Abstract

In this study, the effect of Spathiphyllum blandum on the removal of ibuprofen (IB) and conventional pollutants such as chemical oxygen demand (COD), total nitrogen (TN), ammonium (NH4+-N), total phosphorus (TP), and total suspended solids (TSS) is reported; this, through its use as an emergent vegetation in fully saturated (FS) constructed wetlands (CWs) at mesocosm level treating polluted river water. With the exception of TP and COD, it was found that for TN (12%), NH4+-N (11%), TSS (19%), and IB (23%), the removals in systems with vegetation were superior to systems without vegetation (p < 0.05). These findings demonstrate the importance of the species S. blandum, in particular, for the removal of ibuprofen, which is an anti-inflammatory drug commonly found in effluents of wastewater treatment plants. Thus, the results obtained provide information that can be used for the design of future efficient large-scale systems using a new ornamental species, mainly under tropical climatic conditions.

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INTRODUCTION

The use of pharmaceutical products in large quantities and their improper disposal have led them to be found in rivers, lakes, seas, wetlands, and groundwater (Quesada-Peñate et al. 2009; Veras et al. 2019). In the last decade, interest in removing pharmaceutical compounds from wastewater has increased, mainly non-steroidal anti-inflammatory drugs due to their ability to negatively affect aquatic ecosystems. Ibuprofen is one of the most commonly prescribed anti-inflammatory agents found in effluents from wastewater treatment plants in concentrations between 10 ng.L−1 and 169 μg.L−1 and is the third most manufactured drug in the world with more than 15,000 tons per year produced (Ghauch et al. 2012). On the other hand, the high costs of construction and implementation of technologies that have proven efficient for the removal of this type of compound, such as advanced oxidation, UV radiation, membrane biofilm reactors, etc., (Zhang et al. 2017) are expensive to solve this problem, in particular for developing countries. Fortunately, recent studies with CWs for the treatment of different types of wastewater have shown that it is feasible to eliminate drugs such as carbamazepine (Tejeda et al. 2017), acetaminophen, diclofenac, ibuprofen (Ávila et al. 2013), etc., with this technology. However, it is still necessary to study the influence of design parameters and CW components such as the filter medium and vegetation, in addition to the impact of environmental factors (Li et al. 2014). Moreover, very few studies have been carried out in tropical conditions where there is a great biodiversity. Recent studies include that performed by de Oliveira et al. (2019), who evaluated in Brazil, the removal of ibuprofen and caffeine in mesocosm-scale CWs planted with Heliconia rostrata and Eichhornia crassipes and obtained removal efficiencies >80% for both pharmaceuticals; that carried out by Zhang et al. (2018) in a subtropical climate in the south of China, for the removal of acidic pharmaceuticals (ibuprofen, gemfibrozil, naproxen, ketoprofen, and diclofenac) in subsurface flow CWs planted with Canna indica L., finding that the macrophytes favored the removal of ibuprofen and gemfibrozil; and that conducted by Lancheros et al. (2019), who evaluated the removal of ibuprofen and naproxen in horizontal subsurface flow CWs planted with Cyperus ligularis in the tropical climate of Colombia. On the other hand, within the wide range of tropical ornamental vegetation, it has been found that the Sphathiphylum family adapts easily to the flood conditions that prevail in CWs. Zamora et al. (2019) reported the use of Sphathiphylum wallissi in subsurface flow CWs for phosphorus and organic matter from community wastewater. For this reason, it is worth evaluating S. blandum, a species that grows faster than S. wallissi in the vicinity of natural aquatic bodies in rural areas in southeastern Mexico (Díaz-Jiménez et al. 2015; Villaseñor 2016). Therefore, the aim of this study was to evaluate the effect of S. blandum on the removal of ibuprofen and conventional contaminants such as chemical oxygen demand (COD), total nitrogen (TN), ammonium (NH4+-N), total phosphorus (TP), total suspended solids (TSS), in fully saturated (FS) CWs at mesocosm level from polluted river water; this river receives discharges of untreated municipal wastewater.

