Degradation of metalaxyl and folpet by filamentous fungi isolated from Portuguese (Alentejo) vineyard soils

Degradation of xenobiotics by microbial populations is a potential method to enhance the effectiveness of ex situ or in situ bioremediation. The purpose of this study was to evaluate the impact of repeated metalaxyl and folpet treatments on soil microbial communities and to select soil fungal strains able to degrade these fungicides. Results showed enhanced degradation of metalaxyl and folpet in vineyards soils submitted to repeated treatments with these fungicides. Indeed, the greatest degradation ability was observed in vineyard soil samples submitted to greater numbers of treatments. Respiration activities, as determined in the presence of selective antibiotics in soil suspensions amended with metalaxyl and folpet, showed that the fungal population was the microbiota community most active in the degradation process. Batch cultures performed with a progressive increase of fungicide concentrations allowed the selection of five tolerant fungal strains: Penicillium sp. 1 and Penicillium sp. 2, mycelia sterila 1 and 3, and Rhizopus stolonifer. Among these strains, mycelium sterila 3 and R. stolonifer presented only in vineyard soils treated with repeated application of these fungicides and showed tolerance >1,000 mg l−1 against commercial formulations of metalaxyl (10 %) plus folpet (40 %). Using specific methods for inducing sporulation, mycelium sterila 3 was identified as Gongronella sp. Because this fungus is rare, it was compared using csM13-polymerase chain reaction (PCR) with the two known species, Gongronella butleri and G. lacrispora. The high tolerance to metalaxyl and folpet shown by Gongronella sp. and R. stolonifer might be correlated with their degradation ability. Our results point out that selected strains have potential for the bioremediation of metalaxyl and folpet in polluted soil sites

Non-target impact of fungicide tetraconazole on microbial communities in soils with different agricultural management

Effect of the fungicide tetraconazole on microbial community in silt loam soils from orchard with long history of triazole application and from grassland with no known history of fungicide usage was investigated. Triazole tetraconazole that had never been used on these soils before was applied at the field rate and at tenfold the FR. Response of microbial communities to tetraconazole was investigated during 28-day laboratory experiment by determination of changes in their biomass and structure (phospholipid fatty acids method—PLFA), activity (fluorescein diacetate hydrolysis—FDA) as well as changes in genetic (DGGE) and functional (Biolog) diversity. Obtained results indicated that the response of soil microorganisms to tetraconazole depended on the management of the soils. DGGE patterns revealed that both dosages of fungicide affected the structure of bacterial community and the impact on genetic diversity and richness was more prominent in orchard soil. Values of stress indices—the saturated/monounsaturated PLFAs ratio and the cyclo/monounsaturated precursors ratio, were almost twice as high and the Gram-negative/Gram-positive ratio was significantly lower in the orchard soil compared with the grassland soil. Results of principal component analysis of PLFA and Biolog profiles revealed significant impact of tetraconazole in orchard soil on day 28, whereas changes in these profiles obtained for grassland soil were insignificant or transient. Obtained results indicated that orchards soil seems to be more vulnerable to tetraconazole application compared to grassland soil. History of pesticide application and agricultural management should be taken into account in assessing of environmental impact of studied pesticides. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10646-016-1661-7) contains supplementary material, which is available to authorized users

Liver biomarkers response of the neotropical fish Aequidens metae to environmental stressors associated with the oil industry

The Acacias River in Colombia receives large volumes of industrial effluents mostly derived from the oil industry. To contribute to the study of the possible effects of industrial wastewaters on the aquatic environment and particularly on fish populations, a native neotropical fish, Aequidens metae was used as a sentinel species. Wild specimens of A. metae were caught at three different places of the Acacias River taking as reference the point of discharge of an oil industry effluent; upstream, downstream, and at the vicinity of the discharge pipe. A fourth sampling site was chosen as a reference site away from urban settlements. Samplings were performed twice, during the rainy and dry seasons. After anesthesia animals were weighted and measured, and humanely sacrificed. Livers were extracted, frozen on site and transported to the laboratory. Condition indices were calculated. Total protein content and the detoxification 7-ethoxyresorufin-O-deethylase (EROD) enzyme activity were estimated. Histopathological alterations were also evaluated. Water quality was estimated through the measurement of several variables. Results obtained evidenced that the highest induction in EROD activity and the strongest histological alterations in liver of the monitored fish appeared during the dry seasons at the discharge site and downstream to this point.The authors wish to thank the students and research assistants of the Research Group BioTox for their valuable participation during the sampling procedures. This study was funded by Colciencias, ANH and Universidad de los Llanos Project number 112272151869, contrato 162-2016, grant 721–2015 “Convocatoria para la formación de recurso humano en Colombia en el área de hidrocarburos, a través de proyectos de investigación”).Peer reviewe

