نشریه مهندسی بهداشت محیط
سال دهم شماره 2 (پیاپی 39، زمستان 1401)

Nowadays, trace elements are known as useful indicators for monitoring of environmental pollution caused from traffic emmissions. Therefore, this study was conducted to assess the effect of urban traffic and distance from the street side on heavy metals (Pb, Cd and Cu) concentration in surface soil and plant species of roadsides environment of city of Hamedan, west of Iran.

In this descriptive study, a total of 48 surface soil and plant samples were collected from four areas of city of Hamedan with different traffic density. After samples preparation, the concentrations of the analyzed elements in the soil and plant samples were determined using ICP-OES. Also, all statistical analyses of the obtained data were performed using SPSS software version 19.0.

Based on the results obtained, metals accumulation in soils and plants of the area with heavy traffic volume especially Basij Boulevard were higher than the other sampling areas. Also, distance from street side had been inverse relation with metals accumulation in soil and plant samples. So as the most accumulation of elements was recorded for samples collected at a distance of 5.0 m from street side.

Generally, inverse relation of metals accumulation in soil and plant samples with distance from street side might be related to vehicular emissions. Moreover, the results of this study also could be useful for managers and planners in the fields of architecture and urban design, urban land use planning, and urban traffic control managers.

The remediation of heavy metal manganese from industrial wastewaters has always been a challenging issue for environmental experts. It has been found that different species of microalgae, including Spirulina platensis, can be used in industrial wastewater treatment to remove heavy metals. The main goal of this research is to reduce or remove the heavy metal manganese from the industrial wastewaters of factories by microalgae Spirulina platensis.

In this research, 8 types of industrial wastewaters were collected from different factories and after the algae reached the logarithmic phase, they were mixed with industrial wastewaters. Then, the concentration of manganese metal, the amount of metal absorption and the percentage of microalgae cleaning efficiency were determined by atomic absorption measurement. Also, cutting enzymes were designed for nucleotide sequencing of α-phycocyanin subunit gene from Spirulina microalgae. Then Clonewin software was used to confirm the primers and the target fragment was placed in the expression vector.

The results of atomic absorption evaluation showed that after exposure of spirulina to industrial wastewater for one hour, a significant decrease in the volume of the heavy metal manganese occurred. Also, the result of the α-phycocyanin subunit gene sequence showed 100% homology with the α-phycocyanin subunit gene sequence in the gene bank.

Therefore, Spirulina platensis has the ability to absorb manganese metal in industrial wastewaters from factories, and different expression vectors can be used for homogenization and expression of alpha subunit genes.

Construction and demolition wastes (CDW) are among the bulkiest municipal wastes which are often made of concrete. According to the high volume of these wastes, it is essential to use the recycling strategy to manage C&D wastes. Recycling has three major advantages to make CDW management more efficient, including; reducing the demand for natural resources, reducing the cost of energy production, and increasing the capacity of the landfills. According to this, the aim of current study is to review concrete waste recycling methods.

In the initial search of articles, a total of 74 articles from 2005 to 2022 were found which was reduced to 50 after removing duplicates. Then, in the screening stage, the title and abstract of the articles were reviewed and at the end, 28 articles remained. Then, to obtain related articles, the full text of the screened articles was studied and finally, 22 articles remained which were used in the present study..

Recycled aggregates usually have limited use in the construction industry; but the technologies discussed in this study can increase the quality of recycled aggregates and therefore these aggregates can be used in better and more applications.

There are advantageous suggestions for the improvement of construction waste recycling including; the proper destruction of buildings, revision of construction methods, and encouragement to design structures based on native architectural potentials. The main ways to achieve these goals include; government support, raising public awareness, establishing an administrative system for recycled materials, approving relevant laws, and devising construction methods based on local capabilities.

In the dry and semi dry regions of the world, due to almost 90% of their required water is provided from groundwater resources, these resources are vital. Therefore, this study was conducted to assessment of potentially toxic elements (As, Pb, Cd and Cu) pollution in groundwater resources of city of Sonqor, Kermansah Province, west of Iran in 2022 using MI and PoS indices.

In this descriptive cross-sectional study, a total of 36 groundwater samples were collected randomly from 12 sampling sites during summer and autumn seasons. The value of some qualitative parameters including T, pH, EC and TDS were determined insitu. After samples preparation, the contents of As, Pb, Cd and Cu were determined using ICP-OES. Also, the metal (MI) and the PoS indices were computed for qualitative assessment of groundwater resources. Moreover, all statistical analyses were done using SPSS version 19.0

Based on the results obtained, the mean contents of the analyzed elements (µg/l) in groundwater samples collected in the summer season were found to be 4.22 for As, 0.125 for Pb, 0.387 for Cd and 0.598 for Cu, while the mean levels of As, Pb, Cd and Cu in groundwater samples of the autumn season were 2.98, 0.137, 0.213 and 0.610, respectively. Also, in comparison, the mean concentrations of the analyzed elements in the groundwater samples of both seasons were lower than the maximum permissible concentrations (MPCs) established by WHO, EPA and Iran DOE. Besides, the MI and PoS indices of the summer season with mean values of 1.00 and 203, respectively, showed that the quality of groundwater resources of the study area was classified as 'slightly affected' and 'low quality degradation level'. Whereas, in the autumn season the mean values of MI with 0.830 and PoS with 144, showed that the quality of groundwater resources of the study area was classified as 'pure' and 'none–low quality degradation level', respectively.

