细化搜索
结果 1701-1710 的 7,990
Mitigating N2O emission by synthetic inhibitors mixed with urea and cattle manure application via inhibiting ammonia-oxidizing bacteria, but not archaea, in a calcareous soil
2021
Tao, Rui | Li, Jun | Hu, Baowei | Chu, Guixin
Synthetic inhibitors and organic amendment have been proposed for mitigating greenhouse gas N₂O emissions. However, their combined effect on the N₂O emissions and ammonia-oxidizer (ammonia-oxidizing bacteria and archaea, AOB and AOA) communities remains unclear in calcareous soils under climate warming. We conducted two incubation experiments (25 and 35 °C) to examine how N₂O emissions and AOA and AOB communities responded to organic amendment (urea plus cattle manure, UCM), and in combination with urease (N-(n-butyl) thiophosphoric triamide, NBPT) and nitrification inhibitor (nitrapyrin). The treatments of UCM + nitrapyrin and UCM + nitrapyrin + NBPT significantly lowered total N₂O emissions by average 64.5 and 71.05% at 25 and 35 °C, respectively, compared with UCM treatment. AOB gene abundance and α-diversity (Chao1 and Shannon indices) were significantly increased by the application of urea and manure (P < 0.05). However, relative to UCM treatment, nitrapyrin addition treatments decreased AOB gene abundance and Chao 1 index by average 115.4 and 30.4% at 25 and 35 °C, respectively. PCA analysis showed that UCM or UCM plus nitrapyrin notably shifted AOB structure at both temperatures. However, fertilization had little effects on AOA community (P > 0.05). Potential nitrification rate (PNR) was greatly decreased by nitrapyrin addition, and PNR significantly positively correlated with AOB gene abundance (P = 0.0179 at 25 °C and P = 0.0029 at 35 °C) rather than AOA (P > 0.05). Structural equation model analysis showed that temperature directly increased AOA abundance but decrease AOB abundance, while fertilization indirectly influenced AOB community by altering soil NH₄⁺, pH and SOC. In conclusion, the combined application of organic amendment, NBPT and nitrapyrin significantly lowered N₂O emissions via reducing AOB community in calcareous soil even at high temperature. Our findings provide a solid theoretical basis in mitigating N₂O emissions from calcareous soil under climate warming.
显示更多 [+] 显示较少 [-]Ecological risk and early warning of soil compound pollutants (HMs, PAHs, PCBs and OCPs) in an industrial city, Changchun, China
2021
Peng, Jingyao | Chen, Yanan | Xia, Qing | Rong, Guangzhi | Zhang, Jiquan
Soil ecological risk caused by compound pollutants is a topic that deserves increasing attention, and soil risk early warning is a more in-depth discussion on this topic. In this study, we collected soil samples from Changchun, a typical industrial city, and determined the contents of 13 heavy metals (HMs) (0.00 mg kg⁻¹-6380 mg kg⁻¹), 16 polycyclic aromatic hydrocarbons (PAHs) (0.00 mg kg⁻¹-27.7 mg kg⁻¹), 7 polychlorinated biphenyls (PCBs) (0.30 μg kg⁻¹-168 μg kg⁻¹), and 8 organochlorine pesticides (OCPs) (0.00 mg kg⁻¹-4.52 mg kg⁻¹). The soil ecological risks of compound pollutants were assessed. The results showed that PAHs were the greatest risk pollutants, followed by PCBs and HMs, and OCPs were the smallest risk pollutants. Most of the ecological risks of compound pollutants were classified as “moderate severity” level according to the (contamination severity index) CSI evaluation criteria. With the help of modern industrial economic theory, through the analysis of the annual accumulation of pollutants, it is possible to predict the future pollutant content in Changchun, and the soil risks could be forewarned. The results showed that if active measures were not taken to reduce the accumulation of PAHs in Changchun soil, the CSI-PAHs would be classified as “ultra-high severity” level in 2035.
