Environments, Volume 9, Issue 12 (December 2022) – 10 articles

Climate warming threatens the future sustainability of mountains, and tropical mountains are particularly threatened with loss of biodiversity and associated ecosystem services. Conservation biologists increasingly turn to habitat suitability models to guide the establishment and assessment of protected area networks to protect the highest number of species, yet this focus often neglects the values, attitudes, and beliefs of the people living around protected areas. If we consider protected areas as dynamic social–ecological systems, habitat suitability modeling for conservation planning must pay greater attention to the role of biocultural diversity, rather than biodiversity alone. Here, we describe a conservation assessment of the Afroalpine grassland ecosystem in the northern highlands of Ethiopia. We use a cultural keystone species known as guassa grass (Festuca macrophyhlla) to focus our modeling efforts and evaluate the potential distribution of this endemic species in relation to current national and community-based protected areas. Our model performed highly according to the area under the curve (AUC = 0.96), yet nearly 80% of highly suitable guassa habitat falls outside the range of our training data and thus must be interpreted conservatively. We found that guassa grass distribution is primarily limited by low mean temperature in the warmest quarter (BIO10, 36.7%), high precipitation in the wettest quarter (BIO16, 21%), and low precipitation in the driest quarter (BIO17, 15.6%). As climate change causes rapid warming at high elevations and alters rainfall patterns in the Ethiopian highlands, we urge managers to carefully monitor the changing populations of guassa grass to evaluate whether the species is experiencing an extinction debt. We also recommend four additional areas as potential community-based conservation areas, with government and NGO support for peer-to-peer communication networks. Spatially explicit modeling may be a valuable tool to determine whether these existing and proposed protected areas can sustain future populations of guassa grass. Full article

Groundwater of northern Mexico contains high concentrations of geogenic fluoride (F⁻), a contaminant known to affect human health. The origin of F⁻ in groundwater in this region has been related to the weathering of rhyolite and other volcanic rocks present in the alluvium. However, the relationship of F⁻ concentration to water depth has not been established. F⁻ concentrations, pH, and total dissolved solids (TSD) were determined for 18 wells within the Meoqui-Delicias aquifer in 2021. The F concentrations varied between 0.62 mg L⁻¹ and 4.84 mg L⁻¹, and 61% of the wells exceeded the 1.5 mg L⁻¹ guideline. F⁻ concentrations did not correlate to TDS but correlated to well depth (r = −0.52, p < 0.05). Because of the less-than-strong correlation coefficient value obtained, a diagram of F⁻ concentrations vs. well depth was constructed. The diagram showed a distinct enrichment of F⁻ in shallow wells, suggesting that groundwater residence time and evaporation may be important factors in explaining the F⁻ content within the aquifer. This pattern was confirmed after plotting 2003 and 2006 data for the same wells. These findings are important to better understand the distribution of F⁻ in neighboring alluvial aquifers as well as in alluvial aquifers elsewhere. Full article

Soil plays an important role in the accumulation and transport of potentially toxic elements (PTEs), from surface into aquifer. PTEs can get to the environment naturally, but also from different kinds of contamination sources. In this study, a soil profile located in the vicinity of well field Petruševec, one of the most important well fields related to the public water supply of the City of Zagreb, was analyzed. The main aim of this study was to determine soil properties which can influence retention/mobilization of Ni and Cr in alluvial soil, as well as to define their origin in the investigated soil profile. Results suggest that Cr is geogenic, while Ni is probably of dominantly anthropogenic origin. Observed concentrations, enrichment factors and I_geo values showed no enrichment for Cr, while for Ni, they showed minor to very severe enrichment, i.e., that in some soil horizons, moderate to strong pollution exists. Evaluation of wind directions and location of possible contamination sources that prevail in the study area suggest that Ni can come by aerodeposition from different sources. Results showed that mineral composition can have important influence on retention of analyzed PTEs. Soil horizons, which have very high concentrations of Ni, in general have higher proportion of clay minerals, especially chlorites, as well as Fe oxyhydroxides which can act as an adsorption phase for the investigated PTEs. Results suggest that more detailed research about the investigated PTEs presents a necessity if measures for soil and groundwater protection want to be effectively implemented. Full article

