فصلنامه پژوهش در بهداشت محیط
سال نهم شماره 2 (تابستان 1402)

Urban waste leachate due to had organic matter, minerals and heavy metals as one of the environmental problems has require treatment. Surface absorption is one of the methods used in absorbing contaminants by absorbent materials. In this study, the efficiency of removal of zinc from leachate of landfill waste in Hamadan city by absorbent of banana skin modified by acidic solution has been investigated.

In study of descriptive-analytical, the effect of contact time, adsorbent amount, pH and concentration variables performed on the efficiency of Zn metal removal from leachate. In order to investigate the interaction between the adsorbent and the absorbed object were used the absorption models of Langmuir and Freundlich isotherm and aspect investigation the velocity of the adsorption process were used from the adsorption kinetics of first and second order pseudo-adsorption.

The highest efficiency of zinc removal (92%) was caused by adsorbent of banana fruit skin modified in the optimum pH 7, the contact time 70 minutes, the adsorbent amount 6 g/l concentration 1 mg/l. The maximum absorbent absorption capacity was also determined 34 mg/g. The results showed that the behavior of the desired process followed Langmuir adsorption isotherm model and its kinetics is adapted to the second-order pseudo-reaction.

The use of natural adsorbent banana fruit skin modified by nitric acid solution has a high ability to remove zinc metal from leachate and can be used as an appropriate replacement for reducing the problems caused by common chemical adsorption.

Balkhli River, which flows into Yamchi Dam, is the main supplier of drinking water in Ardabil City. This research aims to investigate the effect of the Ghaynarjeh Spring on Balkhli River based on surface waters quality indices.

First, monthly monitoring and analysis of Ghaynarjeh spa spring (station 1), river before acceptance and after acceptance of spring water (stations 2 and 3) was done for one year. Despite the low discharge of the spring compared to the river, The concentration of some cations and anions in the river increased greatly. In this article, by determining IRWQISC as the surface water quality index of Iran and NSFWQI as an international index, the water quality for three stations was determined.

The results showed that the quality of the river water after entering the spring water was degraded; In other words, the IRWQISC index of the quality of the river's water quality decreased from relatively good to average. Due to the presence of about 2,000 ppb of arsenic, about 7,000 ppb of iron and about 2,500 ppb of manganese in Ghaynarjeh Spring of Nir City, Therefore, the IRWQIST index was also considered in this research. As a result of entering the spring into the river, the river's toxicity index dropped two levels from a relatively good condition to a relatively bad one.

Considering the high impact of ghaynarjeh spring on the quality of Balkhli Chai River from the perspective of IRWQISC and especially IRWQIST indicators and considering the importance of Balkhli Chai River in supplying drinking water in Ardabil city, the necessity of purifying the spring water before entering the Balkhli Chai River is quite evident.

Today, sewage sludge disposal methods include drying, burning and application in land, but each of these methods has its own vulnerability. Sewage sludge management is difficult not only because of high levels of production, but also because of high concentrations of heavy metals and pathogens. Research has shown that the transfer of sewage sludge to organic fertilizers, including organic fertilizer, is due to its many advantages, including less heavy metals, easy to use with irrigation systems, faster absorption by plants, and increased their growth efficiency etc. which have been very much considered. The purpose of this study was to investigate the properties of sewage sludge and the liquid fertilizer produced from it.

In this study, biological sludge was transformed into liquid fertilizer using a 0.25 molar solution. Characterization of biological sludge and liquid fertilizer by conducting heavy metal concentration tests (Zn, Pb, Cd, Cr, Ni, Fe and Cu), total nitrogen, total phosphorus, soluble potassium, total sodium concentration, electrical conductivity and pH was done.

The results showed that total nitrogen, soluble potassium, heavy metals concentration decreased with increasing of organic matter extraction from sludge whereas, the amount of phosphorus, total sodium content, electrical conductivity and pH increased.

The results of this study showed that the liquid fertilizer produced from sewage sludge due to its characteristics can be used as a soil modifier in agricultural sector.

Municipal and hospital waste land fills that have various contaminants, especially pharmaceuticals, provide a suitable habitat for resistant bacteria which play a special role in the transfer of resistance genes. Therefore, the abundance of microorganisms and the antibiotic resistance of bacteria in soil and leachate samples of municipal and hospital waste burial sites in Hamedan city were investigated.

The characteristics of soil and leachate as well as the abundance of their microorganisms were tested and counted. Also, the percentage of bacteria resistant to ten commonly used antibiotics ampicillin, amoxicillin, cefixime, gentamicin, streptomycin, tetracycline, doxycycline, chloramphenicol, lincomycin and metronidazole was investigated. In addition, the response of bacteria from two virgin soils and new rubbish landfill to different concentrations of three antibiotics, ampicillin, gentamicin and tetracycline, were measured.

The log of population of fungi, actinomycetes, pseudomonas, and enterobacters, was the highest in new rubbish landfill. They were 5.35, 5.28, 6.13, and 5.98 respectively. The percentage of bacteria resistant to all ten antibiotics was higher in samples of new rubbish landfill than in other locations and lower in virgin soil than in other locations. These results were also seen in the dose response of ampicillin, gentamicin and tetracycline antibiotics. The inhibitory concentrations of these antibiotics for new rubbish landfill bacteria were 1500, 1000 and 100 mg/l, respectively. But for virgin soil, they were much less (10, 18 and 50 mg/l respectively).

In general, this research showed that municipal and hospital waste landfills provide a suitable habitat for antibiotic-resistant bacteria, which may increase the transfer of resistant genes among soil native bacteria. Therefore, the bacteria that reach the soil through waste can be more harmful.

