RESUMO
Eighteen species of seaweeds were collected from the coastal area of Karachi [Pakistan] and analyzed for their elemental composition by Perkin-Elmer 3100, Atomic Absorption Spectrometer. Many elements e.g. Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Na, Pb, Zn were detected quantitatively. Among these Ca, Fe, K, Mg and Na were found in large amounts [on the average 3509.86-48354.21 ppm] Co, Cu, Pb and Zn were present in small amount [on the average 11.21-80.08 ppm] while Cr and Cd were detected in extremely small amount [on the average 0.25-1.18 ppm]. The average quantity of K. was detected to be the highest among these algae [48354.2 ppm] followed by Na [21733.61 ppm] and Fe [3509.86 ppm]. The average amount of Zn [80.08 ppm] and Cd [1.18 ppm] were quite low, Cr was found in the lowest quantity [0.25 ppm]