Global Journal of Environmental Science and Management
Volume:8 Issue: 2, Spring 2022

The spread of COVID-19 is very fast because it is transmitted from human to human. Non-pharmaceutical control is one of the important actions in reducing the spread of COVID-19, such as the use of masks and physical distancing. This study aims to model COVID-19 by incorporating people''s habits as a non-pharmaceutical preventive measure. The model formed emphasizes the importance of preventing with masks and physical distancing. The implication of this action is that the infected population is decreasing, resulting in less interaction between the susceptible and the infected. In this case, the virus has not vanished from the community, but the use of masks in certain populations or subpopulations is lower than before, which can reduce mask waste in the environment.

This study expands on a previous MERS-CoV research model using the susceptible-exposed-infected-quarantine-recovery model by incorporating behavioral control, specifically the use of masks and physical distancing as preventive measures. The susceptible population that interacts with the carrier/exposed and infected population is used to calculate mask use. The susceptible population was divided into two subpopulations based on their willingness to wear masks. The following breakthrough is the application of the same system to the infected population, which is required to wear masks at all times during their self-isolation period. The model-generated equation system is a nonlinear system of differential equations. The developed model is examined by determining the equilibrium point and the basic reproduction number.

The model resulted an asymptotically stable disease-free equilibrium and endemic equilibrium. The disease-free stability is only examined if the compliance with physical distancing exceeds 0.55 and the compliance with the use of distancing exceeds 0.55. This compliance condition resulted in a decrease in basic reproduction number ranging from 0.48 to 0.07. The endemic stability is only investigated if compliance with physical distancing is 0.1 and compliance with use of distancing is 0.2. The endemic condition can arise if masks and physical separation are not used. Physical distancing compliance and mask use have values less than 0.1 and 0.2, respectively.

The analysis of the equilibrium points and basic reproduction numbers, show that increasing compliance in carrying out the health protocol measures of physical distancing and mask use causes a decrease in the spread of COVID-19, so that the disease will disappear over time.

In landfills, containment is provided by natural or artificial clayey materials known for their low permeability and for their pollutant retention capacity. However, the properties of these media are modified by leachates, whose migration they are supposed to limit. This study aims to reconsider the criteria for choosing suitable materials to make a bottom liner through both their long term hydraulic and mechanical performances.

Two fine materials sampled in Burkina Faso (West Africa) have been characterized in order to compare their hydro-mechanical behavior in the presence of household waste leachates. The first material is classified as an inorganic clay of low to medium plasticity according to Casagrande plasticity diagram, it is mainly kaolinitic with some traces amounts of smectites. The second one is classified clayey sand of low to medium plasticity, the predominant mineral clay being kaolinite. Hydro-mechanical tests were performed on both sampled materials to judge the sealing properties of these materials, as well as the characteristics of deformation and rupture which have an important effect to ensure the durability of a bottom liner. All these tests were performed first with distilled water then with leachates as interstitial fluids in order to understand the modification of the hydro-mechanical properties of the clayey soils.

Leachate contamination always alters hydraulic properties of the materials. However, between the two soils, the most clayey and the most impervious (soils from Nouna) undergo the deeper weathering. Indeed, hydraulic conductivity of these soils in contact with a synthetic leachate increases from 1.71x10-10 to 1.51x10-9 m/s. In contrast to soils from Boudry, these soils also undergo very significant settlements over the long term with compressibility indexes varying from 0.164 to 0.225. For both soils, the shear strength increases showing that, from this point view, the leachate work in the sense of of the bottom liner stability. For soils from Nouna, the effective cohesion increases from 3 to 21 kPa with a slight decrease of friction angle; for soils from Boudry a slight increase of cohesion is noticed while friction angle increases from 34 to 37°.

This comparative study is of practical use to environmental geotechnics professionals because it shows that the choice in designing a bottom liner must be a compromise between long term hydraulic and mechanical behaviors of soils. It is also important to know the nature of the flows to contain in order to ensure the durability of the structure.

Rapid development has increased the microplastics discharges into marine environments, including coastal waters at Jakarta Bay, Indonesia. This study is proposed to assess microplastics abundance and distribution in surface water and sediment from coastal water at Jakarta Bay.

The samples were collected from 12 locations representing Ancol, Muara Baru, and Muara Angke - Muara Karang. Samples of water and sediment were extracted to obtain the microplastics. The microplastics were identified based on their morphology (shape) and numbered for their abundance. The polymer of microplastics was determined using Raman Spectrophotometer.

The results showed that microplastics were successfully identified and counted in water and sediment samples at all collection points. The number of microplastics was 1532 particles in the water sample and 1419 particles in the sediment sample. The shape of microplastics observed in the water and sediment samples were fibers, films, fragments, and pellets. Among those, fiber and film were the most dominant microplastic detected both in surface water and sediment in all locations. Three polymers, namely polyethylene, polypropylene, and polystyrene, were detected in the microplastic samples. These findings prove that microplastics with their various types are capable contaminate the aquatic environment.