显示更多 [+] 显示较少 [-]Integration of α, β and γ components of macroinvertebrate taxonomic and functional diversity to measure of impacts of commercial sand dredging
2021
Meng, Xingliang | Cooper, Keith M. | Liu, Zhenyuan | Li, Zhengfei | Chen, Juanjuan | Jiang, Xuankong | Ge, Yihao | Xie, Zhicai
Effects of commercial sand mining on aquatic diversity are of increasing global concern, especially in parts of some developing countries. However, understanding of this activity on the diversity of macroinvertebrates remains focused on the α component of species diversity, rather than community functioning. Thus, there remains much uncertainty regarding how each component of taxonomic (TD) and functional (FD) diversity respond to the activity both in freshwater and marine environments. Here, we assessed the effect of sand dredging on α, β and γ components of TD and FD during different dredging periods based on the response of macroinvertebrate communities over 4 years in the second largest freshwater lake in China. After three years of active dredging, substantial reductions in each component (α, β and γ) of TD and FD were observed within the dredged area. Moreover, after one year of natural recovery, a distinct restoration was observed with an obvious return in multiple facets of TD and FD indices. No such changes were observed within the adjacent and reference areas. Decreases in the multiple components of TD and FD within the dredged area were most likely associated with the direct extraction of substrate and associated benthic fauna and indirect variations of the water and sediment environment (e.g., increases in water depth and decreases in %Clay). Furthermore, dispersal processes and mass effects mainly contributed to the maintenance of TD and FD during the dredged and recovery stages. In addition, the fast recovery of TD and FD was also related to the simple taxonomic structure and highly connected nature of the study area. Our results suggest that a more precise experimental design (BACI) should be pursued to avoid potentially confounding effects (e.g., natural disturbance) because the sensitivity of diversity indices depends upon different experimental designs. Moreover, measurement of the impacts of sand dredging on macroinvertebrate diversity can be undertaken within a rigorous framework for better understanding the patterns and processes of each component of TD and FD under the sand dredging disturbance.
显示更多 [+] 显示较少 [-]Quality of urban green spaces influences residents’ use of these spaces, physical activity, and overweight/obesity
2021
The quality characteristics of urban green spaces (UGS) have been suggested to play a critical role in their use and their potentials to exert health effects. However, epidemiological studies evaluating such a role are scarce. These studies have generally focused on a limited number of quality dimensions. We studied the association between 10 UGS quality dimensions, assessed through a comprehensive multidimensional tool, and physical activity, overweight/obesity, and UGS use. Our study was based on 2053 adults participating in the Barcelona Health Survey (2016) and the quality of 149 UGS located in Barcelona, Spain. For each participant, we abstracted the average and maximum quality score separately for each of the 10 quality dimensions and an overall quality score for the UGS within 300 m of the participant’s residential address. Data on the study outcomes were obtained through face-to-face interviews. We developed logistic regression and negative binomial models to assess our evaluated associations and conducted mediation analyses between the different outcomes. We observed that the overall quality of UGS was associated with higher likelihood of engaging in moderate-to-vigorous physical activity (OR:1.13; 95% CI:1.00–1.27), lower risk of overweight/obesity (OR: 0.88; 95% CI: 0.79–0.98), and increased use of UGS (exponentiated regression coefficient: 1.08; 95% CI:1.01–1.15). For the quality dimensions, we observed different patterns of associations depending on the outcome; however, bird biodiversity and amenities seem to be relevant to all of our evaluated outcomes. The mediation analysis suggested that UGS use mediate the association between quality and physical activity, while physical activity mediates the association between quality and overweight/obesity. The novel results from this study will allow decision-makers better design UGS and directly pinpoint relevant quality dimensions to promote physical activity, reduce the risk of overweight/obesity and boost the use of UGS amongst citizens.
显示更多 [+] 显示较少 [-]Occurrence and distribution of typical semi-volatile organic chemicals (SVOCs) in paired indoor and outdoor atmospheric fine particle samples from cities in southern China
2021
Interest in the potential human health of semi-volatile organic chemicals (SVOCs) in indoor and outdoor environments has made the exposure assessment and source appointment a priority. In this study, paired indoor and outdoor atmospheric fine particle (PM₂.₅) samples were collected from 15 homes representing five typical urban cities in southern China. Four typical SVOCs, including 16 congeners of polycyclic aromatic hydrocarbons (PAHs), 13 congeners of organophosphorus flame retardants (OPFRs) and 8 congeners of polybrominated diphenyl ethers (PBDEs), as well as tetrabromobisphenol A (TBBPA) and its three debrominated congeners were analyzed. The highest total concentrations were found for OPFRs, followed by PAHs, PBDEs, and TBBPA. The indoor concentrations of two alkyl-OPFR isomers, tributylphosphate (TBP) and tris (2-butoxyethyl) phosphate (TBEP), were 4.3 and 11 times higher, respectively, than those of outdoors (p < 0.05). Additionally, the ratios of indoor to outdoor concentrations of alkyl-OPFR isomers varied greatly, suggesting that these compounds originated mainly from different household goods and products used in individual homes. The outdoor concentrations of PAHs and highly brominated PBDEs (BDE-209) typically exceeded the indoor concentrations. Significant correlations were also found between indoor and outdoor PM₂.₅ samples for PAHs and BDE-209, indicating that outdoor sources such as vehicle exhausts and industrial activities strongly influence their atmospheric occurrence. Additionally, the concentrations of debrominated TBBPA derivatives were higher than those of TBBPA in over 33% of both indoor and outdoor air particle samples. Nevertheless, our results indicated that inhalation exposure to typical SVOCs posed no non-carcinogenic risks to the human body. Although we observed notable differences in the sources, occurrences, and distributions of typical SVOC congeners, more studies using matched samples are still needed to unambiguously identify important indoor and outdoor sources in order to accurately assess the contributions of different sources and the associated human exposure risks.
