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An experiment was conducted to investigate the effect of standing water levels on methane gas emission and yield of transplanted Aman rice (cv. BRRI dhan51) during July to December 2015 at medium low-lying area of Mohangonj upazila under Netrokona district. The experiment comprised five standing water levels on surface paddy soil viz., 5 cm, 10 cm, 15 cm, 20 cm and 25 cm. Methane (CH4) gas emission, yield components and yield of transplanted Aman rice were significantly affected by standing water levels on surface paddy soil. CH4 emission was gradually increased with rising standing water levels and remained static condition at 20-25 cm water level. The highest CH4 emission was observed at 20 cm standing water level and the lowest CH4 emission was recorded at 5 cm water level. The highest CH4 peak recorded at 85 days after transplanting (DAT). The highest CH4 flux (36.59 mg/m2/h) was observed in treatment 20 cm water level whereas the lowest CH4flux (21.17 mg/m2/h) was observed in 5 cm water level. Finally, the CH4 emission dropped at 108 DAT. On and average, the CH4 emission rate during rice cultivation followed 20 cm > 25 cm> 15 cm > 10 cm > 5 cm water level. Soil Eh gradually decreased with progress of time and plant growth and at 85 DAT highly reduced condition developed in all treatments. The maximum reduced condition was observed (-238.67 mV) in treatment 20 cm water level and minimum one (- 214.667 mV) was found in 5 cm water level. The highest grain (5260 kg ha-1) and straw (6725.0 kg ha-1) yields were obtained at 10 cm standing water level while the lowest grain (4191.6 kg ha-1) and straw (5050.0 kg ha-1) yields were recorded in 5 cm and 15 cm water level, respectively. It may be concluded that 10 cm standing water level is beneficial for transplant Aman rice (cv. BRRI dhan51) cultivation in low lying area in respect of grain yield and environmental issues.

Climate change and water scarcity may badly affect existing rice production system in Bangladesh. With a view to sustain rice productivity and mitigate yield scaled CH4 emission in the changing climatic conditions, a pot experiment was conducted under different soil water contents, biochar and silicate amendments with inorganic fertilization (NPKS). In this regard, 12 treatments combinations of biochar, silicate and NPKS fertilizer along with continuous standing water (CSW), soil saturation water content and field capacity (100% and 50%) moisture levels were arranged into rice planted potted soils. Gas samples were collected from rice planted pots through Closed Chamber technique and analyzed by Gas Chromatograph. This study revealed that seasonal CH4 emissions were suppressed through integrated biochar and silicate amendments with NPKS fertilizer (50–75% of the recommended doze), while increased rice yield significantly at different soil water contents. Biochar and silicate amendments with NPKS fertilizer (50% of the recommended doze) increased rice grain yield by 10.9%, 18.1%, 13.0% and 14.2%, while decreased seasonal CH4 emissions by 22.8%, 20.9%, 23.3% and 24.3% at continuous standing water level (CSW) (T9), at saturated soil water content (T10), at 100% field capacity soil water content (T11) and at 50% field capacity soil water content (T12), respectively. Soil porosity, soil redox status, SOC and free iron oxide contents were improved with biochar and silicate amendments. Furthermore, rice root oxidation activity (ROA) was found more dominant in water stress condition compared to flooded and saturated soil water contents, which ultimately reduced seasonal CH4 emissions as well as yield scaled CH4 emission. Conclusively, soil amendments with biochar and silicate fertilizer may be a rational practice to reduce the demand for inorganic fertilization and mitigate CH4 emissions during rice cultivation under water stress drought conditions.

