فصلنامه پژوهش در بهداشت محیط
سال هفتم شماره 2 (تابستان 1400)

The presence of drugs in water and wastewater sources poses risks to humans and the environment. These materials are not completely eliminated by conventional water and wastewater treatment methods. This study aimed to investigate the photocatalytic removal of acetaminophen from aqueous solutions by the advanced UV/H2O2/ZnO oxidation method.

In this experimental analytical study, zinc oxide and hydrogen peroxide were used in a 500 ml reactor under UV-C irradiation to remove acetaminophen. The effects of initial parameters of acetaminophen, solution pH, contact time, hydrogen peroxide concentration, and zinc oxide nanoparticle concentration were investigated. Experiments were designed and analyzed using the CCD method by Design Expert 10 software.

Themaximum removal efficiency of acetaminophen was obtained as 94% at pH 7, contact time 8 min, the initial contaminant concentration 62.5 mg/l, catalyst dose 0.0275 g, and H2O2 concentration 2 ml. By changing the time to 1 and 15 minutes, the removal rate decreased by 26 and 76%, respectively, and by increasing the catalyst dose from 0.0275 g to 0.05 g, the removal rate increased by 99%.

In this study, the efficiency decreased with increasing contaminant concentration. The removal efficiency was higher in neutral conditions than in acidic and alkaline conditions. The photocatalytic process (UV/H2O2/ZnO) is highly potent for removing acetaminophen from aqueous solutions.

In recent years, the release of persistent pollutants from wastewater treatment plants into the environment has led to health and ecosystem problems. Therefore, the present study aimed to activate heterogeneous peroxymonosulfate (PMS) with magnetic nanoparticles (Fe3O4) for the degradation of reactive black 5 (RB5).

The present analytical study was performed in a column scale for RB5 dye degradation by PMS activated with Fe3O4 nanoparticles. The effect of parameters such as pH (3-11), PMS concentration (0.25-4 mM), catalyst concentration (50-500 mg/L), and solution temperature (10-50 °C) on the degradation efficiency of RB5 was investigated. Stability experiments and trapping of reactive species were studied under optimal conditions obtained from the influence of parameters.

The maximum dye removal efficiency (94.86%) was obtained at Fe3O4 dosage of 250 mg/L, PMS dosage of 2 mM, pH of 7, and reaction time of 60 min. In comparative experiments, Fe3O4 showed appropriate catalytic activity in PMS activation and RB5 degradation compared to the PMS process and adsorption alone. The degradation rate of RB5 improved with increasing temperature but decreased in the presence of anions in aqueous solutions due to the consumption of reactive species. Highly reactive magnetic nanoparticles showed four consecutive degradation cycles in a column reactor. Trapping experiments emphasize that both hydroxyl radicals and sulfate play an important role in the degradation of pollutants; however, sulfate radicals are the predominant species of RB5 degradation. The continuous column reactor provided 95.65%, 80%, and 50% degradation efficiencies for RB5 in synthetic, surface water, and textile wastewater samples, respectively.

Based on the results, it can be concluded that the PMS/Fe3O4 process is a promising technology for the degradation of RB5 from aqueous solutions.

Nosocomial infections have always been one of the major health problems, and it is becoming increasingly important and a challenge for the health system of different countries. In this study, the contamination in the environment and equipment of two hospitals of Mashhad were studied.

This cross-sectional study was performed in two academic hospitals. The sampling method was convenient based on policy of infection control committee of each hospital. Environmental samples were collected from water, sink, patient bed and incubators. Samples were cultured in bacterial culture media and phenotypically identified. .

Out of 323 samples, 272 (84.2%) were from Qaem Hospital and 51 (15.8%) from Imam Reza Hospital. Overall, 47.1% of samples of Imam Ghaem hospital (128 samples) and 33.3% of samples of Imam Reza hospital (17 samples) were positive (p = 0.071). Overall, the most prevalent organisms were Bacillus (54 samples, 16.7%) followed by Staphylococcus epidermidis (22 samples, 6.8%) and Staphylococcus saprophyticus (16 samples, 0.5%). Others were consisted of Acinetobacter, Enterobacter and pseudomonas spp.