MATERIALS AND METHODS

The experimental units of FS CWs at mesocosm level consisted of ten cylindrical plastic units adapted as 20 L subsurface wetlands. These units were established outdoors and each unit was filled with tezontle (diameter between 1 and 1.8 cm); five units were planted with S. blandum and five units remained without vegetation, as control systems. The wastewater used for the study was collected every 8 days from a branch of the Sordo River (that receives municipal wastewaters from the city of Xalapa, Veracruz, Mexico) and pumped into a 500 L storage tank into which ibuprofen was added at a concentration of 50 μg.L−1. Ibuprofen was obtained from the drug Motrin®-infantile in a concentration of 2 g.100 mL−1. Additionally, it was found that in the river, the concentration of ibuprofen was in the range of 8 to 11 μg.L−1 before the addition of ibuprofen for this study; afterwards, the final concentration of ibuprofen was around 60 μg.L−1.

The experimental units operated at a continuous flow of 5.3 L/d. The monitoring of the systems began 30 days after the FS CWs were installed and lasted eight months, from March to October 2018. For the measurement of contaminants such as COD, TSS, NH4+-N, TN, and TP, samples were taken every 15 days at the input and outputs of the systems; while for the quantification of ibuprofen, samples were taken every 30 days. Conventional pollutants were measured using standard methods (APHA-AWWA & WEF 2005). Ibuprofen was quantified according to Cervantes et al. (2017) in a Waters Acquity UPLC H-Class coupled to a Xevo TQD (triple quadrupole) mass spectrophotometer equipped with an electrospray ionization source (EIS). Prior to the UPLC analysis, water samples were filtered through filter paper to remove suspended solids. Then, the analyte was extracted with dichloromethane, concentrated to dryness with a rotary evaporator at 35 °C and reconstituted by using 1 mL of ethanol. Each resuspension was filtered through a 0.2 μm PTFE filter. The recovery rate was 95.7 ± 1.8%. A Waters column (Symmetry C18), 50 mm long, 2.1 mm internal diameter and 1.7 μm in particle size was used. The mobile phase was formic acid at 0.01% in water, and formic acid at 0.01% in methanol, the flow rate was 0.3 mL/min. The limit of detection was 1 μg.L–1.

The results were analyzed in SPSS® Statistics 19. A variance analysis was performed to find statistical differences (p ≤ 0.05) between the influent and effluents of the systems. Prior to statistical analysis, all data were analyzed to determine their normality and statistical distribution. The homogeneity of the variance was tested using the Levene test.

RESULTS AND DISCUSSION

Plant development

During this study, under the average climatic conditions of 21 °C and 82% relative humidity, the S. blandum reached a height between 76 and 98 cm. This growth was 2.1% higher than in its natural habitat during a similar period (Chízmar-Fernández 2009). On the other hand, light intensity during the study averaged 805.81 lux, which falls in the intensity ranges for tropical zones (500 to 2,100 lux) (Sandoval-Herazo et al. 2018).

Removal of conventional pollutants

It can be seen from Table 1 that the removal of COD in mesocosms planted with S. blandum and without vegetation were, on average, 72.29% and 66.40%, respectively. Statistically, there was no significant difference (p > 0.05) in the removal of COD between these mesocosms; similar to that reported by Albalawneh et al. (2016) when evaluating vegetated and unvegetated systems. Regarding phosphorus, there was also no significant difference (p > 0.05).

