1. • 22 genera of cyanobacteria were found, 3 were
reported as toxic genera (Anabaena spp., Microcystis
spp. and planktothrix spp.).
Results and Discussions
• Very high concentration of phosphorus and nitrogen in
twenty water samples indicates a hypertrophic
condition.
• Cyanobacterial biovolume
higher than recommended
threshold of alert level
1 for drinking waters
(fig. 2).
• Increased levels of pH are
more favourable for
cyanobacterial growth (fig.3).
• Sampled at 18 lakes and ponds in Hanoi, Vietnam (Fig. 1).
• Phytoplankton and zooplankton were collected to know water quality degradation and
counted with inverted microscopy.
• Nutrient analysis were performed with phenate, colorimetric, ultraviolet
spectrophotometric and ascorbic acid method.
• Biovolume was used as a proxy for phytoplankton biomass.
• Multivariate statistical analyses were used to explore the phytoplankton and zooplankton
data as well as their relation to the environment.
Methodology
Conclusions
WATER QUALITY DEGRADATION AND CYANOBACTERIAL
BLOOMS OF LAKES AND PONDS IN HANOI, VIETNAM:
an overview of current state and potential health risk
(based on thesis of Hien Nguyen Tranh, 2009)
Fig 1.
Map of Hanoi indicating the geographical positions of the lakes and ponds.
Recommendations
• Alarming degradation of water quality due to extreme
hypereutrophication in combination with tropical climate condition.
This has led to massive phytoplankton growth in all water bodies of
the city.
• All the lakes and ponds ranged from moderate probability of
adverse health effects to high probability of adverse health effects.
• Conduct comprehensive monitoring to build up a best practice for
restoration and to provide information on environmental hazard.
• Implement a pilot study based on acquired information to
improve water quality and halter cyanobacterial blooms.
Fig 2.
Cyanobacteria biovolume in relation to the vigilance and
allert level for drinking water supplies.
Fig 3.
CCA triplots (sites, species and environmental variables.)
Introduction Objectives
• Cyanobacterial blooms are an increasing concern throughout the
world. Once they occur they contribute aesthetic problems, impair
recreational use and even effect the taste of treated drinking water.
• In Hanoi, Vietnam, lakes and ponds are highly polluted which results to
harmful cyanobacterial blooms. These have led to an alarming
underestimate of the risk of such environmental hazards. Therefore, to
minimize the adverse impacts of harmful blooms, this study is
important to understand the dynamic of cyanobacteria and their
interactions with the environment.
• To assess the human risk and to estimate the dynamic of
cyanobacteria in relation to different environmental conditions in
lakes and ponds in Hanoi, Vietnam.
• To determine the composition of phytoplankton, zooplankton and their
biomass in relqtion to physico-chemical parameters.
• To assess the state of cyanobacteria with respect to human health risk.
and to investigate the relationship between cyanobacteria
proliferation
with environmental variables.
Poster by:
Aryshandy, C., Cotillas, C., Prasetiya, F. and Vaes, T.
Vrije Universiteit Brussel – Universiteit Antwerp
BELGIUM
Fig 3.
CCA triplots (sites, species and environmental variables.)
Fig 3.
CCA triplots (sites, species and environmental variables.)
• Lakes with higher
cyanobacteria biomass
showed higher values of pH,
DO and temperature. The
correlation between pH and
cyanobacteria biovolume
(CBV) (r = 0.48).