AIMS Environmental Science最新文献

In 2019, Malaysia faced a deterioration of air quality due to transboundary haze, which brought negative implications, especially for public health. In light of the above scenario, continuous particulate matter (PM₁₀, PM_2.5 and PM₁) and meteorological parameters amid the haze period were taken to unravel the influence of haze on particulate matter variations and to investigate the association between particulate matter concentrations with meteorological parameters and fire hotspots in Kota Kinabalu, where it is rarely studied. Particulate matter and the meteorological parameters were monitored during the haze season, continuously from 21 August–30 September 2019, using AirMate, a ground-based air monitoring equipment. Air mass backward trajectories were simulated using the HYSPLIT Model, and fire hotspot data was obtained from the Greenpeace Global Fire Dashboard. The results showed increasing particulate matter concentrations during the haze period, with PM_2.5 exceeding the New Ambient Air Quality Standards (2020) on multiple days. For meteorological parameters, all parameters showed a significant weak positive relationship with respective particulate matter. However, the correlation between particulate matter and fire hotspots in Indonesia showed a moderate positive relationship. The backward trajectories simulated indicated the influence of south-westerly winds in transporting the pollutants from fire hotspots in the Indonesia region. Thus, we provide beneficial information about the impacted area during the 2019 transboundary haze episode, where the interactions between the particulate matter variations and the parameters studied were unraveled.

Customers' growing concern for environmentally friendly goods and services has created a competitive and environmentally responsible business scenario. This global awareness of a green environment has motivated several researchers and companies to work on reducing carbon emissions and sustainable supply chain management. This study explores a sustainable supply chain system in the context of an imperfect flexible production system with a single manufacturer and multiple competitive retailers. It aims to reduce the carbon footprints of the developed system through uncertain human learning. Three carbon regulation policies are designed to control carbon emissions caused by various supply chain activities. Despite the retailers being competitive in nature, the smart production system with a sustainable supply chain and two-level screening reduces carbon emissions effectively with maximum profit. Obtained results explore the significance of uncertain human learning, and the total profit of the system increases to 0.039% and 2.23%, respectively. A comparative study of the model under different carbon regulatory policies shows a successful reduction in carbon emissions (beyond 20%), which meets the motive of this research.

The "Trojan horse effect" of microplastics for organic and inorganic contaminants is an interesting topic. So far, the scientific community has focused on microplastics strictly as contaminants, but their role as vectors is still undefined. Adsorption of pollutants follows the Freundlich model by physisorption mechanism. Furthermore, ages and types of microplastics influence the adsorption of pollutants onto microplastics. Moreover, natural particles, like algae particles, present in the environment can interfere in the adsorption mechanisms. Due to their chemical composition of mainly O and N, it has been suggested that natural particles have a stronger adsorption affinity for some pollutants. Furthermore, microplastic's role as vector of pollutants into organisms is controversial. In fact, it has been suggested that the release is species-specific. In T. japonicus, accumulation of Hg loaded onto microplastics increased by 2.5 times, whereas a reduction of bioavailability of Hg was observed in R. lens.

Lychee plantation areas are typically located at varying elevations on mountains to ensure proper drainage. This placement has direct effects on stream and river water flows and consequently influences pesticide residue, water quality and aquatic biodiversity. This research aims to examine the relationships between cypermethrin residue, water quality and phytoplankton diversity in the lychee plantation catchment area in Phayao Province, Thailand, from January to May 2022. The study area was divided into six sampling sites. Water samples were collected for the investigation of cypermethrin residual, physicochemical and biological water quality parameters. The water quality index was used as an overall measurement of water quality. The study also examined the diversity of phytoplankton species and the relationship among cypermethrin residue, water quality and phytoplankton diversity were studied using canonical correspondence analysis. The findings revealed an increasing trend of cypermethrin residue, with the maximum concentration reaching 29.43 mg/L in March. The trend of decreasing water quality scores from Station S1 to Station S5 indicated the influence of land use changes and human activities, especially in the community area (S5), which was characterized by deterioration of water quality. A total of 174 phytoplankton species were categorized into 5 divisions, with Chlorophyta accounting for 61.49% of the total, followed by Bacillariophyta (28.16%) and Cyanophyta (6.32%). The highest Shannon's diversity index and evenness were observed at Stations S3 and S4, respectively. The canonical correspondence analysis revealed an interesting relationship among cypermethrin residue, ammonia nitrogen, chlorophyll a and three algal species: Pediastrum simplex var. echinulatum, Pediastrum duplex var. duplex and Scenedesmus acutus at Station S3. This research implies that pesticide residue and water quality have a direct impact on phytoplankton distribution, illustrating the environmental challenges that occur in various geographical areas. This information can be applied to assist in the development of future sustainable land use management initiatives.

The effect of biochar on hydrologic fluxes was estimated using a single hillslope version of a gridded soil moisture routing (SMR) model. Five grid cells were aligned linearly with varied slopes to simulate a small undulating hillslope with or without a restrictive layer beneath the soil profile. Biochar amendments (redwood sawdust and wheat straw biochar) at concentrations of 0%, 4%, and 7% were applied to the topmost grid-cell by mass of dry soil. Simulated streamflow hydrographs for restricted and non-restricted soil profiles were manually calibrated with measured Palouse River streamflow data. Evapotranspiration, percolation, lateral flow, baseflow, and streamflow were all modeled yearly. Two generally reported field capacities (FC) in literature at −6 and −33 kPa were considered to assess the effect of biochar. Field capacity considered at −6 kPa corresponds to higher moisture content, and hence higher moisture storage capacity between FC and permanent wilting point than at −33 kPa. At −6 kPa FC, biochar effectively increased evapotranspiration and reduced the lateral flow of the system. Increased soil porosity from biochar amendment enhanced the water holding capacity of the soil and plant available water. These mechanisms impacted the streamflow generated from the system indicating positive outcomes from biochar amendment in both restricted and non-restricted soil profiles. Biochar amendment showed an order of magnitude smaller effects with −33 kPa FC compared to −6 kPa FC; the increased porosity appeared to be less influential at lower field capacity values. Additionally, the results showed that the over-application of coarse biochar might negatively affect retaining soil moisture. These findings point to positive results for using biochar as a water management strategy if applied less than 7% in this study, but further exploration is needed to find the optimum level of biochar with different biochar and soil properties.