Undaria pinnatifida, Wakame is a popular edible seaweed in its native Asia and was first recorded in New Zealand in Wellington
Harbor in 1987. It
is classified as an unwanted species under the Biosecurity Act 1993, but there
is growing interest in harvesting this seaweed for human consumption. The aim
of this study was to evaluate the concentrations
of metals in U. pinnatifida from several
locations (Marlborough Sounds and Wellington harbor) and across seasons. In brief, the highest
monthly mean concentration of metals found in New Zealand wild U. pinnatifida was Ca (16.97g·kg-1), K (48.48 g·kg-1),
Mg (9.47 g·kg-1), P (12.05 g·kg-1), Cr (1.04 mg·kg-1),
Cu (3.78 mg·kg-1), Mn (14.61 mg·kg-1), Ni (2.78 mg·kg-1), Se (0.83 mg·kg-1), Zn (35.03 mg·kg-1), As (46.71 mg·kg-1),
Cd (2.91 mg·kg-1), Hg (0.042 mg·kg-1) and Pb (0.31 mg·kg-1).
These results showed that New Zealand U. pinnatifida is a good source of the
nutritionally important minerals calcium, magnesium, potassium and phosphorus.
They also contained trace amounts of minerals such as chromium, copper,
manganese, nickel, selenium and zinc. Contaminants such as arsenic,
cadmium, mercury and lead were found at very low, safe, levels.