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Monitoring
of Some Endocrine-Disrupting Chemicals (EDCs) in the Hydrosphere of
Vietnam
Prof. P. H. Viet, P. M. Hoai, P. T. Hung, T. T. Lieu, V. T.
Le, P. T. N. Anh and L. H. Tuyen Research Center for Environmental
Technology and Sustainable Development Vietnam National University.
In recent years, the presence of many classes of chemicals, so called
Endocrine Disrupting Compounds (EDCs), in the environment has become
one of the most concerns of the managers and scientists because they
are identified as having deleterious effects to the hormonal control
systems of some organism including human beings. Bisphenol-A, alkylphenols
and some organochlorine compounds are that synthetical agents being
present in the environment.
In order to evaluate possible levels of bisphenol-A and alkylphenols
in the aquatic environment in Vietnam, three sites: Red river (Hanoi
city), Balat estuary (Thaibinh province), Tamgiang-Cauhai-Langco lagoon
(Thue Thien - Hue province), were selected. The survey was conducted
twice during the period of year 2000 in the frame of the project “Environmental
Monitoring and Governance: EDC Pollution in the East Asia Coastal
Hydrosphere”, which is conducted simultaneously by nine partner countries
in the East Asia region. Surface water samples were collected in order
to analyzed compounds: 4-t-butylphenol, 2,4-dichlorophenol, 4-n-butylphenol,
4-n-pentylphenol, 4-n-hexylphenol, 4-t-octylphenol, 4-n-heptylphenol,
4-nonylphenol, 4-n-octylphenol, pentachlorophenol and bisphenol-A.
In general, concentrations of alkylphenolic and bisphenol-A compounds
were ranged from ng L-1 to tens of ng L-1 and were recognized as changing
with season, higher in dry season and lower in rainy season. It is
also realized that these compounds were generally distributed higher
in Red river, inland and very near to the residential and industrial
dischargers, than in Balat estuary and river body that near to the
estuary and far from dischargers.
Evaluation of the status and the temporal change of organochlorine
compounds in surface water was also conducted at the same three sites
in the period of year 2000. Obtained results showed that the organochlorine
compound of major concern was DDTs with concentrations of 4.39-4.47
ng L-1 and 2.00-3.77 ng L-1 in the rainy season in Red river and Balat
estuary, respectively; while those in the dry season came up to 4.11-6.11
ng L-1 and 4.78-6.88 ng L-1, correspondingly. Similar to the results
reported in the annual report year of the last year (1999), aldrin,
dieldrin, endrin and HCHs were not present in quantifiable amounts
in any of the collected samples. Therefore, it once again affirms
the possibility of not using of these compounds around the study areas.
The concentrations of organochlorine compounds obtained in the events
of this study showed as very low, about ng L-1, generally smaller
than those in the events of the year 1999 and little decreased in
dry season compared to the rainy season.
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