Geysa B. Brito

Levels and spatial distribution of trace elements in macroalgae species from the Todos os Santos Bay, Bahia, Brazil.

Concentrations of elements (As, Ba, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, V, and Zn) were determined in ten species of macroalgae collected from six sites in the Todos os Santos Bay, Brazil, between May and July of 2010. An optimized microwave-assisted digestion procedure was used to digest the samples. The elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). A wide range of metal concentrations were observed between the species analysed. Somewhat higher concentrations of Cd (5.99μg g(-1)), Co (372μg g(-1)), Mn (640μg g(-1)), Ni (17.2μg g(-1)) and Zn (51.4μg g(-1)) were found in the brown macroalgae species Padina spp., whereas elements, such as As (19.7μg g(-1)) and Pb (8.27μg g(-1)), were mainly concentrated in the species Sargassum spp. and Bostrychia montagnei, respectively. Statistical analyses (ANOVA) of the Padina data showed significant inter-site differences for all metals examined except nickel.

Preliminary results of mercury levels in raw and cooked seafood and their public health impact

Mercury is toxic for human health and one of the main routes of exposure is through consumption of contaminated fish and shellfish. The objective of this work was to assess the possible mercury contamination of bivalves (Anomalocardia brasiliana, Lucina pectinata, Callinectes sapidus), crustacean (C. sapidus) and fish (Bagre marinus and Diapterus rhombeus) collected on Salinas da Margarida, BA (Brazil), a region which carciniculture, fishing and shellfish extraction are the most important economic activities. The effect of cooking on Hg concentration in the samples was also studied. The results showed that Hg concentration was generally higher in the cooked samples than in raw samples. This increase can be related to the effect of Hg pre-concentration, formation of complexes involving mercury species and sulfhydryl groups present in tissues and/or loss of water and fat. The highest concentrations were found in B. marinus samples ranging 837.0-1585.3 μg kg(-1), which exceeded those recommended by Brazilian Health Surveillance Agency (ANVISA). In addition, Hg values found in the other samples also suggest the monitoring of the Hg concentrations in seafood consumed from the region.

Multi-element determination of copper, iron, nickel, manganese, lead and zinc in environmental water samples by ICP OES after solid phase extraction with a C18 cartridge loaded with 1-(2-pyridylazo)-2-naphthol

A pre-concentration solid-phase procedure has been developed for the sensitive and simple determination of copper, iron, nickel, manganese, lead and zinc in environmental water samples by inductively coupled plasma optical emission spectrometry (ICP OES). After pH adjustment, the samples were percolated with the aid of a peristaltic pump on a Sep-Pak C18 cartridge loaded with 1-(2-pyridylazo)-2-naphthol (PAN). The analyte elution was carried out with the passage of HCl through the cartridge for subsequent determination by ICP OES. The experimental conditions for pre-concentration were optimized considering the following factors: the concentration and volume of the eluent, sample volume, flow-rate and pH. The optimized conditions corresponded to the use of 5 mL of 0.8 M HCl as the eluent, a sample volume of 50 mL, a flow-rate of 1.9 mL min−1 and pH 9.0. Under these conditions, the detection limits for Cu, Fe, Mn, Ni, Pb and Zn varied between 0.11 and 21 μg L−1. The relative standard deviation (RSD) for the analytes of this study did not exceed 9%, after the application of the proposed pre-concentration procedure (n = 10, 0.50 mg L−1). The effect of possible interfering species on the recovery of the analytes was also investigated. The accuracy of the method was evaluated by the analysis of a certified reference material (SLEW-3 Estuarine Water Reference Material for Trace Metals) and the proposed method was applied to samples of groundwater, drinking water and river water. The samples were analyzed by using inductively coupled plasma mass spectrometry (ICP-MS) as a comparative method and no significant differences among these results and the results obtained by the proposed method were observed.

Aluminium as chemical modifier for the determination of lead in sugar cane spirits using electrothermal atomic absorption spectrometry

Aluminium was used as a chemical modifier for the determination of lead in sugar cane spirit samples by electrothermal atomic absorption spectrometry (ET-AAS). Pyrolysis temperature, pyrolysis time and atomisation temperature were 800 °C, 20 s and 1800 °C, respectively. The aluminium mass was 3 µg. Lead was quantified with limits of detection and quantification of 0.14 and 0.47 µg L−1, respectively, and a characteristic mass of 24 pg. Analyte addition experiments demonstrated that external calibration can be performed with aqueous standards. The precision, expressed as relative standard deviation (RSD%), was 3.11% for a sample with a lead concentration of 3.00 µg L−1. There is currently no certified reference material for sugar cane spirits, so a standard reference material of orchard leaves was used to confirm accuracy. The proposed method was used to determine the lead content of five sugar cane spirit samples from Salvador City, Brazil. Their lead contents varied from 3.00 to 19.61 µg L−1. The samples were also analysed by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion in a closed system. No statistical difference was observed between the results obtained by both methods.

Baseline trace elements in the seagrass Halodule wrightii Aschers (Cymodoceaceae) from Todos os Santos Bay, Bahia, Brazil

Trace elements concentrations (As, Ba, Cd, Cr, Cu, Ni, Pb, V and Zn) were found in samples of Halodule wrightii Aschers (Cymodoceaceae) seagrass from Todos os Santos Bay, Bahia, Brazil by inductively coupled plasma mass spectrometry (ICP-MS). This bay has been impacted by the presence of industrial activity that includes chemical and petrochemical plants as well as an oil refinery and harbor activities located in the north and northeastern area. Samples were collected at 4 stations to evaluate the distribution of element concentrations in this area and under different climatic conditions. The mean concentrations, in mgkg(-1), found in dry tissues for all the studied metals and stations were: As (1.08-5.42), Ba (3.72-32.0), Cd (0.135-1.68), Cr (1.15-10.4), Cu (2.23-13.4), Ni (1.95-9.87), Pb (0.873-5.18), V (3.39-22.4) and Zn (13.1-39.5). Statistical analysis (ANOVA) of the seagrass data showed significant inter-site differences for all elements examined except nickel and vanadium.

Multivariate data analysis of trace elements in bivalve molluscs: Characterization and food safety evaluation

Four species of bivalve molluscs (Anomalocardia brasiliana, Iphigenia brasiliana, Lucina pectinata and Trachycardium muricatum) were collected in the Todos os Santos Bay (TSB), Bahia, Brazil, in order to evaluate As, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, Se, V and Zn levels and, consequently, the risk of bivalve mollusc consumption in humans. The samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) after closed-vessel microwave digestion. The accuracy was confirmed using the certified reference materials of oyster tissue (NIST 1566b) and mussel tissue (NIST 2977), and the results were statistically equivalent to the certified values. Application of principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed a tendency to form two groups between samples of Lucina pectinata and Trachycardium muricatum. All species showed As and Cr concentrations higher than the maximum tolerable limit specified in Brazilian legislation.