ABSTRACT: Biosolids are residues from the treatment of urban fluids used as a source of nutrients for agricultural and forestry crops. The organic matter contained in this residue and its chemical characteristics may interfere with the behavior of herbicides in the soil. The objective of this study was to evaluate the influence of biosolids on the potential for leaching herbicides mimicking auxin. Two simultaneous experiments were performed: a leaching test of picloram + 2.4-D in soil column with addition of thermally treated biosolids or solarized biosolids and another one to evaluate the effect of leachate application from the leaching tests under inert material. Each type of biosolid was incorporated in sandy soil in the proportions of 0%, 50%, 100% and 150% of the maximum recommended dose for subsurface fertilization for eucalyptus. The soil was conditioned in PVC columns and the herbicide columns based on picloram + 2.4-D (Turuna® Commercial Formulation), corresponding to 240 g L-1 of 2.4-D + 64 g L-1 of picloram at a dose of 3.5 L ha-1 of the commercial product. The columns were submitted to rain simulation and the resulting leachate was collected, followed by its application in sand-filled pots. The Cucumis sativus was sown along the profile of the soil columns and in the pots. The incorporation of the biosolid, independently of the type and dose tested did not interfere in the leaching potential of picloram + 2.4-D. Symptoms of intoxication were observed along all soil columns and pots. Therefore this residue is not very effective for the resolution of environmental problems caused by the leaching of auxin-mimicking herbicides in the soil.
RESUMO: O biossólido é um resíduo proveniente do tratamento de fluidos urbanos utilizado como fonte de nutrientes para culturas agrícolas e florestais. A matéria orgânica contida nesse resíduo e as características químicas dele podem interferir no comportamento de herbicidas no solo. Objetivou-se neste estudo avaliar a influência do biossólido sobre o potencial de lixiviação de herbicidas mimetizadores de auxina. Implantaram-se dois experimentos simultâneos, sendo um teste de lixiviação do picloram + 2,4-D em coluna de solo com adição de biossólido termicamente tratado ou de biossólido solarizado e outro para a avaliação do efeito da aplicação do lixiviado proveniente dos testes de lixiviação sob material inerte. Cada tipo de biossólido foi incorporado em solo arenoso nas proporções de 0% 50%, 100% e 150% da dose máxima recomendada para adubação subsuperficial para o eucalipto. O solo foi acondicionado em colunas de PVC e aplicou-se, na superfície das colunas, herbicida à base de picloram + 2,4-D (formulação comercial Turuna®), correspondente a 240 g L-1 de 2.4-D + 64 g L-1 de picloram, na dose de 3,5 L ha-1 do produto comercial. As colunas foram submetidas à simulação de chuva e fez-se a coleta do lixiviado resultante, seguida de sua aplicação em vasos preenchidos com areia. Foi semeado Cucumis sativus ao longo do perfil das colunas de solo e nos vasos. A incorporação do biossólido, independentemente do tipo e da dose testada, não interferiu no potencial de lixiviação do picloram + 2,4-D. Observaram-se sintomas de intoxicação ao longo de todas as colunas de solo e nos vasos. Portanto, esse resíduo é pouco eficaz para a resolução de problemas ambientais causados pela lixiviação de herbicidas mimetizadores de auxina no solo.
The present study investigates the antinociceptive effect of the pyrazolyl-thiazole derivative 2-(5-trichloromethyl-5-hydroxy-3-phenyl-4,5-dihydro-1 H-pyrazol-1-yl)-4-(4-bromophenyl)-5-methylthiazole (B50) in mice. Male albino Swiss mice (30-40 g) were used in the acetic acid-induced abdominal writhes and tail-immersion tests. B50 caused dose-dependent antinociception (8, 23 and 80 µmol/kg, sc) in the acetic acid writhing assay (number of writhes: vehicle: 27.69 ± 6.15; B50 (8 µmol/kg): 16.92 ± 3.84; B50 (23 µmol/kg): 13.85 ± 3.84; B50 (80 µmol/kg): 9.54 ± 3.08; data are reported as means ± SEM for 9 animals per group). On the other hand, B50 did not cause antinociception in the tail immersion assay. Naloxone (2.75 µmol/kg, sc) prevented B50-induced antinociception (number of writhes: vehicle-saline: 31.11 ± 3.15; vehicle-naloxone: 27.41 ± 3.70; B50 (80 µmol/kg)-saline: 8.70 ± 3.33; B50 (80 µmol/kg)-naloxone: 31.84 ± 4.26; morphine-saline: 2.04 ± 3.52; morphine-naloxone: 21.11 ± 4.26; 8-9 animals per group). The removal of the methyl group of the thiazole ring of B50 or substitution of the bromo substituent with the methyl at position 4 of the phenyl group, which is attached to the thiazole ring of B50, resulted in loss of activity, suggesting that these substituents are important for antinociceptive activity. B50 had no effect on spontaneous locomotion or rotarod performance, indicating that the antinociceptive effect of B50 is not related to nonspecific motor effects. The antinociceptive profile of B50 seems to be closer to nonsteroidal anti-inflammatory drugs than to classic opioid agents, since it had no analgesic effect in a thermally motivated test.