Characterization and modelling of colloidal particles transport in relation to bisphenol a in Bentong River, Malaysia
Bisphenol A is considered one of the most prominent endocrine disrupting chemicals worldwide. Upon entering aquatic environments, BPA can adsorb onto solids or colloidal particles which play a significant role in determining its behaviour, distribution and fate due to their unique characteristics...
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Main Author: | |
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Format: | Thesis |
Language: | English |
Published: |
2021
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Subjects: | |
Online Access: | http://psasir.upm.edu.my/id/eprint/98278/1/FPAS%202021%202%20-%20IR.pdf |
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Summary: | Bisphenol A is considered one of the most prominent endocrine disrupting
chemicals worldwide. Upon entering aquatic environments, BPA can adsorb
onto solids or colloidal particles which play a significant role in determining its
behaviour, distribution and fate due to their unique characteristics, and may
inhibit its degradation in water and aid in its transport to distant places posing a
severe threat to the ecosystem. This issue was highlighted in Bentong River,
which is exposed to sewerage discharge and is a main water supply for the
Semantan water intake, a part of the Pahang-Selangor Raw Water Transfer
(PSRWT) project that provides millions of people with potable water across the
two states, rendering this river a critical importance for public safety. The
emphasis was directed toward the possibility of colloidal-bound BPA reaching
the water intake downstream of Bentong River. Analytical work consisted of
identifying particle size distribution in water while BPA analysis involved isolation
from water samples through solid phase extraction followed by analysis using
LC-MS/MS. Experimental work involved illustrating the interaction and
relationship between BPA and colloidal particles in terms of recovery and
competitive sorption. The final step was incorporating the obtained figures and
results into an environmental model (WASP) to simulate the fate and transport
of colloidal-bound BPA in Bentong River. Results showed that BPA levels in
Bentong River varied between 1.13-5.52 ng L-1 in the soluble phase while the
highest BPA concentration in the colloidal phase was 2.06 ng L-1.
Experimentally, BPA recovery rate declined by 17% with increasing colloidal
organic concentration, and BPA’s extraction via SPME was hampered by
inhibition interactions with colloidal particles causing an apparent decrease of
16% in recovery rate. Modelling results demonstrated the significance of spatial
detail and highlighted the effects of colloidal particles’ concentration and density
on BPA’s removal from the water column. All scenarios showed that after 7.5-10
km mark BPA’s concentration started to reach a steady state with very low concentrations which indicated that a downstream transport of colloidal-bound
BPA was less likely due to minute BPA levels. The various model scenarios
implied that particles with low densities, flowing in aqueous conditions that
generate low attachment efficiency milieus and with low colloids, while SPM
concentrations have a higher tendency to stay suspended within the water
column, and consequently have higher propensity to get transported or relocated
to farther distances away from the emission point. Even though a downstream
transport of colloidal-bound BPA was less likely due to minute BPA levels as
proven in this study, the possibility still exists especially if these levels were to
increase later on. |
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