Atomic Absorption Spectrometry For Hg Research Articles

Arsenic quantification techniques and ISO/IEC 17025 accreditation in Brazil

The importance of arsenic (As) quantification in environmental compartments is due to its risks to ecosystems and public health. There are reports of high concentrations of this metalloid in Brazil and technological differences between states are observed. The objective of this work was to present and discuss current scenarios of accreditation and compare the limit of quantification (LOQ) of As by analytical technique in Brazil. Data from accredited laboratories were collected on Inmetro website and in state metrological networks and then grouped and analyzed by state, matrix and analytical technique. There are large discrepancies between the number of laboratories per state and a good correlation with gross domestic product (GDP). Almost all laboratories have a LOQ less than the environmental limits. The observed list of techniques sorted from lowest to highest LOQ values is: for liquid samples ICP MS (inductively coupled plasma mass spectrometry), ET AAS (electrothermal atomic absorption spectrometry), HG AAS (hydride generation combined with atomic absorption spectrometry) or HG ICP OES (hydride generation combined with inductively coupled plasma optical emission spectrometry) and UV VIS (visible ultraviolet spectroscopy); for solids samples HG ICP OES, ICP MS, HG AAS, ET AAS and FAAS (flame atomic absorption spectrometry); and for bioindicators ICP MS, HG ICP OES. Analysis of As species is accredited in only one laboratory, but does not include all species.

Heavy Metal Concentrations in Free-Living Southern Caracaras (Caracara plancus) in the Northeast Region of Brazil

Background: With the continuously increasing release of heavy metals in the environment, mostly from anthropogenic sources, there is a need to find ways of evaluating and managing the issuance of these contaminants and correct its damages. The birds being at the top of some food chains reflect the presence of metals in the environment, keeping this in perspective, raptors have been successfully used for heavy metals biomonitoring studies in the past. The purpose of this study was to identify and quantify cadmium (Cd), mercury (Hg), lead (Pb), copper (Cu), and chromium (Cr) in the feathers and livers of free-living southern caracaras, live and dead, from Recife, Pernambuco state, Northeast of Brazil.Material, Methods & Results: Sixty-two feathers from live and dead southern caracaras and 21 livers from dead southern caracaras were analyzed by atomic absorption spectrometry for Hg and by inductively coupled plasma optical emission spectrometry for Cd, Cr, Pb, and Cu. Concentrations of Cr and Cu elements were detected in all feather and liver samples analyzed from live and dead caracaras. There was no difference in the concentration of metals between feathers of dead and live caracaras: Pb (P = 0.3576), Cd (P = 0.0792), Cr (P = 0.5475), and Cu (P = 0.3603), but significant variation was observed for Hg (P = 0.0459). The highest concentrations of Pb (P < 0.0001) and Cr (P < 0.0001) were found in the feathers than in the liver. On the other hand, the highest concentrations of Cu were found in liver samples (P = 0.0011). No significant variation in the concentrations of Cd (P = 0.7770) and Hg (P = 0.3669) was found between feathers and liver samples.Discussion: Chromium, as well as Hg, and Cu have a high affinity for keratin, which may explain the higher concentrations of Cr in caracaras feathers in this research. Lead was detected in all liver samples analyzed. Elevated levels were also found in the feathers of dead (95.2%) and live (75.6%) caracaras. The presence of Pb may be due to external contamination by pollutants, such as fossil fuels. Higher concentrations of Hg were observed in dead caracaras feathers, this concentrations change during molting but are not affected by external contamination. Metals, such as Hg, and Cd, accumulate in organisms from different trophic levels, which may indicate that this contamination comes mainly from feed. Pearson’s coefficient here showed no correlation between metals from dead caracaras feathers and livers, although a few previous studies have shown a correlation between metal concentrations from tissues and feathers. This pattern can be attributed to the different time of exposure of feathers to metals in relation to livers. The concentrations of metals in hepatic tissues reflect the levels of elements in the diet of these birds, characterizing acutely the contamination of the ecosystem. On the other hand, feathers represent the exposure in the time of molting, when the artery supplies metals, thus representing a chronic exposure. In feathers from live birds, the Pearson’s correlation analysis showed a high to moderate correlation between metals, which may suggest that they come from a similar source, but there is no way to specify the origin since the metals surveyed could be present in the soil, water, or in the prey eaten by these animals. For the purpose of environmental analyses, it is required to determine the exact source of contamination. Considering that it is possible to confirm the presence of these heavy metals in southern caracaras, these birds may be important environmental bioindicators. The development of systematic research on animals and the environment is essential for monitoring the levels of metal pollutants and evaluating their impact in order to guide measures to protect fauna and human health.

