Metals In Seawater Samples Research Articles

Simultaneous determination of picomolar level of dissolved silver with other key trace metals in seawater samples using solid phase extraction and isotope dilution methods

Simultaneous determination of dissolved silver (dAg) with other key GEOTRACES trace metals is difficult because dAg in seawater tends to form negatively charged chloride species that result in only 75% recovery efficiency with commonly used NOBIAS PA-1 chelating resins. In this study, we developed a method using solid phase extraction coupled with isotope dilution that enables full quantification (97.9 ± 2.1%) of dAg along with other major trace metals including cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni), and lead (Pb) (recovery efficiency = 100% to 102%) in seawater samples. Seawater samples were first spiked with Ag-109 and allowed to reach isotopic equilibrium before extraction using NOBIAS PA-1 chelating resin. Then, dAg isotope ratios (Ag-109/Ag-107) before and after solid phase extraction were determined and used to quantify dAg. Determination of dAg with dissolved Cd, Cu. Mn, Ni, and Pb in reference seawater material CASS-6 resulted in deviations of between 1.0% and 8.8% from the consensus values, which are well within the standard error of measurement. We then successfully determined the concentrations of dissolved Cd (0.05–0.2 nM), Cu (0.5–13 nM), Mn (10–140 nM), Ni (2–12 nM), Pb (5–110 nM), and Ag (10–40 pM) in Otsuchi Bay, Japan and its surrounding rivers. Evaluation of the behavior of dAg under a salinity gradient using estuarine samples collected from Samunsam River, Malaysia shows increasing dAg concentration with salinity (R2 = 0.68), which suggests release of sedimental Ag under high ambient chloride concentrations. Our new method enables rapid and simultaneous measurements of dAg with other key GEOTRACES trace metals in a single analysis, which is expected to expedite analysis and increase availability of oceanic dAg data globally.

Baseline study on the levels of heavy metals in seawater and macroalgae near an abandoned mine in Manicani, Guiuan, Eastern Samar, Philippines.

Lateritic nickel ore stockpiles are still present in Manicani Island after mining activities were suspended in 2001. This study aimed to assess the water quality in the island by measuring the levels of Pb, Ni and Cu in seawater and Sargassum polycystum samples collected quarterly in 2018. The levels of the three heavy metals in seawater samples were 0.388 ± 0.058-1.508 ± 0.120 mg/L Pb, 0.457 ± 0.003-0.531 ± 0.005 mg/L Cu, and 0.122 ± 0.008-0.628 ± 0.281 mg/L Ni. All values are above the permissible limits recommended by DENR and USEPA. Ni (13.630 ± 7.341-160.120 ± 3.375 mg/kg) had the highest concentration in S. polycystum, significantly higher than Pb (<LD-21.579 ± 0.730 mg/kg) and Cu (2.825 ± 0.110-6.302 ± 0.864 mg/kg). Ni levels in S. polycystum near the mining runoff were significantly higher than in samples from other stations. The results of this study show the contribution of the abandoned mine to the heavy metal pollution of the marine waters in Manicani Island.

Temporal-spatial variations, source identification and ecological risks of nutrients and dissolved metals in seawater of the Southeastern Mediterranean Sea, Egypt

ABSTRACTThe Egyptian Mediterranean coastal zone suffers from several types of pollutants, due to different inputs from industrial, sewage effluents, shipping activities, spillage and coastal activities. In the present study, the nitrogen, phosphorus compounds and dissolved metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) concentrations in the Egyptian Mediterranean seawater were investigated during 2012 to 2015. The aim of the study was to understand the temporal and spatial variations of the determined parameters and their ecological risk along the Egyptian Mediterranean seawater. The relative dominance of metals was in the following decreasing order: Fe>Zn>Mn>Cu>Pb>Cr>Ni>Cd in 2012, Fe>Zn>Pb>Cu>Ni>Cr>Mn>Cd in 2013, Fe>Cu>Zn>Ni>Cr>Mn>Pb>Cd in 2014 and Fe>Ni>Cr>Cu>Zn>Pb>Mn>Cd in 2015. Relatively high levels of Cu, Cr, Cd, Ni, Zn and Pb were detected in El-Mex bay which is one of the most important industrial and trade regions of Alexandria city. While, higher mean values of Fe and Mn were registered in El Burg and El Dekhaila, respectively. El-Dekheila harbor is considered as a part of El-Mex bay which is subjected to several sources of wastewater and the degree of water contamination of the harbor depends on seawater circulation in the bay. The contamination by metals in seawater samples were assessed using metal pollution index, enrichment and contamination factors. Descriptive statistical analysis showed that terrestrial inputs via Nile River and sewages may be the main sources for the dissolved metals and nutrients contamination.

