Total arsenic, inorganic arsenic, lead and cadmium contents in
edible seaweed sold in Spain
Concepcio ´n Almela, MaJesu ´s Clemente, Dinoraz Ve ´lez*, Rosa Montoro
Instituto de Agroquı ´mica y Tecnologı ´a de Alimentos (CSIC), Apdo. 73, 46100, Burjassot, Valencia, Spain
Received 26 August 2005; accepted 9 June 2006
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.
? 2006 Elsevier Ltd. All rights reserved.
Keywords: Lead; Cadmium; Arsenic; Inorganic arsenic; Edible seaweed
In Western countries, the use of seaweed has tradition-
ally concentrated on the extraction of compounds used
by the pharmaceutical, cosmetics and food industries (pro-
duction of agar, alginates, carrageenan, etc.) (Mabeau and
Fleurence, 1993; Caliceti et al., 2002). In recent decades
there has been an increase in direct consumption of sea-
weed as food, partly because of the nutritional (Mabeau
and Fleurence, 1993; Darcy-Vrillon, 1993) and therapeutic
(van Netten et al., 2000) benefits that these products pro-
vide. The mean intake of seaweed in Western countries is
far from equalling that of Eastern countries, estimated
for the Japanese population as 3.3 g dry seaweed per day
(Darcy-Vrillon, 1993), but we must not forget the existence
in all countries of extreme consumers, such as those who
follow a macrobiotic diet.
From a nutritional point of view, seaweeds are interest-
ing because of their high content of dietary fibre (33–50%),
rich in soluble fractions with hypocholesterolemic and
hypoglycemic effects (Mabeau and Fleurence, 1993; Jime ´-
nez-Escrig and Sa ´nchez-Muniz, 2000). They are a source
of proteins, with an amino acid composition of nutritional
interest (Fleurence, 1999; Wong and Cheung, 2000). Min-
erals also attain considerable levels (8–40%), so that sea-
weed could be used as a food supplement in order to
reach the recommended daily intakes of some macrominer-
als and trace elements (Ru ´perez, 2002). Finally, because of
their low lipid content, 1–2%, they constitute a negligible
energy source (Darcy-Vrillon, 1993). On the other hand,
seaweed has a high metal pollution accumulation capacity.
This reason it has been used as a bio-indicator for marine
environment contamination (Riget et al., 1997), and there
are studies on heavy metal contamination in different spe-
cies of environmental and commercial importance (Hou
0278-6915/$ - see front matter ? 2006 Elsevier Ltd. All rights reserved.
*Corresponding author. Tel.: +34 963 900 022; fax: +34 963 636 301.
E-mail address: email@example.com (D. Ve ´lez).
Food and Chemical Toxicology 44 (2006) 1901–1908
reaches the systemic circulation) are aspects to be taken
into account with a view to making a more realistic evalu-
ation of the food safety of seaweed.
Thisresearch wassupportedby projectMCyT
AGL2001-1789, for which the authors are deeply indebted.
The results of total and inorganic arsenic are the property
of the Spanish Ministry of Agriculture, Fishing and Food.
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