International audience | Environmental contaminants affect ecosystems worldwide and have deleterious effects on biota. Non-essentialmercury (Hg) and lead (Pb) concentrations are well documented in some taxa and are described to cause multipledetrimental effects on human and wildlife. Additionally, essential selenium (Se) is known to be toxic at highconcentrations but, at lower concentrations, Se can protect organisms against Hg toxicity. Crocodilians areknown to bioaccumulate contaminants. However, the effects of these contaminants on physiological processesremain poorly studied. In the present study, we quantified Hg, Pb and Se concentrations in spectacled caimans(Caiman crocodilus) and investigated the effects of these contaminants on several physiological processes linkedto osmoregulatory, hepatic, endocrine and renal functions measured through blood parameters in 23 individuals.Mercury was related to disruption of osmoregulation (sodium levels), hepatic function (alkaline phosphataselevels) and endocrine processes (corticosterone levels). Lead was related to disruption of hepatic functions(glucose and alanine aminotransferase levels). Selenium was not related to any parameters, but the Se:Hg molarratio was positively related to the Na+ and corticosterone concentrations, suggesting a potential protective effectagainst Hg toxicity. Overall, our results suggest that Hg and Pb alter physiological mechanisms in wild caimansand highlight the need to thoroughly investigate the consequences of trace element contamination incrocodilians.

International audience | Treatment wetlands for raw wastewater from small communities (< 2000 p.e.) represent 20% of the wastewater treatment plants in France today. The classical French Vertical Flow Treatment Wetland consists of two stages filter beds intermittently fed with raw wastewater (inflow concentrations TSS 387 +/- 70 mg/L, COD 880 +/- 188 mg/L, TKN 110 +/- 16 mg/L). The system has a good removal performance for TSS and COD with > 90% and TKN of approx. 85% after filter maturation (months 12 to 24 of the trial), but efficiencies can vary between 10 and approx. 20% according to the material type, filter age, and filter depth. This study presents how these systems can be costly optimized when outlet requirements are not too stringent or when carbon is required for a subsequent denitrification step. The study shows the effectiveness of using different gravel depths and types (pea and crushed gravel) over almost 2 years regarding removal performances, carbon source availability, and nitrification. Core samples were taken to evaluate the dry matter accumulation. Tracer tests using fluorescein were performed to assess the internal hydrodynamics related to filter depth. The removal performance was not significantly affected by the filter depth, but the filter filled with 30 cm of pea gravel performed significantly better than the one with 30 cm of crushed gravel: for COD with a removal of 83% compared to 76%, TSS of 87% to 81%, and TKN of 64% to 57%, respectively. This is another indication that the shape of crushed gravel affects biofilm attachment and hydrodynamics in the filters due to irregular compaction.

The potential of carbon sequestration of tree species in the Chintapalle forest range, of Narsipatnam Division, was estimated by using a non-destructive method. The sequestration of 6033 trees belonging to 22 species was investigated; the approximate height of tree species and the diameter at breast height (DBH) were measured for the estimation of CO2 sequestration. The maximum weight of carbon was observed in Pongamia pinnata (L.) Pierre species i.e (37987.06 kg) and the minimum weight of carbon was noted in Phyllanthus emblica L. species i.e is (61.8kg). The total carbon sequestrated by the entire tree species was (2370614.0 kg), The average carbon sequestered was (39865.81 kg). The highest sequestration was noted in the species P. pinnata (L.) Pierre i.e. (139271.95 kg) and the lowest (226.79 kg) was noted in the species P. emblica L. The maximum average DBH with maximum carbon sequestration potential was observed in Ficus benghalensis L. species, with higher total green (AGW) observed in all sites, whereas minimum average DBH with minimum carbon sequestration potential was noted in Bambusa vulgaris species. The regression analysis tests the relationship between two variables. The height of trees has no significant impact on the amount of CO2 sequestered F (32085087175.84, 12946607900) = 2.478262; P ≥ 0.05, which indicates that the tree height plays an insignificant role in CO2 sequestration (β = 2713.28 P ≥ 0.05). The dependent variable CO2 sequestered was also regressed on the predictor variable soil organic carbon (SOC) to test the relationship. SOC insignificantly predicted CO2 sequestrated F (5.83, 2.62) = 0.2236; P ≥ 0.25, indicating that the SOC has an insignificant role in CO2 sequestration (β = 102780.3 P ≥ 0.05). Insignificant relation was observed between the parameters SOC and height of tree species to the rate of carbon dioxide sequestered, and gave a regression equation of y = 10278x + 50863 with R2 = 0.100; y=2713.285803x-209800.8762 with R2 = 0.553 respectively.

