Brown algae (Phaeophyta) for monitoring heavy metals at the Sudanese Red Sea coast

Abstract

This study aimed at monitoring some heavy metals at the Sudanese Red Sea coast using Brown algae (Phaeophyta) as biomonitor. The total contents of heavy metals in four species (Turbinaria sp., Sargassum sp., Cystoseira sp. and Padina sp.) as well as seawater were examined. Twenty-six algae samples were collected from seven locations. The ranges of concentrations (µg/g, dry wt.) of heavy metals in algae were 4.95–16.95 for Cr, 2.93–257.32 for Mn, 1.35–7.43 for Ni, 0.83–14.10 for Cu, 4.13–19.13 for Zn, 0.03–0.15 for Cd and 0.45–2.18 for Pb. The ranges of the pH and the salinity of seawater from the same locations were 8.11–8.82 and 38.00–41.00 PSU, respectively. The ranges of concentrations (µg/L) of heavy metals in seawater were 7.00–11.00 for Cr, 2.90–10.20 for Mn, 6.70–10.10 for Ni, 1.70–5.00 for Cu, 0.94–5.70 for Zn, 0.09–0.14 for Cd and 0.93–1.80 for Pb. No significant correlations between metal concentrations in algae and seawater were observed. Some locations in the study area recorded relatively high levels of heavy metals in algae indicating possible contribution from manmade activities. Cr recorded higher levels in the study area than those in other coastal areas in the word. Padina sp. and Cystoseira sp. were better bioindicator than Turbinaria sp., Sargassum sp. for their high metal uptake.