Understanding seasonal variations in As and Pb river fluxes and their regulatory mechanisms through monitoring data.

The Doce River Basin (DRB) suffers with the adverse impacts of mining activities, due to its high level of urbanization and numerous industrial operations. In this study, we present novel insights into contaminant flow dynamics, seasonal variations, and the primary factors driving concentration levels within the region. We conducted an extensive analysis using a database sourced from the literature, which contained data on the contamination of arsenic (As) and lead (Pb) in the Doce River.

Seasonal variation, contribution and dynamics of trace elements in the drainage basin and estuary of the Serinhaém river, BA.

In the present study a mass balance calculation was used to quantify trace elements (Al, Ba, Cd, Cr, Cu, Fe, Mn, Pb, Ti, V and Zn) fluxes exported from the Serinhaém River estuary to the Atlantic Ocean. The studied elements exportation in the particulate fraction showed higher fluxes in the first sampling campaign and a high export rate to the Atlantic Ocean during this period. The physical-chemical parameters showed the highest values in sampling campaign 1.

Flood pulse as a driving force of Pb variation in four fish guilds from Puruzinho Lake (western Amazon).

The Brazilian Amazon is heavily impacted by mining activities, especially by gold and cassiterite mining. Pb is a contaminant released during cassiterite extraction, and it stands out for its high toxicity. The present study aimed to evaluate the effect of flood pulse on Pb dynamics in four fish species with different feeding habits (Cichlapleiozona: carnivorous, Mylossomaduriventre: herbivorous, Prochilodus nigricans: detritivorous, and Serrasalmus rhombeus: piscivorous) over four hydrological periods in Puruzinho Lake (Brazilian Amazon), which receives water from the Madeira River.

Mercury levels in an environmentally protected estuarine area in Northeast Brazil: partitioning in the water column and transport to the ocean.

In this study, total Hg concentrations (HgT) were determined in the suspended particulate matter (SPM) and the dissolved fraction of the water column to evaluate their behavior through a gradient of physical-chemical parameters in a continuum between rivers and the Serinhaém River estuary of the Pratigi Environmental Protection Area, a pristine environment without point sources of Hg contamination, located in Northeast Brazil. Twelve points were sampled, forming a river-estuary transect, and two samplings were carried out (April and September 2019). Significant spatial and temporal effects were detected only for particulate HgT and not for dissolved HgT.