Measurement of polycyclic aromatic hydrocarbons in edible oils and potential health risk to consumers using Monte Carlo simulation, southwest Iran.

Persistent organic pollutants, such as polycyclic aromatic hydrocarbons, are hazardous trace contaminants frequently observed in food ingredients, such as edible oils. This study aimed to measure PAHs in forty brands of edible oils marketed in southwest Iran. Additionally, we characterized the daily intake of MOE and ILCR using Monte Carlo simulation. To analyze the content of PAHs, the liquid-liquid extraction method followed by GC-MS was utilized. The average concentration of PAHs was mostly lower than the maximum value for individual PAH (2 µg/Kg); however, the average concentration of fluorene (3.86 µg/Kg) and benzo(a)anthracene (3.13 µg/Kg) was more than the permitted level. The highest residual concentrations of PAHs were mostly observed in canola and corn oils. The daily intake of BaP and 4-PAH for 95% of consumers was 0.01 ng/kg BW/day and 0.04 ng/kg BW/day, respectively. Also, MOE was more than 10,000 for the percentiles of 5%, 50%, and 95%. The modeled ILCR showed that consumption of oil does not currently pose a cancer risk for Iranian consumers due to PAHs exposure. Concerning potential health risks, consumption of edible oils is safe; however, regular monitoring and assessment are required.

Multi-route human health risk assessment from trihalomethanes in drinking and non-drinking water in Abadan, Iran.

Natural organic matter reacted with chlorine used for disinfection, and finally, trihalomethanes (THMs) are formatted. The main purpose of this study was to determine four THM concentrations and human health cancer risk and non-cancer risk assessment from exposure through oral ingestion, dermal contact, and inhalation for males and females in Abadan. Two sampling sites were selected, and five samples before and after treatment by two different water treatment systems (RO and ion exchange) were collected every week. Results showed that total THM concentrations before and after treatment by RO were 98.1 and 8.88 µg/L, and ion exchange ranged between 101.9 and 14.96 µg/L, respectively, that before treatment was upper than the maximum of 80 mg/L recommended by USEPA. Inhalation was the primary route of exposure by around 80-90% of cancer risk. Total cancer risk was higher than the USEPA acceptable limit of 10-6 via three exposure routes. Oral route has the higher hazard index values than dermal ways.

Selecting the best stabilization/solidification method for the treatment of oil-contaminated soils using simple and applied best-worst multi-criteria decision-making method.

Oil-contaminated soils resulted from drilling activities can cause significant damages to the environment, especially for living organisms. Treatment and management of these soils are the necessity for environmental protection. The present study investigates the field study of seven oil-contaminated soils treated by different stabilization/solidification (S/S) methods, and the selection of the best treated site and treatment method. In this study, first, the ratios of consumed binders to the contaminated soils (w/w) and the treatment times for each unit of treated soils were evaluated. The ratios of consumed binders to the contaminated soils were between 6 and 10% and the treatment times for each unit of treated soils were between 4.1 and 18.5 min/m3. Physicochemical characteristics of treated soils were also determined. Although S/S methods didn't change the water content of treated soils, they increased the porosity of soils. Unexpectedly, the cement-based S/S methods didn't increase the pH of the treated soils. The highest and the lowest leaching of petroleum hydrocarbons was belonging to S/S using diatomaceous earth (DE) and the combination of Portland cement, sodium silicate and DE (CS-DE), respectively. The best acid neutralization capacity was obtained for soils treated using the combination of Portland cement and sodium silicate (CS). Based on the best-worst multi-criteria decision-making method (BWM-MCDM), the soils treated using CS-DE was select as the best. The BWM-MCDM can be used as an effective tool for the selection of the best alternative in all areas of environmental decontamination.

4-Chlorophenol degradation using ultrasound/peroxymonosulfate/nanoscale zero valent iron: Reusability, identification of degradation intermediates and potential application for real wastewater.

In this study, nanoscale-zero valent iron (nZVI) was synthesized and its function was assessed in ultrasound (US)/peroxymonosulfate (PMS)/nZVI process to degrade 4-chlorphenol (4-CP). The influential operation parameters of US/PMS/nZVI were evaluated on 4-CP degradation. 95% of 4-CP was degraded during 30 min under the conditions of pH = 3.0, nZVI = 0.4 g/L, PMS = 1.25 mM, US power = 200 W. The rate constants of 4-CP degradation for US/PMS/nZVI, PMS/nZVI, US/PMS and US/nZVI were 0.1159, 0.03, 0.0134 and 0.0088 min-1 respectively. Simultaneous application of US and nZVI synergistically increased 4-CP degradation and PMS activation. nZVI was compared with Fe2+, Fe3+ and micro-ZVI and their results indicated high performance of nZVI compared to others. Reusability of nZVI was examined in four cycles. nZVI exhibited that reusability was acceptable in three runs. The results of effect of anions showed that phosphate had significant inhibitory effect on 4-CP degradation in US/PMS/nZVI process. The scavenging experiments indicated that hydroxyl radical had more contribution compared to sulfate radical. Intermediates of 4-CP degradation were identified including five aromatic compounds. Reaction pathway of 4-CP degradation was proposed. Finally, the performance of US/PMS/nZVI process was evaluated on real petrochemical wastewater. The results showed that US/PMS/nZVI can be a suitable pretreatment for biological treatment.

Simultaneous use of iron and copper anodes in photoelectro-Fenton process: concurrent removals of dye and cadmium.