Although COVID-19 has given an opportunity to the earth to restore her ecosystem, its role in bringing changes in every sector including social, economic, agricultural, industrial, education and health is enormous. The study was conducted to assess the socio-economic impacts of COVID-19 in Bangladesh by collecting data from different sources. The result depicted that during the first wave of COVID-19, the detection rate was less than 5%, exceeding almost 30% after detecting the deadlier Indian variant where 65% of the death is noticed by the people older than 50 years. Among all the frontline service providers during Covid, the highest rate of death was observed for doctors in Bangladesh. This study also discussed the impact of COVID-19 on mental health and found that women faced more depression and anxiety than men as well as 43% of children had subthreshold mental disturbances. Three-fourths of the adolescents have been distressed with household stress during the pandemic. Women and girls have encountered increased domestic violence whereas early marriages dropped out many rural girls from education. Decreasing remittance from non-residents and shutting down of RMG industry resulted loss of job and have badly affected economic section. Almost 20 million workers lost their jobs in Bangladesh from the informal sector. Moreover, the healthcare workers who have treated the corona virus patients have been socially stigmatized due to the fear of infection. Corona Virus has jeopardized the agriculture sector and 66% farmers (53% crop and vegetables, 99% fish farmers) got lower price than they used to get in a normal situation. Together with Government, non-government organizations, researchers, doctors, industrialists, international organization as well as individuals should come forward to handle this pandemic., Graphical Abstract Image, graphical abstract

This study investigates the major chemical components, particle-bound water content, acidity (pH), and major potential sources of PM

A total of 85 PM2.5 samples were collected at a site located in a large industrial zone (Porto Marghera, Venice, Italy) during a 1-year-long sampling campaign. Samples were analyzed to determine water-soluble inorganic ions, elemental and organic carbon, and levoglucosan, and results were processed to investigate the seasonal patterns, the relationship between the analyzed species, and the most probable sources by using a set of tools, including (i) conditional probability function (CPF), (ii) conditional bivariate probability function (CBPF), (iii) concentration weighted trajectory (CWT), and (iv) potential source contribution function (PSCF) analyses. Furthermore, the importance of biomass combustions to PM2.5 was also estimated. Average PM2.5 concentrations ranged between 54 and 16 μg m−3 in the cold and warm period, respectively. The mean value of total ions was 11 μg m−3 (range 1–46 μg m−3): The most abundant ion was nitrate with a share of 44 % followed by sulfate (29 %), ammonium (14 %), potassium (4 %), and chloride (4 %). Levoglucosan accounted for 1.2 % of the PM2.5 mass, and its concentration ranged from few ng m−3 in warm periods to 2.66 μg m−3 during winter. Average concentrations of levoglucosan during the cold period were higher than those found in other European urban sites. This result may indicate a great influence of biomass combustions on particulate matter pollution. Elemental and organic carbon (EC, OC) showed similar behavior, with the highest contributions during cold periods and lower during summer. The ratios between biomass burning indicators (K+, Cl−, NO3 −, SO4 2−, levoglucosan, EC, and OC) were used as proxy for the biomass burning estimation, and the contribution to the OC and PM2.5 was also calculated by using the levoglucosan (LG)/OC and LG/PM2.5 ratios and was estimated to be 29 and 18 %, respectively.

A yearlong sampling campaign (2012-2013) was conducted in six major cities of the Veneto region to investigate the spatial-temporal trends and the factors affecting the polycyclic aromatic hydrocarbon (PAHs) variations and identify the local sources. Sixty samples per city were collected for analyses in every alternate month (April, June, August, October, December, and February): 10 samples per sampling site in 10 consecutive days of the months selected. Samples were ultrasonically extracted with acetonitrile and processed through high-performance liquid chromatography. Total Σ-PAH concentrations ranged from 0.19 to 70.4 ng m

