Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon

Abstract

This study aimed to evaluate the EDC (endocrine disruptors compounds) in the city of São Paulo’s water sources, from samples collected at predetermined sampling points and to evaluate the adsorptive capacity of these compounds in different types of activated carbon. The effects of these EDC on humans are not well established due to the necessary large exposure time for the effect’s manifestation. After tests using powdered and granular activated carbon, all samples were filtered under vacuum using cellulose acetate membrane (0.45 µm) to remove eventual impurities, and posteriorly carried out the solid-phase extraction SPE (solid-phase extraction) and chromatographic analysis. The results lead to the conclusion that both powdered activated carbon have removal effectiveness of these compounds by adsorption. Furthermore, great amount of endocrine disruptors were found at several sampling points in river and city’s water reservoirs, which shows different levels of pollution of water sources, some of them responsible for the watersupply of the city of São Paulo, Brazil.

Full text

Journal of Civil Engineering and Architecture 11 (2017) 653-662
doi: 10.17265/1934-7359/2017.07.003
Determination and Removal of Endocrine Disruptors in
Wastewater by Activated Carbon
Marcelo A. Nolasco1, Kamila O. Guimarães1 and Grace Cardoso2
1. School of Arts, Sciences and Humanities, University of São Paulo-USP, São Paulo 03828-000, Brazil;
2. Graduate Program in Architecture and Urbanism (PPGARQ), Meridional Faculty (IMED), Passo Fundo-RS, 99070-220, Brazil
Abstract: This study aimed to evaluate the EDC (endocrine disruptors compounds) in the city of São Paulo’s water sources, from
samples collected at predetermined sampling points and to evaluate the adsorptive capacity of these compounds in different types of
activated carbon. The effects of these EDC on humans are not well established due to the necessary large exposure time for the
effect’s manifestation. After tests using powdered and granular activated carbon, all samples were filtered under vacuum using
cellulose acetate membrane (0.45 µm) to remove eventual impurities, and posteriorly carried out the solid-phase extraction SPE
(solid-phase extraction) and chromatographic analysis. The results lead to the conclusion that both powdered activated carbon have
removal effectiveness of these compounds by adsorption. Furthermore, great amount of endocrine disruptors were found at several
sampling points in river and city’s water reservoirs, which shows different levels of pollution of water sources, some of them
responsible for the watersupply of the city of São Paulo, Brazil.
Key words: Activated carbon, endocrine disruptors, adsorption, solid-phase extraction, chromatographic analysis, micropollutants.
1. Introduction
Increasing cities’ urbanization due to increased
population, has generated several environmental
impacts worldwide, and these changes have happened
quickly and uncontrollably [1], highlighting the
disposal of municipal wastewater, which collects much
of the by-products regarding this intense urbanization.
In this regard, measures to control the pollution have,
as one of the main objectives, to protect water bodies
from compounds and materials dumps that can cause
eutrophication processes, oxygen depletion, toxicity,
among other negative impacts, which consequently
reduce biological diversity and also turn it dangerous
for drinkable water and other human consumption
purposes. Among these compounds, whose most part
has final destination directly to the environment, are
highlighted PPCPs (pharmaceutical and personal care
products) [2, 3]. With the increasing in production and
consumption of more and new chemicals compounds,
Corresponding author: Grace Tibério Cardoso de Seixas,
Ph.D. candidate; research field: climate dynamics applied to
building. E-mail: gracetiberio@hotmail.com.
which in many cases have yet unknown properties, but
harmful to the health and the environment, or even
recognized with deleterious properties, there is a
worsening of the problem because of the inefficiency in
collection and treatment of municipal sewage and
industrial effluents in developing countries, which are
often thrown inadequately into the environment. These
facts enable emerging concentration of contaminants in
the environment [4].
The emerging contaminants class, such as PPCPs,
covers various groups of anthropogenic and natural
substances, among which are included drugs, toilets,
industrial byproducts and hormones that, even if in the
environment at low concentrations (μg/L to pg/L), are
capable of causing organisms’ harmful effects. Some
of these emerging contaminants, such as estrogens,
phytoestrogens, alkylphenols, brominated flame
retardants, are classified also as endocrine disruptors.
These compounds are harmful to ecosystems and,
despite its occurrence in different environmental
compartments, do not have specific regulation in Brazil
and many countries and, therefore, are not properly
D
DAVID PUBLISHING

Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon
654
monitored [4, 5].
The endocrine disruptors are substances that have
the ability to interact and cause changes in endocrine
system’s functions, simulating the activity of
endogenous hormones that may cause damage to the
body and their descendants. These substances are
divided into three groups: the natural estrogens,
synthetic estrogens and xenoestrogens [4].
Synthetic estrogens are steroids with a modified
molecular structure, found in drugs, especially those
assigned to hormone therapies replacement, treatment
of neoplasms and contraceptives. They have high
potential to interfere and cause damage to the human
endocrine system, and the 17α-ethinylestradiol (EE 2),
derived from the 17β-estradiol (E2), is one of its
greatest representatives found in oral contraceptives. In
the case of natural estrogens, these substances
constitute a portion of the hormones produced by the
organism, mainly the 17 β-estradiol (E2), estrone (E1)
and estriol (E3). These hormones are related to
feminine characteristics and other important processes,
such as growth, development and behavior, immune
and cardiovascular systems, with influence to brain
development. Xenoestrogens, for example,
BisphenolA monomer, they are generally less harmful
and more widely found in the environment, but also
possess the ability to mimic and block the endogenous
estrogens activity [4]. Natural and synthetic estrogens
act in ng/L order of magnitude and alkylphenol
compounds (nonylphenol) demonstrate estrogenic
activity in mgL-1 concentrations [6, 7].
Although the effects of these substances in humans
are not well known due to the long time required for the
manifestation of the effects, the impacts of
environmental estrogens in aquatic life are already
known [8]. Studies regarding environmental estrogens
involving animals confirm that these compounds are
manifested differently, when compared in terms of
toxicology to the term “dose-response” traditional, so,
these studies produce significant responses at
extremely low concentrations [9]. Several studies have
studied the major toxic effects of pharmaceutical
compounds and natural hormones [10], although these
emerging compounds presence is the subject of studies
in STPs (sewage treatment plants) in Europe and
United States, little has been studied under Brazilian
conditions.
2. Treatment Technology: Activated Carbon
Adsorption
Several solid materials have been applied to remove
endocrine disruptors in water, and among those, the
processes and techniques currently in using activated
carbon, are promising due to their high efficiency in
removing various contaminants [11, 12]. PAC
(powdered activated carbon) is more widely used in
relation to GAC (granular activated carbon); it is more
common to apply PAC in conventional treatment
stations, because it is easier to control the dosage and
needs a lower investment cost. However, it cannot be
regenerated after its use and is difficult to remove from
water after treatment. Also, the GAC use is more
restricted to situations in which the water is very
polluted. Nevertheless, this type of treatment has the
advantage of GAC’s regeneration, in addition to
providing the development of biological activity
enabling the organic compounds removal which has
greater biodegradability than adsorption [8].
Activated carbon is a microporous adsorbent with a
high surface area and the presence of various functional
groups on this surface, due to the thermal treatment
made under high temperature. It can be derived from
various carbonaceous materials (vegetable, mineral
and animal) and is widely used in the treatment of
industrial effluents for adsorption of organic
compounds. The compounds adsorption by activated
carbon occurs mainly by physical or chemical
processes (chemisorption). In physical adsorption,
there is a predominance of Van der Waals Forces
between the adsorbent (activated carbon) and the
adsorbate (organic micropollutant). In relation to
chemisorption, the adsorbent and the adsorbate create a

Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon
655
chemical bond due to the electrostatic forces’
predominance (polarization interactions), resulting in
molecular structure change [8].
To characterize the affinity sorption between
endocrine disruptors and organic material (activated
carbon), it is used the octanol-water partition
coefficient (KOW). Two sorption types can occur:
hydrophobic interactions related to absorption, which
is given by logKow value; and adsorption, that is
determined by acid dissociation constant (pKa).
Substances with higher logKow and molecular weight
tend to be adsorbed, while those with lower logKow, due
to their less potential for adsorption, tend to appear in
higher concentrations in water sources [4].
3. Experimental Methods
This research aimed to evaluate: (1) the
effectiveness of analytical standards removal of
environmental estrogens estrone (E1), 17β-estradiol
(E2), estriol, 17α-ethinylestradiol (EE2), and
xenoestrogens BPA (bisphenol A) and NP
(nonylphenol), dissolved in deionized water in fixed
concentrations by adsorption on powdered activated
carbon (106/90 and 108/90) and granular activated
carbon (8x30 and 12x40); and (2) surface natural water
samples were collected at sampling points of Billings
and Guarapiranga Reservoirs and Tietê river in São
Paulo, Brazil, conducted bimonthly by CETESB
(Environmental Company of São Paulo State). After all
analysis with activated carbons, the concentration of
these compounds was also determined at selected
sampling points.
Samples were stored in amber glass bottles (1 L)
with polished cover, and transported from CETESB to
the laboratory in a thermal container with ice.
Posteriorly, the filtration of the sample was made
by cellulose acetate membrane with 0.45 µm porosity.
Sulfuric acid was added to preserve them stored under
4 °C refrigeration until their use in the experiments.
4. Material and Methods
4.1 Compounds' Determination
The identification and quantification processes of
estrogens estrone (E1), 17β-estradiol (E2), estriol,
17α-ethinylestradiol (EE2), and xenoestrogens BPA
(bisphenol A) and nonylphenol (NP), were conducted
in stages [13-15]. Firstly samples of 500 mL were
filtered in vacuumn through a cellulose acetate
membrane (0.45 µmporosity); the compounds of
interest were extracted from the water samples through
a solid-phase extraction using Strata X cartridges.
Subsequently, the matrix interferences were removed
(particularly those with high polarity), isolating the
analytes which were retained in the cartridge with 5 mL
of deionized water (flow rate of 3-5 mL/min), leaving it
for 5 min in the vacuum.
The samples were eluted and concentrated using the
organic solvent ACN (acetonitrile) (HPLC-UV (high
performance liquid chromatograph with
ultravioletgrade)). The elution was carried out using
two volumes of 5 mL ACN in each cartridge connected
to the vacuum manifold (flow rate of 3-5 mL/min), and
posteriorly collected in vials of 10 mL capacity for
each one. After all ACN flowed, the cartridges
remained about 5 min in vacuum to ensure the passage
of entire solvent. Thus, each eluted sample in the vial,
with 10 mL ACN concentration, remained in contact
with a nitrogen flow (gas) to evaporate until completely
dry. Then the samples were reconstituted in the same
vial with 0.5 mL MeOH (HPLC-UV grade) to desorb
the analytes of interest and concentrate it in 0.5 mL
(Fig. 1). Consecutively, 0.5 mL samples were analyzed
using a HPLC-UV detection.
The whole process was adapted from Araújo [16],
Lanças [14], López de Alda and Barceló [17],
Raimundo [18], and Verbinnen et al. [19].

Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon
656
Fig. 1 Experimental equipment used in the SPE (solid-phase extraction) phase.
5. Adsorption by Activated Carbon
5.1 PAC (Powdered Activated Carbon)
Two types of PAC produced from vegetable source
(Pinus), one of them 106/90 (600 mg/g iodine number)
and other 108/90 (800 mg/g iodine number). Powdered
activated carbon was used to treat 500 mL standard
solutions of deionized water containing 1 mg/L
compound of interest’s solution (estrone, 17β-estradiol,
estriol, 17α-ethinylestradiol, Bisphenol A and nonylphenol).
Experiments were performed in triplicate for both
types of powdered activated carbon totaling 54 tests,
varying the activated carbon concentration and its
contact time with the standard solution. Solutions with
powdered activated carbon treatment were submitted to
constant agitation (120 rpm) in the jar test equipment
(Fig. 2). After mixing, the samples were filtered under
vacuum using cellulose acetate membrane (0.45 µm
porosity) to remove the PAC, and posteriorly carried
out the solid phase extraction SPE and
chromatographic analysis aforementioned.
5.2 GAC (Granular Activated Carbon)
Two types of GAC were used in experiments, one
with smaller granulometry (8 × 30 mm) and other with
largergranulometry (12 × 40 mm). Experiments were
conducted in glass column 5 × 30 cm (internal
diameter × height), filled with 33 g of each GAC to the
percolation of 500 mL standard solution in descending
continuous flow, varying the time of standard solution
passage by flow control. Although the CAG can be
regenerated, in this present study, it was discarded and
completely replaced at the moment that its saturation
started in the columns.

Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon
657
Fig. 2 Jar test equipment.
Table1 p-values for each factor.
Compounds p-values time p-values concentration p-values time × concentration
Estriol 0 0 0
Estrone (E1) 0.434 0.458 0.008
17α-ethinylestradiol (EE2) 0.442 0.476 0.001
17β-estradiol (E2) 0.284 0.006 0
Bisphenol A (BPA) 0 0 0
Nonylphenol (NP) 0.313 0 0.761
After the conclusion of the assays, the samples were
filtered under vacuum using cellulose acetate membrane
(0.45 µm porosity) to remove any eventual impurities
from the GAC, and posteriorly also carried out the SPE
and chromatographic analysis aforementioned.
6. Results and Discussion
6.1 Evaluation of Estrogens Removal Process by
Powdered Activated Carbons (PACs)
ANOVA (analysis of variance with interaction) was
used to evaluate the estrogens removal by powdered
activated carbon (106/90 and 108/90), which enabled
the comparison of quantitative factors (treatments):
time (contact time between PAC and samples),
concentration (PAC concentration in the sample) and
time versus concentration (interaction between two
factors). The factors showed statistical significance
(probably true), so, they influenced the estrogens
removal by adsorption when p-value was lower than
0.05. Thus, the factor’s significance will be greater for
removing the compound of interest.
6.2 Powdered Activated Carbon 106/90 (PAC 106/90)
Tests performed by PAC 106/90, only estriol and
Bisphenol A presented p-value less than 0.05 for time
factor, i.e., the contact time between these compounds
and activated carbon influenced its removal. In this
case, one hour of contact showed more effective
removal for both compounds. In relation to the
concentration factor, the p-value less than 0.05 was
obtained for removal of estriol, 17β-estradiol,
bisphenol A and nonylphenol, and 50 mg/L of
activated carbon was the most effective concentration
in the removal process (Table 1).
However, the interaction analysis between time and
concentration was significant for all compounds

Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon
658
(except for nonylphenol) with 1 and 2 hours of
variation in removal time, and 50 mg/L activated
carbon as the most effective concentration This result
was expected because there is a contact surface loss
with minor amounts of PAC. The mechanical agitation
of samples by jar test may also have interfered in the
kinetics of chemical reaction hindering the
chemisorption process by collisions between the
adsorbent (PAC) and adsorbate
(estrogens/xenoestrogens), with a possible
predominance of physical adsorption. In physical
adsorption, weaker chemical bonds (Van der Waals
Forces) between activated carbon and
estrogen/xenoestrogens enable the occurrence of
desorption, affording the return of the compounds to
the sample again.
6.3 Powdered Activated Carbon 108/90 (PAC 108/90)
For removal using PAC 108/90, estriol was the only
compound that presented a p-value less than 0.05 for
the time factor, which indicated that contact time
between compounds and activated carbon, in general,
was not decisive in the removal process. Nevertheless,
concentration factor was significant for removal of
estriol, 17α-ethinylestradiol, 17β-estradiol, bisphenol
A and nonylphenol (p-value less than 0.05 or very close
to 0.05), with 50 mg/L of activated carbon as the most
effective concentration in the process. In relation to
factor interaction between time and concentration, the
greater significance was obtained from removal of
estriol and bisphenol, with 4 hours and 50 mg/L of
activated carbon as the most effective time and
concentration, respectively (Table 2). As previously
seen for PAC 106/90, concentration was the greater
significant factor (50 mg/L activated carbon as more
effective), due to the larger surface contact and
therefore more binding sites for compounds.
6.4 Evaluation of Estrogens Removal Process by GACs
(Granular Activated Carbons)
From the experiments using granular activated
carbon (GAC), it was verified the efficiency of removal
process (Table 3) by two different granulometry (8 ×
30 and 12 × 40).
Table 2 p-values for ecah factor.
Compounds p-values time p-values concentration p-values time × concentration
Estriol 0.013 0 0
Estrone (E1) 0.387 0.195 0.483
17α-ethinylestradiol (EE2) 0.253 0.053 0.180
17β-estradiol (E2) 0.318 0.053 0.439
Bisphenol A (BPA) 0.404 0.001 0.001
Nonylphenol (NP) 0.920 0.015 0.523
Table 3 Removal efficiency by GACs.
Compounds CAG 8 × 30 (%) CAG 12 × 40 (%)
E1 21.1 38.2
E2 17.4 41.4
E3 14.1 41.9
EE2 14.1 36.8
BPA 19.6 48.2
4n-NP 12.8 25.1

Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon
659
The removal efficiency percentages shown (Table 6)
were lower than expected, according to studies using
granular activated carbon [20], which obtained up to
approximately 99% organic compound removal
(2,4-D), using a concentration solution 100 times
higher and lower granular activated carbon mass,
compared to the concentrations used in this study. The
lower removal efficiency of compounds in this research
compared to Loureiro [20], may possibly be related to
the filling of GAC in the columns, due to occurrence of
air bubbles in some tests, or because the sample flowed
quickly through the column. However, as it was
expected, the GAC with large granulometry (12 × 40
mm) showed more effectivity in compounds removal
than GAC with smaller granulometry (8 × 30 mm).
6.5 Determination of Estrogens/Xenoestrogens in São
Paulo's Water Sources
The determination step for estrogens estrone,
17β-estradiol, estriol, 17α-ethinylestradiol and
xenoestrogens bisphenol A and nonylphenol, from
sampling points at Billings and Guarapiranga
Reservoirs, and Tietêriver (near to Remédios
and Bandeiras Bridges), in São Paulo, Brazil,
showed a high level of water quality degradation as
expected. The raw sewage, untreated wastewater and
the variety of waste released directly in the water
sources can be responsible for this degradation in São
Paulo.
Figs. 3-6 show the distribution of
estrogens/xenoestrogensat sampling points selected in
the dams and Tietêriver.
Billings and Guarapiranga reservoirs presented
higher levels for estrone and nonylphenol. In Tietêriver,
at sampling point near to Bandeiras Bridge, bisphenol
A and estriol showed the largest concentrations while
at Remédios Bridge’s sampling point higher amounts
of estriol and estrone were detected.
Fig. 3 Distribution of estrogens and xenoestrogens at Billings reservoir (sampling point) during May, July, September and
November, 2012.

Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon
660
Fig. 4 Distribution of estrogens and xenoestrogens at Guarapiranga reservoir (sampling point) during May, July, September
and November, 2012.
Fig. 5 Distribution of estrogens and xenoestrogens at Bandeiras bridge (Tietêriver sampling point) during May, July,
September and November, 2012.

Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon
661
Fig. 6 Distribution of estrogens and xenoestrogens at Remédios bridge (Tietêriver sampling point) during May, July,
September and November, 2012.
7. Conclusions
In the experiments with estrogens estrone,
17β-estradiol, estriol, 17α-ethinylestradiol, and
xenoestrogens bisphenol A and nonylphenol, it was
verified the removal effectiveness of these compounds
by adsorption using powdered activated carbon 106/90
and 108/90. For both types of PAC, the concentration
factor was decisive, wherein 50 mg/L carbon
concentration was the most effective. However, for
both types of granular activated carbon, only removal
efficiencies were checked, which proved unsatisfactory,
possibly due to operational problems.
As for the determination of interest compounds in
water sources that supply São Paulo, they were found at
selected sampling points. This situation concerns for
water’s degradation and pollution that currently do not
receive specific treatment to remove these compounds,
and it has been used for human consumption in the city.
Nevertheless, more research is necessary in order to
investigate estrogenic potential of more chemicals
substances, as well as the search for viable technology
for removing such compounds, with the goal to
regulate and reduce these substances in the
environment, besides avoiding the irregular disposal of
several wastes.
Acknowledgments
The authors would like to thank the National Council
for Scientific and Technological Development (CNPq),
and the Meridional Foundation IMED, for all financial
support to the development and publication of this
work.
References
[1] Marsalek, J., Jiménez-Cisneros, B. E., Malmquist, P.-A.,
Karamouz, M., Goldenfum, J., and Chocat, B. 2006.
Urban Water Cycle Processes and Interactions.
Technical documents in hydrology, 78,UNESCO,
Paris.
[2] Blair, B. D., Crago, J. P., Hedman, C. J., Treguer, R. J. F.,
Magruder, C., Royer, L. S., and Klaper, R. D. 2013.

