EMCB-ENVIS Node ENVIRONMENTAL BIOTECHNOLOGY

EMCB-ENVIS Centre
Bioaccumulation
A A Hamdy. (Microbial and Natural Products Chemistry Department, National Research
Center, Dokki, Cairo, Egypt). Biosorption of Heavy Metals by Marine Algae. Current
Microbiology, 41(4) (2000), 0232 – 0238.
The ability of four different algae (three brown and one red) that have not been previously
studied to adsorb Cr 3+ , Co 2+ , Ni 2+ , Cu 2+ , and Cd 2+ ions was investigated. The metal uptake was
dependent on the type of biosorbent, with different accumulation affinities towards the tested
elements. The HCl-treated biomass decreased the metal biosorptive capacity particularly in the
case of Cr 3 adsorption with Laurencia obtusa. The extent of uptake of the different metals with
the tested algae was assessed under different conditions such as pH, time of algal residence in
solution with the metal, and concentration of algal biomass. The rate of uptake of the different
metals was very fast in the first 2 h; thereafter the increase in metal uptake was insignificant. The
amount of the metal uptake (5-15 mg range) increased steeply by increasing the weight of the
biomass. An exception was L. obtusa, where a parallel increase of the uptake of different metals
was observed on increasing the algal mass from 5 to 50 mg.
A. E. El-Enany, A. A. Issa. (Botany Department, Faculty of Science, Assiut University,
Assiut, Egypt). Cyanobacteria as a biosorbent of heavy metals in sewage water.
Environmental Toxicology and Pharmacology, 8(2) (2000), 95-101.
The effect of sewage water on some physiological activities of cyanobacteria was studied. Metaltolerant
cyanobacterium (Nostoc linckia) and metal-sensitive (Nostoc rivularis) were grown at
three levels of sewage water (25, 50 and 75%). The growth rate showed significant stimulation in
low and moderate levels (50% for N. linckia and 25% for N. rivularis). Not only the number of
cells was elevated but also, the time required to reach the exponential and the stationary phases
was reduced. Also, low levels of sewage water increased chl.a content, photosynthetic O2evolution,
respiration and protein content. Similarly, heterocyst frequency as well as nitrogenase
activity were increased in cyanobacteria grown at low and moderate levels (25 and 50% sewage).
On the other hand, the high level of waste (75%) reduced growth and metabolic activities of the
two species. N. linckia accumulated about 30-fold of Zn and ten-fold of Cd than those of growth
medium (50% sewage water). Also, N. rivularis accumulated about ten-fold of Zn and two-fold
of Cd. The distribution of Cd and Zn in cells were investigated. About 65–60% of Cd or Zn were
found in pellets (sediment) as insoluble form in the two species. The soluble form (cytosolic
fraction) after being fractionated on sephadex G-(75-100) revealed two peaks with molecular
weights of 70–75 and 40–45 kDa. These peaks were in coincidence with Cd and Zn maxima.
Nostoc rivulais showed more sensitivity to heavy metals than N. linckia, and accumulated less
amount of metal-binding proteins. Nostoc linckia seems to be tolerant to heavy metals (Zn and
Cd) and is able to accumulate this metal by adsorption on the pellets (cell surface) and/or
through sequestration via metal-binding protein. Therefore it can be recommended it to be
employed in the purification of waste contaminated with these heavy metals.
A. Heikens, W. J. G. M. Peijnenburg, A. J. Hendriks. (Institute for Inland Water Management
and Waste Water Treatment, PO Box 17, 8200 AA Lelystad, The Netherlands. National
Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The
Netherlands). Bioaccumulation of heavy metals in terrestrial invertebrates.
Environmental Pollution, 113(3) (2001), 385-393.
In this literature study, accumulation data of metals in terrestrial invertebrates were collected and
compared (Arthropoda and Lumbricidae). Based on total soil concentrations and body
concentrations, regression equations were calculated for each metal (Cd, Cu, Pb and Zn) and
each taxonomic group. We also tried to find out whether or not accumulation levels of metals in
Lumbricidae are representative for all of the studied terrestrial invertebrates. Taxonomic groups
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