Southern Brazil is an agricultural region that is experiencing strong growth in both cereal and animal production. The intensification of agricultural practices, as well as the growing urbanization in this region, also generates strong anthropogenic pressures on the aquatic environment. In Brazil, the lack of sewage treatment and the wide use of waste (liquid or solid) for the fertilization of soils are likely to favor the spread of pharmaceuticals in the surrounding environment. Considering the benefits of the determination of anthropogenic markers in the environment, the study aimed to monitor the presence of carbamazepine (CBZ) and sucralose (SCR) in the Guaporé River, representative of a southern Brazilian rural watershed. Both carbamazepine and sucralose are measured in water by polar organic chemical integrative samplers (POCIS) (CBZ: lower than limit of detection (< LOD) to 746 μg g−1 and SCR: 

Brazil is one of the largest consumers of pesticides in the world. The high rainfall rate and inadequate soil use and management promote the transfer of these compounds to the aquatic system. The aim of this study was to identify and quantify pesticides present in epilithic biofilms in order to evaluate the effectiveness of this matrix as a bioindicator able to discriminate areas and periods with different inputs of pesticides. Among the 25 pesticides analyzed in the biofilms, 20 compounds were detected. The epilithic biofilms picked up pesticides independent of their polarities, even in the period of lower use. The frequency and median concentration of five herbicides (2,4-D, atrazine, desethyl-atrazine, simazine, nicosulfuron), three fungicides (carbendazim, epoxiconazole, tebuconazole), and one insecticide (imidacloprid) were highest in biofilms sampled in summer crops during the growing period. Biofilms collected in the upper region of the catchment, where genetically modified soybean and corn cultivated in a no-tillage system prevail, the highest frequency and median concentration of three herbicides (2,4-D, thifensulfuron, isoproturon), four fungicides (carbendazim, epoxiconazole, tebuconazole, metconazole), and one insecticide (imidacloprid) were observed. Despite the excessive amounts of pesticides used in the catchment, the median values of all pesticides in the epilithic biofilm were considered low. The lower diversity and concentration of pesticides observed in the autumn/winter season is representative of lower use of pesticides, barriers to pesticide transfer from soil to water, and the biofilm's resilience capacity to decompose pesticides.

Knowledge concerning the ecotoxic effects of nanomaterials, chemical structures with novel properties owing to their small sizes (1 to 100 nm), is wanting and deserves to be documented more fully. In this study we conducted testing with the MARA (microbial array for risk assessment) assay-an 11 microbial species 96-well microplate toxicity test measuring growth inhibition-to determine the toxic potential of four metallic nanopowders (MNPs): copper zinc iron oxide, samarium (III) oxide, erbium (III) oxide, and holmium (III) oxide. MTC (microbial toxicity concentration) endpoint values showed a range of toxicity responses generated by individual strains that was MNP-specific. Cluster analysis undertaken with the (n = 11) MTC values of the four MNPs, reflecting a toxic fingerprint proper to each nanochemical, indicated that their modes of action may be different. Experiments were also conducted with an artificial sediment, composed of varying concentrations of silica sand and kaolin (fine particles &lt; 0.004 mm), spiked with each MNP to assess the contribution of fine particles on the resulting elutriate toxicity. The latter was shown to increase as fines contents decreased, except for CuZnFeO where no particular trends were observed. Toxicity testing was then undertaken with each MNP spiked into natural Saint Lawrence River freshwater sediments displaying low, medium, and high fines contents. Once again, analogous results to those obtained with the artificial sediment experiments were observed for MNP elutriate toxicity. Overall, MARA bioassay data indicate that MNP toxicity can be modulated by sediment grain size and that resulting adverse effects on aquatic biota will in part depend on such sediment characteristics.

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El objetivo es analizar el impacto de los residuos urbanos e industriales del municipio de Marau (Rio Grande do Sul -Brasil) en la calidad del agua del río Marau. Para ello, se evaluaron: pH, turbidez, conductividad eléctrica, tensión superficial, carbono orgánico, metales, nitrito, nitrato, cloruro, fosfato, sulfato y fósforo. Las colectas de agua del río ocurrieron en septiembre de 2014 y 2016 en los puntos: aguas arriba de la ciudad de Marau y de La curtiembre; aguas arriba de la curtimbre; en el punto de mezcla del efluente de La industria de curtiembre y el río; aguas abajo de la ciudad de Marau. El análisis físico-químico del agua mostró que los efluentes de la ciudad son la fuente principal de contaminación local, teniendo valores de Al, Pb y P mayores que los permitidos por La legislación. Se concluye que las actividades industriales y los efluentes no tratados de la ciudad de Marau tienen un impacto negativo en la calidad del agua del río.