Polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) in PM₂.₅ were first observed at a background site (Yuzhong site: YZ site) in the northwestern highlands of China in five seasonal campaigns. Compared with major northwestern cities, PAHs and NPAHs at the YZ site were at a lower level but showed consistent seasonal differences. The PAH and NPAH concentrations peaked in the winter campaigns, which were 36.11 ± 6.54 ng/m³ and 418.11 ± 123.55 pg/m³, respectively, in winter campaign 1 and 28.97 ± 10.07 ng/m³ and 226.89 ± 133.54 pg/m³, respectively, in winter campaign 2. These values were approximately a dozen times larger those in other campaigns. The diagnostic ratios indicate that vehicle emissions were the primary source of the PAHs throughout the five campaigns, and coal and biomass combustion also contributed during the winter, summer, and fall campaigns. Among NPAHs, 2-nitrofluoranthene and 2-nitropyrene were generated through OH radical-initiated reactions during atmospheric transport, while 1-nitropyrene came from combustion sources. There is an observation worth pondering, which is that the ratio between pyrene and fluoranthene increased abnormally in the spring and fall campaigns, which is presumably caused by the burning of Tibetan barley straw in the northwestern highlands. The backward trajectories over Tibetan areas in Qinghai and southwestern Gansu are consistent with this hypothesis. In addition, this study reported for the first time that the burning of Tibetan barley straw has become a seasonal contributor to air pollution in northwestern China and is participating in the atmospheric transport of air pollutants driven by the monsoon in East Asia, which urgently requires further research.

Recent advances in research on algae inhibition by using low-cost straw proposed a possible mechanism that reactive oxygen species (ROS) generated by the solar irradiation of straw-derived dissolved organic matter (DOM) might contribute to cyanobacteria inhibition. However, this process is not clearly understood. Here, DOM from three types of straw (barley, rice, and wheat) and natural organic matter (NOM) isolates were investigated in terms of their photochemical properties and ROS generating abilities. Results demonstrated that the DOM derived from the aeration decomposition of barley straw (A-DOMbs) yielded the best formation efficiencies of hydrogen peroxide (H₂O₂) and hydroxyl radicals (•OH) under solar-simulated irradiation in all organic matter samples. Correlation analysis implies that optical parameters and phenolic hydroxyl group contents can signify ROS generating abilities of different DOM solutions. Bioassay results show that A-DOMbs possesses the highest inhibition performance for M. aeruginosa in all DOM samples, much higher than those of NOM isolates. The addition of catalase greatly relieves the inhibition performance, making the loss of chlorophyll a content decreased from 37.14% to 7.83% in 2 h for A-DOMbs, which implies that for cyanobacteria growth inhibition, photochemically-produced H₂O₂ from SOM is far more important than singlet oxygen (¹O₂), •OH, and even SOM itself. Our results show that H₂O₂ photochemically generated from straw-derived DOM is able to result in rapid inhibition of M. aeruginosa in a relatively short period, furthering the understanding of complicated mechanisms of cyanobacteria inhibition by using low-cost straw in eutrophic waters.

The objective of this research is to analyse the feasibility of reusing the fly ash waste, which is produced in biomass plants, during the production of renewable energy, for controlling phosphorus contamination in the wastewater being processed in sewage treatment plants. The research examines the efficiency of using different types of ash, obtained from representative biomass materials after combustion in an energy plant (paulownia wood, wheat straw and barley straw), in removing phosphorus from water. The ashes were respectively mixed with synthetic water, rich in phosphorus; then, using batch experiments, the effects that the pre-treatment of ash, adsorbent dosage, contact time and temperature had on the adsorption process were studied. The main results show that phosphorus adsorption by the tested ashes augments as temperature increases. Similarly, the adsorbed amount of phosphorus increases by increasing the dose of the adsorbent. In addition, the adsorption of phosphorus by these three materials has been described well by the Langmuir isotherm equation. It has been found that the removal process of phosphorus was endothermic. Finally, this study concludes that waste ash from biomass plants can be used to remove phosphorus from wastewater in sewage treatment plants.