Today, polyethylene plastics have become a big problem of environmental health, i.e. excessive production of waste, and it has endangered the environment. But insects have come to the aid of the environment, and in the meantime, the large wax-eating moth (Galleria mellonella) is able to digest polyethylene plastic, polyester, aluminum foil, and even fabric masks with the help of the microbiome of its larva's stomach. This study was also designed to investigate the ability of G. mellonella larvae to remove polyethylene plastic .

First, G. melonella larvae were collected from Gonabad honey apiaries in June 2022. The larvae were reared in the Gonabad University of Medical Sciences medical entomology laboratory with beeswax and synthetic food in plastic boxes and dark rooms (temperature 25±2 oC and humidity 33%). To feed the larvae, pieces of plastic film were cut into diameters (10×10 cm) from the freezer, garbage, and shopping bag (so-called with handles) and placed on ten Petri dishes with a diameter of (8×8 cm) containing ten larvae. Another petri dish (with a hole for larvae to breathe) was placed on the polyethylene films. The produced biomass of larvae related to each type of plastic was analyzed separately with Fourier transform infrared spectrometry (FT-IR).

Analysis of 8 types of biomass produced by larvae feeding from wax (control) compared to polyethylene plastics (target item) with FT-IRIt revealed functional groups C-CL, C=O, C=C, R-OH, CH2, -C-C-, which is a sign of polyethylene plastic degradation. Also, the comparison of the amount of plastic removal among the larvae fed on different types of polyethylene film revealed a significant difference (P<0.05).

G. melonella larvae as a biological method can be effective in removing plastic from nature in the future.

Road transportation is one of the most important and main sources of metal pollution, which has turned roadside ecosystems into metal sensitive areas. Therefore, this study was conducted to analysis and source identification of Zn, Pb, Cd, Co, Cr, Cu, Mn, and Ni in the surface soils along some roads in Hamedan Township in 2019.

In this study, a total of 63 surface soil samples were collected along 700 m from a 9 km section of Goltepe (G), Razan (R) and Kermanshah (K) roads. After preparing soil samples, the contents of elements were determined using ICP-OES. The enrichment contamination severity index (CSI) was also calculated. All statistical analyses of the obtained data were performed using SPSS software.

The highest amounts of all the analyzed elements were found in the samples collected from the R site with 122, 0.320, 1.92, 17.3, 334 and 22.2 mg/kg for Zn, Cd, Co, Cr, Mn, and Ni, respectively, and from K site with 26.4 and 25.0 mg/kg for Pb and Cu, respectively, showing the effect of traffic volume. The values of the CSI index showed the acceptable quality of the soil in the studied sites. Also, the results of multivariate statistical analyzes (PCC, PCA and HCA) showed that Mn in roadside soils is probably caused by soil raw materials and exhaust emissions. While the origin of Zn, Pb, Cd, Co, Cr, Cu and Ni emission was mainly from non-exhaust sources (such as wear of brakes, tires, engines and lubricating oil).

The findings were indicated the impact of traffic activities on soil contamination with heavy metal in the study areas; therefore, regular and periodic monitoring of soil samples is recommended to control of emission sources of pollutants in order to maintain the health of ecosystems and humans.

Corona disease (COVID-19) is an infectious disease that spread rapidly in the world and became a pandemic only a few months after the official announcement of the first reports. The purpose of this study is to determine the influencing factors on employees' compliance with health issues based on the health belief model.

This descriptive analytical (cross-sectional) study was conducted on 65 employees of Khorasan-Razavi Regional Water Company in 2019. Information was collected using an online questionnaire and the data was analyzed using SPSS software.

Examining the relationship between demographic qualitative variables and knowledge, attitude and behavior constructs showed that the average score of knowledge, attitude and behavior did not differ significantly in any of the gender, educational and occupational groups (p-value<0.05). There was a positive and significant relationship between the variables of awareness and attitude (p-value=0.009) and awareness and behavior (p-value=0.02). Other variables did not show a significant relationship with each other (p-value<0.05). Also, the results showed that the structure of awareness had a statistically significant effect on the behavior of the people studied (p-value=0.01). In general, the level of knowledge and attitude of employees in preventing corona virus is at a favorable level.

The results of this study show that providing the necessary facilities, including the standardization of the work environment, the provision of transportation services, masks and disinfectants will play an effective role in reducing the cases of corona.

Distribution of heavy metals in all types of sediments is one of the important and new topics in environmental sedimentology. This study was conducted with the aim of investigating the amount of factor pollution, concentration of cadmium and lead metals, geochemical accumulation index and ecological risk category in the soil downstream of Taibad Landfill.

15 stations were selected at a distance of 100 meters from each other and along the waterway exiting the site from a distance of 100 to 1500 meters. After sampling 5 samples and repeating 3 times from each station, the samples were taken to the laboratory for analysis.

In stations 2 and 6, because the pollution factors (CF) are between 1 and 3, the level of pollution in these stations is average, in station 10 it is very high, and for the rest of the stations, because the pollution factors are between 3 and 6, the level of pollution is high. For cadmium metal, the pollution factor (CF) in all stations is between 3 and 6 and the pollution is high. Based on the results, the amount of lead and cadmium metals in the risk category They are ecologically average.

The amount of lead metal pollution in station 2 and 6 is moderate, station 3 is very high and in other stations it is high. Cadmium metal contamination was reported in all stations. Both metals are in the medium category in terms of ecological risk.The concentration mentioned metals in the soil downstream of the landfill is significantly higher than the global soil average and the earth's crust. It seems that this pollution is caused by the landfill, which was spread to the downstream lands by seasonal runoff