Integrated assessment of the Tarut Island coast, Arabian Gulf, Saudi Arabia

In order to assess pollutants on the Tarut Island coast, Saudi Arabian Gulf, 38 coastal sediment samples, 40 mollusk specimens, and 26 seawater samples were collected for Fe, Cu, Pb, Mn, Cd, Se, As, Co, B, Cr, Hg, Mo and Zn analysis using inductively coupled plasma–mass spectrometer. The analysis indicated that the coastal sediments were enriched, polluted and contaminated with As, Pb, Cd and Hg. Gastropods were good accumulators for Fe, Cu, Zn, Pb, Mn, Cd and Co while bivalves were good accumulators for Se, Cr and Hg. The spatial distribution of heavy metals in seawater samples indicated no obvious trend along the studied coast. Land reclamation, dust storms, petrochemical industries, oil leakage, desalination plants and sewage effluents were the significant sources of heavy metal pollutants along Tarut coast. The comparison between heavy metals in the Tarut Island coast and other worldwide coasts was emphasized.

Study of heavy metal levels in seawater in the vicinity of Single Buoy Moorings at Mina Al Fahal, Sultanate of Oman

ABSTRACTThis study was conducted to determine the concentrations of cadmium, copper, lead, and vanadium in seawater samples taken from the vicinity of Single Buoy Mooring 3 (SBM3) at Mina Al Fahal in the Sultanate of Oman. SBM3 is one of three locations at Mina Al Fahal (SBM1 and SBM2) associated with importing and exporting refined petroleum products. Using graphite furnace atomic absorption spectrophotometry, concentrations of these four metals in seawater samples were measured in six samples. None of the metals was present in concentrations greater than the European Commission/United Kingdom Environmental Quality Standards, but a comparison to previous data collected at SBM2 indicates that concentrations have increased approximately 40% over the past two decades. To better identify sources of the metals, it is imperative to monitor effluents and collect more targeted samples at and/or near discharge points.

Sample Pretreatment Using Chitosan-based Chelating Resin for the Determination of Trace Metals in Seawater Samples by Inductively Coupled Plasma-Mass Spectrometry

A sample-pretreatment method using a chitosan-based chelating resin, ethylenediamine-N,N,N'-triacetate-type chitosan (EDTriA-type chitosan), was developed for the preconcentration of trace metals in seawater and separation of the seawater matrix prior to their determination by inductively coupled plasma-mass spectrometry (ICP-MS). The resin showed very good adsorption for transition metals and rare-earth elements without any interference from alkali and alkaline-earth metals in an acidic media. In the proposed method, an aliquot of a 50-mL sample at pH 4 was used. Metals adsorbed on the resin were eluted using 10 mL of 1 M nitric and measured by ICP-MS. The method was evaluated by the analysis of NASS-5 seawater reference materials for trace metals. Good agreement was obtained for most metals, which indicates that by the proposed pretreatment using the synthesized resin, seawater samples can be favorably measured by ICP-MS.

Synthesis of hydrophilic macroporous chelating polymers and their versatility in the preconcentration of metals in seawater samples

We systematically synthesized hydrophilic matrix polymers using glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA) by the radical suspension copolymerization method. Methyl iso-butylketone added to the monomer phase as a porogen was effective in the formation of macroporous structures. Triethylenetetramine (TTA) was introduced on the matrix polymers as a chelating moiety (PGMA-EGDMA-TTA), and the adsorption and desorption characteristics of the obtained chelating polymers for several metals were investigated. A better candidate, PGMA-EGDMA-TTA polymer, was packed into a column and the applicability for the preconcentration of metals in seawater samples was tested. A PGMA-EGDMA-TTA possesses the preferable adsorptivity for metals at the seawater pH and a favorable desorption profile using an acid eluent. In addition, a PGMA-EGDMA-TTA-packed column was effective for the preconcentration of metals in the seawater samples.