Remote sensing technology has changed the way disasters like earthquakes and tsunamis are detected, monitored, and mapped in recent years. This paper summarizes the general theoretical study of Tsunami generation, propagation, and its inundation for deep, intermediate, and coastal waters. Tsunami is a Japanese word, which is made up of two words: “tsu” means harbor, and “nami” means waves. It means that Tsunami is the coastal gravity waves, which propagate close to the coastline. This analysis presents a novel method to explore the effects of tsunami waves on coastal areas. The methodology includes remote sensing nearness examinations and alteration identification strategies in remote sensing to outline a number of support routes along the coast and divide them into four homogenous sub-regions. The adjustments in the land spread are then measured in these sub-regions when the tidal wave occurs. The proposed paper gives a more solid and exact method than ordinary strategies to assess spatial examples of harmful territories through various land qualities along the coastline. The generative phase of tsunami development comprises the creation of an early disruption at the surface of the ocean due to the earthquake-generated distortion on the seafloor. Various comparative studies are also carried out using spatial technology to examine tsunami routes around the globe, taking into account the most recent tsunami occurrences.

Nitrate nitrogen (N-NO3-), the most common pollutant in groundwater, is a result of the effect of diffuse sources of pollution like agriculture and animal husbandry intensive. The land use for these economic activities is very common in the Los Ríos sub-region in the state of Tabasco, Mexico, where the Los Ríos and Boca del Cerro aquifers are located. The aim of this research was to assess the concentrations of nitrate-nitrogen (N-NO3-) in groundwater, determine the quality in agreement with the maximum permissible limits established by national and international regulations, and the risks to the public health and aquatic life. The spatial distribution of N-NO3- was determined using the inverse distance weighted (IDW) interpolation technique. The average nitrate-nitrogen concentration was 0.76 mg.L-1, while the maximum concentration observed was 3.98 mg.L1. This does not exceed the maximum permissible limit (MPL) established in the national and international normativity for drinking water. However, in 50% of the sampling sites, the concentrations of N-NO3- exceed the MPL established in Mexico for the protection of the life of seawater. Relatively low concentrations of N-NO3- have shown to be toxic to certain aquatic organisms, and the aquifers studied discharge a third of the water to the rivers in the area, which flow into the Laguna de Términos Campeche and the Gulf of Mexico. Laguna de Términos Campeche is one of the most diverse and rich environmental systems on earth, where numerous ecosystems converge such as coastal lagoons, wetlands, mangroves, seagrasses, and coral reefs.

Groundwater is essential to the sustainability of India’s environment, economy, and living conditions because it isn’t just the primary source of domestic supply of water in rural areas, but it is also the major and most productive origin of the water. The increased demand for groundwater as a result of reduced rainfall has put a strain on groundwater resources in areas where groundwater is the primary supply of water. The main aim of this study is to identify and explore the groundwater potential zones in Talupula Mandal of 280.3 km2 in Ananthapur district in Andhra Pradesh, India with semi-arid climatic conditions. Based on the field survey approach, groundwater availability is found out in the villages. Schlumberger Vertical Electrical Sounding (VES) survey technique was used to discover the resistivity and thickness of the unmistakable layers. It was carried out in 18 randomly selected sites where groundwater plays an important role in agricultural and domestic use. The thickness and resistivity of first- and second-layer crack sites of the various layers were separated from ground data using IPI2WIN programming. Using software, graphs were plotted and groundwater potential zones were identified for recharging the groundwater. Based on the results, different models of recharge structures for the study area are identified and recommended. Hence the management of groundwater paves the way for sustainable groundwater levels.

