The Stockholm Convention on Persistent Organic Pollutants(POPs)is a legally binding instrument for 186 Parties(status:April 2023).Accordingly,among other responsibilities,countries are obliged to report the production...The Stockholm Convention on Persistent Organic Pollutants(POPs)is a legally binding instrument for 186 Parties(status:April 2023).Accordingly,among other responsibilities,countries are obliged to report the production,import,or export of the POPs listed in Annexes A,B,or C;provide information to registers;maintain inventories;and monitor the presence of POPs in the environment.In the broader context of international chemicals and waste management,producer responsibilities,harmonized reporting,and compliance with national and international regulations,Ecuador has addressed the newly listed group of perfluorinated alkyl substances(PFAS)in its national implementation plan and sent selected products from its national market for PFAS analysis.The products analyzed came from the initially listed fields of specific exemptions and acceptable purposes,including:fire-fighting foams;photographic aids;greasers/degreasers;various kinds of paper/packaging;textiles;and leather,coatings,cleaners,metal plating,and pesticides.Our results showed that the three PFAS presently listed in the Stockholm Convention could be quantified in only a few samples;additional PFAS,not yet listed in the Convention also had low detection frequencies.Although the number of samples was limited,the samples covered a large spectrum of sample matrices,making it possible to conclude that—once these products become waste and are regulated under the Basel Convention—they would not constitute a disposal problem.Nevertheless,verification of the presence of PFAS in products on the market is expected to pose an analytical challenge for both,developed and developing countries.展开更多
A series of BiOBr@biomass carbon derived from locust leaves materials(BiOBr@BC)were fabricated and the photocatalytic property was investigated for photocatalytic degradation of rhodamine B(RhB)under visible light.The...A series of BiOBr@biomass carbon derived from locust leaves materials(BiOBr@BC)were fabricated and the photocatalytic property was investigated for photocatalytic degradation of rhodamine B(RhB)under visible light.The morphology,structure and photoelectrochemical properties of the photocatalysts were characterized by means of SEM,TEM,XRD,XPS,FT-IR,BET,PL,UV-vis/DRS,and EIS techniques.The results showed that the introduction of BC significantly enhanced the photocatalytic activity.When the content of biomass carbon(BC)in a composite is 3%(based on the mass of BiOBr),the obtained BiOBr@BC-3 exhibits excellent photocatalytic activity,degrading 99%of RhB within 20 min.The excellent degradation efficiency after the introduction of BC can be attributed to the enhanced visible light absorption,narrower band gap,and fast electron-hole pair separation rate.The photocatalytic mechanism on the degradation of RhB was illustrated based on the radicals'trapping experiments and semiconductor energy band position.The proposed material is expected to be of significant application value in the field of wastewater treatment.展开更多
Constructed wetlands(CwW)are well known nature-based systems for water treatment.This study evaluated the efficiency and effectiveness of seven domestic wastewater treatment systems based on horizontal flow CWs in Jar...Constructed wetlands(CwW)are well known nature-based systems for water treatment.This study evaluated the efficiency and effectiveness of seven domestic wastewater treatment systems based on horizontal flow CWs in Jarabacoa,the Dominican Republic.The results showed that the CWs were efficient in reducing the degree of contamination of wastewater to levels below the Dominican wastewater discharge standards for parameters such as the 5-day biochemical oxygen demand(BOD5)and chemical oxygen demand,but not for the removal of phosphorus and fecal coliforms.In addition,a horizontal flow subsurface wetland in the peri-urban area El Dorado was evaluated in terms of the performance of wastewater treatment in tropical climatic conditions.The concentrations of heavy metals,such as zinc,copper,chromium,and iron,were found to decrease in the effluent of the wetland,and the concentrations for nickel and manganese tended to increase.The levels of heavy metals in the effluent were lower than the limit values of the Dominican wastewater discharge standards.The construction cost of these facilities was around 200 USD per population equivalent,similar to the cost in other countries in the same region.This study suggested some solutions to the improved performance of CWs:selection of a microbial flora that guarantees the reduction of nitrates and nitrites to molecular nitrogen,use of endemic plants that bioaccumulate heavy metals,combination of constructed wetlands with filtration on activated carbon,and inclusion of water purification processes that allow to evaluate the reuse of treated water.展开更多
This paper revealed that after spending years overseas for learning, Cambodian fellows realized that a clean society more likely results from the adopting of a waste management system. The lack of such is the main bar...This paper revealed that after spending years overseas for learning, Cambodian fellows realized that a clean society more likely results from the adopting of a waste management system. The lack of such is the main barrier for waste separation willingness and practices in Cambodia. Self-transcendence values and volunteerism are empirically found as the fundamental factors for any interventions designed to promote pro-environmental intentions and practices respectively. The fellows engaging in volunteerisms appear to do waste separation, ignoring how inconvenient the waste management system or facilities are. Similarly, the fellows concerning the environmental and social issues appear to spare their valuable time to do waste-separation which they find not difficult. This is not the case in this COVID-19 epidemic though. The study results imply that in a society where an inconvenient waste management system is in place the fellows without past volunteering, no matter how knowledgeable they are, will less likely engage in the waste-sorting practice.展开更多
Behavioral traits of species can play an important role in the functioning of the ecosystem and in evolving behavioural adaptations to survive according to environmental conditions.This note documents evidence of addi...Behavioral traits of species can play an important role in the functioning of the ecosystem and in evolving behavioural adaptations to survive according to environmental conditions.This note documents evidence of adding a rare observation by providing photographic evidence of the entanglement of a carcass of a juvenile Black Kite(Milvus migrans)from a nest and the use of nest by an adult individual,guarding the carcass.Documenting such behavior contributes to our understanding of the natural history and management of native species in an urban environment.Further,scientific studies/observations are needed to be conducted to reach some conclusion as to why species perform such behaviour.展开更多
The experiment was conducted at the animal experimental station of the Faculty of Animal Sciences,Royal University of Agriculture,commenced from 10 January to 14 March,2022.The CRD(Completely Randomized Design)was use...The experiment was conducted at the animal experimental station of the Faculty of Animal Sciences,Royal University of Agriculture,commenced from 10 January to 14 March,2022.The CRD(Completely Randomized Design)was used with 5 treatments and 4 replications.The 500 chicks at one-day-old,local bread,were purchased from farmers who run their small scale hatchery farm.The chicks were kept together till 21 days old,and then were allocated randomly into in five diets(treatments),25 chicks per replication.The feed formulas for this study were designed and calculated to maintain a protein content of approximately 17%,dividing into 5 feed formulas(Treatments),such as concentrated feed only(control treatment:T0),plus 10%of fresh sweet potato vine(T1),plus 20%of fresh sweet potato vine(T2),plus 30%of fresh sweet potato vine(T3)and plus 20%of sweet potato vine meal(T4).The results showed that the treatment T1,had a similar final weight with the treatment T4,but was slightly lower than the treatment T0 which used concentrated feed alone.Feed intake and FCR(Feed Conversion Ratio)were not significantly different among those treatments.In conclusion,the average daily weight gain of chickens seemed to decrease with increasing the level of fresh sweet potato vine.Thus,the optimum level of fresh sweet potato vine was 10%,which may have little effect on the growth performance of local chickens.In addition,it was not far different from the positive control treatment and the treatment using sweet potato vine meal.However,the producers can increase the amount of sweet potato vine in feed formula by processing it into meal and mixing with concentrated feed or using as feed ingredients.展开更多
Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining,...Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining, industrial activities, improper usage of fertilizers and pesticides, and indiscriminate open waste disposal bring about an increase in the presence of heavy metals in the environment. In the Keffi Metropolis, different elements lead to land contamination which debilitates soil quality, plant survival, human well-being, and the environment as a result of extensive dispersion or quantity of heavy metals in the soil and water. In recent years, biochar has emerged as a promising soil amendment for mitigating heavy metal pollution due to its unique physicochemical properties. This paper provides the effects of softwood pellet biochar on the retention of heavy metals in contaminated soils. A microcosm experiment was carried out to investigate the effects of biochar on the retention of heavy metals in contaminated soils. This research aimed to give an overview of the effects of softwood biochar at different temperatures (550˚C and 700˚C) on the retention of heavy metals and metalloids released from the soil during water inundation. The results show that the addition of organic matter (grass chippings) minimizes heavy metal mobilization. Also, biochar at high temperatures is more effective than those at low temperatures. The expected outcome of the research analysis includes providing insights into the role of biochar in retaining heavy metal contamination and further understanding the use of biochar as a sorbent for the management of contaminated soil.展开更多
This study evaluated the potential of Botswana’s sustainable energy production using ERA5 reanalysis data of solar irradiance variability on an optimally inclined plane from 1971 to 2020. Spatial-temporal solar irrad...This study evaluated the potential of Botswana’s sustainable energy production using ERA5 reanalysis data of solar irradiance variability on an optimally inclined plane from 1971 to 2020. Spatial-temporal solar irradiance fluctuations were the focus of the study, and the relation to cloud cover and aerosol optical depth was investigated. The key findings suggest that the summer/rainfall season (November to March) is the peak season with average monthly solar irradiance of 313 - 445 W/m2 across southern, central, and northern parts of Botswana, the Kalahari Desert and the Makgadikgadi Pans being identified as prime sites for solar energy projects. The long-term trend analysis showed a decrease in solar irradiance in December but a consistent increase from August to October, indicating a potential shift in solar resources toward an earlier season. Contrary to other studies that found that aerosol optical depth dominates effects on long-term trends and year-to-year variability of solar irradiance, for this case, cloud cover, particularly mid-level clouds, is found to have a more dominant role in Botswana. Solar irradiance characteristics of three distinct regions were identified through K-means clustering. Moreover, Ensemble Empirical Mode Decomposition (EEMD) analysis showed the commonality and time scale linkage between solar irradiance and cloud cover between the identified regions. These results highlight the importance of including cloud-related weather patterns under the global warming scenario in solar energy planning and emphasize the secondary role of aerosols in Botswana, thus providing critical information for the region’s solar energy development and policy formulation.展开更多
Microstructure, tensile and impact toughness properties and fracture location of friction stir welded AISI 1018 mild steel were revealed. The AISI 1018 mild steel plates with thickness of 5 mm were friction stir welde...Microstructure, tensile and impact toughness properties and fracture location of friction stir welded AISI 1018 mild steel were revealed. The AISI 1018 mild steel plates with thickness of 5 mm were friction stir welded by tungsten based alloy tool with tool rotational speed of 1 000 r/min and welding speed of 50 ram/rain. Tensile strength of stir zone is higher （8%） compared to that of the base metal. This may be due to the formation of finer grains in the weld nugget region under the stirring action of the rotating tool. The ductility and impact toughness of the joints are decreased compared to those of the base metal owing to the inclusion of tungsten particles in the weld region.展开更多
To assess the risks of forchlorfenuron after application, a residue analysis method for ferchlorfenuron in cucumbers and the red soil of Southern China was established, and the dissipation behavior and residue charact...To assess the risks of forchlorfenuron after application, a residue analysis method for ferchlorfenuron in cucumbers and the red soil of Southern China was established, and the dissipation behavior and residue characteristics of forchlorfenuron were studied under field conditions. The field trials, including dissipation and residue experiments, were conducted in Hunan, Yunnan and Hainan Provinces. Forchlorfenuron was applied at 32 a.i.g ha^-1 rate for the dissipation study and both 21 and 32 a.i.g ha^-1 for the residue study. Representative cucumbers and soil samples were collected at predetermined intervals for HPLC for UV- detector analysis. The average recoveries of the method were 80.8%-92.0% with coefficients variation （CV） between 0.4% and 11.8%. The detection limit of forchlorfenuron in cucumbers and soil samples was 0.003 mg·kg^-1 and the minimum detectable amount was 3.0× 10^-10 g. The half life of forchlorfenuron in cucumbers in the three provinces changed as： Yunnan （5.50 days）, Hunan （5.88 days）, and Hainan （6.53 days） and in the soil was observed： Hainan （6.54 days）, Hunan （7.64 days）, and Yunnan （8.39 days）. The maximum terminal residue in cucumbers at 32 a.i.g ha^-1 rate after 5 days was 0.009 mg·kg^-1 （Yunnan） followed by 0.0085 mg·kg^-1 （Hainan） and 0.0082 mg·kg^-1（Hunan） which was below MRL value of 0.01 mg·kg^-1 established by the USA, EPA. So a waiting period of 5 days should be established after spaying on cucumbers to avoid hazard to human beings.展开更多
Revegetation on bauxite residue disposal areas is the most promising strategy to reduce its potential ecological risk during stacking or disposing.Migration of salt ions in bauxite residue is one of the major issues t...Revegetation on bauxite residue disposal areas is the most promising strategy to reduce its potential ecological risk during stacking or disposing.Migration of salt ions in bauxite residue is one of the major issues to stimulate soil formation to support plant growth.21 residue samples were collected and the related parameters including exchangeable cations,soluble ions,total salt,pH,electrical conductivity(EC)and exchangeable sodium percentage(ESP)were selected to evaluate alkalization and salinization of bauxite residue.High levels of ions,cation exchange capacity(TOC),total salt,exchangeable sodium percentage(ESP)and cation exchange capacity(CEC)in bauxite residue were detected with greater coefficient of variation(CV),which indicated that distribution characteristics of salt ions varied significantly.The percentage of sulfate-chloride-soda type in the residues accounted for 71.43%.The mean value of pH was 10.10,whilst mean value of ESP was 52.05%.It indicated that the residues in this case study belonged to sulfate-chloride-soda saline and alkaline soil.The research results could provide theoretical basis for soil formation in bauxite residue.展开更多