Graphene-oxide-based metal hybrids (GM) are used for the rapid and efficient reduction and removal of toxic adulterants in the environment. The exceptionally high specific surface area, versatile surface chemistry, and exceptional customization efficiency of graphene oxide nanosheets combined with the adaptable chemistry of metal nanoparticles enable the formation of GM hybrid nanocomposites. However, little is known about the architecture of GM nanocomposite engineering, interaction mechanisms, and environmental compatibility. This review aims to describe the environmental performance of graphene oxide–metal hybrids for the removal of environmental pollutants, carbon capture, EMI shielding efficiency, and microbial elimination of engineered graphene oxide composites anchored with metal particles. We also developed an essential link between the material properties of GM nanohybrids and their performance, which identified the fundamental parameters that influence the contaminant removal capability and EMI resistance efficiency. The influence of the thermodynamic parameters of GM on the adsorption of radioisotopes, heavy metals, organic pollutants, and dyes was considered. Finally, we comment on the remaining challenges and provide suggestions for future developments in this field. Full article

This paper reported a study based on the application of SWIR (shortwave infrared) spectroscopy to assess the presence of brominated flame retardants (BFRs) in plastic scraps coming from an e-waste stream composed by CRT (i.e., cathode-ray tube) monitors and televisions. An X-ray fluorescence (XRF) analysis was performed on plastic scraps to determine the presence and content of bromine (Br). The presence in plastic waste-flow streams, fed to or resulting from a recycling process, of individuals characterized by high concentrations of Br does not allow their use as secondary raw materials, imposing the need for an ad hoc separation processes. Chemometric methods were adopted for setting up models able to discriminate Br content. In more detail, principal component analysis (PCA) was used as an exploratory tool, while partial least squares (PLS) and locally weighted regression based on PLS regressions (LWRPLS) were used as multivariate regression models to test the ability of the spectra to predict Br content. The LWRPLS, showing an R_p² of about 0.9, demonstrates the ability of this algorithm to establish a good correlation between the spectral signatures of plastic scraps and their Br content. Full article

The inter-row soils in conventionally run citrus orchards in Eastern Spain lose fertility, either physically, chemically, or biologically, as a consequence of machinery traffic and the use of herbicides. In order to regain inter-row soil fertility, two grass-cover management alternatives to the commonly used herbicide-kept bare management, namely, spontaneous plants and fescue, were established and left for four years until their effects on several physical, chemical, and biological parameters were monitored for two years more. The fescue ground cover exhibited lower average and maximum soil temperatures due to higher evapotranspiration rates but also higher annual soil water content on average and, additionally, higher rhizodeposition. Despite the fact that these new beneficial conditions helped enhance the soil’s biological fertility under fescue, the physical or chemical fertilities did not improve and neither did the organic carbon (SOC). The spontaneous plants also enhanced the biological fertility, but in this case, beneficial conditions were reflected by improvements in the chemical fertility, particularly the exchangeable potassium, and in the physical fertility by increasing the surface hydraulic conductivity and decreasing the bulk density. In the inter-rows of this citrus orchard, a seeded grass cover does not seem able to provide any soil fertility enhancement in comparison to a spontaneous one; rather the opposite. However, a lack of natural or man-driven nitrogen inputs poses a constraint to SOC gains. For this aim, the annual surface application of organic nitrogen-rich materials or even better, the fostering of N-fixing organisms would be recommended. Full article

Surface water samples were collected using a low-tech aquatic debris instrument (LADI) at six nearshore locations on the north and northwestern coasts of Iceland to investigate the prevalence of mesoplastic (5–10 mm) and microplastic (0.3–5 mm) in the region. This sampling strategy involved sampling each transect three times for a total of 18 samples collected in order to assess uncertainties related to heterogeneous distribution of plastic in surface waters. Samples in all six nearshore locations contained meso- and/or microplastic, though concentrations were highly variable. Visual, physical, and FTIR analyses were performed on 71 suspected plastic particles collected, confirming and identifying 40 of those particles as one of six types of plastic: polypropylene (PP), polyethylene (PE), high-density polyethylene (HDPE), polyester, low-density polyethylene (LDPE), and polyvinyl chloride (PVC). Lines originating from fishing gear were the most prevalent types of plastic detected across the samples. This study is among the first to quantify and identify microplastic particles collected in Icelandic nearshore surface waters. Full article

