Soil organic matter chemistry. Part 1. Characterization of several humic preparations by proton and carbon‐13 nuclear magnetic resonance spectroscopy

Both laboratory and commercial preparations of humic substances (HSs) such as fulvic acids and humic acids along with HC1‐HF preparation of Manitoba peat soil organic matter were characterized using Fourier Transformation (FT) proton (¹H) and carbon‐13 (¹³C) nuclear magnetic resonance (NMR) spectroscopy. All the samples were dissolved in a solution of 0.4 N NaOD in D₂O. In the case of ‘H‐NMR spectroscopy, all the investigated humic samples displayed resonance absorption peaks in the region of 1–4 ppm indicating the likely presence of aliphatic protons in the preparations. However, with the exception of one fulvic acid preparation (extracted from Manitoba Carrol clay‐loam soil with 0.5 N NaOH), ¹H‐NMR spectra of all other samples provided evidence for strong aromatic character. The aliphatic and aromatic characteristics of such samples of HSs were further confirmed with the aid of ¹³C‐NMR spectra.     

Higher nitrates, P and lower pH in soils under medicinal plants versus crop plants

This report shows a higher soil quality under medicinal plants versus food-crop plants. Long-term continuous cultivation of food crops induces changes of soil properties that can lead to fertility loss and, in turn, decline of food productivity. Effect of cropping on soil changes has been studied mainly for food crops and vegetables worldwide, whereas soil changes in herbal fields are scarcely known. Therefore, we compared here soil nutrients and soil chemical properties of herbal fields, cultivated with Chinese medicinal plants, and food-crop fields. Fields are located at the famous traditional planting base of Chinese medicinal plants in Anguo, China. The results showed that in herbal fields, soil nitrate, available P, soil organic matter (SOM), and electrical conductivity decreased with soil depth, whereas soil pH and soil water content increased with depth. In herbal fields, soil nitrate, available P contents, and soil electrical conductivity were higher than those of food-crop fields at various soil layers. SOM and soil water content were similar in herbal and food-crop fields. Soil pH of herbal fields at 0–20 cm was lower than those of food-crop fields. Findings show overall that soil nutrient accumulation and changes under medicinal plants are higher than food-crop fields.     

High photocatalytic decomposition of the air pollutant formaldehyde using nano-ZnO on bone char

Air pollution is a major issue leading to many serious illnesses. Exposure to formaldehyde may occur by breathing contaminated indoor air, tobacco smoke, or ambient urban air. Exposure to formaldehyde has been associated with lung and nasopharyngeal cancer. Therefore, there is a need for methods to degrade formaldehyde. Here, we studied the photocatalytic decomposition of gaseous formaldehyde over nanosized ZnO particles on bone char. The conditions were UV/bone char, UV/ZnO nanoparticles, and UV/ZnO-bone char in continuous flow mode. We investigated the effects of humidity, initial formaldehyde concentration, and residence time on decomposition of formaldehyde. Agglomeration of ZnO particles in the bone char pores was characterized by Brunauer, Emmett, and Teller surface area, and scanning electron micrograph. Results show that maximum decomposition efficiency of formaldehyde was 73 %. The optimal relative humidity was by 35 %. Findings also indicated that immobilization of ZnO nanoparticles on bone char has a synergetic action on photocatalytic degradation. This is explained by the strong adsorption of formaldehyde molecules on bone char, resulting in higher diffusion to the catalytic ZnO and thus a higher rate of photocatalysis.     

Risk factors and the psychological impacts of the COVID-19 outbreak: perspectives and experiences of Iranian healthcare workers on the frontline

Frontline healthcare workers (HCWs) looking after COVID-19 patients are at high risk of developing mental health problems. Both preventive and interventional initiatives are essential, therefore, to maintain and improve the mental health of HCWs and ultimately to enhance the quality of care that they provide. This qualitative content analysis study, conducted in Iran between September 2020 and February 2021, involved the gathering of data on the issue through face-to-face interviews with 22 HCWs working directly with COVID-19 patients. Data analysis led to the generation of 163 codes, 45 categories (16 risk factors and 29 consequences), and 9 themes. Overall, the results suggest that caring for a patient with COVID-19 is associated with positive and negative psychological impacts. Measures such as increasing sensitivity to crisis situations, self-adjustment skills training, and identifying signs of job burnout owing to moral conflicts can reduce or eliminate the risk of negative psychological consequences among HCWs.     

Residues of endosulfan in cotton growing area of Vehari,Pakistan: an assessment of knowledge and awareness of pesticide use and health risks

This study is based on self-reported information collected from selected farmers of Vehari District, Punjab, Pakistan, to determine their technical knowledge and awareness about pesticide use and associated environmental and health risks. Moreover, soil contamination by routinely used persistent organochlorine pesticide, endosulfan, was also evaluated. Survey data revealed very low literacy rate (on an average 9th grade education) and technical knowledge (almost missing) of the farmers in Vehari District. The farmers are unable to fully read and understand the instructions about the use of pesticide marked on the containers. They are not fully aware of pesticide persistence and toxicity (73%), unable to identify cotton pests and diseases (86%), and do not know which crop to grow in cotton adjacent fields (100%). Data also revealed that the farmers (100%) do not follow safety measure during pesticide application and are unaware of pesticide toxicity symptoms in human as well as the basic first-aid practices (89%).