Photoelectro-Fenton (PEF) was carried out for concurrent removals of inorganic and organic pollutants with simultaneous applications of two different anodes (iron and copper). Cadmium and Direct Orange 26 (DO26) were selected as samples of the contaminants of textile wastewater and influential parameters (pH, current density, H2O2 dosage and electrolysis time) of PEF were evaluated on Cd and DO26 removals. Both mechanisms of coagulation and oxidation affected the removal of both pollutants. Optimal conditions were achieved with pH = 4.0, current density of 5 mA/cm2, 3 mM H2O2 and 40 min electrolysis time, and under these conditions, the dye was completely removed and the Cd removal efficiency was about 80%. Unlike H2O2, persulfate had no scavenging effect in high dosages. The effects of different anions and two matrixes (tap water and wastewater) on Cd and dye removals were investigated. The results showed that decolorization was reduced by the phosphate and nitrate ions while chloride ion accelerated the decolorization rate. In terms of Cd removal, no significant change was observed in the presence of the anions except for phosphate ion. The sludge of PEF was assessed by Fourier transform infrared, field emission scanning electron microscope and energy-dispersive X-ray spectroscopy.

Catalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) by nano-Fe2O3 activated peroxymonosulfate: Influential factors and mechanism determination.

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most applicable herbicides in the world. Therefore, its residue in aquatic environment threatens the human health and ecosystems. In this study, Fe2O3 (hematite) nanoparticles (HNPs) were synthesized, and the characteristics of the obtained HNPs were determined using X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) technique, and particle size analyzer (PSA). The catalytic activity of HNPs was evaluated for the activation of peroxymonosulfate (PMS) for the degradation of 2,4-D. The effects of the operating parameters were studied for the PMS/HNPs system. The results showed that the acidic condition provided higher efficiency, while overdosing of PMS had a scavenging effect. The PMS/HNPs showed high efficiency in comparison with the homogeneous forms of iron (Fe2+ and Fe3+). Reusability of HNPs was studied in five consequent usages. The presence of the anions (chloride, nitrate, and hydrogen phosphate) reduced the 2,4-D degradation. Moreover, the catalytic activity of HNPs was also investigated in the presence of other oxidants. UV irradiation increased the function of PMS/HNPs and its mechanism was described. The order of 2,4-D removal for the oxidants was PMS > persulfate > H2O2 > percarbonate. A total of 29.7% of 2,4-D chlorine content was released during the destruction of 2,4-D. The quenching study showed that sulfate radical was the major agent in the degradation of 2,4-D.

Optimizing COD removal from greywater by photoelectro-persulfate process using Box-Behnken design: assessment of effluent quality and electrical energy consumption.

Greywater (GW) is a potential source for water reuse in various applications. However, GW treatment is still a vital issue in water reuse in cases of environmental standards and risk to public health. This study investigates optimization and modeling of a hybrid process for COD removal from GW. Persulfate (PS) was simultaneously activated by electrogenerated ferrous ion (EC) and UV to generate sulfate radical. Photoelectro-persulfate (PEPS) was optimized by Box-Behnken design and the effects of four variables (pH, PS dosage, current density, and electrolysis time) were evaluated on COD removal. The results and several coefficients showed that the obtained model was acceptable for predicting the COD removal. Moreover, under optimum conditions (pH = 6.9, PS = 8.8 mM, current density = 2.0 mA/cm(2), and 49.3 min electrolysis time), BOD5, turbidity, TSS, phosphate, and UV254 were effectively removed and COD and BOD5 values reached to discharge standards. Different configurations of the processes were assessed for COD removal. The order of COD removal efficiency followed: PS < Fe(II) < UV/PS ≤ Fe(II)/PS < Fe(II)/PS/UV < electrocoagulation ≤ electrocoagulation/UV < electro-PS < PEPS. The monitoring PS concentration during 60 min reaction time in the aforesaid processes indicated that PEPS could remarkably activate PS. The solution pH was also monitored and related results revealed that the presence of PS during the 10 min first time decreased pH value while production of hydroxide ion at cathode increased pH significantly. Finally, the contribution of electrochemical process in the electrical energy consumption was far less than that of photolysis process in hybrid PEPS process.

The combination of coagulation, acid cracking and Fenton-like processes for olive oil mill wastewater treatment: phytotoxicity reduction and biodegradability augmentation.

Olive oil mill wastewater (OOMW) is one of the most important industrial wastewaters in the world due to high organic load and phenolic compounds. In this study, an integration of three processes including coagulation, acid cracking and Fenton-like was evaluated to treat OOMW. The performance of alum, ferric chloride and polyaluminum chloride was studied as coagulants. Among coagulants, ferric chloride showed the best results in comparison with the others. Coagulation process with FeCl3 removed 91.2% chemical oxygen demand (COD), 91.3% phenol, 98.9% total suspended solids and 99.2% turbidity at condition of pH = 6 and 3,000 mg/L coagulant dosage. Acid cracking process following the coagulation process with ferric chloride could slightly degrade organic compounds and provided suitable condition for the next process. Fenton-like process with zero valent iron (ZVI) was applied after coagulation and acid cracking. The optimal removal efficiency was achieved by Fenton-like process which was accomplished in condition of 7 g/L ZVI, 1,000 mg/L H2O2 and 180 min reaction time. The biodegradability of final effluent of this integration was improved significantly and biochemical oxygen demand5/COD value increased from 0.14 to 0.83. The results of germination tests revealed that phytotoxicity of the final effluent decreased.