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Mercury wet deposition in the urban and industrialized region of Campinas, southeast Brazil

Amauris Hechevária-Hernandez, Jose Martins Viana, ANNE HELENE FOSTIER

Abstract

Rationale Data on Hg wet deposition in Brazil, as well as in the rest of the Southern Hemisphere, are sparse. To fill this gap, this study presents a comprehensive dataset from a long-term monitoring effort (nearly 2 years) that focuses on Hg concentrations in rainwater and wet Hg deposition in Campinas, one of Brazil's largest industrial and populated regions located in São Paulo state (Southeast Brazil). Methodology A total of 66 rain events were collected from April 2019 to December 2020 using a manually operated rain collector. The total Hg concentration was determined using Cold Vapor Atomic Fluorescence Spectrometry (CVAFS), and the wet Hg deposition was calculated. Results The volume-weighted mean (VWM) Hg concentration ranged from 5.59 to 15.3 ng L⁻¹, with the highest value recorded during the driest season; the overall average for the sampling period was 6.42 ng L⁻¹. Annual Hg wet deposition varied from 6.5 to 7.1 µg m⁻² y⁻¹. Discussion These results indicate a clear seasonal variation in Hg deposition and suggest that precipitation depth is the primary influencing factor at our study site. Both the VWM and Hg deposition levels were comparable to those observed in many urban and industrial sites in the Northern Hemisphere. More long-term wet deposition monitoring is needed in urban and industrialised areas of the southern hemisphere to improve our understanding of the impacts of human activities on the Hg cycle.

EN24089  Accepted 10 December 2024

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