The algae can be used as bioindicators for assessment of water quality and pollution control. They respond rapidly to variations in ecosystem composition and densities. The main goals of this study are (I) synthesis of novel nanocomposite for
pre-concentration and determination of heavy metals contents in algal samples, (II) investigating their distribution using
chemometrics approaches, and (III) suggesting algae species as a biomarker for aquatic ecosystem of Persian Gulf. A novel
reusable double layer modifed magnetic nanocomposite was fabricated for pre-concentration extraction of Fe2+, Hg2+, Pb2+,
Cu2+, Zn2+, and Mn2+ ions in Persian Gulf alga samples. The Fe3O4-NPs-silica mesoporous core–shell nanocomposites were
synthesized and further modifed with layers of (3-chloropropyl)-trimethoxysilane and l-cysteine (Fe3O4@SiO2-ChPr-lCys). The nanocomposite was fully characterized by FT-IR, thermal gravimetry (TGA), energy dispersive X-ray (EDAX),
carbon, hydrogen, and nitrogen (CHN) elemental analysis, X-ray difraction. The efect of experimental parameters afecting
the pre-concentration was carefully investigated. The eluted analytes were measured by fame atomic absorption spectrometry (FAAS). The detection limits obtained were 0.001, 0.027, 0.066, 0.043, 0.078, and 0.075 µg/L for Hg2+, Cu2+, Mn2+,
Zn2+, Pb2+, Fe2+ ions, respectively. The clustering results showed that anthropogenic and pedo-geochemical are the main
sources of the metals contamination, and average metals concentration in algae extract increased in the following sequence:
Fe>Hg>Zn>Mn>Cu>Pb. The Enteromorpha sp., and Laurencia papillosa could be used as an excellent bioindicators
for monitoring of Fe2+ and Mn2+ and green algae for Hg2+, Pb2+, Cu2+ and Zn2+ ions in this area.