The maximum and minimum values of lE/Rn (latent heat fluxes/Net radiation) ratio in Aman rice field were 0.63 MJm 2 , and 0.16 MJm -2 , respectively whereas the average value was 0.41 MJm -2 during wet condition. H (Sensible heat fluxes) was positive during the day with few fluctuations and the ratios of H/Rn fluctuated from 0.67 MJm -2 to 0.22 MJm -2 while the average value was 0.45 MJm -2 and this phenomenon was due to available moisture availability in the Aman rice field. The maximum G/Rn ratio was 0.20 MJm -2 while the minimum ratio was 0.09 MJm -2 and their average value was 0.14 MJm -2 . The value of G was considerably small due to the canopy architecture in Aman rice cropping system. In post Aman rice field, sensible heat flux density of the fallow rice field showed highest 25.66 MJm -2 . On an average, H was 58.6 % of the whole Rn while the minimum and maximum portions were5.68 % and maximum of 114.86 %, respectively in well irrigated fields. The measured average H/Rn ratio was 0.54 MJm -2 in post Aman rice field while their maximum and minimum values were 0.79 MJm -2 , 0.07 MJm -2 , respectively. The lE/Rn ratios ranged from 0.05 MJm -2 to 0.76 MJm -2 with an average value of 0.30 MJm -2 . G/Rn accounted maximum 0.24 MJm -2 , minimum 0.07 MJm -2 and on an average 0.16 MJm -2 and G was considerably larger than vegetative fields due to the less crop canopy architecture in post Aman rice fallow field. In Boro rice field variations in Rs mainly observed due to weather condition. H/Rn ratios from the rice field and observed that the maximum 0.88 MJm -2 , minimum 0.20 MJm -2 and on an average 0.49 MJm -2 , this phenomenon due to seasonal weather characteristics. The lE/Rn ratios in the Boro rice field observed maximum 0.60 MJm -2 , minimum 0.04 MJm -2 and on an average 0.35 MJm -2 . G accounted maximum 0.22 MJm -2 , minimum 0.08 MJm -2 and on an average 0.16 MJm -2 and G was considerably small due to the canopy architecture Boro rice cropping system. In post Boro fallow rice field the maximum value of the ratio of lE/Rn was 0.82 MJm -2 while the minimum value was 0.41 MJm -2 with an average of 0.66 MJm -2 . The lE/Rn ratios exhibited the highest ratios among the all observation periods and due to more availability of water. The H/Rn ratios observed maximum 0.50 MJm -2 , minimum 0.12 MJm -2 and on an average 0.25 MJm -2 . G accounted maximum 0.14MJm -2 , minimum 0.06 MJm -2 and on an average 0.09 MJm -2 and G was considerably smaller than vegetative fields due to the less crop canopy architecture and much water availability in post Boro rice fallow field. DOI: http://dx.doi.org/10.3329/jesnr.v6i1.22065 J. Environ. Sci. & Natural Resources, 6(1): 195-201 2013

An experiment was conducted to investigate the factors responsible for the partitioning of energy balance components over BRRI dhan 28 (Boro season) rice crop at the paddy field of Bangladesh Agricultural University Farmland, Mymensingh during August 2010 to July 2011. The whole measurement period was divided into two seasons such as Boro rice and Post Boro fellow. Energy balance components were measured in this experiment using sophisticated sensors. The cropping season differences in water and energy fluxes were attributed by the availability of sunlight and abundance of water at the site as well as differences in sunshine hours during winter. Irrigation during winter Boro had substantial influence on the seasonal and inter-annually variability of energy partitioning at rice field. Of the papers diurnal variations in energy balance components are shown and variations in the energy balance components are discussed.DOI: http://dx.doi.org/10.3329/jesnr.v6i1.22031 J. Environ. Sci. & Natural Resources, 6(1): 01-06 2013

The study was conducted in Madhupur Sal Forest, which is very well known for its characteristics as deciduous forest, to describe the diversity of plant species and animal species and to examine the diversity status in Madhupur Sal Forest. A stratified random quadrate method was employed in the study. A total of 40 plant species were recorded of which 21 were tree species, 9 were herbs, 5 were shrubs and rests 5 were climbers. Total 17 animal species were recorded of which 9 were birds, 3 were amphibians, 2 were reptiles and 3 were mammals. With regards to the quantitative attributes of total flora and fauna species, the highest number was found in trees (mean, 14.20) and the lowest number was found in mammals (mean, 0.80). The result showed very high significant variation among them. It was evident from the study that the people around the forest collect forest flora (75.45%) and fauna (8.18%) illegally is the major cause of biodiversity loss. The people are not aware of the importance of forest in various aspects like social, economical, ecological and environmental aspects. Forest authorities are trying to involve the people in and around the forest in community forestry through motivation and training.DOI: http://dx.doi.org/10.3329/jesnr.v6i1.22064 J. Environ. Sci. & Natural Resources, 6(1): 187-193 2013

