Terrestrial nanoparticles and geospatial optics: Implications for environmental impact from anthropogenic contaminants in the Caribbean region.

Atmospheric contaminants from natural processes and anthropogenic activities pose a major problem to the environment. Here we analyze the dynamics of atmospheric and terrestrial contaminant concentrations in sediments containing chemical elements, such as nanoparticles (NPs) and ultrafine particles in hydrological sources of the Caribbean region of Colombia. Terrestrial sediments were collected from 2022 to 2024, and quantified for major chemical elements in the form of NPs and ultrafine particles in runoff receiving areas along the banks of Colombia's Ciénaga Grande in Santa Marta Bay, on the Isla de Salamanca. Additionally, atmospheric carbon monoxide (CO) and nitrogen dioxide (NO) levels were detected using TROPOMI, coupled with the Sentinel-5P satellite, from 2019 to 2024. Sampling was performed during both summer and winter, focusing on the Sierra Nevada de Santa Marta National Park, Isla de Salamanca, and the cities of Santa Marta and Barranquilla. Sediment samples were collected from 25 fixed sites on Isla de Salamanca and analyzed in the laboratory. The CO and NO concentrations were detected at 122 "collection points," with a spatial resolution of 7 km × 3.5 km, an average normalization of 0.83 μg/mg, and a maximum error of 6.62 %. The results revealed abundant Fe particles containing Cr, Ti, Zn, and Zr (1-2.5 μm in size), with nanohematite (iron oxide) particles containing C, As, and S detected via EDS. The CO concentrations peaked in Barranquilla and Santa Marta (up to 0.042 mol/m), while NO concentrations reached 2.4 × 10 mol/m, similar to the levels in Sierra Nevada de Santa Marta National Park and Ciénaga Grande de Santa Marta. These findings highlight the impact of forest fires on air quality in the region and support the development of new public policies to mitigate pollution and to protect ecosystems in this ecologically relevant area.