Open-pit mining generates airborne particulate matter that can accumulate on vegetation and potentially influence herbivore foraging behaviour. However, the relative importance of foliar particulate deposition compared with habitat quality in driving habitat selection remains poorly understood in arid ecosystems. We investigated whether semi-quantitative foliar particulate indicators derived from scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS) were associated with habitat patch selection by cattle (Bos taurus), sheep (Ovis aries), goats (Capra hircus), and springbok (Antidorcas marsupialis) in an arid shrub–grass savanna adjacent to an operational iron-ore mine in South Africa. Leaf-surface particulate signatures were quantified as elemental weight percentages (wt%) of aluminium (Al), magnesium (Mg), and silicon (Si), and compared between preferred and avoided habitat patches using stratified Wilcoxon (van Elteren) tests with animal identity treated as the stratification variable. Habitat-quality variables were subsequently evaluated alongside the measured foliar particulate indicators. Elemental signatures showed substantial overlap between preferred and avoided habitat patches. Although three element-by-growth-form comparisons were statistically significant, preferred patches consistently exhibited equal or higher elemental values than avoided patches, providing no evidence that the measured foliar particulate indicators were associated with habitat avoidance. In contrast, vegetation height and greenness showed stronger and more consistent relationships with habitat selection across species. These findings indicate that habitat quality outweighed the measured foliar particulate indicators in explaining grazer patch selection within this arid mining landscape. Because the SEM–EDS-derived elemental signatures cannot distinguish mine-derived particulates from natural background dust, these results should not be interpreted as evidence that mining-derived dust has no ecological effects. Rather, they demonstrate that the specific foliar particulate indicators measured in this study were poor predictors of observed habitat use, highlighting the need for future studies incorporating source-resolved dust measurements and quantitative particulate loading.
Chlorinated paraffins (CPs), complex polychlorinated alkanes, are persistent organic pollutants (POPs) of growing concern. They are used as flame retardants, plasticizers, and lubricants, and enter agroecosystems via wastewater irrigation, sewage sludge, atmospheric deposition, and industrial runoff, exhibiting strong sorption, long half-lives, and bioaccumulative potential. While short-chain CPs (SCCPs) are regulated under the Stockholm Convention, medium- and long-chain CPs (MCCPs, LCCPs) are increasingly detected in soils, sediments, and crops but remain poorly categorized for toxicity and environmental fate. Evidence indicates that CPs can alter soil microbial diversity, inhibit enzymatic activity, disrupt nutrient cycling, and accumulate in plants, posing risks of food-chain transfer and human exposure. However, significant knowledge gaps persist regarding their long-term ecotoxicological impacts, degradation and transformation processes, and interactions with soil organic matter that govern their mobility, persistence, and bioavailability. This review discusses the existing literature on CP occurrence, fate, and ecological effects in agricultural environments, emphasizing analytical techniques and monitoring approaches for assessing soil-plant-human exposure, and identifies key research needs. Addressing these gaps is essential for improving risk assessment, guiding regulatory development, and protecting soil health, crop productivity, and food safety. CPs represent a “silent contaminant” in agriculture, threatening soil health, crop productivity, and food safety. Future research should integrate advanced detection methods, pilot-scale remediation strategies, and comprehensive risk assessments to inform policy, protect vulnerable populations, and safeguard sustainable agricultural production.
Macroinvertebrates such as snails and crabs influence aspects of salt marsh structure and function through herbivory and bioturbation. However, the effects of physico-chemical variables and habitat composition on their abundance and distribution remain underexplored. This study examined the influence of environmental factors on snail and crab populations across salt marsh habitats in the Berg River Estuary on the west coast of South Africa, hypothesising greater abundance in the intertidal than in the supratidal zone, driven by salinity and elevation. Snail and crab abundance were assessed using manual counts in triplicate quadrats (10 & times; 10 cm for snails; 25 & times; 25 cm for crab burrows) across six transects. Physicochemical variables of sediment and groundwater were also analysed. Six snail species (Davisassiminea sp. 1, Davisassiminea sp. 2, D. capensis, D. globulus, Afrolittorina africana and Melanoides tuberculata) and one crab species (Hymenosoma orbiculare) were recorded. Crab burrow density differed significantly between habitats, with the highest abundance at creek edges (85.37 burrows m-2) and lowest in supratidal habitat (8.57 burrows m-2). Snail richness and abundance declined with elevation; Davisassiminea sp. 2 and D. capensis occurred only at creek edges. Habitat and environmental variables explained 32% of the variation in macroinvertebrate abundance, with sediment conductivity and organic content being key predictors. Generalised linear models indicated that species richness declined with increasing sediment redox potential (t = -2.25, p = 0.025), organic matter (t = -2.07, p = 0.040) and clay content (t = -3.07, p = 0.003). These findings highlight the influence of local environmental conditions in shaping and predicting species distributions under a changing climate.
Solid-state reaction (SSR) method was used to prepare undoped and Dy3+-doped magnesium cadmium pyrophosphate (MCP) nanopowders (NPs). The average crystallite size was determined using Scherrer’s technique and W–H plot method in the powder X-ray diffraction study. Further, Rietveld refinement was carried out using the GSAS-II software package with Cu Kα radiation (λ = 1.5418 Å). The surface morphology of the prepared samples shows a clustered pattern that resembles a stone-like structure in FE-SEM analysis. Raman spectral analyses confirmed the presence of the pyrophosphate groups, and FT-IR study was used to assess the vibrational modes of the samples. According to DRS study, optical bandgap values of the prepared samples are in the range 2.99–3.49 eV. The PL spectra of the samples exhibit emission at 574 nm when excited at 347 nm. The maximum emission intensity was observed at 574 nm for the 0.01
Industrial effluents from metallurgy, chemicals, and other sectors are major releasers of heavy metals polluting the environment. Within this study, chitosan (CS) and nanocellulose (NCs) were extracted from fish scales and coconut fiber, respectively, and co-precipitated in sodium alginate (ALG) solution to produce a biocomposite hydrogel (CS@NCs/ALG). The adsorptive efficiency of the new composite was determined for detoxification of 2 heavy metals (Hg2+, Zn2+) from aqueous solution. The main physicochemical properties of CS@NCs/ALG were characterized by application of spectroscopy (FTIR, XRD, SEM-EDX), with analytical methods including BET, TGA, pHPZC. The results show that CS@NCs/ALG exhibits a heterogenous and mesoporous structure with surface functional groups including -OH, -NH2, and -COOH groups. Removal tests indicated that the adsorption of these metals was strongly influenced by solution pH. Modelling of the adsorption results indicated best fits to the pseudo-second order kinetic and Langmuir isotherm models. High adsorption capacities (402.89 and 500.48 mg g− 1) were obtained for Hg2+ and Zn2+. Thermodynamic analysis revealed that the adsorption of both ions was thermodynamically favorable, spontaneous, and accompanied by decreased randomness. These findings demonstrate that the hydrogel composite has high adsorption potential and can be effectively applied for bivalent heavy metal detoxification from contaminated aquatic systems.