Low-cost techniques, such as mid-infrared (MIR) spectroscopy, are increasingly necessary to detect soil organic carbon (SOC) and nitrogen (N) changes in rangelands following improved grazing management. Specifically, Adaptive Multi-Paddock (AMP) grazing is being implemented to restore grassland ecosystems and sequester SOC often for commercialization in C markets. To determine how the accuracy of SOC and N predictions using MIR spectroscopy is affected by the number of calibration samples and by different predictive models, we analyzed 1000 samples from grassland soils. We tested the effect of calibration sample size from 100 to 1000 samples, as well as the predictive ability of the partial least squares (PLS), random forest (RF) and support vector machine (SVM) algorithms on SOC and N predictions. The samples were obtained from five different farm pairs corresponding to AMP and Conventional Grazing (CG), covering a 0–50 cm soil depth profile along a latitudinal gradient in the Southeast USA. Overall, the sample size had only a moderate influence on these predictions. The predictive accuracy of all three models was less affected by variation in sample size when >400 samples were used. The predictive ability of non-linear models SVM and RF was similar to classical PLS. Additionally, all three models performed better for the deeper soil samples, i.e., from below the A horizon to the –50 cm depth. For topsoil samples, the particulate organic matter (POM) content also influenced the model accuracy. The selection of representative calibration samples efficiently reduces analysis costs without affecting the quality of results. Our study is an effort to improve the efficiency of SOC and N monitoring techniques. Full article

Compelling evidence demonstrates links between greenspaces and human well-being. However, the existing evidence has a strong bias towards high-income countries. Rapidly urbanising cities in low- and middle-income countries (LMICs) remain largely unexplored. The rising prevalence of mental disorders in LMICs highlights the need to better understand the role greenspaces can play in mitigating mental ill-health. We carried out a cross-sectional household survey to investigate links between measures of greenspace exposure and human well-being, and tested pathways that could underpin any such interactions in Kathmandu, a rapidly urbanising low-income city in Nepal. While we found no consistent relationship between measures of greenspace exposure and human well-being outcomes, we provide evidence that greenspaces in a rapidly urbanising low-income setting could be important for encouraging physical activity and fostering social cohesion. Further, we revealed that a medium perceived variety of biodiversity attributes of greenspaces was associated with the highest levels of physical activity and social cohesion. Our findings support the view that greenspaces in LMICs may be less likely to provide well-being benefits. Moreover, medium levels of biodiversity may best promote well-being in LMICs. More research is needed to understand how greenspaces can support human well-being in LMICs. Full article

A micro segmented-flow approach was utilized for the isolation soil bacteria that can degrade synthetic polymers as polyethylene glycols (PEG) and polyacrylamide (PAM). We had been able to obtain many strains; among them, five Achromobacter spanius strains from soil samples of specific sampling sites that were connected with ancient human impacts. In addition to the characterization of community responses and isolating single strains, this microfluidic approach allowed for investigation of the susceptibility of Achromobacter spanius strains against three synthetic polymers, including PEG, PAM, and Polyvinylpyrrolidone (PVP) and two organic solvents known as 1,4-dioxane and diglyme. The small stepwise variation of effector concentrations in 500 nL droplets provides a detailed reflection of the concentration-dependent response of bacterial growth and endogenous autofluorescence activity. As a result, all five strains can use PEG600 as carbon source. Furthermore, all strains showed similar dose-response characteristics in 1,4-dioxane and diglyme. However, significantly different PAM- and PVP-tolerances were found for these strains. Samples from the surface soil of prehistorical rampart areas supplied a strain capable of degradation of PEG, PVP, and PAM. This study demonstrates on the one hand, the potential of microsegment flow for miniaturized dose-response screening studies and its ability to detect novel strains, and on the other hand, two of five isolated Achromobacter spanius strains may be useful in providing optimal growth conditions in bioremediation and biodegradation processes. Full article