Sentinel-3B OLCI satellite imagery and advanced electron microscopy of nanoparticle analysis in a marine estuary and watershed: Robust multi-analytics and geospatial assessment of key contaminants

Abstract

Globally, hydrographic basins are routinely contaminated by anthropogenic contaminants originating from coal mining, swine farming, urban sewage, pesticide use, and other various sources. These contaminants not only spread pollution but also nanoparticles (NPs) capable of contaminating the fauna and flora of estuaries in addition to being harmful to human health. The use of images from the Sentinel-3B OLCI (Ocean Land Color Instrument) satellite makes it possible to obtain spectral data aimed at identifying the presence of possible contamination in large regions, which can be complemented by advanced electron microscopies. The general objective of this study is to analyze the dispersion of NPs and ultrafine particles (UFPs) in a region that contains multiple contaminants through the use of images from the Sentinel-3B OLCI satellite. The authors examined images taken after two particularly intense tropical rain events in December 2018 and 2021, in the region of the Laguna estuary located in the Brazilian state of Santa Catarina. Suspended sediments (SSs) were collected from seventeen points on the Tubarão River in 2018. These samples were then submitted to an analytical laboratory for various analyses such as X-ray Diffraction (XRD), and transmission and scanning electron microscopes. Additionally, images from the Sentinel-3B satellite OLCI in the Laguna estuary region from 2018 and 2021 were analyzed based on the following variables: water turbidity (TSM_NN), chlorophyll-a (CHL_NN) and suspended pollution potential (ADG_443_NN). The SSs demonstrated the presence of massive crystals of ultrafine pyrite in a pseudomorph crystal of jarosite containing nanospheres with hazardous elements (e.g. As, Hg, Cd and Pb), which represent important pollutants. The Sentinel-3B OLCI images in relation to the variables TSM_NN, CHL_NN and ADG_443_NN (2018 and 2021), identified high turbidity in the waters of the Tubarão River. Analysis of SSs and satellite images are suitable for identifying contaminants toxic to the marine ecosystem and human health on a global scale.