Olívia Maria Cordeiro de Oliveira

Phytoremediation in mangrove sediments impacted by persistent total petroleum hydrocarbons (TPH’s) using Avicennia schaueriana

This study evaluated the efficiency of Avicennia schaueriana in the implementation of phytoremediation compared with intrinsic bioremediation in mangrove sediments contaminated by total petroleum hydrocarbons (TPHs). The experiment was conducted for 3months at a pilot scale under conditions similar to a mangrove: the dynamics of the tides were simulated, and physical, chemical, microbiological and biogeochemical parameters were monitored. After the 90 days, it was found that the phytoremediation was more efficient in the degradation of the TPHs compared to bioremediation, reducing the initial concentration of 32.2-4.2 mg/g. A. schaueriana was also more efficient in mediating the degradation of different fractions of hydrocarbons, achieving a removal efficiency of 87%. The microbiological results consisted of a higher growth in the model with the plants, demonstrating the phytostimulation ability of the plants. Finally, the experiment showed that phytoremediation is a promising alternative in mangrove impacted by oil.

Integrated assessment of mangrove sediments in the Camamu Bay (Bahia, Brazil)

Camamu Bay, an Environmentally Protected Area, may be affected by the pressures of tourism and oil exploration in the adjacent continental platform. The current quality of the mangrove sediments was evaluated by porewater bioassays using embryos of Crassostrea rhizophorae and by an analysis of benthic macrofauna and its relationships with organic compounds, trace metals and bioavailability. Porewater toxicity varied from low to moderate in the majority of the samples, and polychaetes dominated the benthos. The Grande Island sampling station (Station 1) presented more sandy sediments, differentiated macrobenthic assemblages and the highest metal concentrations in relation to other stations and guideline values, and it was the only station that indicated a possible bioavailability of metals. The origin of the metals (mainly barium) is most likely associated with the barite ore deposits located in the Grande and Pequena islands. These results may be useful for future assessment of the impact of oil exploration in the coastal region.

Estudo mineralógico do sedimento de manguezal da baía de Camamu-Ba

The Camamu Bay, an important fishing, mining and tourist site, is located at the South Coastal Region of the State of Bahia, Brazil. This large water body is surrounded by extensive mangrove forest and has been the object of many geo-environmental studies. The objective of this work is to present partial results of one of these studies, a mineralogical evaluation in the sediments of the Camamu Bays mangrove. This semi-quantitative study showed that in the stations next the mining zone the sediment is rich in quartz, barite and clays, with small percentage of pyrite and jarosite. However, for the majority of the stations, the mineralogy is predominantly: quartz and clays, with a variety of percentages of barite, pyrite and crude gypsum in some stations. The results obtained in this work indicated that, for this studied mangrove, the mineralogical composition of the sediments seems to be intimately related to the geologic processes occurring locally. The processes can be: either weathering processes in situ, or man made processes with posterior carriage; or through mineralogical modifications in situ, resulting from the physical-chemical conditions operating at the environment.

Critical study using experimental design of the determination of lead by high-resolution continuum source hydride generation atomic absorption spectrometry

The present study critically evaluates quartz tube (QT) atomisation and high-resolution continuum source hydride generation atomic absorption spectrometry (HR-CS HG-AAS) for the determination of lead. A full two-level factorial design was performed to characterise the effects of the following reagent concentrations on the analytical procedure: sodium tetrahydroborate, potassium hexacyanoferrate(III) and nitric acid. This chemometric tool demonstrated that an increasing acid concentration increases hydrogen production, which dilutes the analyte in the quartz tube during analytical measurements. The experimental conditions established in the final procedure were determined using a Box–Behnken design. The method was used to determine the concentration of lead in water samples, with limits of detection and quantification of 0.13 and 0.40 μg L−1, respectively. Method precision, expressed as relative standard deviation (RSD), was 6.36% and was obtained with a 10.00 μg L−1lead solution. The accuracy was confirmed by determining the lead concentration in the NIST standard reference material, SRM 1643d, for trace elements in natural water. This method was then used to determine the lead concentration in eighteen water samples collected in the Sao Paulo River (Bahia State, Brazil). The lead concentrations varied from 0.62 to 3.73 μg L−1. All samples were also analysed by inductively coupled plasma mass spectrometry (ICP-MS). Statistical tests demonstrated that there was no difference between the results obtained by both procedures.

Relationship of metal content and bioavailability with benthic macrofauna in Camamu Bay (Bahia, Brazil)

Camamu Bay (Bahia, Brazil) is an Environmental Protected Area with mangroves of economic and ecological importance. The objective of this study was to elucidate, through the distribution of the benthic macrofauna and its relationships with trace metals and bioavailabilty, if the current quality of the mangrove sediments of Camamu Bay is acceptable for the protection of aquatic life. Seven sampling stations were selected as representative of the meso-littoral region of Camamu Bay. It was found 581 macrobenthic organisms distributed in 38 species. The highest values of metals occurred at stations located in areas that influenced by barite extraction, while the lowest concentrations were found in areas with relatively lower anthropogenic influence. Analysis of acid volatile sulphide and simultaneously extracted metals showed the occurrence of the ratio SEM/AVS >1, indicative of possible bioavailability of metals, at only one station. The results suggested that Camamu Bay is a nearly pristine area.