The most common microplastics shapes in sediment were fiber (55.7%) > film (31.1%) > fragment (9.9%) > pellet (3.2%) and for the surface water were film (53.5%) > fiber (33.9%) > fragment (7.8%) > pellet (4.7%). The abundance of microplastics in the sediment (166.8 particles/kg, 95%CI: 148.0-185.0) was significantly higher (p < 0.05) than in surface water (70.9 particles/L, 95%CI: 55.6-86.2). The abundance of microplastics was significantly different among locations (p < 0.05, F = 2.115), with microplastics in sediments were higher in Ancol, and Muara Angke - Muara Karang have the highest microplastics in surface water. These results can provide valuable information on which parts of the Jakarta Bay areas should be prioritized first regarding microplastics management.

Cycling has been widely promoted as an alternative mode of transport to help the reduction of environmental impact and improve users' health. Promoting cycling will help enhance the "Green City" initiative in Thailand. While several studies have addressed social issues of cyclists, the environmental impacts and economic viability of cycling infrastructure are yet unknown. Quantifying its environmental impact and the costing aspect are essential to prove that cycling would positively affect a city. This study compares the expected environmental and economic impacts before and after constructing a bicycle lane in Mahasarakham, Thailand.

This study uses life cycle assessment and life cycle costing to assess a bicycle lane's environmental and economic viability. Life cycle assessment and life cycle costing are tools used to analyze environmental impact and cost during the life cycle of a product or service. The scope of this study covers the processing of raw material acquisition, transportation, construction, use, and disposal. The functional unit set for this study is the use of a bicycle lane for one year. The environmental impact examined is greenhouse gas emissions along the product's life cycle (the so-called "carbon footprint").

According to the results, approximately 0.2 million tons of carbon dioxide equivalent of carbon footprint could have been reduced in 2020 had a bicycle lane been installed. The use phase plays the leading role in reducing carbon footprint. The reduction in environmental impacts is due to reduced fuel consumption by cars and motorcycles when bicycles are used. Even though a low rate (26%) of road users, who participated in this research, were willing to ride bikes had a bicycle lane been provided, a considerable amount of environmental impact could still have been reduced.

The carbon footprint expected to be reduced in a year is valued at about 4.7 million baht of carbon credit. In comparison, the life cycle cost of bicycle lanes for one year is approximately 3.7 million baht. Furthermore, it is anticipated that had a bicycle lane been installed since 2015, the city would have reduced overall carbon footprint emissions by more than 1.15 million tons of carbon dioxide equivalent by 2020. Therefore, the results of environmental impact and cost assessment from this study are helpful for urban environmental management.

Indonesia's economic growth is estimated to be driven by high levels of consumption which lead to large amounts of waste. Education is required to raise environmental awareness among the population as it is one of the ways to overcome the waste issue, especially in urban areas, which are the engines of economic growth. This study aims to determine whether the higher levels of education have a greater impact on citizens regarding environmental concerns such as littering.

 The study took logistics regression on the primary data survey from 7 cities (Jakarta, Jambi, Muaro Jambi, Ambon, Padang, Surabaya, and Tasikmalaya) in Indonesia during 2019-2021. The survey includes 563 observations on the household level, involving a total of 2,349 respondents. The logistic regression predicts the likelihood of urban citizens to litter, given their socio-economic backgrounds and existing littering behavior and environmental awareness.

This study found that education did not affect decreasing the value of littering behavior as expected since it is estimated that an increase of 1 year in school will increase the probability of littering by 0.0189. Formal education is not enough to decrease the probability of littering behavior on the individual level. In contrast, informal education taught on keeping a clean environment matters is better than conventional formal education. Besides that, having self-initiative on environmental caring and good habits from childhood will decrease the probability of littering on an individual level. An individual has a self-initiative, the probability of littering will be 0.1732 times lower than those who do not have self-initiative. This study also found that per capita income and per capita expenditure in big cities in Indonesia ranged between USD 156,903 and USD 116,857. These economic factors affect the behavior of citizens not to litter. The per capita expenditure increasing by USD 1 per person per day will decrease the probability of littering by -0.0468. However, these factors are not enough to minimize the littering behavior since the disposal place availability becomes another keys factor in decreasing littering behavior on urban citizens.

 The government should also focus on building citizens' behavior regarding waste management awareness especially building good habits since childhood and individual initiative, simultaneously implementing the programs to reduce waste production.

Although the characteristics food waste have been well studied, some of the problems associated with result reporting have not been addressed. The related data are usually reported by referring to the global statistics, using the empirical models, and performing the laboratory analysis. The aims of the current study were to analyze the municipal food waste characteristics (including physical, proximate, ultimate and heating value analysis), monitor the differences among the laboratory methods, and highlight the significant differences among the food waste characteristics more accurately.

