MECHANISM UPTAKE METALS OF POLLUTED LAKES-SEA WATER FOR BIOLOGICAL TREATMENT BY SOME ALGAE AND PROTECTIVE EFFECT

MECHANISM UPTAKE METALS OF  POLLUTED LAKES–SEA WATER FOR
BIOLOGICAL TREATMENT BY SOME ALGAE
AND PROTECTIVE EFFECT

Tartiel El-Sayed Mohamed Badawy

Central Laboratory for Aquaculture Research, Abbassa, Ecology and Biology Department, Agricultural Research Center, Ministry of Agriculture, Cairo, Egypt.

Abstract

This study aimed to investigate the use of two algal species Dunaliella spp. and Sargassum spp. as biological treatment and protective effect on some heavy metals . Two elements were chosen mercury Hg and lead Pb to study biosorption and desorption mechanisms by algae and influence on some biochemical parameters in Nile tilapia (Oreochromis niloticus). Fingerlings were investigated with an average weight 28.5±6.5g\fish were applied in glass aquaria each was stocked randomly with 20 fingerlings each reared in aquarium (60x70x50 cm) for six treatments polluted water in addition to control treatment non- polluted water. Active transport was the mechanism for Hg and Pb uptake by two algal species. Sargassum spp. showed higher accumulation ratios than living algal cells, the reverse was true for Dunaliella spp. Mercury Hg and lead Pb residues in the muscles and gills of experimented fish were measured together with some biochemical parameters. All investigated biochemical parameters increased significantly (P< 0.05) during accumulation period and returned back to the normal values after elimination period, it was significantly higher in fish group T₅ and
T₆ compared to that of fish group T₃ and T₄ (P< 0.05). There were significant differences (P< 0.05) in AWG, ADG and SGR among treatments, The higher values of heavy metals mercury Hg and lead Pb were accumulated in fish group T₁ and
T₂ (P< 0.05), while the lowest value was obtained at fish group T₅ and
T₆ (P< 0.05). Accumulation rate increased with the increasing of exposure concentration or period and elimination significantly decreased the levels of both mercury and lead. Body dry matter (%) was not significantly (P< 0.05) affected by the experimental treatments, while CP%, EE% and ash% significantly differed among treatments (P< 0.05). Tilapia fingerlings in T₅ and
T₆ produced lower value of Creatinine, Cholesterol, Glucose and Uric acid while gave higher value of total protein, follicle stimulating hormone (FSH) and gave best value of AST, ALT in plasma. Dried. Sargassum spp. can be used successfully for bioremediation of mercury Hg and lead Pb from the contaminated water, while living Dunaliella
spp. could be used for the removal of these elements from lakes and sea water and metals bioremediation from aquatic environment. The results also demonstrated the efficiency of algae in reducing the pollutant effect of some heavy metals in water, and decreasing their negative impact, where it gave better water quality and fish safety adverse health human effects.

Key words:
Dunaliella spp.٭, Sargassum spp.٭, protective effect, mercury and lead, polluted, aquatic environment, bioremediation, Nile tilapia, growth performance, accumulation and elimination, biochemical parameters.