Multivariate optimization of a procedure employing microwave-assisted digestion for the determination of nickel and vanadium in crude oil by ICP OES

This work presents the optimization of a sample preparation procedure using microwave-assisted digestion for the determination of nickel and vanadium in crude oil employing inductively coupled plasma optical emission spectrometry (ICP OES). The optimization step was performed utilizing a two-level full factorial design involving the following factors: concentrated nitric acid and hydrogen peroxide volumes, and microwave-assisted digestion temperature. Nickel and vanadium concentrations were used as responses. Additionally, a multiple response based on the normalization of the concentrations by the highest values was built to establish a compromise condition between the two analytes. A Doehlert matrix optimized the instrumental conditions of the ICP OE spectrometer. In this design, the plasma robustness was used as chemometric response. The experiments were performed using a digested oil sample solution doped with magnesium(II) ions, as well as a standard magnesium solution. The optimized method allows for the determination of nickel and vanadium with quantification limits of 0.79 and 0.20μgg-1, respectively, for a digested sample mass of 0.1g. The precision (expressed as relative standard deviations) was determined using five replicates of two oil samples and the results obtained were 1.63% and 3.67% for nickel and 0.42% and 4.64% for vanadium. Bismuth and yttrium were also tested as internal standards, and the results demonstrate that yttrium allows for a better precision for the method. The accuracy was confirmed by the analysis of the certified reference material trace element in fuel oil (CRM NIST 1634c). The proposed method was applied for the determination of nickel and vanadium in five crude oil samples from Brazilian Basins. The metal concentrations found varied from 7.30 to 33.21μgg-1 for nickel and from 0.63 to 19.42μgg-1 for vanadium.

Oil-suspended particulate material aggregates as a tool in preventing potential ecotoxicological impacts in the São Paulo river, Todos os Santos Bay, Bahia, Brazil: Influence of salinity and suspended particulate material

Recent studies have revealed the occurrence of a natural process of interaction between oil droplets and suspended particulate material, resulting in the formation of aggregates which are dispersed in the water column, known as oil-suspended particulate material aggregates (OSAs). The experiments aimed to investigate the contribution of OSAS in indicating where most likely is the oil sedimentation in the São Paulo river, Todos os Santos Bay, Brazil, in order to predict possible ecotoxicological risks caused by oil spills. The results showed that salinity and MPS concentration interfere on the formation of aggregates. In addition, the point 3 was nominated as the most vulnerable area to the potential ecotoxicological impacts of oil spills and should be treated as a priority area for the application of preventive and mitigating techniques.

Distribution and ecotoxicology of bioavailable metals and As in surface sediments of Paraguaçu estuary, Todos os Santos Bay, Brazil.

Surface sediments collected in the intertidal zone of Paraguaçu estuary in July, 2013, were analyzed for organic matter, nitrogen, phosphorus, grain size fractions and partial concentrations of 16 metals. The USEPA 3051A method and ICP-OES and CV-AAS techniques were chosen to metal analysis. Pollution indices (EF, Igeo and PIN) and a comparison with sediment quality guidelines (UET, ERL, ERM, TEL and PEL of NOAA) were conducted in order to evaluate the potential metal impacts over the area. Principal Component Analysis (PCA) and Pearson correlation results showed the importance of organic matter content and the fine-grained fraction of sediments on the control of the bioavailable metals distribution. The Paraguaçu estuary already has anthropogenic enrichment relative to the background level, especially for Mn, whose values exceeded almost 30 times the background at one site (Mn: 1197.30 mg kg(-1)). However, metal levels are still below the reference values with the exception of Hg at one site (Hg: 0.25 mg kg(-1), exceeded TEL and ERL).

Capability of Paraguaçu estuary (Todos os Santos Bay, Brazil) to form oil–SPM aggregates (OSA) and their ecotoxicological effects on pelagic and benthic organisms

For experiments concerning the formation of oil-suspended particulate matter (SPM) aggregates (OSA), oil and sediment samples were collected from Campos Basin and six stations of Paraguaçu estuary, Todos os Santos Bay, Brazil, respectively. The sediments samples were analyzed for organic matter determined by the EMBRAPA method, nitrogen determined by the Kjeldahl method, and phosphorus determined by the method described by Aspila. The oil trapped in OSA was extracted following the method described by Moreira. The experiment showed a relationship between the amount of organic matter and OSA formation and consequently the dispersion of the studied oil. On the basis of the buoyancy of OSA and the ecotoxicological effects on pelagic and benthic community, the priority areas for application of remediation techniques are Cachoeira, Maragogipe, and Salinas da Margarida because of the large amount of oil that accumulated at the bottom of the experiment flask (5.85%, 27.95%, and 38,98%; 4.2%, 17.66%, and 32.64%; and 11.82%, 8.07%, and 10.91% respectively).

Chapter 27 – Hydrocarbon Sources and Biotechnology Applications in Todos os Santos Bay, Brazil

Abstract This chapter presents advances in studies related to the monitoring and development of biotechnologies for the restoration of mangrove areas in Todos os Santos Bay that have been impacted by petroleum. The results of surface sediment monitoring show that the estuary of the Sao Paulo River has the most pollution from petroleum-derived hydrocarbons. Our biostimulation and bioaugmentation tests indicated that in relation to a control (natural attenuation), biodegradation was more rapid when using either of these techniques. The results showed greater degradation of the saturated hydrocarbons in the units receiving a nitrogen–phosphorus–potassium fertilizer blend, indicating the better biostimulation efficacy of this fertilizer. The bioaugmentation experiment indicates that the consortiums showed promise for use in bioremediation: they increased the degradation by approximately 30%. Greater efficacy in removing organic compounds from sediments was observed in two phytoremediation models (approximately 89% removal). The three models were effective in the removal of fraction 3A (C16–23), but the two phytoremediation models achieved much greater degradation of fractions 3B (C23–34) and 4 (C34–40). The data indicate that the two phytoremediation models were more effective than the intrinsic bioremediation model in the degradation of petroleum hydrocarbons.