Assessment of essential elements and chemical contaminants in thirteen fish species from the Bay Aratu, Bahia, Brasil / Avaliação de elementos químicos essenciais e contaminantes em treze espécies de peixes da Baía de Aratu, Bahia, Brasil

Abstract Concentrations of ten elements (Cd, Cr, Cu, Fe, Ni, Pb, Se, Sr, V and Zn) were determinate in muscle tissues of 13 fish species from Aratu Bay, Bahia, Brazil by inductively coupled plasma optical emission spectrometry. The accuracy and precision of our results were checked by using two certified reference materials: BCR-422 cod muscle and SRM 1566b oyster tissue. The average trace element concentrations in the fish species varied in the following ranges, in μg g–1: 0.03-0.8 for Cr; 2.0-33.7 for Cu, 2.4-135.1 for Fe, 1.6-25.6 for Se; 1.6-35.1 for Sr; and 2.8-40.5 for Zn. The Diaptereus rhombeus (carapeba) specie presented the highest concentrations of Se, Cu and Fe. Chromium and Se were present at levels above the limit of tolerance allowed by the National Agency of Sanitary Vigilance (ANVISA). The results were also evaluated using the multivariate analysis techniques: principal component analysis (PCA) and hierarchical cluster analysis (HCA).

Resumo Foram determinadas as concentrações de dez elementos (Cd, Cr, Cu, Fe, Ni, Pb, Se, Sr, V and Zn) em tecidos de músculos de treze espécies de peixes da Baía de Aratu, Bahia, Brasil, utilizando a espectrometria de emissão ótica com plasma indutivamente acoplado. A precisão e exatidão dos resultados foram analisadas utilizando dois materiais de referência certificada: BCR-422 cod muscle e o SRM 1566b oyster tissue. A concentração média dos elementos traço nas espécies de peixes variaram nas seguintes faixas, em μg g−1: Cr = 0,03-0,8; Cu = 2,0-33,7, Fe = 2,4-135,1, Se = 1,6-25,6; Sr = 1,6-35,1; Zn = 2.8-40.5. A espécie Diaptereus rhombeus (carapeba) apresentou as maiores concentrações de Se, Cu e Fe. Cromo e Se apresentaram níveis acima do limite de tolerância estabelecido pela Agência Nacional de Vigilância Sanitária (ANVISA). Os resultados ainda foram avaliados usando técnicas de análises multivariadas: análise de componente principal (PCA) e análise de agrupamento hierárquico (HCA).

Assessment of essential elements and chemical contaminants in thirteen fish species from the Bay Aratu, Bahia, Brasil.

Concentrations of ten elements (Cd, Cr, Cu, Fe, Ni, Pb, Se, Sr, V and Zn) were determinate in muscle tissues of 13 fish species from Aratu Bay, Bahia, Brazil by inductively coupled plasma optical emission spectrometry. The accuracy and precision of our results were checked by using two certified reference materials: BCR-422 cod muscle and SRM 1566b oyster tissue. The average trace element concentrations in the fish species varied in the following ranges, in µg g-1: 0.03-0.8 for Cr; 2.0-33.7 for Cu, 2.4-135.1 for Fe, 1.6-25.6 for Se; 1.6-35.1 for Sr; and 2.8-40.5 for Zn. The Diaptereus rhombeus (carapeba) specie presented the highest concentrations of Se, Cu and Fe. Chromium and Se were present at levels above the limit of tolerance allowed by the National Agency of Sanitary Vigilance (ANVISA). The results were also evaluated using the multivariate analysis techniques: principal component analysis (PCA) and hierarchical cluster analysis (HCA).

Distribution of trace elements in tissues of shrimp species Litopenaeus vannamei (Boone, 1931) from Bahia, Brazil.