Sampling was performed weekly at a disposal site located in Sari, Mazandaran, Iran. Food waste was extracted from the municipal solid waste samples. Moisture content, pH, organic matter, ash content, organic carbon, carbon to nitrogen ratio, low heating value and chemical equation of the waste were determined and compared by statistical indices.

The results showed no significant difference between proximate analysis and global statistics for sampling including organic matter and moisture content. In ultimate analysis, statistical investigation of the laboratory results showed that Walkley and black, Kjeldahl, and dry ashing/ion chromatography methods had more accuracy compared to determination by elemental analyzer which puts direct impact on extracted chemical equation. In addition, heating value investigation by empirical models based on proximate analysis (13.6 MJ/kg) was closer to the bomb calorimeter results (13.4 MJ/kg) in average. However, the models developed based on ultimate analysis, including Dulong, Steuer, and Scheurer-Kestner, had a lower accuracy (with higher heating value of 1.4 to 5 MJ/kg). Surveying the reliable sources highlighted the gap in extracted chemical equation and heating value of the food waste with real amount. These findings provided appropriate information about solid waste management and characterization.

Investigation of the gap among laboratory methods revealed that determination method was a key factor in accurate characterization of food waste. Thus, without using the most accurate laboratory methods, the implementation of waste management plans would face major problems.

Safeguarding water resources became a major concern in many parts of the world as it aims to provide safe and healthy water for humans. Water quality monitoring is a popular tool in ensuring water quality is safe and within the allowable limits and standards for the health of the community. To provide interventions and strategies for the rehabilitation, a water quality monitoring plan was conducted to describe the water quality and the classification of the river.

This study conducted an environmental analysis to determine existing conditions and processes in the surrounding environment such as the land use, drainage pattern, reconnaissance survey of the river, and a key interview to describe the barangay profile and the community's water use and practices. The water quality monitoring covers the evaluation of ten water quality parameters: temperature, pH, dissolved oxygen, total dissolved solids, total suspended solids, phosphate, nitrate, oil and grease, chloride, and E. coli.

Results of the study presents the water quality against the ten water quality criteria. Phosphate measured on four stations ranges between 2.40-4.50 mg/L exceeding the allowable 0.50mg/L; the oil and grease exceeds the standards 2 mg/L with measured values of 2.40-4.60 mg/L in stations 2, 3, and 4; while measured chloride in all stations prove that the water is salty with values exceeding the freshwater requirement of 250mg/L; and the measured TSS in stations 2, 3 and 4 ranges from 32.30 to 49.3 mg/L exceeds the standards of 30mg/L.  E. coli was also detected in water samples collected in all sampling stations. The computed water quality index of 39.02 described water as poor, always impaired, and threatened by the surrounding environment.  

The measured concentrations for phosphate, oil/ grease, chloride, and TSS exceeds the water quality requirement suggesting that the water is contaminated. The E. coli detected in all water samples, further recommends prohibition of recreational activities to avoid accidental intakes and skin contact on the polluted water.  The existing activities in the surrounding residential, commercial and agricultural areas contributed to water contamination as aggravated by the unreliable drainage system, absence of proper sanitation facilities, and collection and disposal behavior of the community. From this, a scientific basis can be drawn on how the river can be rehabilitated and protected and serve as guide for policymakers and water managers on implementing strategies to achieve sustainable water resources.

The effect of infrastructure equipment is taking a toll on the health and economic well-being of residents all around the world. This is mainly because it contributes to ambient air pollution, noise, and vibration in the surroundings.  The study aimed at analyzing the effects of the road infrastructure equipment on the surroundings in Uganda. The emissions of carbon dioxide, carbon monoxide, nitrogen dioxide, hydrocarbons, and particulate matter were analyzed.

Six road infrastructure equipment were sampled consisting of an excavator, roller, grader, concrete mixer, tamper, and wheel loader, obtained from a case study project in Kampala city, Uganda. The diesel exhaust air emissions were computed and analyzed using the emissions rate equation model for non-road equipment, developed by Environmental Protection Agency.  This was based on the horsepower and power rating of the equipment. Noise and vibrations levels were obtained using a sound level meter, seismometers, and accelerators, while following the National Environment Regulations.

The greenhouse gas of carbon dioxide was the most predominant accounting for 84.1 percent of the total emissions. The grader was the highest emitter of this greenhouse gas, at 1,531.5 g/h, representing 37.1%. The lowest air pollutant emission was nitrogen dioxide at 1.43 g/h for the concrete mixer, representing 1.4%.  Overall, the equipment emitted more greenhouse gases than air criteria pollutants at 88.8% and 11.2% respectively. The highest criteria air pollutant was particulate matter at 100.5 g/h, emitted by the grader.  Most of the emissions met the standards stipulated by Environmental Protection Agency, for reducing emissions back to the environment, except particulate matter. However, the concentrations of some pollutants like carbon monoxide and nitrogen dioxide did not satisfy the limits required for ambient air quality that is safe for workers. All the equipment had noise levels way above the recommended 70.00 decibel, except for the wheel loader. Only the excavator produced vibrations higher than permissible vibration limit by 4%.

