ecological potential evaluation and site selection of suitable areas for establishment of aquaculture farms can be prevent the interference of different land uses, minimize the environmental impact of aquaculture development and prevent disruptions in development. Therefore, the currentstudy was conducted to ecological potential evaluation of rainbow trout (Onchorynchus mykiss (culture as coldwater fish species in Hamedan province, west of Iran.

In the current study, biological requisites of rainbow trout, socioeconomic factors, springs information, water flow, water temperature, pH, slope, protected areas and antiquities were used for ecological potential evaluation and site selection of suitable sites for rainbow trout culture. In so doing, 'Makhdoum Aquaculture Model' and ArcGIS 10.3 were used.

Based on the results obtained, 1420 ha of Nahavand county, 571 ha of Razan county, 472 ha of Bahar county, 311 ha of Hamedan county, 263 ha of Malayer county, 145 ha of Toyserkan county, 121 ha of Asadabad county and 84.0 ha of Kabudarahang county were identified as the suitable areas for establishment of rainbow trout culture farms.

Ecological potential evaluation and site selection for aquaculture by considering the land suitability could be taking to sustainable development and reduce of environmental stress of the aquaculture farm.

Primary schools are a social institution where an important period of children's lives is spent. Observing the environmental health of the school is a kind of social investment that helps improve health-oriented programs for the next generations. the present study was also conducted with the aim of investigating environmental health and safety status of DarehShahr primary schools in 2023.

The current research is a cross-sectional descriptive study in which all the primary schools in the city (28) were investigated by census method. The required data was obtained using the school health inspection checklist with form code 140/920318. Finally, the data were analyzed with excel software.

In this research, the percentage of health compliance with the regulations in the subject of personal health indicators, tools and equipment hygiene, building hygiene and building safety in Darrehshahr primary schools in 2023 were equal to 64.73, 83.52، 75, 64.29%, respectively. In total, the percentage of health compliance with regulations in the studied schools was 71.89 percent.

In order to improve the environmental health status of DarehShahr elementary schools, it is necessary to put fundamental changes in the factors of environmental health and school safety, especially in the field of deficiencies observed in the personal health and safety of school buildings.