Land use planners require up-to-date and spatially accurate time series land resources information and changing pattern for future management. As a result, assessing the status of land cover change due to population growth and arable expansion, land degradation and poor resource management, partial implementation of policy strategies, and poorly planned infrastructural development is essential. Thus, the objective of the study was to quantify the spatiotemporal dynamics of land use land cover change between 1995 and 2014 using 5 multi-temporal cloud-free Landsat Thematic Mapper images. The maximum likelihood (ML)-supervised classification technique was applied to create signature classes for significant land cover categories using means and variances of the training data to estimate the probability that a pixel is a member of a class. The final Bayesian ML classification resulted in 12 major land cover units, and the spatiotemporal change was quantified using post-classification and statistical change detection techniques. For a period of 20 years, there was a continuously increasing demand for arable areas, which can be represented by an exponential growth model. Excepting the year 2009, the built-up area has shown a steady increase due to population growth and its need for infrastructure development. There was nearly a constant trend for water bodies with a change in slope significantly less than +0.01%. The 2014 land cover change statistics revealed that the area was mainly covered by cultivated, wood, bush, shrub, grass, and forest land mapping units accounting nearly 63%, 12%, 8%, 6%, 4%, and 2% of the total, respectively. Land cover change with agro-climatic zones, soil types, and slope classes was common in most part of the area and the conversion of grazing land into plantation trees and closure area development were major changes in the past 20 years.

Land use, air pollution, and climate change are closely related. This article analysed the contributions of urban land use to ambient air quality in Bahir Dar and Hawassa cities. A total of 32 geo-referenced locations, 16 each in Bahir Dar and Hawassa, representing different land uses, were assessed for carbon monoxide (CO), carbon dioxide (CO₂), and volatile organic compound (VOC). CO₂ concentration (ppm) for Bahir Dar and Hawassa ranged from 385.10 ± 15.34 ppm (recreational land use) to 555.50 ± 80.79 ppm (commercial land use) and 388.07 ± 19.79 ppm (recreational land use) to 444.50 ± 54.05 ppm (industrial land use), respectively, whereas mean concentration of CO was 0.01 ± 0.01 ppm (recreational land use) to 2.59 ± 0.69 ppm (circulation land use) and 0.12 ± 0.11 ppm (recreational land use) to 4.66 ± 1.41 ppm (circulation land use), respectively. The VOC values were 882.10 ± 147.05 ppm (residential land use) to 1436.00 ± 932.06 ppm (institutional land use) and 1377.30 ± 233.23 ppm (institutional land use) to 2132.33 ± 739.71 ppm (circulation land use). Inadequate monitoring, occasioned by dearth of equipment, poor urban management strategy, fossil fuel combustion, and aged vehicles were some of the factors responsible for the observed concentrations. Elevated levels of CO, CO₂, and VOC in the atmosphere have a significant impact on global warming, with adverse effects on human health. Capacity for monitoring, analysis, reporting, and validation of air quality data in the cities should be strengthened.

The quantification of the UV characteristics of smoke aerosols is valuable to UV Index forecasting, air quality studies, air chemistry studies, and assessments of the impacts on regional and global environmental changes. The wavelength dependence of the light absorption by smoke aerosol has been researched throughout the UV and visible spectral region and varies with fire type and aerosol composition. An objective of this study is to investigate the spectral optical properties (eg, extinction coefficient, single-scattering albedo, and asymmetry parameter), UV actinic fluxes, and radiative forcing of smoke of different fire regimes. The smoke aerosol information (eg, simulated smoke fields from biomass burning emission and vertical distribution of the mass concentration of smoke components) from WRF-Chem is used to distinguish 2 smoke types: flaming and smoldering. To compute the spectral optical properties for the fire regimes, the representative size distribution and spectral refractive index have been implemented into the Mie code, and the optical properties are used to run the tropospheric ultraviolet and visible radiative transfer model. We make comparisons between simulated model and measured actinic flux in the UV and visible spectra under smoke aerosol laden conditions. The WRF-Chem-SMOKE model simulates the smoke plume matched with fire locations and comparable aerosol optical depth (AOD) with satellite measurements. However, the correlation between the simulated and observed AOD is small, which implies that adjusting the fire size for the emission inputs and improving meteorological fields are required for further research. The smoke at selected locations reduces the UV actinic flux and increases the visible actinic flux above the plume at small solar zenith angles. The specific spectral response is dependent on the smoke type. Overall, the results of this investigation show that this approach is valuable to estimate the impact of smoke on UV and visible radiative fluxes.