Biosorbents are the natural origin adsorbents, which popularity in environmental engineering is steadily increasing due to their low price, ease of acquisition, and lack of the toxic properties. Presented research aimed to analyze the possibility of chemical modification of the straw, which is a characteristic waste in the Polish agriculture, to improve its biosorption properties with respect to removal of selected metals from aquatic solutions. Biosorbents used during the tests was a barley straw that was shredded to a size in the range of 0.2–1.0 mm. The biosorption process was performed for aqueous solutions of zinc at a pH 5. Two different modifications of straw were analyzed: esterification with methanol and modification using the citric acid at elevated temperature. The results, obtained during the research, show a clear improvement in sorption capacity of the straw modified by the citric acid. In the case of straw modified with methanol, it has been shown that the effectiveness of zinc biosorption process was even a twice lower with respect to the unmodified straw. Moreover, it was concluded that the removal of analyzed metals was based mainly on the ion-exchange adsorption mechanism by releasing a calcium and magnesium ions from the straw surface to the solution. Graphical Abstract ᅟ

This study analysed the effectiveness of innovative (basalt meal, brown algae extract) and conventional (barley straw) substances which hypothetically alleviate the inhibiting effect of Cd²⁺ on biochemical properties of soil, with particular regard to the activity of arylsulfatase. An analysis of their potential was carried out based on the activity of arylsulfatase and the number of Pseudomonas sp. determined on the 25th and 50th days of the study. Cd²⁺ was applied in the following doses: 0, 4, 40, 80, 120, 160, 200 mg Cd²⁺ kg⁻¹ of DM soil, in the form of CdCl₂·2.5H₂O. A complex formulation of the issue was obtained from the presentation of biochemical properties using the RS (resistance of soil) index. Cadmium caused permanent adverse effects in the soil environment, inhibiting the activity of arylsulfatase and the yield of spring barley. The consequences of stress connected with increasing Cd²⁺ pollution were intensified by an elongation of the accumulation time of the tested metal in the soil. Chances for regeneration of the soil may be sought, most of all, with the application of straw and, to a lesser degree, with basalt meal. Brown algae did not meet the expectations for its potential. An increase in the studied parameters also resulted from sowing the soil with spring barley.

This study was conducted to investigate soil quality, Chinese cabbage growth, and N₂O emission after biochar application in an upland field in South Korea. Each of the barley straw biochar (BC, applied at 10 ton ha⁻¹), inorganic fertilizer (IF, applied at N-P-K = 320–78–198 kg ha⁻¹), and BC + IF treatment areas were separated by a control (Cn) treatment area. Soils treated with BC and BC + IF treatments had lower bulk density and higher porosity than those in the Cn treatment areas. Soil chemical properties (pH, TN, Avail. P₂O₅, and CEC) after biochar addition were improved. In particular, soil pH and CEC related to crop nutrient availability were significantly increased in BC areas compared to those in Cn and IF areas. Fresh weights of Chinese cabbage grown under BC, IF, and BC + IF treatment conditions increased by 64.9, 78.4, and 112.0%, respectively, over that in the Cn treatment area. Total nutrient (TN, TP, and K) uptakes among the treatment areas were, in declining order, BC + IF (14.51 g plant⁻¹) > IF > BC > Cn. More interestingly, the BC application had a positive effect on growth of Chinese cabbage under IF application conditions, and there was a tight relationship between the effect of BC application on Chinese cabbage growth and that of agronomic IF application efficiency. Compared to the IF results, total N₂O flux was lower with BC (flux decreased by 60.6%) or BC + IF (flux decreased by 22.3%) treatments. These results indicate that Chinese cabbage yield, when cultivated in soil conditions such as those in an upland field in South Korea, can be increased by application of BC or a combination of BC and IF.