The application of char from biomass gasification as a filling material in landfill simulation reactors was investigated to evaluate the effect of char on carbon retention and nitrogen leaching, nitrogen denitrification, and waste stabilization. Landfill simulation columns filled with fine fraction of aged refuse (AR) and solid fraction of digestate (SFD) were used, with two char application methods: embedding a char layer between AR and SFD layers and mixing char with the SFD. The experimental results show that char application increased the biodegradable organic matter content as the respiration index (RI₄) of the mixture char-SFD increased up to 37.7%, which could enhance the heterotrophic denitrification. Moreover, 12.3% of ammonia leaching was avoid by applying the SFD mixed with char. These results indicate that char from biomass gasification poses a significant enhancement on nitrogen and carbon retention which might increase the denitrification capacity of the SFD in the long run. Although high nitrogen removal rates were achieved (up to 23.1 mg N/kg-TS day), the addition of char from biomass gasification has little effect on the nitrate removal.

In this study, nano-sized ITO supported Pt-Pd bimetallic catalyst was synthesized for the degradation of methyl parathion pesticide, a common extremely toxic contaminant in aqueous solution. On the characterization with different techniques, a beautiful scenario of honeycomb architecture composed of ultra-small nanoneedles or fine hairs was found. Average size of nanocatalyst also confirmed which was in the range of 3–5 nm. High percent degradation (94%) was obtained in 30 s using 1.5 × 10⁻ ¹ mg of synthesized nanocatalyst, 0.5 mM NaBH₄, and 110 W microwave radiations power. Recyclability of nanocatalyst was efficient till 4th cycle observed during study of reusability. The supported Pt-Pd bimetallic nanocatalyst on ITO displayed many advantages over conventional methods for degradation of methyl parathion pesticide, such as high percent degradation, short reaction time, small amount of nanocatalyst, and multitime reusability. Graphical abstract Schematic illustration of reaction for degradation of methyl parathion

Both cadmium (Cd) and polycyclic aromatic hydrocarbons (PAHs) are known reproductive toxicants, but their co-exposure and interaction effect on semen quality particularly in nonsmokers remain unknown. We included 333 nonsmoking men and analyzed their urine and semen samples for heavy metals and PAH metabolites. Restricted cubic spline models were used to explore the dose-response relationship between each OH-PAHs, Cd, and semen quality parameters; the generalized linear model was performed to examine the interaction of each urinary OH-PAH metabolite and Cd concentration on semen quality. Also, stratified analysis was applied to further illustrate the independent effect of PAHs on semen quality parameters in low and high concentration Cd subgroups. The dose-response and interaction effect of PAHs and Cd on male semen quality was observed. Stratified analysis in the high concentration Cd subgroup showed a negative association of 1-OHPyr concentration with semen motility. Our findings indicate that Cd not only modifies the association between PAHs and semen quality but can also exacerbate the toxic effect of pyrene on semen quality parameters. However, further studies with larger samples are needed to confirm the findings.

Belt and Road initiative has been proposed by China to initiate the cooperation among relevant countries in sector of energy and Trade. The study investigate highlighting the relationship between industrial value added per capita, transport freight and CO₂ emission among the partner countries of Belt and Road initiatives by using panel of 33 economies from 1986-2017. Study includes panel autoregressive distributed lag model (ARDL) to estimate the long-run relationship among variables. Estimated results of pool mean group (PMG) indicates that increase in industrial value added per capita and transport freight deteriorates the quality of environment in long-run. However, short-run results of granger causality reveals positive and unidirectional causality running from industrial value added per capita to emission of CO₂ while transport freight and CO₂ emission shows bidirectional causality. The study emphasized to formulate environment friendly policies in industrial and transport sector.

