The use of epilithic biofilms as bioaccumulators of pesticides and pharmaceuticals in aquatic environments.

Biofilms are a consortium of communities of organisms that live in syntrophic relationships and present a higher organization level than that of individual cells. Biofilms dominate microbial life in streams and rivers, enable crucial ecosystem processes, contribute to global biogeochemical flows and represent the main active bacterial life form. Epilithic biofilms are the main biomass found in rivers; their exposure to contaminants can lead to changes in their structure and composition.

"Modern agriculture" transfers many pesticides to watercourses: a case study of a representative rural catchment of southern Brazil.

The total cultivated area in Brazil reached to 62 million ha in 2018, with the predominance of genetically modified soybean and corn (36 and 17 million ha, respectively) in no-tillage systems. In 2018, 5.3 × 10 Mg of active ingredient of pesticides was applied in cropfields, representing about 7.

Indiscriminate use of glyphosate impregnates river epilithic biofilms in southern Brazil.

Epilithic biofilms are communities of microorganisms composed mainly of microbial cells, extracellular polymeric substances from the metabolism of microorganisms, and inorganic materials. Biofilms are a useful tool to assess the impact of anthropic action on aquatic environments including the presence of pesticide residues such as glyphosate. The present work seeks to monitor the occurrence of glyphosate and AMPA residues in epilithic biofilms occurring in a watershed.

Phosphorus seasonal sorption-desorption kinetics in suspended sediment in response to land use and management in the Guaporé catchment, Southern Brazil.

Phosphate sorption-desorption parameters like maximum phosphorus (P) adsorption capacity (P ), equilibrium phosphorus concentration (EPC), water desorbable P (α), potentially bioavailable P (β), and mobility index (α/β ratio) were determined in order to understand the sediment source-sink nature in Guaporé catchment in southern Brazil during summer and winter 2013 and 2014. The result showed a significant (p = 0.05) variation across sediment site or seasons and revealed the most sorption-desorption parameters (P , α, β) with the increments following the order urban sediments > intensive agriculture under CT > intensive agriculture under NT > low agriculture sub-catchments (sub1 and sub2) > native forest.

Copper and zinc accumulation and fractionation in a clayey Hapludox soil subject to long-term pig slurry application.

Pig slurry (PS) recycling as fertilizer is commonly practiced as an option for minimizing livestock waste. Successive PS applications on the soil can lead to crop toxicity and environmental risk. Despite extensive investigation of macronutrient behavior, the fate of trace metals remains uncertain and only a few long-term field studies have been reported to date.

Combining visible-based-color parameters and geochemical tracers to improve sediment source discrimination and apportionment.

Parameter selection in fingerprinting studies are often time-consuming and costly because successful fingerprint properties are generally highly site-specific. Recently, spectroscopy has been applied to trace sediment origin as a rapid, less expensive, non-destructive and straightforward alternative. We show in this study the first attempt to combine both geochemical tracers and color parameters derived from the visible (VIS) spectrum in a single estimate of sediment source contribution.

Modeling field-scale vertical movement of zinc and copper in a pig slurry-amended soil in Brazil.

Organic amendments often represent a source of trace metals (TMs) in soils, which may partly leach into the groundwater. The objectives of this study were (1) to validate Hydrus-2D for modeling the transport of Zn and Cu in an Alfisol amended with pig slurry (PS) by comparing numerical simulations and experimental field data, and (2) to model the next 50 years of TM movements under scenarios of suspended or continued PS amendments. First, between 2000 and 2008, we collected detailed Zn and Cu data from a soil profile in Santa Maria, Brazil.

Using a two site-reactive model for simulating one century changes of Zn and Pb concentration profiles in soils affected by metallurgical fallout.

Predicting the transfer of contaminants in soils is often hampered by lacking validation of mathematical models. Here, we applied Hydrus-2D software to three agricultural soils for simulating the 1900-2005 changes of zinc and lead concentration profiles derived from industrial atmospheric deposition, to validate the tested models with plausible assumptions on past metal inputs to reach the 2005 situation. The models were set with data from previous studies on the geochemical background, estimated temporal metal deposition, and the 2005 metal distributions.

Pesticide contamination of water alters the metabolism of juvenile silver catfish, Rhamdia quelen.

We investigated how pesticide contamination of water affects the metabolism of the silver catfish, Rhamdia quelen, by studying fish maintained at two sites with low and high anthropic activity (Lino Creek, southern Brazil). Several pesticides were found at both stream sites. After 30 days plasma glucose levels were higher in fish exposed to water in the low anthropic activity site than those exposed to water in the high anthropic activity site.