Chronic exposure to geogenic contaminated groundwaters (GCGs) has caused serious health problems among billions of people worldwide. The hydrogeological features, main sources of geogenic hazardous substances, dominant hydrogeochemical processes and key factors controlling the occurrence of high arsenic (As ≥ 10 μg/L), high fluoride (F ≥ 1 mg/L), and high iodine (I ≥ 100 μg/L) groundwater are discussed in this review. Although the global and/or regional occurrence, and the environmental and geochemical behaviors of groundwater As, F and I have been well documented in the past three decades, there is still a lack of holistic theoretical analysis to demonstrate the hydrogeological patterns of their (co)occurrence. We here propose four basic genetic types of GCGs by summarizing the characteristics of the distribution and major hydrogeochemical processes: leaching-enrichment type, burial-dissolution type, compaction-release type, and evaporation-concentration type. The complex genetic mechanisms of GCGs are thus integrated into a new theoretical framework to improve our understanding of their genesis and our capability of predicting their spatial and temporal distribution. Moreover, new paradigms of interdisciplinary convergent research are required to find best solutions to ensure the sustainable safe supply of groundwater resources and the well-being of the groundwater-dependent ecosystems and the human society.

Offshore oil spills, industrial oily wastewater, and domestic oil pollution are some of the most serious global challenges, and are leading environmental causes of morbidity and mortality. Nanofiber membrane materials manufactured via electrostatic spinning for oil/water separation have become one of the emerging technologies to treat oil/water emulsions. Here, we give a comprehensive review of current progress on electrospinning nanofibers for oil/water separation to promote the field’s advancement. Typical examples of hydrophilic–oleophobic, hydrophobic–oleophilic, and special wettability nanofiber membranes are systematically summarized. The effects of material selection, fiber production processes, and subsequent modifications on the membrane performance are compared and discussed. Potential shortcomings of various types of separation membranes and the potential solutions are provided. The review concludes with a summary and outlook on future directions and innovations in electrospinning nanofibers and membranes for oil/water separation.

¹O₂ as the dominant ROS together with ˙OH, SO₄˙⁻ and O₂˙⁻ were involved in the LaMnO₃/PMS process.