Halophytes are unique in that they can thrive in a wide range of soil conditions, from normal to extremely saline. This has recently prompted researchers to consider using halophytes as a phytoremediation end-product as a source for biogas generation. Therefore, applying the anaerobic digestion process for halophytes may have the potential advantage in terms of efficient land utilization, soil remediation, and biogas production. Based on this, the anaerobic digestion efficiency of high saline biomass was investigated in continuous laboratory-scale anaerobic reactors at two different sludge residence times (SRT) of 40 and 80 days. Under mesophilic atmosphere, two reactors were operated, one reactor used organic substrate with 30 g-Na+.L-1 originating from sodium chloride whereas the other was operated with the presence of sodium bicarbonate and sodium sulfate. The salt-tolerant microorganism was gradually developed and the salt concentrations were selected based on the elemental analyses results of 30 species of wild halophyte plants taken from the saline-affected area of the Aral Sea in Uzbekistan during the early phase of the operation. For 40 and 80 days of SRT, respectively, 65.56 percent and 60.42 percent of the feed COD were converted into methane gas by the chloride system. However, only about 60% of the feed COD was converted into methane for bicarbonate, and the remaining fraction of gas was assigned to sulfide as a final product of increased sulfate reduction bacteria activity. These findings showed that the salt-tolerant microorganism could be incubated and the anaerobic digestion process could be adapted for a high-saline substrate, implying that the biodegradability of phytoremediation end-products may be used for methane production.

This research aims to assess the greenhouse gas (GHG) emissions reductions due to the use of biogas technology in Quang Tri Province. With a total of over 354,000 cattle in Quang Tri Province, Vietnam, waste from livestock becomes large. The GHG emitted from the livestock industry is not small, affecting the environment. Currently, there is little concern or documentation about the reduction of GHG emissions in small farms using biogas digesters in central Vietnam. This province has applied technological solutions, typically biogas digesters, but the amount of biogas production is not calculated accurately. Our survey was conducted in Vinh Linh District and Cam Lo District in March 2019 and involved 50 farms equipped with biogas digesters and 20 farms without it. The respondents were selected based on the information provided by local authorities, satisfying two conditions: livestock households and biogas users. The former group was asked 25 questions and the latter was asked 10 questions needed to calculate GHG emissions such as the number of animals and petroleum gas/ firewood consumption. This study uses formulas described in the 2006 guideline issued by IPCC to estimate reduced GHG emissions. The results showed that the average biogas production is 5.52 m³.household-1.day-1. Only 2% of the farms made the best use of the biogas digester. The surveyed households have not really used the most optimal amount of biogas production. In this scenario, this study recommends some solutions for solving the problem. In addition, the average annual emissions before having a biogas digester are estimated to be 20.53 tons CO2e/household/year. After using the biogas, the GHG emissions are reduced to 4.52 tCO2e.household-1.day-1. Thus, the replacement of daily cooking energies with biogas helps reduce 16.01 tCO2e of greenhouse gas for each farm per year.

The world needs to increase renewable and alternative fuel sources such as Biomass, Bioethanol, and Biodiesel to compete with fossil fuels. Biodiesel is an important renewable fuel source since it can be used in regular diesel vehicles without requiring engine modifications. Conventional biodiesel production takes around 90 min of reaction time. A longer reaction time is not suitable for commercial production. Furthermore, traditional products such as oil react with biodiesel methoxide to produce a maximum of 90% biodiesel yield. As the catalyst is not involved with the reaction, pure methanol and methoxide (methanol with KOH catalyst) are separately added to the system to enhance the pre-reaction step. By changing the methanol to methoxide ratio, biodiesel is produced, and yield is calculated. The highest yield, which is 95%, is obtained with a 5:15% methanol to methoxide ratio. The total reaction time with the new experimental procedure is only 20 min. That is a significant reduction by saving operating costs such as energy consumption. Produced biodiesel show similar properties to that of standard biodiesel.

The “Regional Circular and Ecological Sphere” takes advantage of the SDGs’ concept of integrated solutions to numerous concerns, complementing and supporting resources based on the region’s features while maximizing the utilization of local resources. This research makes a comprehensive evaluation of the three aspects of the environment, economy, and society. First, formulate the evaluation indicators of the regional circulation symbiosis zone. Then, choose the cutting conditions of trees according to geographical factors, use the thinning forecasting system and forest GIS data to evaluate the supply potential of thinned wood in the area, and calculate the heat and power generation of wood biomass. According to the above analysis and calculation, 12,000 tons of unused wood chips can be supplied per year for 36 years from 2016 to 2051. From the economic point of view, the purchase of wood chips of 146 million yen due to the local circulation of wood fuel is expected to save about 50 million yen in intermediate input. And it is estimated that if 12,000 tons of unused wood chips can be supplied in the city per year, and about 98.4 million yen can be saved annually. Finally, from a social perspective point of view, biomass power generation of unused thinned timber using materials worth about 146 million yen is expected to create about 20 jobs.