Human-made impacts on the acoustic environment from marine industries is becoming a more significant issue with increasing public concern of environmental consequences. Even though there are several reports with scientific evidences on harmful influences of anthropogenic underwater sounds on the aquatic ecosystem, most of the studies so far dealt with trigger effects of short term noise impacts on aquatic animals. In the present study, however, long-term experimentation was conducted with Nile tilapia (Oreochromis niloticus) in order to figure out how fish may respond to long-term exposure of underwater sounds and if the level of response may change (increase or decline) over time. A startle reflex as a sign of stress was seen immediately at the start of the playbacks of ship noise or urban sounds in this study. Peaks of elevated respiratory movements of ventilation (opercula beats and pectoral wing rates) retained high over the following 30 days of sound initiation and underwent a declining trend over the following 90 days of exposure. At the end of the 120-day study period, the lowered response of fish after long-term sound exposure is likely due to the increased tolerance of fish to human-generated underwater sounds of urban and shipping noises. Different than short-term noise impacts, information on long-term exposure of anthropogenic underwater sounds is important for environmental management and setting new regulations for the sustainable use of water resources in the world.

Throughout continents, reservoirs tend to have elevated methylmercury (MeHg) concentration transformed from mercury (Hg/total Hg). This impact may be pronounced in the reservoir with less velocity of water during the charging period resulted in the deposition of sediments. In sediments on favorable conditions, methylation may be enhanced by the decomposition of flood organic material, which can release Hg and enhance microbial activity. However, much less is known about the transfer ratio of Hg and its form MeHg from sediment to biota in the hydrological reservoir during the dam charging phase. The objective of our study was to understand the interrelationship between total Hg and MeHg in two key components sediment and fish in the reservoir ecosystem. This study was performed at the Three Gorges Reservoir (TGR) located on upstream of the Yangtze River in China. At the TGR charging phase, during winter time, the water level was high due to blockade of water by Three Gorges Dam (TGD). Sediment and fish samples were collected in winter season for total Hg, MeHg, and several ancillary parameters. The results showed that total Hg in sediment samples of the winter season were ranged from 6.2 ± 0.001 to 193.3 ± 0.001 × 10⁻³ mg/kg, with an average value of 53.76 ± 51.80 × 10⁻³ mg/kg, and for MeHg was ranged from 12.1 ± 0.04 to 348.7 ± 0.16 × 10⁻² ng/g, with an average value of 98.96 ± 93.07 × 10⁻² ng/g. Total Hg and MeHg in fish samples of the winter season were from 42.48 ± 6.71 to 166 ± 52.56 ng/g, with an average value of 76.22 ± 31.23 ng/g, and from 21.09 ± 2.31 to 61.60 ± 13.30 ng/g, with an average value of 37.89 ± 11.96 ng/g. The relationship of total Hg and MeHg concentrations in fish to those of sediments from corresponding sites showed a negative relationship. This might include a strong association of total Hg with an inorganic component of sediment (e.g., bound to sulfides or coprecipitated with other metal oxides such as manganese and iron). The average concentration of fish MeHg found in this study, at rates greater than 1.72 g/day, was estimated hazardous to human health. This study concludes sediment was acting as sequestrate for total Hg and MeHg in TGR. The bioaccumulation of total Hg and MeHg in fish was not controlled by sediment further investigation about pathological routes and dietary habits of fish needed to be identified for total Hg and MeHg study in TGR.

Arsenic contamination of drinking water is a serious water quality problem in many parts of the world. In this study, a low-cost manganese oxide ore from Vietnam (Vietnamese manganese oxide (VMO)) was firstly evaluated for its performance in arsenate (As(V)) removal from water. This material contains both Mn (25.6%) and Fe (16.1%) mainly in the form of cryptomelane and goethite minerals. At the initial As(V) concentration of 0.5 mg/L, the adsorption capacity of original VMO determined using the Langmuir model was 0.11 mg/g. The modified VMOs produced by coating VMO with iron oxide (Feᵃ-VMO) and zirconium oxide (Zrᵃ-VMO) at 110 °C and 550 °C achieved the highest As(V) adsorption capacity when compared to three other methods of VMO modifications. Langmuir maximum adsorption capacities of Feᵃ-VMO and Zrᵃ-VMO at pH 7.0 were 2.19 mg/g and 1.94 mg/g, respectively, nearly twenty times higher than that of the original VMO. Batch equilibrium adsorption data fitted well to the Langmuir, Freundlich, and Temkin models and batch kinetics adsorption data to pseudo-first order, pseudo-second order, and Elovich models. The increase of pH progressively from 3 to 10 reduced As(V) adsorption with a maximum reduction of 50–60% at pH 10 for both original and modified VMOs. The co-existing oxyanions considerably weakened the As(V) removal efficiency because they competed with As(V) anions. The competition order was PO₄³⁻ > SiO₃²⁻ > CO₃²⁻ > SO₄²⁻. The characteristics of the original and modified VMOs evaluated using SEM, FTIR, XRD, XRF, surface area, and zeta potential explained the As(V) adsorption behaviour.

