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Chile is one of the major producers of phytocolloids extracted from seaweed. Multicellular algae are considered to be primary accumulators of arsenic. We analyzed 14 species of algae belonging to the groups Rhodophyceae (10), Phaeophyceae (3) and Chlorophyceae (1) from different coastal zones of Chile in 2003-2004. Dry ashing mineralization (for total As) and acid digestion (for inorganic As) together with quantification by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) were employed. In general, total arsenic concentrations varied between 3.0 and 68mgkg -1, whereas inorganic arsenic concentrations ranged between 0.15 and 1.06mgkg -1. The algal species Durvillaea antarctica and Porphyra columbina, used for direct human consumption, did not have inorganic arsenic levels that represent a health risk to consumers. Among species used for phytocolloids production, such as Macrocystis piryfera, Gracilaria chilensis and Gigartina skottsbergii, observed levels of inorganic arsenic were greater than 1mgkg -1, the limit value established by the regulations of some countries. Among the 14 species of algae tested, inorganic arsenic levels were between 0.8% and 13% of the total arsenic concentrations; that is, arsenic present in these algae was found primarily as organic arsenic.

Soils from the alluvial flats of the Turia River, Valencia, Spain, which were highly contaminated by decades of industrial activity, were surveyed for native plant species that could be candidates useful in phytoremediation. Concentrations of heavy metals and arsenic (As) in soils reached 25,000 mg Kg-1 Pb, 12,000 mg Kg-1 Zn, 70 mg Kg-1 Cd, and 13500 mg Kg-1 As. The predominant vegetation was collected and species identified. Soil samples and the corresponding plant shoots were analyzed to determine the amount of As accumulated by the various plant species. Several were able to tolerate more than 1000 mg Kg-1 As in the soil. Bassia scoparia (Chenopodiaceae) survive in soil with 8375 mg Kg-1 As. Arsenic accumulation in shoots of the various plant species investigated ranged from 0.1 to 107 mg Kg-1 dw. Bassia scoparia (Chenopodiaceae), Inula viscosa (Asteraceae), Solanum nigrum (Solanaceae), and Hirschfeldia incana (Brassicaceae) had the highest values for As accumulation.

Total arsenic, inorganic arsenic, lead and cadmium contents were determined in 112 samples of seaweed preparations sold in Spain (seaweed packed in plastic or cardboard box, seaweed in the form of tablets and concentrates, foods containing seaweed, and canned seaweed). The concentration ranges found, expressed in mg/kg, dry weight, were: total As (0.031-149), inorganic As (<0.014-117), Pb (<0.050-12.1) and Cd (<0.003-3.55). For all the contaminants there were failures to comply with legislated values. In particular, all the samples of Hizikia fusiforme exceeded the inorganic As limit established in some countries, and a considerable number of species exceeded the Cd limit set by international regulations. With respect to food safety, consumption of 3 g/day of the samples analysed could represent up to 15% of the respective Tolerable Daily Intakes (TDI) established by the WHO. The situation is especially alarming for intake of inorganic As from H. fusiforme, which can be three times the TDI established.

Nicotiana glauca transformed with TaPCS1 was tested for its application in phytoremediation. When plantlets were grown in mine soils containing Cu, Zn, and Pb (42, 2600, and 1500 mg kg−1) the plant showed high levels of accumulation especially of Zn and Pb. Adult plants growing in mine soils containing different heavy metal concentrations showed a greater accumulation as well as an extension to a wider range of elements, including Cd, Ni and B. The overexpressed gene confers up to 9 and 36 times more Cd and Pb accumulation in the shoots under hydroponic conditions, and a 3- and 6-fold increase in mining soils. When the hyperaccumulator Thlaspi caerulescens was compared, the results were higher values of heavy metal and Boron accumulation, with a yield of 100 times more biomass. Thlaspi was unable to survive in mining soils containing either a level higher than 11 000 mg kg−1 of Pb and 4500 mg kg−1 of Zn, while engineered plants yielded an average of 0.5 kg per plant.

The aim of this study was to examine arsenic species contents in raw and cooked edible seaweed and the bioaccessibility (maximum soluble concentration in gastrointestinal medium) of arsenosugars (glycerol ribose, phosphate ribose, sulfonate ribose, and sulfate ribose). For the analysis, a new chromatographic separation was developed in anion exchange, coupled with thermooxidation-hydride generation-atomic fluorescence spectrometry. An in vitro digestion (pepsin, pH 2; pancreatin-bile extract, pH 7) was applied to estimate arsenosugar bioaccessibility. Cooking of Undaria pinnatifida and Porphyra sp. did not alter the arsenic species present in the methanol-water extract, but it produced a substantial increase (2 and 5 times) in the As(V) extracted from Hizikia fusiforme. In all of the seaweeds analyzed, arsenosugar bioaccessibility was high (>80%) and did not vary as a result of cooking. Arsenosugar degradation as a result of in vitro digestion was not observed. © 2005 American Chemical Society.

The total arsenic, inorganic arsenic, lead, cadmium, and mercury contents of 18 algae food products currently on sale in Spain were determined. The suitability of the analytical methodologies for this type of matrix was confirmed by evaluating their analytical characteristics. The concentration ranges found for each contaminant, expressed in milligrams per kilogram of dry weight, were as follows: total arsenic, 2.3-141; inorganic arsenic, 0.15-88; lead, <0.05-1.33; cadmium, 0.03-1.9; and mercury, 0.004-0.04. There is currently no legislation in Spain regarding contaminants in algae food products, but some of the samples analyzed revealed Cd and inorganic As levels higher than those permitted by legislation in other countries. Given the high concentrations of inorganic As found in Hizikia fusiforme, a daily consumption of 1.7 g of the product would reach the Provisional Tolerable Weekly Intake recommended by the WHO for an average body weight of 68 kg. A more comprehensive study of the contents and toxicological implications of the inorganic As present in the algae food products currently sold in Spain may be necessary, which might then be the basis for the introduction of specific sales restrictions.

The concentrations of arsenobetaine (AB), tetramethylarsonium ion (TMA+), and trimethylarsine oxide (TMAO) were determined in samples of sole, dory, hake, and sardine, raw and after being subjected to cooking processes - baking, frying, and grilling - at various temperatures. In all cases, the temperature attained inside the product during the cooking process was measured. The arsenic species extracted from the samples with methanol/water were separated by means of a column switching technique between a PRP-X100 column and a PRP-X200 column. AB was detected by hydride generation atomic absorption spectrometry, whereas TMA+ and TMAO were detected by hydride generation atomic fluorescence spectrometry. The results obtained showed that, in all of the types of seafood studied, TMA+ appeared after cooking, possibly because heating facilitates decarboxylation of AB to TMA+.