Table 1

Average concentrations of water quality parameters (±standard deviation, n = 80) at the influent and effluents, as well as removal efficiencies in the FS CWs, during the period of experimentation

ParametersS. blandumControl
COD 
Influent concentration (mg.L−1318.13 ± 102.47 
Effluent concentration (mg.L−188.13 ± 63.30 106.88 ± 73.68 
Removal efficiency (%) 72.29 66.40 
TSS 
Influent concentration (mg.L−1695.63 ± 24.12 
Effluent concentration (mg.L−1337.50 ± 49.79 459.38 ± 32.46 
Removal efficiency (%) 51.48 33.96 
NH4+-N 
Influent concentration (mg.L−122.88 ± 2.70 
Effluent concentration (mg.L−112.25 ± 3.49 14.63 ± 3.62 
Removal efficiency (%) 46.46 36.05 
TN 
Influent concentration (mg.L−1103.75 ± 6.41 
Effluent concentration (mg.L−153.38 ± 5.34 63.75 ± 7.03 
Removal efficiency (%) 48.54 38.55 
TP 
Influent concentration (mg.L−111.21 ± 2.89 
Effluent concentration (mg.L−14.08 ± 1.29 4.15 ± 1.09 
Removal efficiency (%) 63.60 62.97 
ParametersS. blandumControl
COD 
Influent concentration (mg.L−1318.13 ± 102.47 
Effluent concentration (mg.L−188.13 ± 63.30 106.88 ± 73.68 
Removal efficiency (%) 72.29 66.40 
TSS 
Influent concentration (mg.L−1695.63 ± 24.12 
Effluent concentration (mg.L−1337.50 ± 49.79 459.38 ± 32.46 
Removal efficiency (%) 51.48 33.96 
NH4+-N 
Influent concentration (mg.L−122.88 ± 2.70 
Effluent concentration (mg.L−112.25 ± 3.49 14.63 ± 3.62 
Removal efficiency (%) 46.46 36.05 
TN 
Influent concentration (mg.L−1103.75 ± 6.41 
Effluent concentration (mg.L−153.38 ± 5.34 63.75 ± 7.03 
Removal efficiency (%) 48.54 38.55 
TP 
Influent concentration (mg.L−111.21 ± 2.89 
Effluent concentration (mg.L−14.08 ± 1.29 4.15 ± 1.09 
Removal efficiency (%) 63.60 62.97 

However, the presence of S. blandum increased the removal (p < 0.05) of TSS, NH4+-N, and TN by 18%, 11%, and 13%, respectively (Figure 1) in comparison to the unvegetated system.

Figure 1

Concentrations and removal of ibuprofen in the FS CWs during the study.

Figure 1

Concentrations and removal of ibuprofen in the FS CWs during the study.

Removal of ibuprofen in FS CWs

The average concentration of ibuprofen in the polluted river water evaluated in this study was 9 μg.L−1; this value is in agreement with Ghauch et al. (2012), who reported that ibuprofen has been found in wastewater at concentrations between 10 ng L−1 and 169 μg.L−1. Regarding ibuprofen removal, it was higher in vegetated systems (p < 0.05) (71%) in comparison to non-vegetated systems (52%). These values are higher than the 44% reported by Březinova et al. (2018) carried out in a temperate climate, which could be due to the fact that this study was carried out in a tropical climate and higher temperatures favored the removal of the drug. However, they are inferior to what was found by Zhang et al. (2017) (between 68% and 83%) in a tropical climate, probably because the authors performed the study with lower concentrations, i.e., between 11.5 μg.L−1 and 48.5 μg.L−1.

On the other hand, the difference between vegetated and unvegetated systems can be explained by the fact that the plant rhizosphere acts as a microcosm in which recalcitrant chemical compounds such as ibuprofen are degraded (Lancheros et al. 2019). Biodegradation and biotransformation in wetlands occur mainly in the rhizomes; additionally, the exudates released in the radical zones of plants intensify microbial activity and can improve the bioavailability of pharmaceuticals in these systems. In general, it has been found that the presence of vegetation in CWs improves drug elimination (Truu et al. 2015). Furthermore, according to Verlicchi et al. (2012), the removal of ibuprofen is greater in aerobic conditions, since aerobic microorganisms favor the removal of this compound.

CONCLUSIONS

In general, ibuprofen removal was moderately high in the FS CWs. In addition, the presence of S. blandum increased the removal of ibuprofen in FS CWs over unplanted systems by 19%; it also increased the removal of TSS, NH4+-N, and TN. Such results indicate that the presence of the plants probably generated aerobic micro zones that improved the elimination of the drug.

