Simultaneous multielemental analysis of daily food samples by inductively coupled plasma mass spectrometry

Residual levels and health risk assessment of trace metals in Chinese resident diet

Large-scale metal contamination across the food web is an intractable problem due to increasing pollutant emissions, atmospheric transport, and dry and wet deposition of elements. The present study focus on several trace metals that are rarely studied but have special toxicity, including tin (Sn), antimony (Sb), gold (Au), hafnium (Hf), palladium (Pd), platinum (Pt), ruthenium (Ru), tellurium (Te) and iridium (Ir). We investigated trace metals residues and distribution characteristics, and further evaluated the potential health risks from major daily food intakes in 33 cities in China. Sn, Sb, Ir, Hf, and Au were frequently detected in food samples with the concentrations ranged from ND (not detected) to 24.78 µg/kg ww (wet weight). Eggs exhibited the highest residual level of all detected metals (13.70 ± 14.70 µg/kg ww in sum), while the lowest concentrations were observed in vegetables (0.53 ± 0.17 µg/kg ww in sum). Sn accounting for more than 50% of the total trace metals concentration in both terrestrial and aquatic animal origin foods. In terrestrial plant origin foods, Sn and Ir were the most abundant elements. Hf and Au were the most abundant elements in egg samples. In addition, Sb and Ir showed a clear trophic dilution effect in terrestrial environments, while in aquatic ecosystems, Sn, Hf, and Au exhibited obvious trophic amplification effects. The calculated average estimated daily intake (EDI) via food consumption in five regions of China was 0.09 µg/(kg·day), implying the health risk of aforementioned elements was acceptable.

Genetic Dissection of ICP-Detected Nutrient Accumulation in the Whole Seed of Common Bean (Phaseolus vulgaris L.)

Nutrient transport to grain legume seeds is not well studied and can benefit from modern methods of elemental analysis including spectroscopic techniques. Some cations such as potassium (K) and magnesium (Mg) are needed for plant physiological purposes. Meanwhile, some minerals such as copper (Cu), iron (Fe), molybdenum (Mo), and zinc (Zn) are important micronutrients. Phosphorus (P) is rich in legumes, while sulfur (S) concentration is related to essential amino acids. In this research, the goal was to analyze a genetic mapping population of common bean (Phaseolus vulgaris L.) with inductively coupled plasma (ICP) spectrophotometry to determine concentrations of and to discover quantitative trait loci (QTL) for 15 elements in ground flour of whole seeds. The population was grown in randomized complete block design experiments that had been used before to analyze Fe and Zn. A total of 21 QTL were identified for nine additional elements, of which four QTL were found for Cu followed by three each for Mg, Mn, and P. Fewer QTL were found for K, Na and S. Boron (B) and calcium (Ca) had only one QTL each. The utility of the QTL for breeding adaptation to element deficient soils and association with previously discovered nutritional loci are discussed.

Kinetics of cadmium accumulation and elimination in carp Cyprinus carpio tissues

Carp (Cyprinus carpio) were tested for cadmium accumulation and elimination during and after a simulated pollution exposure. Fish were distributed in two 1000-l indoor concrete aquaria supplied with a continuous flow (8 l min(-1)) of well water. The cadmium concentration was maintained at 53 microg l(-1) in one aquarium and 443 microg l(-1) in the other aquarium for 127 days. The exposure phase was followed by a 43-day depuration period. The cadmium accumulation in liver, kidney and muscle was measured by means of ICP-MS. The data showed that cadmium exposure produces significant cadmium uptake in tissues. Cadmium concentrations increased sharply in kidney and liver, whereas the pollutant level in muscle was only significant after 106 days. After 127 days of Cd exposure (53 microg l(-1)), the cadmium concentration in kidney was 4-fold higher than in liver and 50-fold higher than in muscle for a toxic level of 53 microg l(-1). At a Cd of 443 microg l(-1), kidney cadmium content was 2-fold higher than in liver and 100-fold higher than in muscle. In kidney and liver, the toxic concentration increased as the concentration of pollutant in water increased. During the 43 depuration days, the loss of accumulated cadmium was rapid and immediate in muscle. Conversely, no loss of cadmium was observed in kidney and liver.

