EMCB-ENVIS Node ENVIRONMENTAL BIOTECHNOLOGY

EMCB-ENVIS Centre
Thomas A. Davis, Bohumil Volesky, Alfonso Mucci. (Department of Chemical Engineering,
McGill University, 3610 University Street, Montreal, Que., Canada H3A 2B2. Department of
Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Que.,
Canada H3A 2A7). Bioaccumulation. Water Research, 37(20) (2003), 4843-4854.
The passive removal of toxic heavy metals such as Cd2+, Cu2+, Zn2+, Pb2+, Cr3+, and Hg2+
by inexpensive biomaterials, termed biosorption, requires that the substrate displays high metal
uptake and selectivity, as well as suitable mechanical properties for applied remediation
scenarios. In recent years, many low-cost sorbents have been investigated, but the brown algae
have since proven to be the most effective and promising substrates. It is their basic biochemical
constitution that is responsible for this enhanced performance among biomaterials. More
specifically, it is the properties of cell wall constituents, such as alginate and fucoidan, which are
chiefly responsible for heavy metal chelation. In this comprehensive review, the emphasis is on
outlining the biochemical properties of the brown algae that set them apart from other algal
biosorbents. A detailed description of the macromolecular conformation of the alginate
biopolymer is offered in order to explain the heavy metal selectivity displayed by the brown
algae. The role of cellular structure, storage polysaccharides, cell wall and extracellular
polysaccharides is evaluated in terms of their potential for metal sequestration. Binding
mechanisms are discussed, including the key functional groups involved and the ion-exchange
process. Quantification of metal–biomass interactions is fundamental to the evaluation of
potential implementation strategies, hence sorption isotherms, ion-exchange constants, as well as
models used to characterize algal biosorption are reviewed. The sorption behavior (i.e., capacity,
affinity) of brown algae with various heavy metals is summarized and their relative performance
is evaluated.
Uguz, Mesude Iscan, Ayse Ergüven, Belgin Isgor, Inci Togan. (Afyon Kocatepe Universitesi,
Veteriner Fakultesi, A.N. Sezer Kampusu, 03100, Afyon, Turkey. Department of Biological
Sciences, Middle East Technical University, 06531, Ankara, Turkey). The
bioaccumulation of nonyphenol and its adverse effect on the liver of rainbow trout
(Onchorynchus mykiss). Environmental Research, 92(3) (2003), 262-270.
Alkylphenol polyethoxylates (APEs) are widely used as nonionic surfactants. Nonylphenol (NP),
one of the derivatives of APEs, has been found in the aquatic environment in ranges from
nanograms per liter to milligrams per liter. In this study, juvenile rainbow trout were exposed to
0 (control), 66, 220, or 660 μg NP/L for up to 28 days. Fish remained healthy under NP
exposures of 0, 66, and 220 μg/L for the length of the experiment. All fish died after 4 days of
exposure to 660 μg NP/L. Time-dependent NP bioaccumulation was detected in the tissues of
fish exposed to 220 μg NP/L (P