Endocrine disrupting compounds (EDCs) or endocrine disruptors have been a global
concern for many years due to their negative impact on wildlife and human health. The
main sources of EDCs in the environment are humans and animals. EDCs can appear
in a number of environmental matrices such as wastewater, surface water, manure,
sludge, sediments, etc. Several techniques are available for analysing EDCs, each
with its advantages and disadvantages. When selecting a method, the purpose of the
study should be considered, especially an EDC monitoring programme with many
samples.
In Vietnam, environmental pollution, especially of surface water, is currently
increasing. This is an important issue examined in many studies but information on
EDCs is still lacking.
The studies reported in this thesis used the YES assay as a tool to analyse EDCs in
different matrices in Vietnam. These included surface water, river sediments, the liquid
and solid phases of septage slurry and biogas slurry and wastewater.
The Saigon River showed upstream of HCMC EDC values below the limit of detection
(LOD). But in the City and downstream the range of EDCs was 0.02-6.2 ng E2eq/L in
the dry season and 0.33-1.17 ng E2eq/L in the rainy season. EDC concentrations in
sediments ranged from < LOD (upstream) to 0.28 ng E2eq/g (dw).
Total EDCs in septage slurry ranged from 57.92 to 1506.81 ng E2eq/L, with EDC
concentrations in the liquid phase ranging from 11.87 to 184.29 ng E2eq/L and those
in the solid phase from 2.21 to 99.16 ng E2eq/g (dw).
EDC concentrations in influent from biogas plants fed with animal manures were in the
range 56.98-903.91 ng E2eq/L. Most EDCs were found in the solid phase (77.9-
98.7%). The EDC level in fresh cow manure was 3.63 ± 2.23 ng E2eq/g (dw) and
decreased by 95.3±3.52 % of the initial value within 2 months of drying or
vermicomposting.
The largest EDC discharge into surface waters in the Mekong Delta, Vietnam, was
from humans (156 kg E2eq/year), followed by animals (23kg E2eq/year). Wastewater
from fish processing companies contributed the least EDCs, 0.025 kg E2eq/year.
The results presented in this thesis can be used to devise strategies to reduce EDC
discharges to surface waters in Vietnam.