Patcharin Jankong. Arsenic accumulation in freshwater fish and plants collected from arsenic-contaminated area . Doctoral Degree(Biology). Mahidol University. : Mahidol University, 2007.
Arsenic accumulation in freshwater fish and plants collected from arsenic-contaminated area
Abstract:
This work consists of two parts. The first one addresses arsenic contaminations of
freshwater fish whereas the second focuses on the improvement of arsenic uptake in
plants. The striped snakehead (Channa striata), a carnivorous freshwater fish, was
collected from two arsenic-contaminated ponds in southern Thailand as well as from a
reference site. The freeze-dried hackled organs of the fish were analyzed for total
arsenic and arsenic species. The mean arsenic concentration in the muscle tissue of C.
striata was more than six times higher in fish from the contaminated site than from the
reference site. Liver and gills showed a similar relation. Speciation analysis revealed
that arsenate was the major extractable arsenical in the reference samples while
dimethylarsinate was by far the dominant species in the contaminated samples. Three
non-carnivorous fish species (Danio regina, Rasbora heteromorpha, and Puntius
orphoides), collected from Pond B only, had lower arsenic concentrations than did C.
striata, and contained major arsenic in the form of trimethylarsine oxide. This study
shows for the first time a clear effect of water arsenic concentrations on natural fish
tissue arsenic concentrations, and this is the first report of a freshwater fish species
attaining arsenic concentrations comparable with those found in marine fish species.
In an attempt to clean up arsenic-contaminated soil in order to reduce arsenic
leaching into aquatic ecosystem, the effects of phosphorus fertilizer and rhizosphere
microbes on arsenic accumulation by Pityrogramma calomelanos, Tagetes erecta and
Melastoma malabathricum were investigated in greenhouse and field experiments in
the Ron Phibun District, an arsenic-contaminated area in southern Thailand. Soil was
collected there and was used in the greenhouse experiment. Rhizosphere microbes
(bacteria and fungi) were isolated from roots of P. calomelanos plants growing there.
The results showed that the fertilizer as well as the rhizobacteria significantly
increased plant biomass and arsenic accumulation thus enhancing the arsenicphytoextraction.
Rhizofungi also increased plant biomass but significatly reduced the
arsenic concentration exerting their effects on phytostabilization. The effects of the
commercial strains of arbuscular mycorrhizal fungi (AMF) on phytoremediation of
arsenic-contaminated soil by different plant species are different. For P. calomelanos
and T. erecta, AMF are suitable for phytostabilization of arsenic-contaminated soil
due to their ability to reduce arsenic accumulation in plants and to sustain plant
growth. AMF improved the growth and arsenic accumulation for M. malabathricum.
Therefore, AMF has potential in phytoextraction of arsenic by M. malabathricum.