Poor literacy rate and lack of technical knowledge of farmers in Vehari regarding pesticide use and handling are posing serious environmental and health risks among the local inhabitants, particularly among farmers. Soil analysis results showed that concentration of α- and β-endosulfan ranged from 0–14 to 0–14.64 μg/mg, respectively. Principal component analysis showed that soil organic matter is the key soil parameter controlling the occurrence and fate of endosulfan under sandy loam soil conditions of Vehari District. There is a serious need of improving technical and environmental knowledge of farmer about pesticide risks on human health in the studied area, in particular, and the entire country in general. Findings are of great use for policymaking in Pakistan to minimize pesticide risks in Pakistan.

     

Comparison of floating-bed wetland and gravel filter amended with limestone and sawdust for sewage treatment

Environmental Science and Pollution Research - Advancements in the design and technology of constructed wetlands for efficient removal of wastewater contaminants are ever in progress to develop...     

Environmentally friendly synthesis of Fe2O3@SiO2 nanocomposite: characterization and application as an adsorbent to aniline removal from aqueous solution

Environmental Science and Pollution Research - Silica-based nanocomposite syntheses employ many harmful substances, which, in turn, demand the development of new synthetic environmental-friendly...     

Organochlorine pesticide and polychlorinated biphenyl residues in feathers of birds from different trophic levels of South-West Iran

Persistent organochlorine pesticides (OCPs), such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), alpha, beta and gamma-hexachlorocyclohexane (HCH) isomers, together with polychlorinated biphenyl (PCB) congeners (IUPAC Nos. 28, 52, 101, 138, 153 and 180), were determined in tail feathers from 37 birds belonging to 18 species, all originating from the South-West of Iran (Khuzestan, coast of the Persian Gulf). This is the first report on organochlorine contaminants in feathers from museum collections and it is an indication of the concentrations of OCPs and PCBs in the past (1991-1996). Median concentrations of HCHs, DDTs, PCBs and HCB were 22, 14, 11 and 10 ng/g feather, respectively. Significant correlations (p<0.05) were calculated between OCPs (except HCB) and PCBs in the bird feathers. p,p'-DDE and gamma-HCH were the most abundant OCPs, while CB 180, CB 138 and CB 101 were the predominant PCB congeners in almost all species. Significant differences (p<0.05) in the mean concentrations of DDTs and PCBs were detected among species grouped according to their feeding habits. Levels of DDTs and PCBs were highest in the carnivorous species and lowest in the herbivorous species. Levels of OCPs and PCBs in feathers of bids in the 1990s were generally below the thresholds reported to affect reproduction.     

Hospital site selection using fuzzy AHP and its derivatives

Environmental managers are commonly faced with sophisticated decisions, such as choosing the location of a new facility subject to multiple conflicting criteria. This paper considers the specific problem of creating a well-distributed network of hospitals that delivers its services to the target population with minimal time, pollution and cost. We develop a Multi-Criteria Decision Analysis process that combines Geographical Information System (GIS) analysis with the Fuzzy Analytical Hierarchy Process (FAHP), and use this process to determine the optimum site for a new hospital in the Tehran urban area. The GIS was used to calculate and classify governing criteria, while FAHP was used to evaluate the decision factors and their impacts on alternative sites. Three methods were used to estimate the total weights and priorities of the candidate sites: fuzzy extent analysis, center-of-area defuzzification, and the α-cut method. The three methods yield identical priorities for the five alternatives considered. Fuzzy extent analysis provides less discriminating power, but is simpler to implement and compute than the other two methods. The α-cut method is more complicated, but integrates the uncertainty and overall attitude of the decision-maker. The usefulness of the new hospital site is evaluated by computing an accessibility index for each pixel in the GIS, defined as the ratio of population density to travel time. With the addition of a new hospital at the optimum site, this index improved over about 6.5 percent of the geographical area.     

Competitive biosorption of lead, cadmium, copper, and arsenic ions using algae

The present study aims to evaluate the competitive biosorption of lead, cadmium, copper, and arsenic ions by using native algae. A series of experiments were carried out in a batch reactor to obtain equilibrium data for adsorption of single, binary, ternary, and quaternary metal solutions. The biosorption of these metals is based on ion exchange mechanism accompanied by the release of light metals such as calcium, magnesium, and sodium. Experimental parameters such as pH, initial metal concentrations, and temperature were studied. The optimum pH found for removal were 5 for Cd²⁺ and As³⁺ and 3 and 4 for Pb²⁺ and Cu²⁺, respectively. Fourier transformation infrared spectroscopy analysis was used to find the effects of functional groups of algae in biosorption process. The results showed that Pb²⁺ made a greater change in the functional groups of algal biomass due to high affinity to this metal. An ion exchange model was found suitable for describing the biosorption process. The affinity constants sequence calculated for single system was K _Pb > K _Cu > K _Cd > K _As; these values reduced in binary, ternary, and quaternary systems. In addition, the experimental data showed that the biosorption of the four metals fitted well the pseudo-second-order kinetics model.