In this study, concentrations of trace elements in tissues of shrimp species (Litopenaeus vannamei) from farming and zone natural coastal located in the northeastern Brazil were investigated. The elements determination was performed by optical emission spectrometry with inductively coupled plasma (ICP OES). The following ranges of concentrations in the tissues were obtained in µg g-1 dry weight: Al: 13.4-886.5, Cd: 0.93-1.80; Cu: 24.8-152; Fe: 3.2-410.9; Mn: 0.36-24.4; Se: 0.094-9.81 and Zn: 20.3-109.4. The shrimp muscle can be a good iron source (about 88.9 mg-1g dry weight). The distribution of Se concentration in tissues showed much variation between locations, and the concentration levels found in shrimp muscles of wild samples were high, where its levels in 67% of muscle and 50% of others tissues samples exceeded the ANVISA limit, indicating evidence of selenium bioaccumulation. Significant correlation was observed between the following pairs of elements: Fe-Zn (r= -0.70), Mn-Cu (r= -0.74), Se-Cu (r= -0.68), Se-Mn (r= 0.82) in the muscles; Fe-Al (r= 0.99), Mn-Al (r= 0.62), Mn-Fe (r= 0.62), Se-Al (r = 0.88), Se-Fe (r= 0.87), Se-Mn (r= 0.58) in the exoskeleton and Cu-Zn (r = 0.68), Al-Cu (r= 0.88), Fe-Cu (r= 0.95) and Fe-Al (r= 0.97) in the viscera.

Distribution of trace elements in tissues of shrimp species Litopenaeus vannamei (Boone, 1931) from Bahia, Brazil / Distribuição de elementos traço em tecidos do camarão Litopenaeus vannamei (Boone, 1931) da Bahia, Brasil

Abstract In this study, concentrations of trace elements in tissues of shrimp species (Litopenaeus vannamei) from farming and zone natural coastal located in the northeastern Brazil were investigated. The elements determination was performed by optical emission spectrometry with inductively coupled plasma (ICP OES). The following ranges of concentrations in the tissues were obtained in µg g–1 dry weight: Al: 13.4-886.5, Cd: 0.93-1.80; Cu: 24.8-152; Fe: 3.2-410.9; Mn: 0.36-24.4; Se: 0.094-9.81 and Zn: 20.3-109.4. The shrimp muscle can be a good iron source (about 88.9 mg–1g dry weight). The distribution of Se concentration in tissues showed much variation between locations, and the concentration levels found in shrimp muscles of wild samples were high, where its levels in 67% of muscle and 50% of others tissues samples exceeded the ANVISA limit, indicating evidence of selenium bioaccumulation. Significant correlation was observed between the following pairs of elements: Fe-Zn (r= –0.70), Mn-Cu (r= –0.74), Se-Cu (r= –0.68), Se-Mn (r= 0.82) in the muscles; Fe-Al (r= 0.99), Mn-Al (r= 0.62), Mn-Fe (r= 0.62), Se-Al (r = 0.88), Se-Fe (r= 0.87), Se-Mn (r= 0.58) in the exoskeleton and Cu-Zn (r = 0.68), Al-Cu (r= 0.88), Fe-Cu (r= 0.95) and Fe-Al (r= 0.97) in the viscera.

Resumo Esse estudo teve como objetivo avaliar as concentrações de elementos traço em tecidos da espécie de camarão Litopenaeus vannamei coletadas da zona costeira e de carciniculturas localizadas no nordeste do Brasil. Os elementos químicos foram determinados por espectrômetro de emissão óptica com plasma indutivamente acoplado (ICP OES). Foram encontradas as seguintes faixas de concentrações desses elementos nos tecidos (em mg g–1 peso seco): Al: 13,4-886,5; Cd: 0,93-1,80; Cu: 24,8-152; Fe: 3,2-4109; Mn: 0,36-24,4; Se: 0,094-9,81 and Zn: 20,3-109,4. O músculo do camarão investigado pode ser uma boa fonte de ferro (cerca de 88.9 mg-1g peso seco). A distribuição da concentração de Se nos tecidos apresentou muita variação entre as localidades, com níveis acima do estabelecido pela ANVISA para 67% dos musculos e 50% dos outros tecidos investigados, indicando evidências de bioacumulação do selênio. Houve correlações significativas entre os seguintes pares de elementos:: Fe-Zn (r= –0,70), Mn-Cu (r= –0,74), Se-Cu (r= –0,68), Se-Mn (r= 0,82) nos músculos, Fe-Al (r= 0,99), Mn-Al e Mn-Fe (r= 0,62), Se-Al (r = 0,88), Se-Fe (r= 0,87), Se-Mn (r= 0,58) no exoesqueleto e Cu-Zn (r = 068), Al-Cu (r= 0,88), Fe-Cu (r= 0,95) and Fe-Al (r= 0,97) nas vísceras.