The 6：2 FTS was the substitute for perfluorooctane sulfonate（PFOS） in the chrome plating industry in Japan. Electrochemical oxidation of 6：2 FTS was investigated in this study. The degradabilities of PFOS and 6：2...The 6：2 FTS was the substitute for perfluorooctane sulfonate（PFOS） in the chrome plating industry in Japan. Electrochemical oxidation of 6：2 FTS was investigated in this study. The degradabilities of PFOS and 6：2 FTS were tested on the Ti/SnO2–Sb2O5–Bi2O3anode. The effects of current density,potential,and supporting electrolyte on the degradation of 6：2 FTS were evaluated. Experimental results showed that 6：2 FTS was more easily degraded than PFOS on the Ti/SnO2–Sb2O5–Bi2O3anode. At a low current density of 1.42 mA/cm2,6：2 FTS was not degraded on Ti/SnO2–Sb2O5–Bi2O3,while the degradation ratio increased when the current density ranged from 4.25 to 6.80 mA/cm2. The degradation of 6：2 FTS at current density of 6.80 mA/cm2 followed pseudo first-order kinetics with the rate constant of 0.074 hr-1. The anodic potential played an important role in the degradation of 6：2 FTS,and the pseudo first-order rate constants increased with the potential. The surface of Ti/SnO2–Sb2O5–Bi2O3was contaminated after electrolysis at constant potential of 3 V,while the fouling phenomenon was not observed at 5 V. The fouled anode could be regenerated by incinerating at 600°C. The intermediates detected by ultra-performance liquid chromatography coupled with a triple-stage quadrupole mass spectrometer（UPLC–MS/MS） were shorter chain perfluorocarboxylic acids. The 6：2 FTS was first attacked by hydroxyl radical,and then formed perfluorinated carboxylates,which decarboxylated and removed CF2 units to yield shorter-chain perfluorocarboxylic acids.展开更多
The suitability of two common and ubiquitously distributed and exotic ornamental plant species in Nigeria-Delonix regia and Casuarina equisetifolia as biomonitors and as effective bioaccumulators of atmospheric trace ...The suitability of two common and ubiquitously distributed and exotic ornamental plant species in Nigeria-Delonix regia and Casuarina equisetifolia as biomonitors and as effective bioaccumulators of atmospheric trace metals （Cd, Pb, Zn and Cu） has been evaluated. Bark and leaf samples from these plant species were collected in June and July 2006 at five locations in Benin City. Four of the sampling sites were in areas of high traffic density and commercial activities, the fifth site is a remote site, selected to act as a control and also to provide background information for the metals. The plant samples were collected and processed using standard procedures and trace metals were determined using atomic absorption spectrometer. The bark of the plants was able to bioaccumulate the trace metals, especially Pb which originates from anthropogenic contributions in the city. The Pb range of 20.00-70.00 μg/g measured for the bark samples ofD. regia, exceeded the normal plant Pb concentration of 0.2-20.0 μg/g and most Pb data available in literature. The bark of the plants was observed to accumulate more metals compared to the leave, while D. regia was found to be slightly better than C. equisetifolia in trace metal uptake efficiency. Spatial variations in the distributions of Pb and Zn were significant （p 〈 0.05）, and the continuous use of leaded fuel in Nigeria was identified as the predominant source of Pb in the atmosphere.展开更多
Based on morphological and genetic evidence we evaluated the taxonomic status of a newly discovered forest-dwelling population of skink （genus Scincella） from the Keo Selma Wildlife Sanctuary, Mondulkiri Province, C...Based on morphological and genetic evidence we evaluated the taxonomic status of a newly discovered forest-dwelling population of skink （genus Scincella） from the Keo Selma Wildlife Sanctuary, Mondulkiri Province, Cambodia. From phylogenetic analysis of a 668-bp fragment of the mtDNA COl and diagnostic morphological characters we allocate the newly discovered population to the Scincella reevesii-S. rufocaudata species complex and describe it as Scincella nigrofasciata sp. nov. The new skink species can be distinguished from all other Southeast Asian congeners by the following combination of morphological characters： snout-vent length （SVL） 40.0-52.6 mm; relative tail length （TaL/SVL ratio） 1.25-1.94; prefrontals in broad contact; infralabials 6; primary temporals 2; relative forelimb length （FIL/SVL ratio） 0.20-0.22; relative hindlimb length （HIL/SVL ratio） 0.30-0.33; relative forearm length （FoL/SVL ratio） 0.14-0.16; adpressed forelimbs and hind limbs either overlapping （0.4-2.2 mm） or separated （1.9-2.3 mm）; midbody scale rows 32-33, paravertebral scales 69-74, vertebral scales 65-69; dorsal scales between dorsolateral stripes 8; comparatively slender fingers and toes, subdigital lamellae under fourth toe 15-17; dark discontinuous regular dorsal stripes 5-7; distinct black dorsolateral stripes, narrowing to lateral sides and extending to 52%-86% of total tail length. We provide additional information on the holotype of Scincella rufocaudata （Darevsky ＆ Nguyen, 1983）, and provide evidence for the species status of Scincella rupicola. Our discovery brings the number of Scincellaspecies in Cambodia to five and emphasizes the incompleteness of knowledge on the herpetofaunal diversity of this country.展开更多
It has been well-documented that the distribution of ammonia-oxidizing bacteria(AOB) and archaea(AOA) in soils can be affected by heavy metal contamination, whereas information about the impact of heavy metal on these...It has been well-documented that the distribution of ammonia-oxidizing bacteria(AOB) and archaea(AOA) in soils can be affected by heavy metal contamination, whereas information about the impact of heavy metal on these ammonia-oxidizing microorganisms in freshwater sediment is still lacking. The present study explored the change of sediment ammonia-oxidizing microorganisms in a freshwater reservoir after being accidentally contaminated by industrial discharge containing high levels of metals. Bacterial amoA gene was found to be below the quantitative PCR detection and was not successfully amplified by conventional PCR. The number of archaeal amoA gene in reservoir sediments were 9.62 × 10~2–1.35 × 10~7 copies per gram dry sediment. AOA abundance continuously decreased, and AOA richness, diversity and community structure also considerably varied with time. Therefore, heavy metal pollution could have a profound impact on freshwater sediment AOA community. This work could expand our knowledge of the effect of heavy metal contamination on nitrification in natural ecosystems.展开更多
A main question in restoration of degraded forests and forest landscapes recovering from logging and fire is what to expect from natural regeneration through surviving propagules in the soil or seed sources and associ...A main question in restoration of degraded forests and forest landscapes recovering from logging and fire is what to expect from natural regeneration through surviving propagules in the soil or seed sources and associated dispersal agents from the surrounding landscape mosaic,as alternative to tree planting.Tree diversity in secondary forests may be high,but based on newcomer species of low wood density and long-distance,abiotic dispersal modes.We compiled and analyzed three pairs of case studies(totaling 815 plots and 11.8 ha)of secondary forests recovering from logging,fire and conversion to agroforest in Sumatra and Kalimantan(Indonesia)on mineral soils.Data on tree species diversity,wood density frequency distribution(indicative of successional status)and dispersal modes were compared with those of less disturbed comparator forests in the same landscapes.Relatively undisturbed lowland dipterocarp forest in Kalimantan had close to 200 species of trees(>10 cm diameter)at a 1-ha sample scale(and 450 at a 10-ha scale).After repeated fires a sample area of 2 ha was needed to reach the same species richness.Regulation-based logging had little impact on tree species richness.In rubber agroforest with low-intensity management beyond rubber planting,50 tree species were found at a 1-ha scale and close to 100 species in 3 ha.The Kalimantan forest after repeated fires had a markedly higher fraction of lowwood-density trees(40%),but otherwise,all forests sampled were similar in overall wood density profiles.Selectively logged forest managed by a local community(village forest)and rubber agroforest in Sumatra contained larger fractions of heavy-wood-density trees.The majority of trees(50%–70%)had birds,bats and primates as dispersal agents in all sites.Selectively logged forests had higher fractions of autochorous species(15%)compared to other sites.Anemochorous(wind-dispersed)species,especially Macaranga lowii,were most common(20%)in lowland dipterocarp forest.Comparison between secondary forests and agroforests showed the influence of farmer selection regarding what is allowed to grow beyond the pole stage.Wood density and seed dispersal profiles can be used as degradation indicators of species assemblages across various disturbance levels and types,as they reflect the habitat quality of the surrounding landscape mosaics.展开更多
