Assessment of biochemical alterations in the neotropical fish species Phalloceros harpagos after acute and chronic exposure to the drugs paracetamol and propranolol.

Over time, many pollutants of anthropogenic origin have caused the contamination of aquatic ecosystems. Among several characteristics, these compounds can reach the trophic chain, causing deleterious interactions with the biota. Pharmaceutical substances can be included in this scenario as emerging contaminants that reach the aquatic environment because of direct human and veterinary usage, and release by industrial effluents, as well as through domestic dumping of surplus drugs. The effects of these compounds on exposed organisms have been studied since the 1990s, but ecotoxicological data for such chemicals are still scarce especially concerning aquatic organisms from tropical regions. Paracetamol and propranolol were selected for this study since they are frequently found in surface waters. Paracetamol is a drug used as analgesic and antipyretic, while propranolol, a ß-blocker, is used in the treatment of hypertension. The objective of this study was to assess the toxic effects of these substances on the neotropical freshwater fish Phalloceros harpagos after acute (96 h) and chronic (28 days) exposures. In order to understand the effects of these drugs on P. harpagos, biochemical markers were selected, including the enzymes involved in oxidative stress, xenobiotic metabolism, and neurotransmission (catalase, glutathione-S-transferase, and cholinesterase activities, respectively). After acute exposure, no significant alterations were observed for catalase activity, suggesting the absence of oxidative stress. On the contrary, significant alterations in glutathione-S-transferases activity were described for the higher concentrations of both pharmaceuticals after acute exposure. In addition, acute exposure to paracetamol caused a significant increase of cholinesterase activity. None of the tested pharmaceuticals caused significant changes in catalase or cholinesterase activities after chronic exposure. Glutathione S-transferases activity was significantly increased for propranolol following chronic exposure, indicating the potential involvement of phase II detoxification pathway.

Relationship between space distribution of the benthic macroinvertebrates community and trophic state in a Neotropical reservoir (Itupararanga, Brazil) / Relação entre a distribuição espacial da comunidade de macroinvertebrados bentônicos e o estado trófico em um reservatório Neotropical (Itupararanga, Brasil)

The purpose of this work was to verify the benthic macroinvertebrates community responses through environmental factors along a headwater tropical reservoir. Samplings were taken with a Van-Veen grab along the reservoir in littoral and profundal regions and in the headwater, next to the dam and the middle of the reservoir. Samples were taken during both wet and dry seasons. Dissolved oxygen concentrations, electric conductivity, temperature and pH near the sediment have been performed in situ, at every sampling station by using a multiprobe and Secchi disc. Total water phosphorus and chlorophyll a concentrations were analyzed to determine the trophic state index. Sediment's organic matter, total phosphorus, nitrogen concentrations and granulometric composition were measured. In order to verify which environmental variables would have more influence over the benthic macroinvertebrates community, a canonical correspondence analysis (CCA) was performed. The total number of recorded taxa was 28. Among them, the family Chironomidae (Diptera) was the richest group (19 taxa). It can be proposed that the benthic macroinvertebrates community may be influenced by environmental conditions such as nutrient and organic matter availability, as well as dissolved oxygen concentration. Macroinvertebrates are adequate bioindicators of water quality due to their sensibility to environmental changes mentioned before. Chironomus sp, Limnodrilus hoffmeisteri and Branchiura sowerbyi comprises a group that can be considered bio-indicators of eutrophic conditions. A second group can be considered as indicator of mesotrophic conditions. The presence of two or more members from that group which comprises Tanytarsini spp, Fissimentum sp, Pelomus sp and Goeldichironomus sp, like predominant taxa, may indicates mesotrophic conditions.

O objetivo deste trabalho foi verificar as respostas da comunidade de macroinvertebrados bentônicos a fatores ambientais ao longo de um reservatório tropical de cabeceira. As amostras foram coletadas com uma draga do tipo Van-Veen ao longo do reservatório nas regiões profunda e litorânea bem como na cabeceira, próximo à barragem e no meio do reservatório. Amostras foram coletadas tanto na estação seca quanto na estação chuvosa. Foram determinadas as concentrações de oxigênio dissolvido, condutividade elétrica, temperatura e pH próximos ao sedimento, in situ, em todas as estações amostrais com a utilização de um multisensor e disco de Secchi. Foram ainda determinadas as concentrações de fósforo e clorofila a da água para cálculo do índice de estado trófico. Com relação ao sedimento, foram determinados o teor de matéria orgânica, concentrações totais de fósforo e nitrogênio bem como a composição granulométrica. Para se verificar quais variáreis ambientais tiveram maior influência sobre a comunidade de macroinvertebrados bentônicos, uma análise de correspondência canônica (ACC) foi realizada. Foram registrados, ao todo, 28 táxons. Dentre estes, o grupo taxonômico com maior riqueza foi a família Chironomidae (Diptera) com 19 táxons. O estudo indicou que a comunidade de macroinvertebrados bentônicos respondeu às condições ambientais como disponibilidade de nutrientes e matéria orgânica, bem como às concentrações de oxigênio dissolvido. Assim sendo, os macroinvertebrados foram considerados bons indicadores da qualidade da água devido à sua sensibilidade frente às possíveis alterações ambientais supramencionadas. Chironomus sp, Limnodrilus hoffmeisteri e Branchiura sowerbyi formaram um grupo que pode ser considerado como bioindicador de condições eutróficas. Um segundo grupo pôde ser considerado como indicador de condições mesotróficas. A presença de dois ou mais membros deste grupo, que inclui os táxons Tanytarsini spp, Fissimentum sp, Pelomus sp e Goeldichironomus sp, como táxons dominantes, pode indicar tais condições.