Pot experiments were set up to simulate the soil contamination by three initial concentrations of sulfamethoxazole (SMX) (S1, 100 mg/kg; S2, 200 mg/kg; S3, 300 mg/kg). The content of SMX in soil and its accumulation in lettuce were analysed. Additionally, the effects of SMX on soil microorganisms and antibiotic resistance genes were studied by Illumina high-throughput sequencing and droplet digital polymerase chain reaction (ddPCR). The results demonstrated that the SMX content in soil reduced by 97%, 86% and 75% in the S1, S2 and S3 treatment groups after 120 days, respectively. The accumulated SMX in lettuce was positively correlated with the initial concentration of SMX in soil. SMX contamination significantly reduced the bacterial diversity and altered the composition of bacterial and fungal communities in soil. The dominant bacterial and fungal genera in the SMX-contaminated soil were obviously different from those in the control soil. The relative abundance of sul1 (sulfonamide resistance gene) remarkably increased in the SMX-contaminated soil, while that of other ARGs, such as sul2 and tetracycline and quinolone resistance genes, showed no significant change.

Swine farms are one of the important sources of antibiotics in the environment. In this study, 42 samples of compound feed and feces of swine collected at different growth stages from intensive farms were evaluated for the occurrence and concentrations of three tetracyclines (TCs, namely oxytetracycline, chlortetracycline, and doxycycline) and three sulfonamides (SAs, namely sulfadiazine, sulfadimidine, and sulfamethoxazole). To check for other additional sources of antibiotic administration, ratios (R) of the measured and the predicted levels of each antibiotic excreted via feces were also estimated. Our results showed that the maximum concentration of TCs was 376,210 μg kg⁻¹ and 541,020 μg kg⁻¹ in the feeds and feces, respectively, both for oxytetracycline. In contrast, the highest concentration of SAs were 16.98 μg kg⁻¹ for sulfadimidine in the feeds and 14.70 μg kg⁻¹ for sulfadiazine in the feces. The concentrations of ΣTCs (sum of the three tetracyclines) in swine feeds and feces were found to be 1–4 orders of magnitude higher than those of ΣSAs (sum of the three sulfonamides). Approximately 36% of the R values were found to be greater than one, indicating other sources of administration such as injection and/or oral administration (via drinking water) may also contribute to the presence of antibiotics in feces. Most of the higher R values were found in starter pigs, which were generally administrated with antibiotics by multiple routes to prevent disease and promote swine growth. Our study suggests that comprehensive measures may be undertaken to control antibiotic use in intensive swine farms.

Dyes are widely used in many industrial sectors, many contain harmful substances to human health, and their release into the environment entails several environmental problems, generating a major worldwide concern as water resources are increasingly limited. The development of cheap and efficient biosorbents that remove these pollutants is of utmost importance. In this study, powdered seeds of the araticum fruit (Annona crassiflora) were used in the biosorption of crystal violet (CV) dye from aqueous solutions and simulated textile effluents. Through the characterization techniques, it can be observed that the material presented an amorphous structure, containing an irregular surface composed mainly by groups containing carbon, hydrogen, and oxygen. CV biosorption was favored at the natural pH of the solution (7.5) for a dosage of 0.7 g L⁻¹ of araticum seed powder. The pseudo-second-order model was the most suitable to represent the biosorption kinetics in the removal of the CV. Biosorption capacity reached equilibrium in the first minutes at the lowest concentrations, and, at the highest, after 120 min. The equilibrium data were well represented by the Langmuir model, with a maximum biosorption capacity of 300.96 mg g⁻¹ at 328 K. Biosorption had a spontaneous and endothermic nature. In the treatment of a simulated effluent, the biosorbent removed 87.8% of the color, proving to be efficient. Therefore, the araticum seeds powder (ASP) can be used as a low-cost material for the treatment of colored effluents containing the crystal violet (CV) dye.