Elemental composition of ambient aerosols measured with high temporal resolution using an online XRF spectrometer

Abstract. The Xact 625 Ambient Metals Monitor was tested during a 3-week field campaign at the rural, traffic-influenced site Härkingen in Switzerland during the summer of 2015. The field campaign encompassed the Swiss National Day fireworks event, providing increased concentrations and unique chemical signatures compared to non-fireworks (or background) periods. The objective was to evaluate the data quality by intercomparison with other independent measurements and test its applicability for aerosol source quantification. The Xact was configured to measure 24 elements in PM10 with 1 h time resolution. Data quality was evaluated for 10 24 h averages of Xact data by intercomparison with 24 h PM10 filter data analysed with ICP-OES for major elements, ICP-MS for trace elements, and gold amalgamation atomic absorption spectrometry for Hg. Ten elements (S, K, Ca, Ti, Mn, Fe, Cu, Zn, Ba, Pb) showed excellent correlation between the compared methods, with r2 values ≥ 0.95. However, the slopes of the regressions between Xact 625 and ICP data varied from 0.97 to 1.8 (average 1.28) and thus indicated generally higher Xact elemental concentrations than ICP for these elements. Possible reasons for these differences are discussed, but further investigations are needed. For the remaining elements no conclusions could be drawn about their quantification for various reasons, mainly detection limit issues. An indirect intercomparison of hourly values was performed for the fireworks peak, which brought good agreement of total masses when the Xact data were corrected with the regressions from the 24 h value intercomparison. The results demonstrate that multi-metal characterization at high-time-resolution capability of Xact is a valuable and practical tool for ambient monitoring.

Quantification of Heavy Metals and Other Inorganic Contaminants on the Productivity of Microalgae.

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages include high potential yield, use of non-arable land and integration with waste streams. The nutrient requirements of a large-scale microalgae production system will require the coupling of cultivation systems with industrial waste resources, such as carbon dioxide from flue gas and nutrients from wastewater. Inorganic contaminants present in these wastes can potentially lead to bioaccumulation in microalgal biomass negatively impact productivity and limiting end use. This study focuses on the experimental evaluation of the impact and the fate of 14 inorganic contaminants (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, V and Zn) on Nannochloropsis salina growth. Microalgae were cultivated in photobioreactors illuminated at 984 µmol m(-2) sec(-1) and maintained at pH 7 in a growth media polluted with inorganic contaminants at levels expected based on the composition found in commercial coal flue gas systems. Contaminants present in the biomass and the medium at the end of a 7 day growth period were analytically quantified through cold vapor atomic absorption spectrometry for Hg and through inductively coupled plasma mass spectrometry for As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, Se, Sn, V and Zn. Results show N. salina is a sensitive strain to the multi-metal environment with a statistical decrease in biomass yieldwith the introduction of these contaminants. The techniques presented here are adequate for quantifying algal growth and determining the fate of inorganic contaminants.

Evaluation of the three most commonly used analytical methods for determination of inorganic arsenic and its metabolites in urine