The Po Valley is one of the most important hot spots in Europe for air pollution. Morphological features and anthropogenic pressures lead to frequent breaching of air quality standards and to high-pollution episodes in an ~46 × 10

In this study, the impact of Madhupur National Park on local peoples’ livelihoods was assessed. To find local peoples perception on collaborative natural resources management. This study was conducted from July, 2012 to December, 2012 on two villages named Talki and Sholakuri. Data collection was based on stratified random sample. Stratification was based on park proximity of respondent households that is (inside park) 0 km, 0.5 km distance, 1 km distance, 1.5 km distance and 2 km distance from Madhupur National Park boundary. The five strata were compared with respect to household’s natural resource dependency, household’s income, income diversification, income level, assets and perception on present management system. Present management system was also discussed to emphasize park management authority contribution on local livelihood. Based on analysis of collected data from two villages it was assumed that the nearest people were more dependent on natural resource of park than far people. The simple correlation coefficient for the distance of household with natural resource dependency was negatively significant. Household average monthly incomes in two villages were approximately same but Talki villagers were 79.25% depend on park related activity and this dependency decreased with increasing of distance. Present park management system plays an important role to reduce people and park animosity by providing aid and training to the local offensive persons and involve them into park conservation. A trend analysis of decreasing forest offences represented that, the present management system is better than past time and it could be able to reduce people park animosity.DOI: http://dx.doi.org/10.3329/jesnr.v5i2.14603 J. Environ. Sci. & Natural Resources, 5(2): 63-66 2012

An investigation was carried out to quantify the present fluxes of CH 4 and CO 2 from rice soils and also to investigate the controls on gas production. Soil samples were collected from rice field at Mymensingh, Bangladesh to characterize the samples and for ex-situ measurement. Water content was determined by drying to constant weight at 50°C from rice soils. To determine the organic compound present in rice soil, normal pyrolysis was done. Gasclam® was used to measure the gas concentration from both ex-situ and in-situ measurement. Ex-situ measurement was conducted to measure the gas fluxes from the soil and which was validated by measuring concentration ratios in-situ. Moreover, in-situ measurement was carried out to investigate the influences of controls of environment on gas production and migration. In ex-situ measurement the production rate of CH 4 at shallow and deep rice soil was 0.07 mole/tonne dry weight/day and 0.09 mole/tonne dry weight/day, respectively. On the otherhand, the production rate of CO 2 in shallow and deep borehole was 0.23 mole/tonne dry weight/day and 0.29 mole/tonne dry weight/day, respectively. In in-situ measurement the average production rate of CH 4 in shallow soil was 0.34 % while at deep soil it was very low. The CO 2 concentration at shallow and deep soil was 6.37 % and 24.70 %, respectively. The ex-situ measurements of greenhouse gas fluxes are not reliable enough for rice soil as they are invalidated by comparison with concentration ratios of insitu measurements of greenhouse fluxes. There is no strong relationship between atmospheric pressure and patterns of greenhouse gas production in rice soils. Gas concentrations are remarkably constant despite varying pressure. However, the gas production and atmospheric pressure showed fluctuation during the measurement period. There was not enough organic matter in rice soil for detection organic analysis. However in future the organic matter can be extracted and analysed. Key Words: Methane and carbon dioxide flux; Rice field; Environmental controls; Organic analysis DOI: http://dx.doi.org/10.3329/jesnr.v4i2.10123 J. Environ. Sci. & Natural Resources, 4(2): 1-6, 2011

