mazyar peyda

The contamination of food with heavy metals is a significant concern for humans. Among food products, milk and dairy products have received more attention due to their widespread consumption at all ages, particularly among children. The aim of this study is to determine the concentration of lead and cadmium in milk and dairy products in Zanjan.

132 samples of milk, doogh, yogurt, and cream were collected from Zanjan city during the winter and summer of 2020-2021. The lead and cadmium levels in the samples were quantified using microwave digestion and graffiti furnace atomic absorption spectrophotometry.

The average concentrations of lead and cadmium in traditional milk, industrial milk, doogh, full-fat yogurt, low-fat yogurt, and cream samples were 96.23, 89.91, 78.79, 49.79, 53.74, 106.08, and 2.76, 2.07, 2.59, 1.09, 1.34, 5.60 µg/kg, respectively. The mean lead concentrations in milk and dairy products during winter were significantly higher than those during summer, whereas the mean cadmium concentrations during summer were higher than those during winter for all dairy products.

The lead and cadmium concentrations in most of the samples exceeded the WHO-FAO standards of 20 and 2.6 µg/kg for lead and cadmium, respectively. Therefore, prompt action is necessary to address this issue.

The combined use of plant-based and chemical coagulants, such as aluminium or iron salts can reduce the use of chemical coagulants while providing sufficient efficiency in removing suspended solids. This experimental research investigated the effect of Descurainia sophia seed extract (DSSE) in conjunction with the aluminium sulphate (alum) on turbidity removal efficiency.

D-Optimal design using Response Surface Methodology (RSM) was used for experimental design to investigate the effects of operating factors on responses and the potential interactions between these factors.

The results showed that, when starting with an initial turbidity of 200 NTU, the maximum achieved turbidity removal efficiency of 91.45% (Run 1) was attained by using only alum at an optimized concentration of 59.5 mg/L and a pH 6. However, when the initial turbidity was 200 NTU, pH 7, and the alum concentration was reduced to 40 mg/L, and the DSSE/water ratio was increased to 16 mL/L, a turbidity removal efficiency of 93.45% (Run 35) was obtained.

DSSE can be used as a plant-based coagulant along with alum to reduce alum consumption and improve the coagulation and flocculation of suspended solids in water. By incorporating this extract, the removal of impurities and reduction of turbidity can be effectively promoted.

Toxic metals enter the human food chain through water, soil, and plants. High consumption of dairy products makes it necessary to measure their concentrations in milk and its products.

In this study, four samples of dairy products, including milk, dough, yogurt, and cream were selected. They were spiked with concentrations of 0, 20, 40, and 60 μg/kg of lead (Pb) and cadmium (Cd) separately. In all samples, the concentration of these metals was determined using graphite furnace atomic absorption spectroscopy (GFAAS) after microwave, wet, and dry ashing digestion methods. To select the best digestion method, recovery percentage, linearity of increasing concentrations, relative standard deviation (RSD), and the limit of detection were used.

According to the results, the RSD of all measurements was less than 5%. The instrument detection limit for Pb and Cd were 0.188 and 0.157 μg/L, respectively. The recovery efficiency of all digested samples by three methods was between 75.7% and 120%. According to the linearity index and R2, the microwave digestion method with 90 to 110% efficiency was the best for Pb-spiked samples, and the dry digestion method was the best for Cd spiked samples.

Considering all indexes, microwave digestion was the best method for Pb and Cd samples.

Population growth and industrial and agricultural activities have increased the consumption of water, leading to clean water scarcity. Wastewater treatment is an important concern as determining proper sites for wastewater treatment plants (WWTP) largely influences proper operation. The present study aimed to determine an optimized site for WWTP in the rural complexes of Zanjanrood catchment in Zanjan province, Iran.

The site priority map was generated using the geographical information system (GIS) and analytical hierarchy process (AHP). Locating of the plants was based on various parameters. After map preparation, the weight of each parameter was determined using the AHP approach, and the conversion of the layers was performed using the GIS. The site priority map for each sub-catchment was determined and optimized.

In the criteria pairwise comparison matrix, the distance from the city had the highest value (16%), while the distance from the oil and gas transmission pipelines had the lowest value (1%). The site was located at the lowest elevation compared to the villages in each complex.

According to the results, the AHP followed by the optimization method could pinpoint the optimal sites for the environmental protection of treatment plant construction in rural areas.

Endocrine-disrupting compounds (EDCs) as active biological compounds can pose a threat to the environment through acute and chronic toxicity in organisms, accumulation in the ecosystem, and loss of habitats and biodiversity. They also have a range of possible adverse effects on environmental and ecological health. Estradiol, as one of the natural estrogenic hormones released by the humans and livestock, may exert endocrine-disrupting effects on the nanogram-per-liter range and cause serious problems for the aquatic organisms and animals in many aquatic systems. Various studies have reported the presence of synthetic estrogens such as 17 alpha-ethinyl estradiol (EE2) and natural estrogens including 17 beta-estradiol (E2) in wastewater sludge, surface water, river bed sediment, and also digested and activated sludge. The aim of the present study was to review and evaluate the endocrine disrupting compounds especially 17 beta-estradiol, as a representative of estrogen hormones present in the environment and their disturbing effects on humans and wildlife.