The criteria air pollutants of carbon monoxide, nitrogen dioxide, and particulate matter emitted by the equipment were all not safe to the workers. They exceeded the permissible limits of 50 ppm, 5 ppm, and 0.02 g/kW/h respectively. This partly shows why ambient air pollution had been reported in urban centers in Uganda. The study shows the need for strengthening the regulations and monitoring of the construction equipment being used, in order to protect the surroundings.

Sand and gravel product plants are among the significant sources of dust pollutants. This study was conducted to estimate dust concentrations released from these plants in a mineral complex in the southwest of Tehran.

Initially, the amount of silt and moisture content of the samples taken from these plants were determined according to the American Society for Testing and Materials C136 and D2216 methods, respectively. Accordingly, the rates of particulate matter emissions from these plants were determined by the AP-42 dust emission estimation methods published by the United States Environmental Protection Agency. Next, a Gaussian model was used to estimate the particulate matter concentrations in the surrounding residential areas. Finally, the simulated concentrations were compared with the United States Environmental Protect Agency and World Health Organization standards.

Results showed that hauling operations, with producing 70%, 86%, and 90% of total PM2.5, PM10 and total suspended particulates, respectively, were the major sources of dust emission in the sand and gravel product plants. The lowest dust emission was related to stockpiling handling, producing 0.24%, 0.33%, and 0.16% of the total PM2.5, PM10 and total suspended particulates. The results of the presented model indicated that 24-hour average concentrations of PM2.5, PM10, and total suspended particulates produced by mining activities were about 36, 183, and 690 µg/m3 in the working zone and less than 30, 100, and 400 µg/m3 beyond the mineral complex boundary, respectively. Thus, annual average dust concentrations were negligible. The concentrations of PM2.5 and PM10 produced by these plants in the mineral complex ambient air were higher than the standard average values recommended by the United States Environmental Protect Agency and World Health Organization. However, the concentrations of PM2.5 and PM10 from these plants in the residential areas around the complex, were below the standard limits proposed by the Environmental Protection Agency.

Sand and gravel mining activities increased the concentrations of particulate matter in the air of the surrounding areas and, to some extent, farther cities. PM2.5 and PM10 resulting from the sand and gravel mining activities could damage the workers in the mineral complex. They exceeded the 24-hour average permissible limits proposed by the United States Environmental Protection Agency about 1 and 33 µg/m3, respectively. This study showed the necessity of changing the industrial policies adopted to decrease dust emission rates. The results of this study can help the air pollution experts develop proper strategies for improving the air quality in the vicinity of surface mines.

The amount of agricultural waste generated by agro-based industries such as palm oil, rubber, and wood processing plants have more than tripled. Selangor, Perak, and Johor account for 65.7 percent of the total number of recognised pollution sources in the manufacturing and agro-based sectors. Livestock dung is another major cause of pollution, contributing significantly to increase pollution levels in the environment. Large portion of agro-industrial waste is untreated and unused, it is frequently disposed of by replicating or dumping then again off the cuff landfilling.  These untreated wastes wreak havoc on natural change by releasing ozone-depleting chemicals. Aside from that, the usage of fossil fuels is also leading to an increase in ozone-depleting compounds. Agro-waste is a huge environmental hazard in the current epidemic situation. The management of agro-waste and the conversion of agro-waste into a usable product through the application of biotechnological technologies in agriculture are receiving a lot of attention in today''s world. Solid state fermentation is the finest approach for converting agro-waste into valuable bio products among biotechnological instruments.  Various agro-wastes such as wheat straw, barley straw, cotton stalks, sunflower stacks, and oil cakes from various agriculture goods, as well as major horticulture wastes such as apple, mango, orange peels, and potato peels, were used to create beneficial products in this review.  All aspects of the production of industrial products from various agro-waste by using microorganisms such as Amycolatopsis Mediterranean, Xanthomonas campestries, and Aspergillus niger producing biopolymers such as polysaccharides, similar to starch, cellulose, agar, hemi-celluloses, gelatin, alginate, and carrageenan are covered in the current revels. Yeasts and cyanobacteria are commonly employed to make bio-lipids, whereas Bacillus species are utilised to make proteins and bio-enzymes. Cucumber and orange strips, on the other hand, have recently been employed to create proteins and bio-enzymes.  As a result, this review covers the many forms of agro-wastes and their by-products as well as biotechnological technologies used to treat them.