Although based on the findings, the quality of the groundwater resources of the study area was desirable during the implementation of this research, the overuse of agricultural inputs particularly phosphorus and urea fertilizers and also heavy metal-based pesticides (e.g. arsenical pesticides/herbicides), could be pose to decrease of the quality of groundwater resources, and cause irreversible damages in this area. Therefore, regular and periodic monitoring of groundwater quality for environmental and human health maintenance is recommended.

Vermicomposting is a promising, cost-effective, and environmentally friendly technology in organic waste management. In this study, the production of vermicompost by Eisenia Foetida earthworm from agricultural residues and sheep manure has been discussed.

In this study, sheep manure, straw and grape leaves wastes were used in different proportions to produce vermicompost. Perforated plastic boxes were used to support the growth of earthworms. After adjusted different proportions of these residues, their humidity was controlled and a number of earthworms of Eisenia Foetida species were introduced to each box. The pH and EC parameters were measured every two weeks and C/N ratio three times during the experiment. The duration of experiment was 120 days. The ANOVA test was used to compare the averages and Tukey and Kruskal-Wallis post-tests were also used to identify the source of differences in the mentioned variables.

The results showed that the pH increased during vermicomposting process and was acidic again at the end of the process. The highest C/N decrease ratio and the highest EC increase were observed in the 100% sheep manure bed (b1) and the lowest C/N decrease was observed in the 100% straw bed (b6).

Using vermicomposting is effective in waste management. It is recommended to use sheep manure in combination with other wastes to produce high quality fertilizer as well as increase the rate of vermicomposting process.

Nowadays, the entrance of heavy metals as inorganic pollutants into agricultural waters is one of the major concerns in all over the world. In the past few years, the adsorption of heavy metals by various categories of bio-adsorbents has been investigated via different process, including surface and chemical adsorption. In this research, corn silk has been used as an efficient bio-adsorbent for adsorption of lead ions from agricultural effluents.

Firstly, corn silk prepared from the fields around Kermanshah, afterward washed with distilled water and heated in an oven for 24 hours until it dried and rubbed. The prepared sample used for the adsorption of lead metal experiments.

In higher concentration of the adsorbent, the absorption capacity of ions decreases drastically. Also, the optimal pH value for the absorption process obtained around 5. The kinetic data exhibited that the metal adsorption process followed pseudo-second-order kinetics. Furthermore, thermodynamic data revealed that the process of metal absorption is spontaneous and the absorption happened physically.

The results clearly showed that the corn silk as a biosorbent can be effective for the removal of lead ions from aquatic solutions compared to previous reports. We can conclude that, the efficiency of biosorbent refers to the functional groups with high absorption power such as hydroxyl. In addition, the rate of adsorption of pollutants by the corn silk is significant, so that after 30 minutes the surface adsorption process reaches equilibrium stage.

Reviewing and implementing the model of safety, health and environment culture has always been considered as one of the most important concerns in waste management. Recently, focusing on the effective role of management in the causes of accidents has caused a lot of attention to the concept of safety culture. The purpose of this study is to investigate the impact of safety, health and environment culture on waste management.

This research was a descriptive-survey type of field studies. The main variables of the research were safety culture, health and environment. The statistical population of the research was 260 employees of Karaj Waste Management Organization, based on the Morgan table, the number of samples was determined to be 152. The 18-question questionnaire was divided among them and the reliability and validity of the questionnaire was studied.

The reliability of the questionnaire is estimated to be 0.86 based on Cronbach's alpha coefficient. Structural model method and SmartPLS 328 and SPSS 23 software were used to analyze the findings. All hypotheses were confirmed by checking structural model fit and overall model fit.

As a result, according to the confirmation of the influence of all three variables of safety, health and environment culture on waste management, it can be said that the culture of safety, health and environment has a positive and significant impact on waste management.

The emergence of new chemical industries has caused the release of a large amount of organic compounds including industrial by-products, insecticides and other chemicals in nature. Endocrine disrupting compounds are a known group of hazardous and complex pollutants that occurs in wastewater and water sources worldwide, either naturally or as a result of human activities. In this study, an attempt is made to remove diethyl phthalate from water environments by the advanced oxidation process of ozonation in the presence of activated carbon produced from the Skanbil tree.

methods and Materials:

 This experimental study was done in a reactor with a volume of 100 mL. In each experiment, diethyl phthalate solution was poured into the pilot in the desired concentration and ozone with 0.8 mg/min dose was injected into the reaction solution. Process parameters included pH (2-8), reaction times (2 to 30 min), pollutant concentration (5-25 mg/L) and catalyst dose (0.025-0.1 gram). In the end of each experiment, the sample was withdrawn from the pilot and analyzed using HPLC to determine the residual diethyl phthalate.

The results showed that under optimal conditions of pH = 6.8, ozone dose = 0.8 mg/min and contact time = 30 minutes, ozonation could only remove 60% of diethyl phthalate, and under the same conditions, catalytic ozonation with 0.075 g of carbon obtained from the skanbil tree could remove 94% of diethyl phthalate.

The results of this research showed that catalytic ozonation with carbon obtained from the wood waste of shanbil tree can be used as an advanced treatment method.