The Mutis-Timau Forest Complex,one of the remaining mountainous tropical forest areas in Timor Island,eastern Indonesia that covers an area of 31,984 ha,tends to decrease gradually.Efforts to secure mountain forest fu...The Mutis-Timau Forest Complex,one of the remaining mountainous tropical forest areas in Timor Island,eastern Indonesia that covers an area of 31,984 ha,tends to decrease gradually.Efforts to secure mountain forest functions and counteract the negative impact of declining forest areas are often constrained by data uncertainty on factors contributing to deforestation.For this reason,this study attempts to develop models of deforestation and predict future deforestation in the Mutis-Timau Forest Complex.We constructed models of deforestation that describe the relationship between deforestation and factors contributing to deforestation using spatial statistical models.In this model,we used the deforestation data for the 1987-2017 period obtained from a previous study as dependent variables and the potential causes of deforestation generated from Geographic Information System spatial analysis as independent variables.Using the probability of deforestation derived from the model,we predicted future deforestation under two different scenarios,namely,business-as-usual(as the reference scenario)and reducing emission fromdeforestation and forest degradation.Our findings showed that a positive relationship exists between probability of deforestation,distance to the settlement,and population density variables,whereas a negative relationship exists between likelihood of deforestation,elevation,slope,distance to the road,distance to the savanna,and forest management unit variables.During the 2017-2030 period,under the business-as-usual scenario,the Mutis-Timau Forest Complex will lose 1327.65 ha in forest area with an annual deforestation rate of 0.54%.Meanwhile,under the reducing emission from deforestation and forest degradation scenario,the overall forest loss was estimated to be 1237.11 ha with an annual deforestation rate of 0.50%.The predicted area of avoided deforestation in 2017-2030 under the reducing emission from deforestation and forest degradation scenario was 90.54 ha.Such data and information are important for the Mutis-Timau Forest Complex authority in prioritizing actions for combating deforestation and designing appropriate forest-related policies and supporting data for reducing emission from deforestation and forest degradation programme or other incentive schemes in reducing deforestation.展开更多
The concentration of cosmogenic loBe in riverine sediments has been widely used as a proxy for catchment-wide denudation rate （CWDR）. One of the key assumptions of this approach is that sediments originating from su...The concentration of cosmogenic loBe in riverine sediments has been widely used as a proxy for catchment-wide denudation rate （CWDR）. One of the key assumptions of this approach is that sediments originating from sub-basins with different erosional histories are well mixed. A tragic debris flow occurred in the Seti River watershed, central Nepal, on May 5, 2012. This catastrophic debris flow was triggered by slope failure on the peak of Annapurna IV and resulted in many casualties in the lower Seti Khola. However, it provided an opportunity to test the assumption of equal mixing of sediments in an understudied rapidly eroding watershed. This study documents the CWDR of ^10Be to evaluate the extent of the influence of episodic erosional processes such as debris flow on the spatio-temporal redistribution of loBe concentrations. Our data show that the debris flow caused little change in CWDR across the debris flow event. In addition to isotopic measurement, we calculated denudation rates by using the modeled concentrations in pre- and post-landslide sediments based on the local ^10Be production rate. The modeled result showed little change across the event, indicating that the debris flow in May 2012 played a minor role in sediment evacuation, despite the rapid erosion in the catchment. Our study concludes that although the 2012 event caused many casualties and severe damage, it was a low-magnitude, high frequency event.展开更多
This study investigated the conjoined cellular oxidative damage of human embryo kidney 293T（HEK293T） cells induced by cadmium chloride（CdCl2） and nanometer titanium dioxide（nano-TiO2）.RT-PCR technique was used t...This study investigated the conjoined cellular oxidative damage of human embryo kidney 293T（HEK293T） cells induced by cadmium chloride（CdCl2） and nanometer titanium dioxide（nano-TiO2）.RT-PCR technique was used to detect the expressions of Heme oxygenase-1（HO-1） and 8-oxoguanine DNA glycosylase（OGG1）.The activities of superoxide dismutase（SOD） and catalase enzyme（CAT） and concentrations of reactive oxygen species（ROS） and maldondialdehyde（MDA） were measured by different approaches.The results showed that CdCl2 and nano-TiO2 at a low concen-tration of 0.75 total toxic unit（TU） exerted an additive effects on HO-1 gene expression,CAT activities and MDA concentrations.When the total TU was increased to 1 or 1.25 TU,the interaction was syner-getic.Moreover,the mixture with high proportion of CdCl2 produced an additive effect on the OGG1 gene expression,and the interaction was changed to be synergetic when the concentration of CdCl2 was lower than or equal to that of nano-TiO2.Synergetic effects of CdCl2 and nano-TiO2 on cellular oxida-tive damage of HEK293T cells were found as indicated by the changes in the SOD activities and ROS concentrations.It was concluded that CdCl2 and nano-TiO2 exerts synergistic effects on the cellular oxidative damage of HEK293T cells,and the sensitivity of these indicators of oxidative damage varies with the proportion of CdCl2 and nano-TiO2 in the mixture.展开更多
A new method combining QuEChERS (quick, easy, cheap, effective, rugged and safe) and DLLME (dispersive liquid–liquid microextraction) for the simultaneous determination of residues of ten sulfonylurea herbicide in wa...A new method combining QuEChERS (quick, easy, cheap, effective, rugged and safe) and DLLME (dispersive liquid–liquid microextraction) for the simultaneous determination of residues of ten sulfonylurea herbicide in water using UPLC-MS/MS was developed and validated. Analytes were extracted and purified with QuEChERS and concentrated in chlorobenzene by applying the DLLME procedure. Several extraction parameters were tested, such as volume, extractive solvent by the QuEChERS method and subsequently used for DLLME, selection of extractive solvent and its volume, was tested. The developed method was validated on the basis of international guidelines. Mean recoveries ranged from 81.2 to 104.9%. Repeatability and reproducibility were lower than 10%. Limits of detection (LODs) and quantification (LOQs) were below 0.074 μg/L and 0.244 μg/L, respectively. Decision limit (CCα) and detection capability (CCβ) were calculated and CCβ ranged from 0.101 μg/L (pyrazosulfuron-ethyl) to 0.260 μg/L (nicosulfuron). Finally, when the method was applied to real samples, traces of three compounds were found in 42 samples and only thifensulfuon-methyl was detected above the LOQ in three samples at 0.17-0.20 μg/L.展开更多
基金supported by the Government of Ecuador through the Ministry of Environment,Water and Ecological Transition(MAATE)within the National Program for the Environmental Sound Management and Life Cycle Management of Chemical Substances(PNGQ)with contract of Alternativa Visionambiental Cia.Ltda.,Quito,toÖrebro University and prepared within the Project“Diagnóstico sobre el uso,presencia en productos,posible sustitución de COP industriales y elaboración del inventario y plan de acción de nuevas sustancias COP,conénfasis en el sector industrial ecuatoriano”funded by the United Nations Development Programme(UNDP)with funds from the Global Environment Facility(PNUD-ECU-SdP-ADQ-20-103165).