This work compares the three most common analytical methods for determination of inorganic arsenic and its metabolites in urine: high performance liquid chromatography coupled to either inductively coupled plasma mass spectrometry or atomic fluorescence spectrometry via hydride generation (high performance liquid chromatography-hydride generation-inductively coupled plasma mass spectrometry (HPLC-HG-ICPMS) and HPLC-HG-atomic fluorescence spectrometry (AFS), respectively) and atomic absorption spectrometry coupled to HG (HG-atomic absorption spectrometry (AAS)). This was done with the focus to find alternatives to ICPMS, the investment and running costs of which are rather high. Between-laboratory comparison of HPLC-HG-ICPMS and HPLC-HG-AFS showed good agreement for inorganic arsenic, methylarsonate (MA) and dimethylarsinate (DMA) ( R 2 = 0.91, R 2 = 0.92 and R 2 = 0.90, respectively, N = 86). Within-laboratory comparisons of HPLC-HG-AFS, HPLC-HG-ICPMS and HG-AAS showed good agreement for all arsenic species and the sum of inorganic arsenic and its metabolites in urine (HPLC-HG-ICPMS versus HPLC-HG-AFS: R 2 = 0.95; HG-AAS versus HPLC-HG-AFS: R 2 = 0.95 and HPLC-HG-ICPMS versus HG-AAS: R 2 = 0.97; N = 89). HPLC-HG-AFS was found to be a simple, but high quality alternative to HPLC-HG-ICPMS for the speciation and quantification of inorganic arsenic and its metabolites in urine at arsenic concentrations above 10 μg L −1. Because of its considerably lower costs compared to HPLC-HG-ICPMS, it may be a good alternative in laboratories where the high cost of ICPMS is not justified in relation to the intended use of the instrument.

Chemical composition of the sediment from Lake 20 (Antarctica)

Lake 20 (19,000 m2) is located on the coast of the Ross Sea, in the North-Central part of Victoria Land, and its surface is ice-free between the end of December and early February. Within the framework of the Italian National Research Programme in Antarctica, a study was made of the chemical composition of sediments from the lake, with the intention of using this information to contribute to a better understanding of the processes involved in the long range transport of pollutants and their role in global changes. A sediment core from Lake 20 (Antarctica), 18 cm long, was collected in 1994, sliced into 2 cm sections and analysed using X Ray fluorescence spectrometry for 17 elements (Si, Al, Ca, K, Fe, Mg, Ti, S, P, Pb, Zn, Cu, Ni, Mn, Cr, Na, Cl), by CHN Elemental Analyser for C and N, by Flameless Atomic Absorption Spectrometry for As, and by Cold Vapour Atomic Absorption Spectrometry for Hg. The chemical composition of the sediments is consistent with the known geochemical characteristics of the drainage basin. While the chemical analyses reveal that sedimentation in Lake 20 has changed through time, the variations along the core are most probably related to the climatic evolution of the area, to the consequent changes in weathering processes, and possibly to an increase in the primary productivity of the lake, rather than to anthropogenic influences on the biogeochemical cycles of the elements.

Trace metal levels in the raw and tinned squid Loligo patagonica.

The cadmium, silver, lead, copper, zinc, manganese, iron and mercury levels in the edible and inedible tissues of raw and tinned Loligo patagonica squid were determined using flame atomic absorption spectrometry (AAS) for Cd, Ag, Pb, Cu, Zn, Mn and Fe and cold-vapour AAS for Hg. The mean values obtained relative to the wet-weight (mg/kg) for the edible parts (skinless mantle, arms and crone and fin) of the raw and tinned (mantle) squid, and in whole raw and tinned squid, were: 0.32, 0.32, 0.31, 4.3, 3.2 and 3.0 for Cd, 1.0, 0.34, 0.77, 0.27, 0.59 and 0.44 for Pb, 7.8, 5.5, 11, 33, 22 and 26 for Cu, 12, 13, 12, 19, 16 and 17 for Zn, 0.38, 0.45, 0.48, 0.75, 0.48 and 0.73 for Mn and 2.7, 2.3, 3.4, 3.4, 2.2 and 9.4 for Fe, respectively. The content of silver and mercury in the mantle of the tinned squid were 0.18 and 0.012 mg/kg, respectively. As a consequence of whole squid processing, highly elevated levels of cadmium, and also somewhat higher levels of some of the other trace metals, were found in the edible parts of the tinned squid. The content of cadmium in the edible parts of the squid in all instances exceed, and for edible parts of the tinned whole squid considerably exceed, the proposed tolerance limit for cadmium in fishery products (0.05 mg/kg).