显示更多 [+] 显示较少 [-]Effects of reduced pH on an estuarine penaeid shrimp (Metapenaeus macleayi)
2021
Acid sulfate soils are a major problem in modified coastal floodplains and are thought to have substantial impacts on estuarine species. In New South Wales, Australia, acid sulfate soils occur in every estuary and are thought to impact important fisheries species, such as Eastern School Prawn (Metapenaeus macleayi). These fisheries have experienced declining productivity over the last ten years and increasing occurrence of catchment-derived stressors in estuaries contribute to this problem. We evaluated the effect of pH 4–7.5 on School Prawn survival at two salinities (27 and 14.5), pH 5, 6 and 7.5 on the predation escape response (PER) speed at two salinities (27 and 14.5), and pH 4 and 7.5 on respiration rates. While mortality appeared to be greater in the high salinity treatment, there was no significant relationship between proportional survival and pH for either salinity treatment. Respiration was significantly slower under acidic conditions and the average PER was almost twice as fast at pH 7.5 compared to pH 5 (p < 0.05), indicating prawns may fall prey to predation more easily in acidic conditions. These findings confirm the hypothesised impacts of acidic water on penaeid prawns. Given that the conditions simulated in these experiments reflect those encountered in estuaries, acidic runoff may be contributing to bottlenecks for estuarine species and impacting fisheries productivity.
显示更多 [+] 显示较少 [-]Estimation of commercial cooking emissions in real-world operation: Particulate and gaseous emission factors, activity influencing and modelling
2021
Lin, Pengchuan | Gao, Jian | He, Wanqing | Nie, Lei | Schauer, James J. | Yang, Shujian | Xu, Yisheng | Zhang, Yuanxun
Measurements of real-world cooking emission factors (CEFs) were rarely reported in recent year's studies. However, the needs for accurately estimating CEFs to produce cooking emission inventories and further implement controlling measures are urgent. In this study, we collected cooking emission aerosols from real-world commercial location operations in Beijing, China. 2 particulate (PM₂.₅, OC) and 2 gaseous (NMHC, OVOCs) CEF species were examined on influencing activity conditions of cuisine type, controlling technology, operation scales (represented by cook stove numbers), air exhausting volume, as well as location and operation period. Measured NMHC emission factors (Non-barbecue: 8.19 ± 9.06 g/h and Barbecue: 35.48 ± 11.98 g/h) were about 2 times higher than PM₂.₅ emission factors (Non-barbecue: 4.88 ± 3.43 g/h and Barbecue: 15.48 ± 7.22 g/h). T-test analysis results showed a significantly higher barbecued type CEFs than non-barbecued cuisines for both particulate and gaseous emission factor species. The efficacy of controlling technology was showing an average of 50 % in decreasing PM₂.₅ CEFs while a 50 % in increasing OC particulate CEFs. The effects of controlling equipment were not significant in removing NMHC and OVOCs exhaust concentrations. CEF variations within cook stove numbers and air exhausting volume also reflected a comprehensive effect of operation scale, cuisine type and control technology. The simulations among activity influencing factors and CEFs were further determined and estimated using hierarchical multiple regression model. The R square of this simulated model for PM₂.₅ CEFs was 0.80 (6.17 × 10–⁹) with standardized regression coefficient of cuisine type, location, sampling period, control technology, cook stove number (N) and N² of 5.18 (0.02), 5.33 (0.02), 1.93 (0.19), 9.29 (4.18 × 10–⁶), 9.10 (1.71 × 10–³) and −1.18 (2.43 × 10–³), respectively. In perspective, our study provides ways of better estimating CEFs in real operation conditions and potentially highlighting much more importance of cooking emissions on air quality and human health.