文摘The Stockholm Convention on Persistent Organic Pollutants(POPs)is a legally binding instrument for 186 Parties(status:April 2023).Accordingly,among other responsibilities,countries are obliged to report the production,import,or export of the POPs listed in Annexes A,B,or C;provide information to registers;maintain inventories;and monitor the presence of POPs in the environment.In the broader context of international chemicals and waste management,producer responsibilities,harmonized reporting,and compliance with national and international regulations,Ecuador has addressed the newly listed group of perfluorinated alkyl substances(PFAS)in its national implementation plan and sent selected products from its national market for PFAS analysis.The products analyzed came from the initially listed fields of specific exemptions and acceptable purposes,including:fire-fighting foams;photographic aids;greasers/degreasers;various kinds of paper/packaging;textiles;and leather,coatings,cleaners,metal plating,and pesticides.Our results showed that the three PFAS presently listed in the Stockholm Convention could be quantified in only a few samples;additional PFAS,not yet listed in the Convention also had low detection frequencies.Although the number of samples was limited,the samples covered a large spectrum of sample matrices,making it possible to conclude that—once these products become waste and are regulated under the Basel Convention—they would not constitute a disposal problem.Nevertheless,verification of the presence of PFAS in products on the market is expected to pose an analytical challenge for both,developed and developing countries.
基金the National Natural Science Foundation of China(51572185)Natural Science Foundation of Shanxi Province(202203021211158 and 20210302123176)+1 种基金the Key Research&Development Program of Shanxi Province(Social Development,201903D321060)the Key Research&Development program of Shanxi Province(International Cooperation,201903D421079)for the financial support.
文摘A series of BiOBr@biomass carbon derived from locust leaves materials(BiOBr@BC)were fabricated and the photocatalytic property was investigated for photocatalytic degradation of rhodamine B(RhB)under visible light.The morphology,structure and photoelectrochemical properties of the photocatalysts were characterized by means of SEM,TEM,XRD,XPS,FT-IR,BET,PL,UV-vis/DRS,and EIS techniques.The results showed that the introduction of BC significantly enhanced the photocatalytic activity.When the content of biomass carbon(BC)in a composite is 3%(based on the mass of BiOBr),the obtained BiOBr@BC-3 exhibits excellent photocatalytic activity,degrading 99%of RhB within 20 min.The excellent degradation efficiency after the introduction of BC can be attributed to the enhanced visible light absorption,narrower band gap,and fast electron-hole pair separation rate.The photocatalytic mechanism on the degradation of RhB was illustrated based on the radicals'trapping experiments and semiconductor energy band position.The proposed material is expected to be of significant application value in the field of wastewater treatment.
基金support of the Yaque del Norte Water Fund(FAYN),INTEC(Grant No.CBA-330810-2020-P-1)Fondo Dominicano de Ciencia y Tecnologia(FONDOCYT)(Grant No.2022-2B2-161)。
文摘Constructed wetlands(CwW)are well known nature-based systems for water treatment.This study evaluated the efficiency and effectiveness of seven domestic wastewater treatment systems based on horizontal flow CWs in Jarabacoa,the Dominican Republic.The results showed that the CWs were efficient in reducing the degree of contamination of wastewater to levels below the Dominican wastewater discharge standards for parameters such as the 5-day biochemical oxygen demand(BOD5)and chemical oxygen demand,but not for the removal of phosphorus and fecal coliforms.In addition,a horizontal flow subsurface wetland in the peri-urban area El Dorado was evaluated in terms of the performance of wastewater treatment in tropical climatic conditions.The concentrations of heavy metals,such as zinc,copper,chromium,and iron,were found to decrease in the effluent of the wetland,and the concentrations for nickel and manganese tended to increase.The levels of heavy metals in the effluent were lower than the limit values of the Dominican wastewater discharge standards.The construction cost of these facilities was around 200 USD per population equivalent,similar to the cost in other countries in the same region.This study suggested some solutions to the improved performance of CWs:selection of a microbial flora that guarantees the reduction of nitrates and nitrites to molecular nitrogen,use of endemic plants that bioaccumulate heavy metals,combination of constructed wetlands with filtration on activated carbon,and inclusion of water purification processes that allow to evaluate the reuse of treated water.
文摘This paper revealed that after spending years overseas for learning, Cambodian fellows realized that a clean society more likely results from the adopting of a waste management system. The lack of such is the main barrier for waste separation willingness and practices in Cambodia. Self-transcendence values and volunteerism are empirically found as the fundamental factors for any interventions designed to promote pro-environmental intentions and practices respectively. The fellows engaging in volunteerisms appear to do waste separation, ignoring how inconvenient the waste management system or facilities are. Similarly, the fellows concerning the environmental and social issues appear to spare their valuable time to do waste-separation which they find not difficult. This is not the case in this COVID-19 epidemic though. The study results imply that in a society where an inconvenient waste management system is in place the fellows without past volunteering, no matter how knowledgeable they are, will less likely engage in the waste-sorting practice.
文摘Behavioral traits of species can play an important role in the functioning of the ecosystem and in evolving behavioural adaptations to survive according to environmental conditions.This note documents evidence of adding a rare observation by providing photographic evidence of the entanglement of a carcass of a juvenile Black Kite(Milvus migrans)from a nest and the use of nest by an adult individual,guarding the carcass.Documenting such behavior contributes to our understanding of the natural history and management of native species in an urban environment.Further,scientific studies/observations are needed to be conducted to reach some conclusion as to why species perform such behaviour.