In the present study, the photocatalytic (TiO2/UV) batch process has been used for the methyl orange (MO) degradation.
In the catalyst range from 0.25 to 1.5 g/L, the optimum concentration of TiO2 was found to be 0.5 g/L. The kinetic behavior of MO degradation has been evaluated using the non-linear form of pseudo-first order and pseudo-second order models.
The goodness of the fit was evaluated using the correlation coefficient R2 value and the mean square error (MSE) function.
The kinetic studies revealed that the pseudo-first order model (k1 = -0.0593 min-1) is more suitable to fit the experimental data (R2 = 0.957, MSE = 0.00271) of MO degradation.

Background; Contamination of water and soil through non-point sources such as road runoff causes environmental concern. The aim of this study is to determine the effect of Zanjan – Chavarzagh road on the total organic carbon (TOC) content of sediments in tributaries and the river that lead to Taham Lake.
Methods; In tributaries and the river 69 soil and sediment samples were taken and the Total organic carbon (TOC) was measured according to Walkely-Black method. Also, Taham Dam Basin area and its hydrologic properties were calculated by Global Information System (GIS) software.
Results; Results showed that, TOC concentration has a significant negative relationship with the distance from the lake. TOC in soil samples taken from hillside of the road had significantly lower mean and median concentration ( median= 3262 , mean = 4083 ± 3461 mg/kg) than the valley side ( median = 5324 , mean = 6178 ± 3980 mg/kg). The check dams across the tributaries and the river have not been effective in the reduction of TOC in sediments.
Conclusion; Roads in the Taham Dam Basin, increases TOC content of soil and sediments in Taham dam basin. TOC moves toward Taham dam lake.

Background; Enzymes are well known as sensitive catalysts in the laboratory and industrial scale. To improve their properties and for using their significant potential in various reactions as a useful catalyst the stability of enzymes can often require improvement. Enzymes Immobilization on solid supports such as epoxy- functionalized ferric silica nanocomposite can be effective way to improve their characteristics.
Methods; In this study silica coated magnetite nanoparticles were Functionalized with GPTSM as a linker, then immobilization reaction performed by using various amounts of lipase B from Candida Antarctica (CALB), for the next step immobilization effects on thermal stability and optimum pH were investigated in comparison with free CALB.
Results; Results illustrated enzyme was successfully immobilized on nano particles and immobilized derivative retains 100% of its activity by 55°C while free CALB loss its activity at the same condition.
Conclusion; Immobilization of CALB on Fe3O4@SiO2 particles resulted in significant improvements in its characteristics such as thermal stability and methanol tolerance compared to the free CALB.

Water treatment sometimes needs a coagulation and flocculation process to remove suspended and colloidal materials. Inorganic coagulants used create concerns about pollution of the environment and harmful effects on the human’s health. The studies carried out previously indicated the capability of an active coagulant agent extracted from Descurainia Sophia seed to remove turbidity of water.
The purpose of this study was to investigate the effect of NaCl (0.05-1 gL-1), NaOH (0.01-0.1 gL-1), extraction duration (1-25 min) and the ultrasound frequency (0-45-75 kHz), used in the extraction of Descurainia Sophia seed, on the generation of color in purified water and to provide a model to predict the effects of the studied variables on color generation. Extraction was performed using water as solvent, supplemented with NaCl and NaOH and irradiated by ultrasound. Design of experiments and analysis of results were conducted by the D-optimal method based on the response surface methodology (RSM).
The results demonstrated that only the effect of concentration of NaOH is significant in color generation (with p The effect of NaOH on color generation in purified water is predictable by the use of a statistically valid linear model at a confidence level of 95%.

Turbidity removal using inorganic coagulants such as iron and aluminum salts in water treatment processes causes environmental and human health concern. Historically, the use of natural coagulant to purify turbid water has been practiced for long time. Recent research indicates that Descurainia Sophia seed can be effectively used as a natural coagulant to remove water turbidity.
In this work, turbidity removal efficiency of Descurainia Sophia seed extract was compared with Ferric chloride. Experiments were performed in laboratory scale. The coagulation experiments were done with kaolin as a model soil to produce turbidity in distilled water. The turbidity removal efficiency of Descurainia Sophia seed extract and Ferric chloride were conducted with jar test apparatus. In all experiments, initial turbidity was kept constant 100(NTU). Optimum combination of independent variables were used to compare two different types of coagulants.
Results showed that Ferric chloride could remove 89.75% of the initial turbidity, while in case of Descurainia Sophia this value was 43.13%. The total organic carbon analysis of the treated water using seed extract showed an increased concentration of TOC to 0.99 mg/L.
The Descurainia Sophia seed extract has an acceptable potential in the coagulation/flocculation process to treat turbid water.