Organic and elemental carbon (OC-EC) were measured in 360 PM2.5 samples collected from April 2012 to February 2013 at six provinces in the Veneto region, to determine the factors affecting the carbonaceous aerosol variations. The 60 daily samples have been collected simultaneously in all sites during 10 consecutive days for 6 months (April, June, August, October, December and February). OC ranged from 0.98 to 22.34 μg/m(3), while the mean value was 5.5 μg/m(3), contributing 79% of total carbon. EC concentrations fluctuated from 0.19 to 11.90 μg/m(3) with an annual mean value of 1.31 μg/m(3) (19% of the total carbon). The monthly OC concentration gradually increased from April to December. The EC did not vary in accordance with OC. However the highest values for both parameters were recorded in the cold period. The mean OC/EC ratio is 4.54, which is higher than the values observed in most of the other European cities. The secondary organic carbon (SOC) contributed for 69% of the total OC and this was confirmed by both the approaches OC/EC minimum ratio and regression. The results show that OC, EC and SOC exhibited higher concentration during winter months in all measurement sites, suggesting that the stable atmosphere and lower mixing play important role for the accumulation of air pollutant and hasten the condensation or adsorption of volatile organic compounds over the Veneto region. Significant meteorological factors controlling OC and EC were investigated by fitting linear models and using a robust procedure based on weighted likelihood, suggesting that low wind speed and temperature favour accumulation of emissions from local sources. Conditional probability function and conditional bivariate probability function plots indicate that both biomass burning and vehicular traffic are probably the main local sources for carbonaceous particulate matter emissions in two selected cities.

Atmospheric particulate matters were collected on quartz fibre filters for 24 hours with a low volume sampler from January 2014 to March 2014 at the Southeast Asian mega city (Dhaka, Bang- ladesh). Particulate matters samples were analysed for eleven trace metals with inductively cou- pled plasma mass spectrometer (ICP-MS) at Ca Foscari University of Venice, Italy. Trace metals were extracted from filters with digestion method using a mixture of HNO3 and H2O2. The average concentration of the determined trace metals of As, Cd, Ni, Cu, Pb, Cr, Fe, Mn, Zn, Sband Se were 3.06, 6.28, 3.77, 11.98, 305.6, 9.2, 2057.0, 42.2, 303.3, 5.47 and 2.43 ng∙m −3 , respectively. Arsenic concentration is much lower in the atmosphere of Dhaka, though Bangladesh has severe arsenic problem in the ground water. Lead and cadmium concentrations showed decreasing trend in Dhaka compared than previous measurements—but still they have very high levels compared than Europe and USA. There is very limited information for Mn, Sb and Se concentrations in Dhaka air. Correlation studies showed that several trace metals had potential joint sources of origin, e.g., manganese is highly correlated with iron (r 2 = 0.97) and nickel (r 2 = 0.84), copper (r 2 = 0.86); lead with arsenic (r 2 = 0.79) and antimony (r 2 = 0.78). Enrichment factors analysis was also done with the data base for the respective metals in earth crust and coal fly ash. As and Cu both have com- bined sources, whereas Cd, Pb and Zn were from coal fly ash.Trace metals concentrations in Dhaka city air were much higher than Europe and USA but comparable or slightly lower than other south Asian countries. This is the first extensive study for the eleven trace metals with ICP-MS in Dhaka, * Corresponding author.

Contamination of feed stuffs and ingredients with heavy metals has become a global issue due to the transmission of toxic substances within the human food chain. Therefore, this study was conducted to investigate the concentration of heavy metals in broiler and fish feed from some selected markets of Mymensingh and Tangail districts. Nine broiler feeds (Swadhin, Paragon, BP feed, Adnan Agro grower, Adnan Agro Sonali, Nourish, United, Sonali Grower and New hope) and six fish feeds (Stella S-3 small size, Stella S-3 big size, Mega 102, Ruposhi Bangla Shift-A 2/P/F, Ruposhi Bangla Shift-A T/G and Mega 301) were selected for this study. Cadmium, lead and chromium concentration of all samples were determined by Atomic Absorption Spectrophotometer (Shimadzu AA-7000). The detected maximum and minimum concentrations of these elements ranged from 0.012-0.027 ppm for cadmium, 0.09-0.17 ppm for lead and >0.05-334.8207 ppm for chromium. The concentrations of heavy metals in feeds were the highest for Cr and the lowest for Pb. It was observed that lower concentrations of Cd and Pb were found in broiler and fish feeds, all of which were below detection limit according to the World Health Organization and European Commission for food safety. Concentrations of Cr in two samples (one fish feed, Stella S-3 small size and one broiler feed, Swadhin feeds) exceeded the standard limits, which indicate that not all the feed samples are safe for human health and Cr may be bio-accumulated to human body through consumption of broiler or fish contaminated with Cr. [J Bangladesh Agril Univ 2020; 18(5.000): 839-844]