Bacillus species have a high persistence in the environment due to Sporulation and their removal will be an indicator of proper environmental health. The presence of potentially pathogenic bacteria in the hospital environment reveals the importance of environmental health control and monitoring programs.

Population growth and increased urban migration in the past decades have led to an increase in population density and size of major cities. Unfortunately, this kind of pollution has mostly gone unnoticed. To prevent these effects and achieve recommended standards, the use of plants as noise barriers in cities is mandatory. Trees offer a range of ecosystem services and remain important in providing human benefits. The aerodynamic effect of trees was identified as a major reason for the change of pollutant distribution in near-road parks, where trees can act as porous barriers and decrease noise pollution. Although not yet fully developed, planting strategies aiming to benefit from the negative effects of vegetation on noise pollution should be encouraged in future park design.

The present study was conducted to investigate the absorption of noise pollution by one of the plants in the landscape of Ahvaz, Dodonaea viscosa L., in Agricultural Sciences and Natural Resources University of Khuzestan. The experiment was conducted as a completely randomized design with different distances between the sound source and the green wall (5, 10, and 15 m) and green wall width (0.5, 1, 1.5, and 0 m as control). After receiving the sound by the receiver, the data were transferred to MATLAB (2015) software. Then, the properties of the sound level were measured including minimum, maximum, elongation, skewness, mean, and variance.

The results showed that with increasing the distance from the sound source, the minimum sound intensity decreased and finally, the green wall with one-meter width at 15-meters distance had the minimum intensity (68.4 dB). It was also found that the maximum sound decreased with increasing distance of the sound source from the green wall so that the maximum was related to the distance of 5 meters (91.6 dB) and the lowest was related to the distance of 15 meters (76.3 dB). Also, the analysis of the data showed that in the control and other thicknesses of the green wall, the average sound intensity decreased with increasing distance from the sound source. The highest variance of sound intensity was found in 1 m width green wall and 5 m away from the sound source and the lowest variance of sound intensity was related to the thickness of the control at a distance of 5 meters from the sound source.

Basically, the sound waves are absorbed by the leaves and branches of trees. The higher the density of the tree and the shorter the distance from the sound source to the tree, the greater the reducing effect. With the shorter distance from the green wall, the sound gradually decreases because it creates an angle at the deflection path of the wave and therefore, the wave has to travel a greater distance to the receiver. According to the obtained results, it is suggested for landscape designers to use this shrub as a green wall and sound barrier, pruning it with a width of one meter and also its distance from a sound source close to about 5 meters.

To maintain the health of consumers and achieve food safety, the control of maximum allowed heavy metals in food should be considered. This study aimed to investigate the concentration of heavy metals of copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) in livestock tissues in the vicinity of Zinc Specialized Industrial Park.

Ten samples were collected from each sheep tissue (including meat, liver, kidney, and bone) in each of the four geographical directions. To compare the current situation, samples from a control area (Qarah Poshtlu area of Zanjan) were also considered. A dry ash method was used to digest organic matter.

Based on the results, the concentration of Cu was significantly high in the muscle and liver of the control group (P <0.05). The concentration of Zn was not affected by the study areas. The accumulation of Pb in the liver and bone and Cd in the muscle and liver of animals was significantly high in the western part of the study area (P <0.05). The levels of Cu in the kidney and bone tissues, Pb in the muscle and kidney tissues, and Cd in the kidney and bone tissues were not affected. The accumulation of Cu was inversely related to Pb and Cd.

In general, the results showed that despite heavy metal accumulation in the west of the study area, the concentrations of these metals in the tissues of sheep around it were within the allowable range and they were not dangerous to consumers.

