Publications by authors named "M Tonha"
The accumulation of trace metals in the environmental compartments of coastal rivers is a global and complex environmental issue, requiring multiple tools to constrain the various anthropogenic sources and biogeochemical processes affecting the water quality of these environments. The Valao fluvio-estuarine system (Rio de Janeiro, Brazil) presents a challenging case of a coastal river contaminated by both modern and historical anthropogenic metal sources, located in the land and in the intra-estuary, continuously mixed by tidal cycles. This study employed a combination of spatial distribution analysis of trace metals including gadolinium (Gd), zinc (Zn) isotopic analyses, and X-ray absorption spectroscopy (XAS) to distinguish between these sources.
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- Marinas play a crucial role in maritime leisure and transport but can negatively impact sediment quality in their vicinity.
- This study analyzed sediment samples from Bracuhy marina in Southeast Brazil to track metal contamination linked to antifouling paints, focusing on elements like Cu, Zn, Pb, Cd, and Sn.
- Results showed significant increases in Cu and Zn levels, up to 15 and 5 times the baseline, indicating severe contamination coinciding with marina activities, highlighting the environmental consequences of such operations.
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- The study examines copper contamination in a Brazilian mangrove, focusing on its sources and stable isotopes as tracers.
- It utilizes multi-isotopic methods and sediment analysis to identify two key stages of copper evolution: pre-1965 showing natural landscape changes and post-1965 indicating increased anthropogenic copper input.
- Findings highlight the effectiveness of copper isotopes as environmental tools for tracing human impacts on mangrove ecosystems while enhancing understanding of copper dynamics over time.
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- * The study used advanced sampling and geochemistry techniques to analyze metal contamination, revealing low dissolved metal levels but high concentrations in tailings.
- * It found that while the tailings had a notable impact on sediment, other local human activities also played a role in the river's ongoing contamination issues.
The Paraiba do Sul (PSR) and Guandu Rivers (GR) water diversion system (120 km long) is located in the main industrial pole of Brazil and supplies drinking water for 9.4 million people in the metropolitan region of Rio de Janeiro. This study aims to discern the trace metals dynamics in this complex aquatic system.
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