نشریه مهندسی بهداشت محیط
سال سوم شماره 2 (پیاپی 10، زمستان 1394)

Producing compost out of municipal solid wastes and organic materials is one of the main ways to recycle organic materials which plays an important role in waste management. Compost can also bring some toxic substances such as heavy metals into the soil and food chain and these substances have negative effects on the living things.
This research is a cross-sectional descriptive study which was carried out during two seasons of spring and summer on Zahedan vermicompost factory. There were 100 samples in the research and the rate of mobility of heavy metals of lead, cadmium, and nickel was measured through five-step sequential extraction method. Then the hazard of the metals was assessed too.
The results show that the highest rate of mobility is related to chromium and then cadmium and lead. Moreover, the risk assessment of heavy metals estimates the average risk of all three metals for the living things in the environment.
Heavy metals of lead and cadmium and nickel in Zahedan compost are less than the standard that is set for Iran.

The burn unit is a suitable environment for the growth of pathogenic bacteria that can reduce these pathogens by appropriate disinfection methods. So, choosing an appropriate disinfectant and applying standard methods of disinfection can be effective in reducing nosocomial infections. The aim of this study is evaluation of efficacy of current disinfectants on pathogens isolated from surface of different parts of Shahid Sadughi accidents burns hospital in city of Yazd.
In this study, the sampling method has done simple randomly and 240 samples were collected from 30 different parts of hospital surfaces (for every disinfectant 30 samples before and 30 samples after disinfection). The samples in the Microbiology laboratory of Medical Sciences University were cultured on blood agar and EMB agar culture. Colonies that were suspected to pathogens were identified by biochemical tests and their colony count was determined. Data were analyzed using Paired T-test.
The average of isolated bacteria at 4 parts of burn unit of hospital before disinfecting by Deconex 50 AF, Descoscid, Epimax SC and Silvosept was 58.02, 18897.28, 30989.05 and 38.52 respectively and after disinfecting was 12.8, 0.62, 1.65 and 5.09 respectively. Reducing of contamination in all disinfectants shown a significant difference (p The results showed that all disinfectants was effective on isolated pathogens and also have shown a significant difference (p

With Regard to importance of environmental health issues in recent decades, coherent and planned efforts to identify environmental health indicators and values and how it is controlled. Primarily for evaluation and monitoring for each subject should be determined the indicators also indicators for the evaluation of air quality should be considered. In the present study Addressed to survey of indicators of air quality, radiation, sound and heavy metals to Iran.
In the present study is that all countries in the world in terms of air quality, Radiation, sound and heavy metals (lead and mercury) are to be examined And according to these criteria, indicators that are commensurate with our country elected. For each of these indicators, the indicators and methods of calculation are determined.
During this study was about 35 indicator Given the importance of health and the environment, it is calculated and information about the index, an indicator of air quality, radiation, sound and heavy metals, 16, 1, 1 and 0 in the first two years of the first respectively.
Among the indicators selected at the beginning of what exists and what indicators in this study were obtained, As can be seen from the 35 indicators surveyed, There are 13 indicators in the country and 22 of the present investigation was added.

In recent decades, due to the scarcity of fresh water resources and high costs of wastewater treatment, cases of irrigation of cultivation of vegetables using raw sewage and polluted effluents or the use of human and animal faeces have been reported. Vegetables are important sources of exposure of human pathogenic pathogens such as fecal coliforms. The aim of this study was to evaluate the performance of three different disinfectant on several kinds of vegetables that would normally be released in Kermanshah.
In this cross sectional study, 180 randomly selected vegetable samples were collected from mobile and fixed stores of vegetables in Kermanshah. Then, to evaluate the effectiveness of disinfectants in eliminating microbial samples, three types of disinfectants containing active ingredient Benzalconium chloride, were studied. Heterotrophic plate count (HPC) surface culture method, coliform count (VRBA) Violet Red Bile Agar purplate method and Yeast Glucose Chloramphemicole Agar (YGCA) surface culture method was used in order to count the microbial load.
The findings of this study suggest that the overall average performance of all three disinfectants was less than 75% and most disinfection efficiency was observed in two-fold concentrations of proposed by manufacturer. Based on the analysis of the resulting data, disinfectants examined in this study had an average efficiency of 76.13% for the removal of coliforms as an indicator of gram-negative bacteria and 100% for the removal of Streptococcus bacteria as indicators gram positive bacteria.
Disinfection can not solely guarantees the maintaining the health of the consumer. We could have declared that recommended disinfection conditions and existing facilities can effectively reduce the microbial load of vegetables. However, preparing vegetables from safe and ensure proper burial are recommended. Moreover, consuming the raw vegetables in sensitive seasons and precarious conditions should be avoided.