Theexcessive consumption of nitrogen fertilizers leads to the production of vegetables with high concentrations of nitrate. High nitrate concentration in crops causes a variety of diseases, especially due to the production of carcinogen nitrosamine in adults. Because of the increase in cancerous and non-cancerous diseases caused by the consumption of foods containing high nitrate, a detailed and comprehensive assessment of the state of nitrate accumulation in vegetables is required. This study was conducted to evaluate the risk of nitrate in high-consumption vegetables in Kermanshah.

In this study, 120 samples of five kilograms of high-consumption vegetables were sampled in different months of each season and sent to the laboratory. Samples included tomato, cucumber, potato, onion (yellow, white, red), lettuce, celery, watercress, and spinach or beet leaves. After sample preparation and extraction, the nitrate concentration was determined by a spectrophotometer at a wavelength of 410 nm.

The nitrate concentration in all vegetables was less than the WHO and ISRI standard limits in winter. But in the summer, the concentration of nitrate in celery, cress, and sugar beet leaves exceeded the standard limits. The hazard quotient (HQ) was less than 1 in all vegetables and both seasons. In summer, the highest HQ values were observed in cress (0.425), beet leaves (0.363), and celery (0.135), in sequence. In the winter, the highest amount of HQ was seen in cress (0.190).

According to the HQ values (less than 1) in all vegetables, the possibility of exposure to non-carcinogenic diseases caused by nitrate from eating vegetables in this study is not serious, but it is necessary to monitor the concentration of nitrate in consumed vegetables at different intervals.

Humans in their environments are always exposed to radiation from radioactive materials in construction materials. Since humans are not far from these materials, the probability of radiation exposure is high. This is a dosimetric study of travertine stones used in Zahedan in 2020 to determine the relationship between stone color and radioactivity.

The building stones that existed and were used in Zahedan city were identified and listed. A total of 70 samples of travertine were analyzed by the MKS model pen dosimeter for determining gamma Dose Rate (EDR) as microsievert per hour, gamma Equivalent Dose (ED) as millisievert, and beta flux density as parts per square centimeter per minute (part/cm2.min).

The highest mean EDR was in travertine rocks in cream color as 0.15 μSv/h and the lowest was 0.01 μSv/h in white rock. The highest mean beta flux density was observed in travertine rocks in the cream color sample as 0.0016 part/cm2.min. The ED value of all samples was determined to be zero.

The maximum amounts of EDR and beta flux for travertine rocks were related to cream-colored rocks, which were slightly higher than the global average. The average EDR for travertine rocks was slightly higher than the allowable limit. Also, the beta flux in travertine rocks was lower than the allowable limit. The mean value of beta beam flux density in the ambient air was zero. In all samples, the amount of ED was zero. The amount of background radiation in the ambient air of Zahedan was the global average.

COVID-19, also commonly referred to as coronavirus disease, is an acute respiratory infection caused by a novel coronavirus. The virus affects the respiratory system and can cause headaches and fever for up to several days. This study aimed to investigate the preventive behaviors regarding COVID-19 based on the health belief model in Kermanshah.

This descriptive-analytical cross-sectional study was performed on 500 individuals in Kermanshah in 2020. The sample was selected by cluster sampling. Data were collected using a researcher-made questionnaire based on a pilot study according to the health belief model. Data were analyzed using Pearson correlation coefficient and linear regression.

The correlation coefficient showed that the strongest correlation was reported between the constructs of perceived barriers and in terms of behavior, the strongest correlation was observed between perceived benefits and behavior. The results of linear regression analysis predicted 17% of the variance of COVID-19 prevention behaviors. Among them, perceived sensitivity (0.593) was the strongest predictor.

The results of this study strongly showed the application of the health belief model in predicting the prevention behavior of COVID-19, and it seems that this model can be used in developing educational programs and interventions to change people's attitudes and behavior.