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Polycyclic aromatic hydrocarbons (PAHs) are part of a class of organic compounds resistant to natural degradation. In this way, heterogeneous photocatalysis becomes useful to degrade persistent organic pollutants, however it can be influenced by environmental variables (i.e.: organic matter) and experimental factors such as: mass of the photocatalyst and irradiation time. The objective of this research was to use a factorial design 2k as a function of the multiple response (MR) to evaluate simultaneously experimental conditions for the photodegradation of polycyclic aromatic hydrocarbons in contaminated mangrove sediment and its application in oil from Potiguar Basin in Brazil. The sediment samples collected in Belmonte city (Southern Bahia state) were contaminated with 0.25 mg kg-1 of Acenaphthene, Anthracene, Benzo[a]Anthracene, Indene[1,2,3cd]pyrene, Dibenzo[ah]anthracene, Benzo[ghi]pyrene. Factors such as mass of the photocatalyst and irradiation time were evaluated in factorial design 22, with triplicate from the central point, to 1g of the PAH contaminated sediment. After performing the experiments, it was found that the best experimental condition for the degradation of all PAHs indicated by MR was the central point (0.5 g of photocatalyst and 12h of irradiation). For such conditions, the half-life of PAHs varied from 3.51 to 9.37 h and the degradation speed constant between 0.0740 to 0.1973 h-1. The comparison of the optimized methodology between photolysis tests and heterogeneous photocatalysis was performed using the Kruskal-Wallis test, which indicated a difference for the reference solution, where heterogeneous photocatalysis was more efficient in the degradation of PAHs. The optimized methodology was apply in samples contaminated with crude oil from Potiguar Basin, no significant difference was observed in the aromatic fraction, using for the Kruskal-Wallis test. Heterogeneous photocatalysis has shown to be a promising remediation technique to remedy aromatic organic compounds in mangrove sediments.

RESUMO

The characterization of petroleum or its products spilled in the environment in relation to its source rocks is an important tool to assist in the resolution of issues of environmental impact and legal responsibility since it clarifies the possible region or the producing country of that type of petroleum. This article analyzes the application of analytical techniques for petroleum geochemistry to identify the type and origin of oily material collected from beaches in Northeast Brazil in 2019. Samples of the oily material collected on the beaches in the states of Bahia and Sergipe were analyzed and for comparison purposes, samples of crude oils produced in Brazil, Middle East, Nigeria and Venezuela were also analyzed. The analytical results showed that the oily material that reached the beaches has geochemical characteristics compatible with those of the Venezuelan oil, indicating it was severely weathered or a product made with heavy oil produced.

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RESUMO

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.

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BACKGROUND: ABCA1 plays an important role in HDL metabolism. Single nucleotide polymorphisms (SNPs) in ABCA1 gene were associated with variation in plasma HDL-c. METHODS: The effect of the ABCA1 SNPs C-14T, R219K and of a novel variant C-105T on serum lipids was investigated in 367 unrelated Brazilian individuals (224 hypercholesterolemic and 143 normolipidemic). The relation between ABCA1 SNPs and the lipid-lowering response to atorvastatin (10 mg/day/4 weeks) was also evaluated in 141 hypercholesterolemic (HC) individuals. The polymorphisms were detected by PCR-RFLP and confirmed by DNA sequencing. RESULTS: Linkage disequilibrium was found between the SNPs C-105T and C-14T in the HC group. HC individuals carrying -105CT/TT genotypes had higher serum HDL-c and lower triglyceride and VLDL-c concentrations as well as lower TG/HDL-c ratio compared to the -105CC carriers (p<0.05). The R219K SNP was associated with reduced serum triglyceride, VLDL-c and TG/HDL-c ratio in the HC group (p<0.05), and with an increased serum apoAI in NL individuals. The effects of ABCA1 SNPs on basal serum lipids of HC individuals were not modified by atorvastatin treatment. CONCLUSIONS: The ABCA1 SNPs R219K and C-105T were associated with a less atherogenic lipid profile but not with the lowering-cholesterol response to atorvastatin in a Brazilian population.

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