Determination and Removal of Endocrine Disruptors in Wastewater by Activated Carbon
662
“Evaluation of a Model for the Removal of
Pharmaceuticals, Personal Care Products, and Hormones
from Wastewater.” Science of the Total Environment 444:
515-21.
[3] Hedgespeth, M. L., Sapozhnikova, Y., Pennington, P.,
Clum, A., Fairey, A., and Wirth, E. 2012.
“Pharmaceuticals and Personal Care Products (PPCPs) in
Treated Wastewater Discharges into Charleston Harbor.”
South Carolina.Science of the Total Environment 437:
1-9.
[4] Raimundo, C. C. M. 2011. “Emerging Contaminants in
Treated Water Sources: Seasonality, Removal and
Estrogenic Activity.” Doctoral dissertation. Campinas
State University—UNICAMP. Accessed July 1, 2013.
http://biq.iqm.unicamp.br/arquivos/teses/000837191.pdf.
[5] Sodré, F. F., Locatelli, M. A. F., and Jardim, W. F. 2010.
“An In-Line Clean System for the Solid-Phase Extraction
of Emerging Contaminants in Natural Waters.” Quim.
Nova 33: 216-9. (in Portuguese)
[6] Beck, I. C., Bruhn, R., Gandrass, J., and Ruck, W. 2005.
“Liquid Chromatography-Tandem Mass Spectrometry
Analysis of Estrogenic Compuonds in Coastal Surface
Water of the Baltic Sea.” Journal of Chromatography A
1090: 98-106.
[7] Routledge, E. J., Sheahan, D., Desbrow, C., Brighty, G.
C., Waldock, M., and Sumpter, J. P. 1998. “Identification
of Estrogenic Chemicals in STW Effluent.2. In Vivo
Responses in Trout and Roach.” Environmental Science &
Technology 32: 1559-65.
[8] Veras, D. F. 2006. “Removal of Endocrine Disruptors
17β-Estradiol and p-Nonylphenol by Different Types of
Powdered Activated Carbon (cap) Produced in
Brazil—Bench-Scale Evaluation.” Master dissertation.
Brasília University—UNB. Accessed February 1, 2013.
http://repositorio.unb.br/bitstream/10482/1553/1/Disserta
%C3%A7%C3%A3o%20Deborah_Freitas_Veras.pdf. (in
Portuguese)
[9] Sadik, O. A., and Witt, D. M. 1999. “Monitoring
Endocrine Disrupting Chemicals.” Environmental Science
& Technology 33: 368A-374A.
[10] Zuccato, E., Castiglioni, S., Fanelli, R., Reitano, G.,
Bagnati, R., Chiabrando, C., Pomati, F., Rossetti, C., and
Calamari, D. 2006. “Pharmaceuticals in the Environment
in Italy: Causes, Occurrence, Effects and Control.”
Environ Sci & Pollut Res. 13: 15-21.
[11] Bautista-Toledo, I., Ferro-García, M. A., Rivera-Utrilla,
J., Morenocastilla, C., and Vegas Fernández, F. J. 2005.
“Bisphenol a Removal from Water by Activated Carbon.
Effects of Carbon Characteristicsand Solution Chemistry.”
Environmental Science Technology 39: 6246-50.
[12] Corwin, C. J., and Summers, R. S. 2011. “Adsorption and
Desorption of Trace Organic Contaminants from
Granular Activated Carbon Adsorbers after Intermittent
Loading and Throughout Backwash Cycles.” Water
Research 45: 417-26.
[13] Comerton, A. M., Andrews, R. C., and Bagley, D. M.
2009. “Pratical Overview of Analytical Methods for
Endocrine-Disrupting Compounds, Pharmaceuticals and
Personal Care Products in Water and Wastewater. Phil.
Trans. R. Soc. A 367: 3923-39.
[14] Lanças, F. M. 2009. Modern Liquid
Chromatography—HPLC/CLAE. Campinas: Átomo. (in
Portuguese)
[15] Rissato, S. R., Libânio, M., Giafferis, G. P., and Gerenutti,
M. 2004. “Determination of Organochlorated Pesticides in
the Water Supply System, Drinking Water and Soil of the
Region of Bauru (SP).” Quim. Nova 27: 739-43. (in
Portuguese)
[16] Araújo, J. C. 2006. “Study of Treatment Effectiveness of
the Domestic Sewage in the City of Araraquara-SP in the
Removal of Sex Hormones.” Master dissertation.
University of São Paulo.
[17] López de Alda, M. J., and Barceló, D. 2000.
“Determination of Steroid Sex Hormones and Related
Synthetic Compounds Considered as Endocrine
Disrupters in Water by Liquid Chromatography-Diode
Array Detection-Mass Spectrometry.” Journal of
Chromatography A 892: 391-406.
[18] Raimundo, C. C. M. 2007. “Occurrence of Endocrine
Disrupters and Pharmaceuticals in Surface Waters of the
Atibaia River Basin.” Master dissertation. Campinas State
University—UNICAMP. Accssed July 1, 2013.
http://biq.iqm.unicamp.br/arquivos/teses/vtls000419516.p
df.
[19] Verbinnen, R. T., Nunes, G. S., and Vieira, E. M. 2010.
“Determination of Estrogens in Drinking Water Using
HPLC-DAD.” Quim. Nova 33: 1837-42. (in Portuguese)
[20] Loureiro, L. F. 2012. “Adsorption Assessment of 2,4-D
Herbicide in Powdered Activated Carbon and Granular
by Analysis of Adsorption Isotherms Using Different
Qualities of Water.” Master dissertation. Espírito Santo
Federal University. Accessed on July 2013.
http://portais4.ufes.br/posgrad/teses/tese_5918_.pdf. (in
Portuguese)