Acute effects on hepatic biomarkers in the freshwater native fish Aequidens metae exposed to polycyclic aromatic hydrocarbons

14 Pág.BACKGROUND AND OBJECTIVES: Polycyclic aromatic hydrocarbons are present in all environmental matrices. Polycyclic aromatic hydrocarbons-rich wastewater from the oil industry is discharged into natural water bodies. Detritivorous fish shown the effects of pollutants in water. Biomarkers of effect make it possible to demonstrate exposure to xenobiotics such as polycyclic aromatic hydrocarbons. The aim of the present study was to evaluate the hepatic and erythrocyte response in Aequidens metae, a detritivorous fish, exposed to polycyclic aromatic hydrocarbons in terms of morphological, biochemical, and genotoxic changes. METHODS: Juveniles of Aequidens metae were exposed to 50 microgram per gram body weight of beta-naphthoflavone, 100 microgram per gram of naphthalene, 50 microgram per gram of phenanthrene and 10 microgram per gram of benzo[a]pyrene, for 72 hours. Water quality variables, total protein content, 7-ethoxyresorufin-O-deethylase activity, liver histopathological changes and genotoxic alterations in peripheral blood were measured during the assay. FINDINGS: In polycyclic aromatic hydrocarbons-exposed fish, analysis of liver tissue revealed parenchymal lesions and changes in the number and shape of hepatocyte nuclei. On the other hand, only fish exposed to benzo[a]pyrene shown significant increase in the 7-ethoxyresorufin-O-deethylase activity compared to solvent control. In peripheral blood erythrocytes, increased presence of nuclear abnormalities was higher in fish exposed to phenanthrene, followed by benzo[a]pyrene, beta-naphthoflavone, and naphthalene. CONCLUSION: It is concluded that Aequidens metae is a suitable bioindicator for polycyclic aromatic hydrocarbons monitoring in aquatic ecosystems. Phenanthrene reveals for the first time a greater genotoxic effect than benzo[a]pyrene at sublethal concentrations. Juveniles of Aequidens metae exposed to concentrations of polycyclic aromatic hydrocarbons close to those found in the environment showed health-compromising damageThis study was funded by Colciencias, Agencia Nacional de Hidrocarburos (ANH) and Universidad de los Llanos with the project number [112272151869, contract 1622016, grant 721–2015] “Convocatoria para la formación de recurso humano en Colombia en el área de hidrocarburos, a través de proyectos de investigación”) and by the Pontificia Universidad Javeriana, under the following research grant: Project ID 8572.Peer reviewe

Persistence of pentolite (PETN and TNT) in soil microcosms and microbial enrichment cultures

Pentolite is a mixture (1:1) of 2,4,6-trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN), and little is known about its fate in the environment. This study was aimed to determine the dissipation of pentolite in soils under laboratory conditions. Microcosm experiments conducted with two soils demonstrated that dissipation rate of PETN was significantly slower than that of TNT. Interestingly, the dissipation of PETN was enhanced by the presence of TNT, while PETN did not enhanced the dissipation of TNT. Pentolite dissipation rate was significantly faster under biostimulation treatment (addition of carbon source) in soil from the artificial wetland, while no such stimulation was observed in soil from detonation field. In addition, the dissipation rate of TNT and PETN in soil from artificial wetland under biostimulation was significantly faster than the equivalent abiotic control, although it seems that non-biological processes might also be important for the dissipation of TNT and PETN. Transformation of PETN was also slower during establishment of enrichment culture using pentolite as the sole nitrogen source. In addition, transformation of these explosives was gradually reduced and practically stopped after the forth cultures transfer (80 days). DGGE analysis of bacterial communities from these cultures indicates that all consortia were dominated by bacteria from the order Burkholderiales and Rhodanobacter. In conclusion, our results suggest that PETN might be more persistent than TNT. © 2016, Springer-Verlag Berlin Heidelberg