Concentrations of heavy metals in macroalgae in the tropical western Atlantic

Abstract

Studies of heavy metal (copper, lead, zinc and iron) in two species of red macroalgae Gracilariopsis carolinensis Liao and Hommersand and Hypnea musciformis (Wulfen) Lamouroux were carried out to monitor the level of bioavailable metals in coastal areas. The macroalgae and hydrological data were sampled in two areas, at the north and south littoral of Pernambuco (Brazil). The metal concentrations were measured by Atomic Emission Spectrophotometer with Inductive Coupled Plasma. Water temperature ranged from 28 to 31°C, salinity from 26.4 to 36.9 UPS and dissolved oxygen from 2.43 to 6.37 mL.L -1. Higher metal concentrations were detected in the south coast, where Hypnea musciformis presented greater retention capacity. A Principal Components Analysis was performed and explained 50.45% of the total data variability. Rainfall presented an important role in the algae metal content. The median metal concentrations of G. carolinensis in the North area were: iron 141 μg.g-1, lead 3.50 μg.g-1, copper 0.95 μg.g-1 and zinc 33.14 μg.g-1; in the South area: iron 347 μg.g-1, lead 2.99 μg.g-1, copper 1.57 μg.g-1 and zinc 28.57 μg.g-1; and to H. musciformis in the North area: iron 675 μg.g-1, lead 8.90 μg.g -1, copper 1.85 μg.g-1 and zinc 49.93 μg.g -1; in the South area: iron 806 μg.g-1, lead 5.49 μg.g-1, copper 2.35 μg.g-1 and zinc 44.57 μg.g-1. No significant (p<0.05) seasonal changes in metal concentration and no distribution pattern were observed in the studied area. © 2009 WIT Press.