Arsenic and cadmium in the marine macroalgae (Porphyra yezoensis and Laminaria Japonica) — forms and concentrations

Abstract

Total arsenic, inorganic arsenic (iAs), total cadmium concentrations and chemical forms of cadmium were analysed in Porphyra yezoensis collected monthly from January to April in 2011 and in Laminaria Japonica collected monthly from March to July in 2010. Results showed that total As concentrations in P. yezoensis were much lower than those in L. Japonica. The iAs concentrations in both macroalgae were all below the maximum limit according to the legislation in China, while total Cd concentrations in all samples of P. yezoensis exceeded the maximum limit. The percentage of iAs to total As decreased in both macroalgae with the time. The results provide important information showing that both macroalgae are able to metabolise inorganic arsenic to organic forms. Thus both macroalgae have evolved arsenic resistance which is linked to the capability of metabolising toxic inorganic arsenic. In addition, the results suggest that the transformation rate of arsenate to organic arsenic in both algae increases with the growth and metabolic rate that increase with elevated environmental temperature. Temperatures rise from January to April in Jiangsu province and from March to July in Liaoning Province. Most Cd was associated with pectates and protein (extractable by 1 M NaCl) in both algae, and only a small percentage of the Cd was inorganic (extractable by 80% ethanol). The Cd chemical forms have no obvious relationship with the time in both algae.

Toxicological Evaluation of Low Molecular Weight Fucoidan in Vitro and in Vivo

“…The total arsenic in the L. japonica of our study was 61.100 ± 3.110 mg/kg, a slightly higher value than the 30–54 mg/kg reported by [ 27 ]. It is believed that the seaweed accumulates arsenic from seawater and the arsenic concentration in the seaweed is related to the environmental conditions, growth, and metabolic rate [ 27 ].…”

“…The total arsenic in the L. japonica of our study was 61.100 ± 3.110 mg/kg, a slightly higher value than the 30–54 mg/kg reported by [ 27 ]. It is believed that the seaweed accumulates arsenic from seawater and the arsenic concentration in the seaweed is related to the environmental conditions, growth, and metabolic rate [ 27 ]. According to the LC-ICP-MS results, the concentrations of the species of arsenic in L. japonica were as follows: AsB (34.31 ± 1.21 mg/kg) > MMA (9.27 ± 0.96 mg/kg) > DMA (9.23 ± 0.83 mg/kg) > AsC (59.00 ± 1.65 mg/kg).…”

Trophic transfer of Cd from duckweed (Lemna minor L.) to tilapia (Oreochromis mossambicus)

“…For example, the largest portion of Cd accumulated in roots and shoots of cabbage was found to be integrated with proteins and pectates (extracted by 1 M NaCl; Qiu et al ). Similar findings were reported as well for Porphyra yezoensis and Laminaria japonica (Zhao et al ). In addition, Wu et al () found that Cd‐resistant barley genotypes had higher concentrations of pectate‐ and protein‐integrated Cd and lower concentrations of Cd in water‐soluble and inorganic forms, compared with Cd‐sensitive genotypes.…”

Characterization of protein, lipid and mineral contents in common Norwegian seaweeds and evaluation of their potential as food and feed

“…As previously mentioned, the inorganic form of arsenic is the more toxic and speciation studies have shown that the predominant form of arsenic in algae is the organic . In addition, many algae are able to metabolize inorganic arsenic into organic forms …”

“…58 In addition, many algae are able to metabolize inorganic arsenic into organic forms. 59 In conclusion, the total composition of the red algae species P. palmata makes it the best candidate for utilization in food and feed. At the other end, the species least suitable for utilization seems to be the green alga C. rupestris.…”