显示更多 [+] 显示较少 [-]Combining sediment management and bioremediation in muddy ports and harbours: A review
2021
Polrot, A. | Kirby, J.R. | Birkett, J.W. | Sharples, G.P.
This paper reviews two important sources of innovation linked to the maritime environment and more importantly to ports: the potential coupling of sediment management and (bio)remediation. The detrimental effects of dredging are briefly considered, but the focus here is on a sustainable alternative method of managing the problem of siltation. This technique consists of fluidizing the sediment in situ, lowering the shear strength to maintain a navigable under-keel draught. Preliminary investigations show that through this mixing, aeration occurs, which results in a positive remediation effect as well. An overview of port contamination, remediation, and the recent research on aerobic (bio)degradation of port contaminants is made in order to show the potential for such innovative sediment management to reduce dredging need and remediate contaminated mud in ports. This review also highlights the lack of full-scale field applications for such potential remediation techniques, that remain largely confined to the laboratory scale.
显示更多 [+] 显示较少 [-]Catalytic upgrade for pyrolysis of food waste in a bubbling fluidized-bed reactor
2021
Ly, Hoang Vu | Tran, Quoc Khanh | Kim, Seung-Soo | Kim, Jinsoo | Choi, Suk Soon | Oh, Changho
Biofuel production via pyrolysis has received increasing interest as a promising solution for utilization of now wasted food residue. In this study, the fast pyrolysis of mixed food waste (MFW) was performed in a bubbling fluidized-bed reactor. This was done under different operating conditions (reaction temperatures and carrier gas flow rate) that influence product distribution and bio-oil composition. The highest liquid yield (49.05 wt%) was observed at a pyrolysis temperature of 475 °C. It was also found that the quality of pyrolysis bio-oils (POs) could be improved using catalysts. The catalytic fast pyrolysis of MFW was studied to upgrade the pyrolysis vapor, using dolomite, red mud, and HZSM-5. The higher heating values (HHVs) of the catalytic pyrolysis bio-oils (CPOs) ranged between 30.47 and 35.69 MJ/kg, which are higher than the HHVs of non-catalytic pyrolysis bio-oils (27.69–31.58 MJ/kg). The major components of the bio-oils were fatty acids, N-containing compounds, and derivatives of phenol. The selectivity for bio-oil components varied depending on the catalysts. In the presence of the catalysts, the oxygen was removed from oxygenates via moisture, CO₂, and CO. The CPOs contained aliphatic hydrocarbons, polycyclic aromatic compounds (such as naphthalene), pyridine derivatives, and light oxygenates (cyclic alkenes and ketones).
显示更多 [+] 显示较少 [-]Patterns of distribution and accumulation of trace metals in Hysterothylacium sp. (Nematoda), Phyllodistomum sp. (Digenea) and in its fish host Hoplias malabaricus, from two neotropical rivers in southeastern Brazil
2021
Rosa Leite, Lucas Aparecido | dos Reis Pedreira Filho, Walter | Kozlowiski de Azevedo, Rodney | Doro Abdallah, Vanessa
Here we evaluated the potential for trace metal accumulation of two parasitic species, Hysterothylacium sp. (Nematoda) and Phyllodistomum sp. (Digenea), found parasitizing Hoplias malabaricus, a characiform fish also known as trahira, collected from two neotropical rivers, Jacaré-Pepira and Jacaré-Guaçú, in southeastern Brazil. Fish were collected between July 2017 and July 2019, totaling 90 fish specimens analyzed, 45 from each river. From fish, we take samples of three different tissues: muscle, intestine and liver. Along with the parasite samples taken from fish hosts, tissue samples were analyzed by an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) for obtaining the trace metal (Al, Cr, Mn, Fe, Ni, Cu, As, Cd e Pb) concentrations. All elements were found in statistically higher concentrations in the parasites, both nematodes and digeneans, than in the host tissues, but in comparison, was observed that Hysterothylacium sp. had higher concentrations than those obtained in Phyllodistomum sp. We also found that uninfected fish had statistically higher concentrations of metals than infected ones. And in those who are infected, the size of the parasitic infrapopulations correlated negatively with the concentrations of trace metals obtained in the hosts tissues, that is, the concentrations in fish showed a tendency to decrease as the parasitic infrapopulations increased, or vice versa. In addition, our results show that the influence of the parasitic infrapopulations on metal concentrations in the fish host is not affected in cases of mono-infection or co-infection.
显示更多 [+] 显示较少 [-]