文摘The experiment was conducted at the animal experimental station of the Faculty of Animal Sciences,Royal University of Agriculture,commenced from 10 January to 14 March,2022.The CRD(Completely Randomized Design)was used with 5 treatments and 4 replications.The 500 chicks at one-day-old,local bread,were purchased from farmers who run their small scale hatchery farm.The chicks were kept together till 21 days old,and then were allocated randomly into in five diets(treatments),25 chicks per replication.The feed formulas for this study were designed and calculated to maintain a protein content of approximately 17%,dividing into 5 feed formulas(Treatments),such as concentrated feed only(control treatment:T0),plus 10%of fresh sweet potato vine(T1),plus 20%of fresh sweet potato vine(T2),plus 30%of fresh sweet potato vine(T3)and plus 20%of sweet potato vine meal(T4).The results showed that the treatment T1,had a similar final weight with the treatment T4,but was slightly lower than the treatment T0 which used concentrated feed alone.Feed intake and FCR(Feed Conversion Ratio)were not significantly different among those treatments.In conclusion,the average daily weight gain of chickens seemed to decrease with increasing the level of fresh sweet potato vine.Thus,the optimum level of fresh sweet potato vine was 10%,which may have little effect on the growth performance of local chickens.In addition,it was not far different from the positive control treatment and the treatment using sweet potato vine meal.However,the producers can increase the amount of sweet potato vine in feed formula by processing it into meal and mixing with concentrated feed or using as feed ingredients.
文摘Heavy metals have been viewed as hazardous environmental pollutants, and anthropogenic activities due to their high toxicity and persistent nature in the environment. Anthropogenic activities such as artisanal mining, industrial activities, improper usage of fertilizers and pesticides, and indiscriminate open waste disposal bring about an increase in the presence of heavy metals in the environment. In the Keffi Metropolis, different elements lead to land contamination which debilitates soil quality, plant survival, human well-being, and the environment as a result of extensive dispersion or quantity of heavy metals in the soil and water. In recent years, biochar has emerged as a promising soil amendment for mitigating heavy metal pollution due to its unique physicochemical properties. This paper provides the effects of softwood pellet biochar on the retention of heavy metals in contaminated soils. A microcosm experiment was carried out to investigate the effects of biochar on the retention of heavy metals in contaminated soils. This research aimed to give an overview of the effects of softwood biochar at different temperatures (550˚C and 700˚C) on the retention of heavy metals and metalloids released from the soil during water inundation. The results show that the addition of organic matter (grass chippings) minimizes heavy metal mobilization. Also, biochar at high temperatures is more effective than those at low temperatures. The expected outcome of the research analysis includes providing insights into the role of biochar in retaining heavy metal contamination and further understanding the use of biochar as a sorbent for the management of contaminated soil.
文摘This study evaluated the potential of Botswana’s sustainable energy production using ERA5 reanalysis data of solar irradiance variability on an optimally inclined plane from 1971 to 2020. Spatial-temporal solar irradiance fluctuations were the focus of the study, and the relation to cloud cover and aerosol optical depth was investigated. The key findings suggest that the summer/rainfall season (November to March) is the peak season with average monthly solar irradiance of 313 - 445 W/m2 across southern, central, and northern parts of Botswana, the Kalahari Desert and the Makgadikgadi Pans being identified as prime sites for solar energy projects. The long-term trend analysis showed a decrease in solar irradiance in December but a consistent increase from August to October, indicating a potential shift in solar resources toward an earlier season. Contrary to other studies that found that aerosol optical depth dominates effects on long-term trends and year-to-year variability of solar irradiance, for this case, cloud cover, particularly mid-level clouds, is found to have a more dominant role in Botswana. Solar irradiance characteristics of three distinct regions were identified through K-means clustering. Moreover, Ensemble Empirical Mode Decomposition (EEMD) analysis showed the commonality and time scale linkage between solar irradiance and cloud cover between the identified regions. These results highlight the importance of including cloud-related weather patterns under the global warming scenario in solar energy planning and emphasize the secondary role of aerosols in Botswana, thus providing critical information for the region’s solar energy development and policy formulation.
文摘Microstructure, tensile and impact toughness properties and fracture location of friction stir welded AISI 1018 mild steel were revealed. The AISI 1018 mild steel plates with thickness of 5 mm were friction stir welded by tungsten based alloy tool with tool rotational speed of 1 000 r/min and welding speed of 50 ram/rain. Tensile strength of stir zone is higher （8%） compared to that of the base metal. This may be due to the formation of finer grains in the weld nugget region under the stirring action of the rotating tool. The ductility and impact toughness of the joints are decreased compared to those of the base metal owing to the inclusion of tungsten particles in the weld region.
文摘To assess the risks of forchlorfenuron after application, a residue analysis method for ferchlorfenuron in cucumbers and the red soil of Southern China was established, and the dissipation behavior and residue characteristics of forchlorfenuron were studied under field conditions. The field trials, including dissipation and residue experiments, were conducted in Hunan, Yunnan and Hainan Provinces. Forchlorfenuron was applied at 32 a.i.g ha^-1 rate for the dissipation study and both 21 and 32 a.i.g ha^-1 for the residue study. Representative cucumbers and soil samples were collected at predetermined intervals for HPLC for UV- detector analysis. The average recoveries of the method were 80.8%-92.0% with coefficients variation （CV） between 0.4% and 11.8%. The detection limit of forchlorfenuron in cucumbers and soil samples was 0.003 mg·kg^-1 and the minimum detectable amount was 3.0× 10^-10 g. The half life of forchlorfenuron in cucumbers in the three provinces changed as： Yunnan （5.50 days）, Hunan （5.88 days）, and Hainan （6.53 days） and in the soil was observed： Hainan （6.54 days）, Hunan （7.64 days）, and Yunnan （8.39 days）. The maximum terminal residue in cucumbers at 32 a.i.g ha^-1 rate after 5 days was 0.009 mg·kg^-1 （Yunnan） followed by 0.0085 mg·kg^-1 （Hainan） and 0.0082 mg·kg^-1（Hunan） which was below MRL value of 0.01 mg·kg^-1 established by the USA, EPA. So a waiting period of 5 days should be established after spaying on cucumbers to avoid hazard to human beings.
基金Project(41701587)supported by the National Natural Science Foundation of ChinaProject(PM-zx703-201803-057)supported by Basic Scientific Research Business of Central Institutes of Environmental Protection,China
文摘Revegetation on bauxite residue disposal areas is the most promising strategy to reduce its potential ecological risk during stacking or disposing.Migration of salt ions in bauxite residue is one of the major issues to stimulate soil formation to support plant growth.21 residue samples were collected and the related parameters including exchangeable cations,soluble ions,total salt,pH,electrical conductivity(EC)and exchangeable sodium percentage(ESP)were selected to evaluate alkalization and salinization of bauxite residue.High levels of ions,cation exchange capacity(TOC),total salt,exchangeable sodium percentage(ESP)and cation exchange capacity(CEC)in bauxite residue were detected with greater coefficient of variation(CV),which indicated that distribution characteristics of salt ions varied significantly.The percentage of sulfate-chloride-soda type in the residues accounted for 71.43%.The mean value of pH was 10.10,whilst mean value of ESP was 52.05%.It indicated that the residues in this case study belonged to sulfate-chloride-soda saline and alkaline soil.The research results could provide theoretical basis for soil formation in bauxite residue.