This 3-year study (2015-2017) was designed to characterize benthic communities (macroinvertebrates) and physical habitat in an agriculturally dominated waterbody in the Central Coast area of California (Santa Maria River). Benthic communities as represented by various metrics that represent richness, composition, tolerance/intolerance and trophic measures were used as response variables for the various stressors described below. Concurrent water quality evaluations, physical sediment parameters (grain size and total organic carbon [TOC]), pyrethroids, bulk metals—including simultaneously extracted metals (SEM) and acid volatile sulfides (AVS) ratios—and nutrients were measured. The relationship of various benthic metrics to physical habitat metrics, pyrethroids, metals, nutrients and sediment characteristics was evaluated for the 3-year data set. Total physical habitat scores in this watershed were considered to be poor. Samples collected for various sediment chemistry measurements were from depositional areas (fine grain areas primarily silt and clay) where hydrophobic chemicals such as pyrethroids could be found if sources exist. Dominant benthic taxa collected were generally considered to be tolerant to moderately tolerant of environmental stressors and rated as impaired based on a benthic index. Potentially toxic sediment concentrations of arsenic, cadmium and nickel were reported at various sites based on a comparison with existing threshold effect levels. Pyrethroid concentrations interpreted by using a highly protective toxics units approach with a laboratory sensitive taxon (Hyalella) suggested potential toxicity at various sites. Nutrient concentrations could not be interpreted within the context of potential impairment because the State of California has not developed nutrient criteria. The results of the stepwise linear regression models comparing benthic metrics with all environmental variables showed that TOC was the most important variable shaping the benthic communities. In contrast, pyrethroids, metals and physical habitat were not shown to be significant factors shaping benthic communities. The summary multivariate canonical correlation analysis indicated that less stressed, more diverse benthic communities tended to be associated more with TOC-rich finer sediments and lower concentrations of phosphorous-based nutrients, and more stressed, less diverse benthic communities tended to be associated with less organically rich, somewhat less fine sediments and higher phosphorous concentrations.

Sources of soil contamination can exist in various types of conditions including in the form of semifluids. In this study, 3 different types of tropical plants, Acacia (Acacia mangium Willd), Mucuna (Mucuna bracteata DC. ex Kurz) and Vetiver (Vetiveria zizanioides L. Nash), were tested under different levels of soil-leachate conditions. The relative growth rate, metal tolerance, and phytoassessment of cadmium (Cd) and lead (Pb) accumulation in the roots and shoots were determined using flame atomic absorption spectrometry. Tolerance index, translocation factor, metal accumulation ratio, and percentage metal efficacy were applied to assess the metal translocation ability among all the 3 types of plants. Significantly higher (P < .05) accumulation of Cd and Pb was exhibited in the roots and shoots of all 3 plants growing under the soil-leachate conditions. However, negative growth performance and plant withering were observed in both Acacia and Mucuna with increased application of higher soil-leachate levels. Vetiver accumulated remarkably higher total concentration of Cd (116.16-141.51 mg/kg) and Pb (156.37-365.27 mg/kg) compared with both Acacia and Mucuna. The overall accumulation trend of Cd and Pb in the 3 plants growing under the soil-leachate conditions was in the order of Vetiver > Acacia > Mucuna. The findings of the study suggest that Vetiver has great potential as Cd and Pb phytoremediator in soil-leachate conditions.

Dispersal of airborne microorganisms is an important ecological process, resulting in the distribution of bacteria to all habitats on Earth. Investigation of this process is limited by the ability to collect uncontaminated high-altitude microbial samples for use with next-generation sequencing approaches. Here, we describe the design of a Remote Airborne Microbial Passive sampling system. Troubleshooting experiments demonstrate that the samplers collect adequate DNA for bacterial 16S rRNA (ribosomal RNA) amplicon–based Mi-Seq sequencing at 2 and 150 m from the ground. When samplers are closed, they retain only a low number of sequences, and may be used as a negative control. We also demonstrate that the optimal amount of collection dishes to include in the sampler is 8, and that freezing collection dishes at −80°C is an alternative to immediate DNA extraction. Samplers may be used to address a variety of ecological and human health–related questions.

The importance of adequate analysis of climatological data cannot be overemphasized as it helps in making vital decision relevant to agricultural practices. Thus, this study gave an overview on nonparametric trend technique for determination of the onset and cessation of rainfall changes over agroecological zones. The rainfall analysis technique reviewed in this study is useful for making decisions at the farm and regional levels and for establishing agroclimatic maps and models for any nation. The study helped to provide baseline information needed for accurate agroclimatic (rainfall) data analysis to enhance agriculture and therefore help farmers in proper planning before and during the growing seasons.

