Many industrial by-products have been disposed along coastlines, generating profound marine changes. Phosphogypsum (PG) is a solid by-product generated in the production of phosphoric acid (PA) using conventional synthesis methods. The raw material, about 50 times more radioactive as compared to unperturbed soils, is dissolved in diluted sulfuric acid (70%) forming PG and PA. The majority of both, reactive hazardous elements and natural radionuclides, remain bound to the PG. A nonnegligible fraction of PG occurs as nanoparticles (<0.1 μm). When PG are used for e.g., agriculture or construction purposes, nanoparticles (NPs) can be re-suspended by Aeolian and fluvial processes. Here we provide an overview and evaluation of the geochemical and radiological hazardous risks associated with the different uses of PG. In this review, we show that NPs are important residues in both raw and waste materials originating from the uses of phosphate rock. Different industrial processes in the phosphate fertilizer industries are discussed in the context of the chemical and mineralogical composition as well as size and reactivity of the released NP. We also review how incidental NPs of PG impact the global environment, especially with respect to the distribution of rare earth elements (REEs), toxic elements such as As, Se, and Pb, and natural radionuclides. We also propose the application of advanced techniques and methods to better understand formation and transport of NPs containing elements of high scientific, economic, and environmental importance.

Increasing population growth and rise global energy petition have made congregation the requests of energy generation and safety a major challenge global. In another hand nanogeoscience is commencing to develop a viable remediation approach of attention in coal mine drainage (CMD) around spontaneous coal combustion (SCC). On the ecological context, nanophases (minerals and/or amorphous phases) are more reactive than bulk compounds, a property that powerfully influences the fate of pollutants in topsoils and drainages. In this work petrographic and geochemical investigations of selected CMD sediments were conducted. The substitution of As, Cd, Hg, and Se in pyrite was most apparent in the CMD sediments. The sampled CMD contained carbon nanotube (CNTs) structures and many others C-nanophases. The CNTs contained several elements, including Hg, Pb, F, Cl, and halogens. While CNTs are known to be produced from coal fires of varying ranks, this seems to be the first report of naturally occurring CNTs. This work also denotes the occurrence of historical NPs-locations in near vicinity to all other, as for illustration deposits of C-NPs and non-crystalline compounds appear only nanometers separately from each other on the contradictory sides of nonaltered amorphous phases. In addition, non-conventional sources, including CMD hosting elevated concentrations of Rare Earth Elements and Yttrium (REY), have been explored as attractive secondary sources for elements recovery. Consequently, in this study we investigate CMD from abandoned coal mines in the South America as a potential REY resource. It is suggested that more work is required on CMD and a few research areas are proposed for future research.

Pollution generated by hazardous elements and persistent organic compounds that affect coal fire is a major environmental concern because of its toxic nature, persistence, and potential risk to human health. The coal mining activities are growing in the state of Santa Catarina in Brazil, thus the collateral impacts on the health and economy are yet to be analyzed. In addition, the environment is also enduring the collateral damage as the waste materials directly influence the coal by-products applied in civil constructions. This study was aimed to establish the relationships between the composition, morphology, and structural characteristics of ultrafine particles emitted by coal mine fires. In Brazil, the self-combustions produced by Al-Ca-Fe-Mg-Si coal spheres are rich in chalcophile elements (As, Cd, Cu, Hg, Pb, Sb, Se, Sn, and Zn), lithophile elements (Ce, Hf, In, La, Th, and U), and siderophile elements (Co, Cr, Mo, Fe, Ni, and V). The relationship between nanomineralogy and the production of hazardous elements as analyzed by advanced methods for the geochemical analysis of different materials were also delineated. The information obtained by the mineral substance analysis may provide a better idea for the understanding of coal-fire development and assessing the response of particular coal in different combustion processes.

The present study is focused on the chemical and nano-mineralogical characterization of sludge from gold mine activities, in order to put forward diverse solution alternatives, where lack of knowledge has been found. The sample was collected from "La Estrella" mine of Suarez, located in Department of Cauca, south-west Colombia. The sludge micro-structure and chemical composition were analyzed using a high resolution transmission electron microscopy (HR-TEM) equipped with a dispersive X-ray detector (EDS). X-ray diffraction technique was employed to identify the mineralogical phases present in the sludge. Additional mineralogical characterization was done by using RAMAN spectroscopy. Main findings points to its potential to be used as a fertilizer, this is why, mine sludge contains macronutrients such as P, Ca and S, together with micronutrients like Cu. However, the presence of goethite could decrease the mobilization of nutrients to soils, thus additional alternatives, for instance, a mixture with humus or another material containing Humic Acids should be done, in order to minimizing its retention effect. Additionally, another possible uses to explore could be as construction and ceramic material or in the wastewater treatment for nutrient retention and organic material removal. Rutile (TiO nanoparticles) particles have been also detected, what could cause health concern due to its nanoparticle toxic character, mainly during gold extraction process.

Spontaneous coal combustion in the La Guajira coals was studied for the presence of carbon nanophases (e.g., carbon nanotubes), occurrence of rare earth elements (REEs) in them, and the probable mechanisms for concentration of these rare compounds. For this purpose, various techniques such as scanning electron microscopy (SEM), Field-emission SEM, transmission electron microscopy (TEM), high-resolution TEM, and focused ion beam (FIB) were used. The development and alteration of the nanoparticles by geo-processes during the early modification periods of coal combustion were explored. Certain types of carbon nanophases and REE compounds may constitute nanominerals and ultra-fine particles accumulated in the coal peat. Assemblages of these nanophases (crystalline and amorphous compounds), predominantly the clay-monazite relationship and its connection to tonsteins in the coal combustion zones in the east region of the coal mines studied in this work, indicate that the coal area was subjected to REE concentration. The carbon nanophases contained several potential hazardous elements (PHEs), including, arsenic, bromine, cadmium, chlorine, fluorine, mercury, and other PHEs. While carbon nanotubes have been known to be produced from spontaneous combustion of coal of varying ranks, the present work is the first report on the naturally occurring REEs and carbon nanophases in the Colombian coal mining area.