Focused microwave-induced combustion for digestion of botanical samples and metals determination by ICP OES and ICP-MS.

The advantages and shortcomings of focused microwave-induced combustion (FMIC) for digestion of plant samples were studied. The effects of sample mass, absorbing solution, oxygen gas flow-rate, and time of reflux step on recoveries of major, minor and trace metals were systematically evaluated. Afterwards, Al, Ba, Ca, Co, Cr, Cu, Mg, Mn, Ni, Sr, V, and Zn were determined by inductively coupled plasma optical emission spectrometry (ICP OES) and by inductively coupled plasma mass spectrometry (ICP-MS). The main advantages of FMIC when compared to microwave-assisted wet digestion (MAWD) and focused-microwave-assisted wet digestion (FMAWD) are the possibility to digest larger masses of samples (up to 3g) using shorter heating times and diluted nitric acid solution for absorbing all analytes. Using the selected experimental conditions for FMIC, residual carbon content was lower than 0.7% for all samples and relative standard deviation (RSD) varied from 1.5 to 14.1%. Certified reference materials (NIST 1515 apple leaves and NIST 1547 peach leaves) were used for checking accuracy and determined values for all metals were in agreement with certified values at a 95% confidence level. No statistical difference (ANOVA, 95% of confidence level) was observed for results obtained by FMIC, FMAWD, and MAWD. Limits of detection were lower when using FMIC in the range of 0.02-0.15 µg g(-1) for ICP OES and 0.001-0.01 µg g(-1) for ICP-MS, which were about 3 and 6 times lower than the values obtained by FMAWD and MAWD, respectively. It is important to point out that FMIC was a suitable sample preparation method for major, minor and trace metals by both determination techniques (ICP OES and ICP-MS). Additionally, since it allows lower LODs (because up to 3g of sample can be digested) and diluted acid solutions are used (without any further dilution), the use of ICP-MS is not mandatory.

ICP-AES determination of small amounts of zinc in copper-base alloys after separation by adsorption of the zinc-TAN complex on Sep Pak C18 cartridges.

The use of ICP/AES for the determination of zinc, in low concentration levels, in matrices containing high levels of copper is difficult because copper interferes in the zinc main emission wavelength (213.856 nm). In the present work, a separation of zinc from copper matrices was possible, using the reaction of zinc(II) cation with 1-(2-tiazolylazo)-2-naphthol (TAN), in the pH range of 6.5-8.0, resulting in a stable red complex. Copper also reacts with TAN but its interference was avoided by the addition of ascorbic acid and thiosulphate in the reaction medium. In this way, the aqueous solution was passed through a SEP PAK C18 cartridge, in which the zinc(II)-TAN complex was quantitatively retained, but it did not occur with copper which passes through the cartridge, as [Cu(2)(S(2)O(3))(2)](2-), with the aqueous solution. The cartridge was washed with water and the complex eluted with ethanol. Then, the alcohol was evaporated and the complex decomposed by nitric acid. It results in both zinc pre-concentration and separation from copper. The zinc quantification was carried out by ICP/AES at 213.856 nm. The relative standard deviations, for ten different aliquots, were 5.7% and the average recovery found for zinc was 96%, even when the concentration ratio Cu/Zn was up to 500/1 (mg l(-1):mg l(-1)). Other metals, like nickel, for example, can react with TAN in the same way as zinc but they do not interfere in the emission wavelength 213.856 nm.

An indirect method for the determination of chromium species in water samples by sequential inductively coupled plasma-atomic emission spectrometry.

Determination of Cr(VI) and Cr(III) in water samples by inductively coupled argon plasma-atomic emission spectrometry (ICP-AES) was performed indirectly employing an on-line system. For this purpose a column with copper shavings was used to reduce Cr(VI) to Cr(III) in acidic media, generating Cu(II) ions in the flow path. This process permitted the evaluation of concentrations in the range of 1-50 mg/l. The protocol allowed a throughput of 100 samples per hour with 10% precision in the concentration.