The aim of this study was to investigate the removal of chromium (VI) by Nanocomposites Chitosan-tragacanth solution from aqueous solution.
In this study, chitosan-tragacanth nanocomposites were synthesized and analyzed by electron microscopy (SEM), (TEM) and Fourier transform spectroscopy (FT-IR) for the size and shape of the surface. The nano-composite of chitosan-tragacanth, for the adsorption of chromium (VI) in aqueous solution was used as adsorbent.
The optimum conditions with multiple experiments to enhance the absorption were evaluated. The highest absorption of Cr (VI) was occurred in the adsorbent dosage of 0.2 g, 8 ppm concentration of chromium ions, the pH=6 and also retention time of 50 min; in 298 ˚K temperature. After determining optimal conditions of adsorption, isotherms equations and study and thermodynamic parameters were applied. Adsorption process of chromium (VI) on nano-composite chitosan - Tragacanth was conformed with Temkin isotherm.
The thermodynamic parameters such as standard Gibbs free energy changes, changes in enthalpy and entropy changes in the standard showed that the adsorption process of Cr (VI) is spontaneous and heating, and kinetics studies of models Lagergren, Ho , Alovich and intraparticle is used, the results show that the adsorption kinetics follows the pseudo-second order.

This study aimed to compare and evaluate the spatial and statistical models to predict PM2.5 concentrations at ground level and at the macro scale in Mashhad.
To investigate the status of air pollution in the metropolis of Mashhad air, three interpolating models including Ordinary Kriging (OK), Universal Kriging (UK) and inverse distance weighting (IDW) were used. Root Mean Square Error (RMSE) and correlation coefficient (R2) were employed to compare three models and choose the best one. As well as to select the most optimal conditions for the implementation of both OK and UK, used from Standardized RMSE.
The results showed that the highest monthly average of PM2.5 was belonged to September and “Sakhteman” station (95.1 μg/m3). Also, the lowest monthly average pollution had happened in "Torogh" station, in November (15.5 μg/m3). According to the data, the OK had the lowest RMSE (10.601) compared to the UK and IDW. Lower RMSE represents lower error between the predicted and measured values. So, OK model selected as better one in interpolation. Also, Judging by correlation coefficient (R2), the highest correlation belonged to OK compared to other two models. UK model showed a greater standard error of predicts than OK. The greatest standard errors of prediction were related to areas that have more distance from air pollution monitoring stations.
it should be noted that the production and use of geo-referenced maps could quickly provide spatial analyses, and because it can be combined with GIS, the user is able to investigate the influence the various concentrations of contaminants.

Microorganisms in hospitals are potential sources of infection to patients and staff. Bioaerosol exposure is associated with a vast range of adverse health effects including infectious diseases, acute toxic effects, allergy and cancer. This study aimed to survey the type and density of bioaerosols in ambient air of different parts of educational hospitals Gorgan 2012.
In this cross-sectional study, different wards of Gorgan educational hospitals including dialysis, patient room and ICU were investigated. Totally, 81 air samples were taken based on NIOSH standard method. Saborad Dextrose agar and Nutrient agarculture medium was used passive method media. Samples collected were shipped to lab and incubated for 48 hours. Finally Concentration was determined in cfu/m2/hr.
The diversity and density of Bioaerosoles the highest and lowest densities were in dialysis (30.65%) and operating rooms (19.55%) wards of panjom azar hospital and surgical women (23.35%) and operating rooms(15.35%) wards of Sayyad Shirazi hospital. The most common fungi and bacteria isolated from air hospitals were Staphylococcus epidermisand (41%) and penicillium (23.45%).
According to the results of the chi-square test for detection of bacterial contamination of surfaces and equipment in the hospitals studied did not show a significant statistical difference (p-value