Migration mechanism of atrazine in the simulated lake icing process at different freezing temperatures based on density function theory.

Atrazine causes concern due to its resistant to biodegradation and could be accumulated in aquatic organisms, causing pollution in lakes. This study measured the concentration of atrazine in ice and the water under ice through a simulated icing experiment and calculated the distribution coefficient K to characterize its migration ability in the freezing process. Furthermore, density functional theory (DFT) calculations were employed to expatiate the migration law of atrazine during icing process. According to the results, it could release more energy into the environment when atrazine staying in water phase (-15.077 kcal/mol) than staying in ice phase (-14.388 kcal/mol), therefore it was beneficial for the migration of atrazine from ice to water. This explains that during the freezing process, the concentration of atrazine in the ice was lower than that in the water. Thermodynamic calculations indicated that when the temperature decreases from 268 to 248 K, the internal energy contribution of the compound of atrazine and ice molecule (water cluster) decreases at the same vibrational frequency, resulting in an increase in the free energy difference of the compound from -167.946 to -165.390 kcal/mol. This demonstrated the diminished migratory capacity of atrazine. This study revealed the environmental behavior of atrazine during lake freezing, which was beneficial for the management of atrazine and other pollutants during freezing and environmental protection.

Characteristics of aerosols from swine farms: A review of the past two-decade progress.

With the rapid development of large-scale and intensive swine production, the emission of aerosols from swine farms has become a growing concern, attracting extensive attention. While aerosols are found in various environments, those from swine farms are distinguished from human habitats, such as residential, suburban, and urban areas. In order to gain a comprehensive understanding of aerosols from swine farms, this paper reviewed relevant studies conducted between 2000 and 2022. The main components, concentrations, and size distribution of the aerosols were systematically reviewed. The differences between aerosols from swine farms and human living and working environments were compared. Finally, the sources, influencing factors, and reduction technologies for aerosols from swine farms were thoroughly elucidated. The results demonstrated that the concentrations of aerosols inside swine farms varied considerably, and most exceeded safety thresholds. However, further exploration is needed to fully understand the difference in airborne microorganism community structure and particles with small sizes (<1 µm) between swine farms and human living and working environments. More airborne bacterial and viruses were adhered to large particles in swine houses, while the proportion of airborne fungi in the respirable fraction was similar to that of human living and working environments. In addition, swine farms have a higher abundance and diversity of potential pathogens, airborne resistant microorganisms and resistant genes compared to the human living and working environments. The aerosols of swine farms mainly originated from sources such as manure, feed, swine hair and skin, secondary production, and waste treatment. According to the source analysis and factors influencing aerosols in swine farms, various technologies could be employed to mitigate aerosol emissions, and some end-of-pipe technologies need to be further improved before they are widely applied. Swine farms are advised not to increase aerosol concentration in human living and working environments, in order to decrease the impact of aerosols from swine farms on human health and restrain the spread of airborne potential pathogens. This review provides critical insights into aerosols of swine farms, offering guidance for taking appropriate measures to enhance air quality inside and surrounding swine farms.

The Migration Rules of Malathion during Indoor Simulated Lake Freezing.

The effect of malathion in ice is a poorly researched area, and ice is an important habitat for organisms at the base of the food web. This study presents laboratory-controlled experiments designed to investigate the migration rule of malathion during lake freezing. Concentrations of malathion were determined in samples of melted ice and in under-ice water. The effects of the initial sample concentration, freezing ratio, and freezing temperature on the distribution of malathion in the ice-water system were investigated. The concentration effect and migration capacity of malathion during freezing was characterized by the concentration rate and distribution coefficient. The results showed that the formation of ice led to the concentration of malathion appearing as follows: concentration in under-ice water > concentration in raw water > concentration in ice. This implied that malathion tended to migrate from the ice to the under-ice water during the freezing process. The increase in the initial malathion concentration, freezing ratio, and freezing temperature caused a more pronounced repulsion of the malathion by the ice and increased the migration to the under-ice water. When the solution of malathion with an initial concentration of 50 µg/L was frozen at -9 °C and the freezing ratio reached 60%, the concentration of malathion in the under-ice water was concentrated to 2.34 times the initial concentration. The migration of malathion to under-ice water during freezing may pose a potential threat to under-ice ecology; therefore, the environmental quality and impact of under-ice water in icebound lakes needs to be given more attention.