基金supported by the National Natural Science Foundation of China (No.21307036)the National High-Tech Research and Development Program of China (No.2013AA062705)the National Key Scientific and Technological Project for Water Pollution Control and Management (Nos.2012ZX07206-002,2012ZX07206-003)
文摘The 6：2 FTS was the substitute for perfluorooctane sulfonate（PFOS） in the chrome plating industry in Japan. Electrochemical oxidation of 6：2 FTS was investigated in this study. The degradabilities of PFOS and 6：2 FTS were tested on the Ti/SnO2–Sb2O5–Bi2O3anode. The effects of current density,potential,and supporting electrolyte on the degradation of 6：2 FTS were evaluated. Experimental results showed that 6：2 FTS was more easily degraded than PFOS on the Ti/SnO2–Sb2O5–Bi2O3anode. At a low current density of 1.42 mA/cm2,6：2 FTS was not degraded on Ti/SnO2–Sb2O5–Bi2O3,while the degradation ratio increased when the current density ranged from 4.25 to 6.80 mA/cm2. The degradation of 6：2 FTS at current density of 6.80 mA/cm2 followed pseudo first-order kinetics with the rate constant of 0.074 hr-1. The anodic potential played an important role in the degradation of 6：2 FTS,and the pseudo first-order rate constants increased with the potential. The surface of Ti/SnO2–Sb2O5–Bi2O3was contaminated after electrolysis at constant potential of 3 V,while the fouling phenomenon was not observed at 5 V. The fouled anode could be regenerated by incinerating at 600°C. The intermediates detected by ultra-performance liquid chromatography coupled with a triple-stage quadrupole mass spectrometer（UPLC–MS/MS） were shorter chain perfluorocarboxylic acids. The 6：2 FTS was first attacked by hydroxyl radical,and then formed perfluorinated carboxylates,which decarboxylated and removed CF2 units to yield shorter-chain perfluorocarboxylic acids.
文摘The suitability of two common and ubiquitously distributed and exotic ornamental plant species in Nigeria-Delonix regia and Casuarina equisetifolia as biomonitors and as effective bioaccumulators of atmospheric trace metals （Cd, Pb, Zn and Cu） has been evaluated. Bark and leaf samples from these plant species were collected in June and July 2006 at five locations in Benin City. Four of the sampling sites were in areas of high traffic density and commercial activities, the fifth site is a remote site, selected to act as a control and also to provide background information for the metals. The plant samples were collected and processed using standard procedures and trace metals were determined using atomic absorption spectrometer. The bark of the plants was able to bioaccumulate the trace metals, especially Pb which originates from anthropogenic contributions in the city. The Pb range of 20.00-70.00 μg/g measured for the bark samples ofD. regia, exceeded the normal plant Pb concentration of 0.2-20.0 μg/g and most Pb data available in literature. The bark of the plants was observed to accumulate more metals compared to the leave, while D. regia was found to be slightly better than C. equisetifolia in trace metal uptake efficiency. Spatial variations in the distributions of Pb and Zn were significant （p 〈 0.05）, and the continuous use of leaded fuel in Nigeria was identified as the predominant source of Pb in the atmosphere.
基金the Russian Foundation of Basic Research(RFBR 15-04-08393RFBR 15-29-02771)for partial support of this project+1 种基金molecular analysis was carried out with financial support from the Russian Science Foundation(RSF 14-50-00029)supported by a grant from the Margaret A.Cargill Foundation
文摘Based on morphological and genetic evidence we evaluated the taxonomic status of a newly discovered forest-dwelling population of skink （genus Scincella） from the Keo Selma Wildlife Sanctuary, Mondulkiri Province, Cambodia. From phylogenetic analysis of a 668-bp fragment of the mtDNA COl and diagnostic morphological characters we allocate the newly discovered population to the Scincella reevesii-S. rufocaudata species complex and describe it as Scincella nigrofasciata sp. nov. The new skink species can be distinguished from all other Southeast Asian congeners by the following combination of morphological characters： snout-vent length （SVL） 40.0-52.6 mm; relative tail length （TaL/SVL ratio） 1.25-1.94; prefrontals in broad contact; infralabials 6; primary temporals 2; relative forelimb length （FIL/SVL ratio） 0.20-0.22; relative hindlimb length （HIL/SVL ratio） 0.30-0.33; relative forearm length （FoL/SVL ratio） 0.14-0.16; adpressed forelimbs and hind limbs either overlapping （0.4-2.2 mm） or separated （1.9-2.3 mm）; midbody scale rows 32-33, paravertebral scales 69-74, vertebral scales 65-69; dorsal scales between dorsolateral stripes 8; comparatively slender fingers and toes, subdigital lamellae under fourth toe 15-17; dark discontinuous regular dorsal stripes 5-7; distinct black dorsolateral stripes, narrowing to lateral sides and extending to 52%-86% of total tail length. We provide additional information on the holotype of Scincella rufocaudata （Darevsky ＆ Nguyen, 1983）, and provide evidence for the species status of Scincella rupicola. Our discovery brings the number of Scincellaspecies in Cambodia to five and emphasizes the incompleteness of knowledge on the herpetofaunal diversity of this country.
基金supported by Guangdong Province Science and Technology Project(No.2016B020240007)the Basic Scientific Research Business of Central Level Public Welfare Scientific Research Institution(No.PM-zx703-201803-070)
文摘It has been well-documented that the distribution of ammonia-oxidizing bacteria(AOB) and archaea(AOA) in soils can be affected by heavy metal contamination, whereas information about the impact of heavy metal on these ammonia-oxidizing microorganisms in freshwater sediment is still lacking. The present study explored the change of sediment ammonia-oxidizing microorganisms in a freshwater reservoir after being accidentally contaminated by industrial discharge containing high levels of metals. Bacterial amoA gene was found to be below the quantitative PCR detection and was not successfully amplified by conventional PCR. The number of archaeal amoA gene in reservoir sediments were 9.62 × 10~2–1.35 × 10~7 copies per gram dry sediment. AOA abundance continuously decreased, and AOA richness, diversity and community structure also considerably varied with time. Therefore, heavy metal pollution could have a profound impact on freshwater sediment AOA community. This work could expand our knowledge of the effect of heavy metal contamination on nitrification in natural ecosystems.