Liquid-liquid extraction of cadmium by sodium diethyldithiocarbamate from biological matrixes for isotope dilution inductively coupled plasma mass spectrometry

A published procedure for the liquid-liquid extraction of Cd by sodium diethyldithiocarbamate (NaDDC) was modified and tested on 12 biological matrixes of plant and animal origin for use with isotope dilution (ID) inductively coupled plasma mass spectrometry (ICPMS). The tested matrixes were reference materials, certified for Cd, and a feces in-house standard. The digested and extracted standards were analyzed for Cd stable isotopes by ICPMS and the resulting isotope ratios examined for isobaric and polyatomic interferences. Cadmium recoveries, after extraction, ranged from 73% to 20% and apparently were inversely related to Cd concentration, even in the presence of excess chelator. For each reference material, the measured isotope ratios for Cd were corrected for instrumental bias and compared to natural abundance Cd isotope ratios. Nonextracted samples had large isotope ratio deviations for all but one or two ratios. Extraction improved all the isotope ratios measured (lowered % error relative to natural abundances), but interferences were noted for a few samples. The extracted human in-house feces standard was found to have Sn signals reduced by 300-fold, but residual Sn concentrations still interfered with 116Cd, though not 112Cd or 114Cd. Thus, evaluation of the NADDC-extracted in-house fecal standard and reference materials indicate the successful removal of interferences that otherwise prevented accurate determinations of Cd by IDICPMS and show that a number of Cd isotope ratios could be accurately measured (< 1.5% error) for multiple stable isotope tracer studies in a broad range of NaDDC-extracted biological matrixes.

Dietary intake of heavy metals in Bombay city, India

Concentrations of heavy metals such as Pb, Cd, Cu and Zn have been estimated in air particulates, water and food samples collected from different suburbs in Bombay during 1991-1994. The concentrations of these metals are translated into intake rates through inhalation and ingestion pathways. Results indicate the highest concentration of Pb and Cu are in pulses (green gram), Cd in leafy vegetables (amaranth) and Zn in meat. Root vegetables and fruits contained a lower concentration of these metals. Total intakes of Zn, Cu, Pb and Cd through air, water and food were 10,500 micrograms/day, 1500 micrograms/day, 30 micrograms/day and 4.3 micrograms/day, respectively. Although the major contribution for the daily intake is the ingestion route, eventual uptake in the body stream is contributed through inhalation for Pb (41%) and Cd (16%) and ingestion for Cu (98.8%) and Zn (99.6%). The total intake of these elements through the duplicate diet study is 9500 micrograms/day for Zn, 1770 micrograms/day for Cu, 27 micrograms/day for Pb and 2.5 micrograms/day for Cd, respectively. The daily intake of these metals by the population of Bombay is well below the recommended dietary values.

Determination of lead and cadmium in food and blood by inductively coupled plasma mass spectrometry: a comparison with graphite furnace atomic absorption spectrometry

To compare inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectometry (GF-AAS) as the method for determining lead and cadmium in the human diet and blood, 418 diet homogenate samples and the same number of blood samples were collected from Chinese and Japanese women and were analyzed by the two methods. The results showed that our ICP-MS method is precise and accurate, being comparable to the GF-AAS method established previously. The ICP-MS method is simple and fast spending only one-tenth of the time necessary for GF-AAS and allows simultaneous analyses of lead and cadmium with low detection limits. When applied to actual sample analysis, however, ICP-MS results tend to be 10-20% lower than GF-AAS results in the analysis of lead in the diet and blood and cadmium in blood. This is possibly due to some interference in ICP-MS and matrix of samples. As the ICP-MS results could be mathematically corrected to be equivalent to the GF-AAS results, we conclude that this ICP-MS method can be used as a routine analytical method for the determination of lead and cadmium in human diet and blood samples.