Effects of biofilter media depth and moisture content on removal of gases from a swine barn.

Media depth (MD) and moisture content (MC) are two important factors that greatly influence biofilter performance. The purpose of this study was to investigate the combined effect of MC and MD on removing ammonia (NH3), hydrogen sulfide (H2S), and nitrous oxide (N2O) from swine barns. Biofiltration performance of different MDs and MCs in combination based on a mixed medium of wood chips and compost was monitored. A 3 × 3 factorial design was adopted, which included three levels of the two factors (MC: 45%, 55%, and 67% [wet basis]; MD: 0.17, 0.33, and 0.50 m). Results indicated that high MC and MD could improve NH3 removal efficiency, but increase outlet N2O concentration. When MC was 67%, the average NH3 removal efficiency of three MDs (0.17, 0.33, and, 0.50 m) ranged from 77.4% to 78.7%; the range of average H2S removal efficiency dropped from 68.1-90.0% (1-34 days of the test period) to 36.8-63.7% (35-58 days of the test period); and the average outlet N2O concentration increased by 25.5-60.1%. When MC was 55%, the average removal efficiency of NH3, H2S, and N2O for treatment with 0.33 m MD was 72.8 ± 5.9%, 70.9 ± 13.3%, and -18.9 ± 8.1%, respectively; and the average removal efficiency of NH3, H2S, and N2O for treatment with 0.50 m MD was 77.7 ± 4.2%, 65.8 ± 13.7%, and -24.5 ±12.1%, respectively. When MC was 45%, the highest average NH3 reduction efficiency among three MDs was 60.7% for 0.5 m MD, and the average N2O removal efficiency for three MDs ranged from -18.8% to -12.7%. In addition, the pressure drop of 0.33 m MD was significantly lower than that of 0.50 m MD (p < 0.05). To obtain high mitigation of NH3 and H2S and avoid elevated emission of N2O and large pressure drop, 0.33 m MD at 55% MC is recommended. IMPLICATIONS: The performances of biofilters with three different media depths (0.17, 0.33, and 0.50 m) and three different media moisture contents (45%, 55%, and 67% [wet basis]) were compared to remove gases from a swine barn. Using wood chips and compost mixture as the biofilters media, the combination of 0.33 m media depth and 55% media moisture content is recommended to obtain good reduction of NH3 and H2S, and to simultaneously prevent elevated emission of N2O and large pressure drop across the media.

[Impacts of electroacupucnture at Zusanli (ST 36) and Feishu (BL 13) on the postoperative inflammatory reaction and pulmonary complications in senile patients after radical resection of pulmonary carcinoma].

OBJECTIVE: To observe the impacts of electroacupuncture (EA) at Zusanli (ST 36) and Feishu (BL 13) applied 30 min before the operation till the end of the operation on the postoperative inflammatory reaction and pulmonary complications in the senile patients after radical resection of pulmonary carcinoma. METHODS: Eighty senile patients of pulmonary carcinoma were selected and randomized into an observation group and a control group, 40 cases in each one. In the observation group, EA stimulation at Zusanli (ST 36) and Feishu (BL 13) was used 30 min before the operation till the end of the operation. In the control group, electric stimulation was not used. Separately, before operation (T1, basic state), 12 h after operation (T2) and 24 h after operation (T3), blood sample was collected from the central vein. The concentrations of plasma tumor necrosis factor-ɑ (TNF-ɑ) and interleukin-10 (IL-10) were detected. Additionally, the radial arterial blood sample was collected at the above time points; oxygen partial pressure (PaO2) was determined; pulmonary alveoli-arterial partial pressure of oxygen (PA-aDO2) and oxygenation index (OI) were calculated. The pulmonary complication in the two days after operation was recorded. RESULTS: Compared with the control group, in the observation group, at T2 and T3, TNF-ɑ concentration and PA-aDO2 were lower (all P<0.05); plasma IL-10 concentration and OI were higher (all P<0.05). In the observation group, the incidences of postoperative pneumonia and acute pulmonary injury were lower than those in the control group (both P<0.05). CONCLUSIONS: EA reduces the postoperative inflammatory reaction in the senile patients with radical resection of pulmonary carcinoma and decreases the postoperative pulmonary complicattizen.