Determination of trace elements in seawater samples by on-line column extraction/graphite furnace atomic absorption spectrometry

An innovative procedure for the on-line coupling of ion chromatography with graphite furnace atomic absorption spectrometry is described, which is particularly effective for the determination of trace metals in seawater samples. The Capillary Injection Device (CID) is used as an interface which allows the eluent to be transferred from the chromatographic column into the graphite tube at a flow rate of as high as 2 ml/min. The analytical procedure is based on the metal complex formation with 8-hydroxyquinoline in the sample solution, followed by the preconcentration of the complexes in a chromatographic column packed with XAD-2 resin. The complexes were then eluted from the column with methanol, and quantitatively injected into the furnace. The procedure was validated by determining cadmium and lead in certified reference seawater samples at a level of 30–40 pg/g, with a typical reproducibility of 10% and an accuracy of better than 5%. Finally, it was tested on a real sample of seawater. Due to the high reproducibility, a pg/g concentration level can be measured.

Inductively coupled plasma mass spectrometric determination of heavy metals in sea-water samples after pre-treatment with a chelating resin disk by an on-line flow injection method.

A new on-line flow injection (FI) pre-treatment system using a disk-type chelating resin (5 mm diameter, 0.5 mm thickness) was developed for the simultaneous multi-element determination of trace metals in sea-water samples by inductively coupled plasma mass spectrometry (ICP-MS). A chelating resin possessing an iminodiacetate (IDA) functional group was used for the collection of trace elements and the elimination of alkali and alkaline earth metals in highly concentrated salt solution. A 1 ml volume of a sea-water sample (pH 5.5) was applied to the chelating resin disk. Considering the removal efficiency for Ca, 50 mM ammonium acetate buffer solution (pH 5.5) was chosen as a sample carrier. The enriched trace metals were eluted with 0.1 M nitric acid and the eluate flowed into the ICP-MS system. The processing time for one sample was < 6 min (350 s). One of the important observations is the possibility of working with a low recovery, even lower than 50%. For example, several elements such as Mn, Cr, As, Mo, Ba and U, the recovery of which was < 50% in a batch-wise method, showed good linearity and reproducibility. The proposed method was evaluated by analyzing two kinds of sea-water certified reference materials, CASS-4 and NASS-5. Analytical data for eight heavy metals, V, Mn, Co, Ni, Cu, Mo, Cd and U, obtained from the present study agreed well with the certified values.

Capabilities and limitations of different techniques in electrothermal atomic absorption spectrometry for direct monitoring of arsenic, cadmium and lead contamination of sea-water

Three atomization techniques for electrothermal atomic absorption spectrometry (ETAAS), namely, wall, platform and graphite probe have been tested and critically compared for the direct determination of arsenic, cadmium and lead in sea-water. The best analytical performance was obtained using totally pyrolytic graphite platforms inserted in pyrolytic graphite coated graphite tubes, peak height measurement mode and the addition of chemical modifier (10 µg of palladium as nitrate). For arsenic determination the modifier was injected together with the sample (WET mode), while for cadmium and lead determination the modifier was previously reduced to Pd0 by in situ thermal decomposition of the palladium nitrate (DRY mode). With regard to sample pre-treatment, the sea-water was injected directly onto the platform for arsenic measurements, while dilution with ultrapure water (1 + 1) was preferable for lead and a dilution (1 + 3) with 25% ammonium nitrate solution was needed for cadmium. The limits of detection (LODs) for the three toxic elements, relative to the real samples (undiluted sea-water) analysed, were 1.7 µg l–1 for arsenic, 1.0 µg l–1 for cadmium and 1.3 µg l–1 for lead. The recoveries obtained for all three metals in sea-water samples were 100 ± 5% using the recommended ETAAS procedures. The analytical performances of the proposed methods are given. Quantification limits observed (5 × LOD) warrant the application of these methods to direct monitoring and control of contaminated waters for arsenic, cadmium and lead. However, when ‘normal’ levels of the metals in sea-water have to be determined adequate preconcentration techniques are needed.