The interactions of Cr (VI) concentrations and amendments (biochar and manure) on growth and metal accumulation of two species of Salicornia in contaminated soil

Environmental Science and Pollution Research - Heavy metals are among the most dangerous contaminants in the environment. Organic components and plant species that can accumulate and stabilize...     

UV-C as an efficient means to combat biofilm formation in show caves: evidence from the La Glacière Cave (France) and laboratory experiments

Environmental Science and Pollution Research - Ultra-violet C (UV-C) treatment is commonly used in sterilization processes in industry, laboratories, and hospitals, showing its efficacy against...     

Environmental planning and management

Environmental Science and Pollution Research -     

Direct and indirect costs of nonfatal road traffic injuries in Iran: A population-based study

Objectives: The objective of this study was to assess the incidence rate as well as direct and indirect costs of nonfatal road traffic injuries (RTIs) in Iran in 2011.

Methods: Data from the 2011 national household survey were used. In this survey, data on demographics, history, and costs of injury were obtained in 2 steps: first, direct face-to-face interview and second, telephone calls. We estimated the incidence rate of nonfatal RTIs in this year. The direct costs included medical care as well as nonmedical costs paid by the patient or insurance services. The indirect costs were estimated by considering the cost of absence from work or education. We also used logistic regression analyses to investigate risk factors of nonfatal RTIs.

Results: We found 76 nonfatal RTI cases (0.96%) out of 7,886 whole reference study cases. These 76 injured patients had a history of RTI in the preceding 3 months. The annual incidence of RTIs was estimated at 3.84%. The mean age of RTI cases was 28.5 ± 10.6 and 88.16% of them were male. Male gender was a major risk factor (odds ratio [OR] = 9.64, 95% confidence interval [CI], 4.79–19.41) and marriage was a protective factor (OR = 0.44, 95% CI, 0.28–0.70) for RTI. The medians of direct, indirect, and total costs were US$214, US$163, and US$387, respectively. The total cost of nonfatal RTIs in Iran was estimated at 1.29% of the gross domestic product (GDP) in 2011.

Conclusions: In Iran, nonfatal RTIs imposed a total cost of almost US$7 billion to the country for one year. Extension and more serious implementation of preventive measurements seem necessary to decrease this notable burden of RTIs.     

Biotoxicity evaluation of zinc oxide nanoparticles on bacterial performance of activated sludge at COD,nitrogen, and phosphorus reduction

• ZnO-NP disrupted metabolic/catabolic balance of bacteria by affecting DHA activity. • ZnO-NPs toxicity was related to Zn²⁺ ion, interaction with cell and ROS generation. • Exposure to ZnO-NPs resulted in changed bacterial community structure at sludge. • The change in the EPS content was observed during exposure to ZnO-NPs. The unique properties and growing usage of zinc oxide nanoparticles increase their release in municipal wastewater treatment plants. Therefore, these nanoparticles, by interacting with microorganisms, can fail the suitable functioning of biological systems in treatment plants. For this reason, research into the toxicity of ZnO is urgent. In the present study, the toxicity mechanism of ZnO-NPs towards microbial communities central to granular activated sludge (GAS) performance was assessed over 120-day exposure. The results demonstrate that the biotoxicity of ZnO-NPs is dependent upon its dosage, exposure time, and the extent of reactive oxygen species (ROS) production. Furthermore, GAS performance and the extracellular polymeric substances (EPS) content were significantly reduced at 50 mg/L ZnO-NPs. This exposure led to decreases in the activity of ammonia monooxygenase (25.2%) and nitrate reductase (11.9%) activity. The Field emission scanning electron microscopy images confirmed that ZnO-NPs were able to disrupt the cell membrane integrity and lead to cell/bacterial death via intracellular ROS generation which was confirmed by the Confocal Laser Scanning Microscopy analysis. After exposure to the NPs, the bacterial community composition shifted to one dominated by Gram-positive bacteria. The results of this study could help to develop environmental standards and regulations for NPs applications and emissions.     

A comparative evaluation of the performance of full-scale high-rate methane biofilter (HMBF) systems and flow-through laboratory columns

Methane biofilter (MBF) technology, a cost effective method to control atmospheric emission of CH₄, is usually developed as a passively aerated system to control low-volume point-source emissions such as those from landfills with gas collection systems. Actively aerated high-rate methane biofilter (HMBF) systems are designed to overcome the shortcomings of passively aerated systems by ensuring the entire filter bed is utilized for CH₄ oxidation. Flow-through column experiments point to the fact that CH₄ oxidation rates of actively aerated systems could be several times higher than that of passively aerated systems. However, reports of the performance of field HMBF systems are not available in literature. Furthermore, there are no studies that demonstrate the possibility of using laboratory data in the design and operation of field systems. The current study was conducted to fill this research gap and involve a comparative study of the performance of laboratory columns to field performance of a HMBF system using solution gas produced at an oil battery site as the CH₄ source. The actively aerated column studies confirmed past results with high CH₄ oxidation rates; one column received air at two injection points and achieved an oxidation rate of 1417 g/m³/d, which is the highest reported value to date for compost-filled columns. Subsequent studies at a specially designed field HMBF filled with compost showed a higher oxidation rate of 1919 g/m³/d, indicating the possibility of exceeding the high CH₄ oxidation rates observed in the laboratory. The achievement of observed field oxidation rates being higher than those in the laboratory is attributed to the capability of maintaining higher temperatures in field HMBFs. Furthermore, results show that field HMBFs could operate at lower than stoichiometric air to CH₄ ratios, and lower retention times than that of laboratory columns. Results indicated that laboratory columns may not truly represent field behavior, and said results could only be used in the preliminary design of field HMBFs.