基金Earlier data collection and current data analysis were part of the CGIAR program on Forests,Trees and Agroforestry (FTA)
文摘A main question in restoration of degraded forests and forest landscapes recovering from logging and fire is what to expect from natural regeneration through surviving propagules in the soil or seed sources and associated dispersal agents from the surrounding landscape mosaic,as alternative to tree planting.Tree diversity in secondary forests may be high,but based on newcomer species of low wood density and long-distance,abiotic dispersal modes.We compiled and analyzed three pairs of case studies(totaling 815 plots and 11.8 ha)of secondary forests recovering from logging,fire and conversion to agroforest in Sumatra and Kalimantan(Indonesia)on mineral soils.Data on tree species diversity,wood density frequency distribution(indicative of successional status)and dispersal modes were compared with those of less disturbed comparator forests in the same landscapes.Relatively undisturbed lowland dipterocarp forest in Kalimantan had close to 200 species of trees(>10 cm diameter)at a 1-ha sample scale(and 450 at a 10-ha scale).After repeated fires a sample area of 2 ha was needed to reach the same species richness.Regulation-based logging had little impact on tree species richness.In rubber agroforest with low-intensity management beyond rubber planting,50 tree species were found at a 1-ha scale and close to 100 species in 3 ha.The Kalimantan forest after repeated fires had a markedly higher fraction of lowwood-density trees(40%),but otherwise,all forests sampled were similar in overall wood density profiles.Selectively logged forest managed by a local community(village forest)and rubber agroforest in Sumatra contained larger fractions of heavy-wood-density trees.The majority of trees(50%–70%)had birds,bats and primates as dispersal agents in all sites.Selectively logged forests had higher fractions of autochorous species(15%)compared to other sites.Anemochorous(wind-dispersed)species,especially Macaranga lowii,were most common(20%)in lowland dipterocarp forest.Comparison between secondary forests and agroforests showed the influence of farmer selection regarding what is allowed to grow beyond the pole stage.Wood density and seed dispersal profiles can be used as degradation indicators of species assemblages across various disturbance levels and types,as they reflect the habitat quality of the surrounding landscape mosaics.
基金funded by the Ministry of Environment and Forestry Republic of Indonesia through the research funding assistance program
文摘The Mutis-Timau Forest Complex,one of the remaining mountainous tropical forest areas in Timor Island,eastern Indonesia that covers an area of 31,984 ha,tends to decrease gradually.Efforts to secure mountain forest functions and counteract the negative impact of declining forest areas are often constrained by data uncertainty on factors contributing to deforestation.For this reason,this study attempts to develop models of deforestation and predict future deforestation in the Mutis-Timau Forest Complex.We constructed models of deforestation that describe the relationship between deforestation and factors contributing to deforestation using spatial statistical models.In this model,we used the deforestation data for the 1987-2017 period obtained from a previous study as dependent variables and the potential causes of deforestation generated from Geographic Information System spatial analysis as independent variables.Using the probability of deforestation derived from the model,we predicted future deforestation under two different scenarios,namely,business-as-usual(as the reference scenario)and reducing emission fromdeforestation and forest degradation.Our findings showed that a positive relationship exists between probability of deforestation,distance to the settlement,and population density variables,whereas a negative relationship exists between likelihood of deforestation,elevation,slope,distance to the road,distance to the savanna,and forest management unit variables.During the 2017-2030 period,under the business-as-usual scenario,the Mutis-Timau Forest Complex will lose 1327.65 ha in forest area with an annual deforestation rate of 0.54%.Meanwhile,under the reducing emission from deforestation and forest degradation scenario,the overall forest loss was estimated to be 1237.11 ha with an annual deforestation rate of 0.50%.The predicted area of avoided deforestation in 2017-2030 under the reducing emission from deforestation and forest degradation scenario was 90.54 ha.Such data and information are important for the Mutis-Timau Forest Complex authority in prioritizing actions for combating deforestation and designing appropriate forest-related policies and supporting data for reducing emission from deforestation and forest degradation programme or other incentive schemes in reducing deforestation.
基金supported by the College of Education,Korea University Grant in 2016
文摘The concentration of cosmogenic loBe in riverine sediments has been widely used as a proxy for catchment-wide denudation rate （CWDR）. One of the key assumptions of this approach is that sediments originating from sub-basins with different erosional histories are well mixed. A tragic debris flow occurred in the Seti River watershed, central Nepal, on May 5, 2012. This catastrophic debris flow was triggered by slope failure on the peak of Annapurna IV and resulted in many casualties in the lower Seti Khola. However, it provided an opportunity to test the assumption of equal mixing of sediments in an understudied rapidly eroding watershed. This study documents the CWDR of ^10Be to evaluate the extent of the influence of episodic erosional processes such as debris flow on the spatio-temporal redistribution of loBe concentrations. Our data show that the debris flow caused little change in CWDR across the debris flow event. In addition to isotopic measurement, we calculated denudation rates by using the modeled concentrations in pre- and post-landslide sediments based on the local ^10Be production rate. The modeled result showed little change across the event, indicating that the debris flow in May 2012 played a minor role in sediment evacuation, despite the rapid erosion in the catchment. Our study concludes that although the 2012 event caused many casualties and severe damage, it was a low-magnitude, high frequency event.
基金the National Investigation Projects of Soil Pollution supported by a grant from Ministry of Environmental Protection of the People's Republic of China
文摘This study investigated the conjoined cellular oxidative damage of human embryo kidney 293T（HEK293T） cells induced by cadmium chloride（CdCl2） and nanometer titanium dioxide（nano-TiO2）.RT-PCR technique was used to detect the expressions of Heme oxygenase-1（HO-1） and 8-oxoguanine DNA glycosylase（OGG1）.The activities of superoxide dismutase（SOD） and catalase enzyme（CAT） and concentrations of reactive oxygen species（ROS） and maldondialdehyde（MDA） were measured by different approaches.The results showed that CdCl2 and nano-TiO2 at a low concen-tration of 0.75 total toxic unit（TU） exerted an additive effects on HO-1 gene expression,CAT activities and MDA concentrations.When the total TU was increased to 1 or 1.25 TU,the interaction was syner-getic.Moreover,the mixture with high proportion of CdCl2 produced an additive effect on the OGG1 gene expression,and the interaction was changed to be synergetic when the concentration of CdCl2 was lower than or equal to that of nano-TiO2.Synergetic effects of CdCl2 and nano-TiO2 on cellular oxida-tive damage of HEK293T cells were found as indicated by the changes in the SOD activities and ROS concentrations.It was concluded that CdCl2 and nano-TiO2 exerts synergistic effects on the cellular oxidative damage of HEK293T cells,and the sensitivity of these indicators of oxidative damage varies with the proportion of CdCl2 and nano-TiO2 in the mixture.
文摘A new method combining QuEChERS (quick, easy, cheap, effective, rugged and safe) and DLLME (dispersive liquid–liquid microextraction) for the simultaneous determination of residues of ten sulfonylurea herbicide in water using UPLC-MS/MS was developed and validated. Analytes were extracted and purified with QuEChERS and concentrated in chlorobenzene by applying the DLLME procedure. Several extraction parameters were tested, such as volume, extractive solvent by the QuEChERS method and subsequently used for DLLME, selection of extractive solvent and its volume, was tested. The developed method was validated on the basis of international guidelines. Mean recoveries ranged from 81.2 to 104.9%. Repeatability and reproducibility were lower than 10%. Limits of detection (LODs) and quantification (LOQs) were below 0.074 μg/L and 0.244 μg/L, respectively. Decision limit (CCα) and detection capability (CCβ) were calculated and CCβ ranged from 0.101 μg/L (pyrazosulfuron-ethyl) to 0.260 μg/L (nicosulfuron). Finally, when the method was applied to real samples, traces of three compounds were found in 42 samples and only thifensulfuon-methyl was detected above the LOQ in three samples at 0.17-0.20 μg/L.