The hydrological response of catchments is determined by the combined hydropedological response of hillslopes. In the Ntabelanga area, 56% of the households use pit latrines and untreated drinking groundwater supplies. Soil morphological properties and their spatial distribution were used to conceptualize hillslope hydropedological behaviour to determine the fate of Escherichia coli and faecal coliform from 4 pit latrines. Four hillslopes below the pit latrines (MT1, MT2, MT3, and MT4) occur above first-order tributaries to the Tsitsa River, South Africa, were studied. The studied sites are adjacent to the proposed footprint of a planned multi-purpose storage dam, Ntabelanga. Apedal soils, without morphological evidence of saturation, dominated the upper slopes of MT1 and the lower slopes of MT2, thus promoting vertical drainage. Hydromorphic properties were observed at the soil/bedrock interface in the lower parts of MT1 and the entire slope of MT4. This signifies slowly permeable bedrock and the occurrence of lateral flow. High clay contents and strong structured soils were dominant in MT3, indicating slow internal drainage with a large adsorption capacity. The conceptual models derived from morphological properties were verified using soil physical and organic pollutant measurements. In general, hydraulic conductivity values support the interpretations made from soil morphological measurements. Faecal coliforms and E coli bacteria counts were mostly <1 CFU/g soil in MT1, MT2, and MT4; hillslope migrations were detected in MT3 posing pollution risks.

Daytime urban heat island effects can be weak compared to night time and even reversed (as in the case of cool islands, where urban locations display lower temperatures than at a rural site), mostly due to shading effects from buildings, vegetation, and other possible obstructions. The study of the relationship between the sky-view factor, an indicator of urban geometry in terms of sky openness, and urban heat island intensity generally focus on night time periods; only a few report on the daytime effect of the SVF. Such effect will also vary according to background atmospheric conditions of the period of measurements. This article is a commentary on a recent publication by the authors on a study of diurnal intra-urban temperature differences in a location with Koeppen’s Cfb climate.

Dyes are a major cause of concern nowadays as large quantities are being released into water bodies causing pollution. In this article, modified chitosan (sulphate crosslinked) has been studied for the removal of Congo red (a benzidine-based anionic diazo dye) which is a toxic dye introduced into water bodies from textile industries. Sulphate-crosslinked chitosan (SCC) was prepared in the laboratory and the characterization of SCC was done by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Various parameters such as pH, contact time, adsorbent dosage, and concentration of adsorbent were optimized. The adsorption capacity was determined at pH 3.0, at which the percentage recovery was about 90% and followed Freundlich adsorption isotherm with an adsorption capacity of 91.8 mg/g. The adsorption followed pseudo-second-order kinetics. Various thermodynamic parameters were also determined for the change in adsorption with temperature. The SCC was regenerated with NaOH and showed good recycling capacity. The modified chitosan was applied for the removal of Congo red from industrial wastewater samples (spiked).

This work evaluates the potential of Adesmia atacamensis, an endemic species from the North of Chile, in phytoremediation processes of copper mining tailings. The selection of this species was based on the fact that its presence was found in 4 copper mining companies that are close to each other, its endemic quality, and its great capacity to adapt to the adverse climatic conditions of the sector of the project, characterized by having a semi-arid climate. In the experiment, the concentrations of 5 metals of environmental connotation for the country’s mining were measured: Cu, Fe, Cd, Pb, and Zn; however, given the small concentrations in Cd, these could not be measured by the team. The applied experimental design quantified the variation of bioconcentration and translocation factors (BCF and TF) for the following treatments: (1) tailing control without amendment (T0), (2) tailing plus 4% CaCO₃ + 3% vermicompost (VC), and (3) tailing + 8% CaCO₃ + 6% VC. In addition, for treatments T1 and T2 (T0 was not considered as it is the control treatment), the following levels of mycorrhiza were considered: 0, 10, 15, and 20 g m⁻². The Baker and Brooks criteria and the BCF were used to evaluate the species as hyperaccumulators. Regarding the first criterion, high concentrations of copper were found in the shoots (shoots) of the specimens, which generally exceeded 1000 mg kg⁻¹, with an average of 1513 mg kg⁻¹, which allowed classifying the species as a copper hyperaccumulator; however, when compared with the BCF criterion, given that all the values were less than 1, they indicated that the species was an excluder of all the evaluated metals. Given the high concentrations of metals in the tailings, in this work, the plant has been considered as a hyperaccumulator of copper. Another indicator was the TF, which, for all experiments, resulted in a value greater than 1 for Fe, Pb, and Zn, which shows that A atacamensis translocates effectively these metals from the roots toward the aerial part and, therefore, presents the potential to accumulate metals in the aerial part. Regarding the treatments carried out, no significant impact was detected.