REFERENCES

Albalawneh
A.
Chang
T. K.
Chou
C. S.
Naoum
S.
2016
Efficiency of a horizontal sub-surface flow constructed wetland treatment system in an arid area
.
Water
8
(
2
),
51
.
https://doi.org/10.3390/w8020051
.
APHA-AWWA & WEF
2005
Standard Methods for the Examination of Water and Wastewater
.
American Public Health Association/American Water Works Association/Water Environment Federation
,
Washington DC
,
USA
.
Březinova
T. D.
Vymazal
J.
Koželuh
M.
Kule
L.
2018
Occurrence and removal of ibuprofen and its metabolites in full-scale constructed wetlands treating municipal wastewater
.
Ecological Engineering
120
,
1
5
.
https://doi.org/10.1016/j.ecoleng.2018.05.020
.
Chízmar-Fernández
C.
2009
Plantas Comestibles de Centroamérica
, 1st edn.
(Edible Plants of Central America) Instituto Nacional de Biodiversidad, INBio
,
Santo Domingo de Heredia
,
Costa Rica
.
de Oliveira
M.
Atalla
A. A.
Frihling
B. E. F.
Cavalheri
P. S.
Migliolo
L.
Magalhães Filho
F. J.
2019
Ibuprofen and caffeine removal in vertical flow and free-floating macrophyte constructed wetlands with Heliconia rostrata and Eichornia crassipes
.
Chemical Engineering Journal
373
,
458
467
.
https://doi.org/10.1016/j.cej.2019.05.064
.
Díaz-Jiménez
P.
Olivera
M. d. l. Á. G.
Thomas
B. C.
2015
Diversidad florística de Araceae en el estado de Tabasco, México. (Floristic diversity of Araceae in the state of Tabasco, Mexico)
.
Botanical Sciences
93
(
1
),
131
142
.
doi:10.17129/botsci.238
.
Ghauch
A.
Tuqan
A. M.
Kibbi
N.
2012
Ibuprofen removal by heated persulfate in aqueous solution: a kinetics study
.
Chemical Engineering Journal
197
,
483
492
.
https://doi.org/10.1016/j.cej.2012.05.051
.
Lancheros
J. C.
Madera-Parra
C. A.
Caselles-Osorio
A.
Torres-López
W. A.
Vargas-Ramírez
X. M.
2019
Ibuprofen and Naproxen removal from domestic wastewater using a horizontal subsurface flow constructed wetland coupled to ozonation
.
Ecological Engineering
135
,
89
97
.
https://doi.org/10.1016/j.ecoleng.2019.05.007
.
Li
Y.
Zhu
G.
Ng
W. J.
Tan
S. K.
2014
A review on removing pharmaceutical contaminants from wastewater by constructed wetlands: design, performance and mechanism
.
Science of the Total Environment
468
,
908
932
.
https://doi.org/10.1016/j.scitotenv.2013.09.018
.
Quesada-Peñate
I.
Jáuregui-Haza
U. J.
Wilhelm
A. M.
Delmas
H.
2009
Contaminación de las aguas con productos farmacéuticos. Estrategias para enfrentar la problemática. (Water pollution with pharmaceutical products. Strategies to face the problem) Revista CENIC
.
Ciencias Biológicas
40
(
3
).
Sandoval-Herazo
L.
Alvarado-Lassman
A.
Marín-Muñiz
J.
Méndez-Contreras
J.
Zamora-Castro
S. A.
2018
Effects of the use of ornamental plants and different substrates in the removal of wastewater pollutants through microcosms of constructed wetlands
.
Sustainability
10
(
5
),
1594
.
https://doi.org/10.3390/su10051594
.
Tejeda
A.
Torres-Bojorges
Á. X.
Zurita
F.
2017
Carbamazepine removal in three pilot-scale hybrid wetlands planted with ornamental species
.
Ecological Engineering
98
,
410
417
.
https://doi.org/10.1016/j.ecoleng.2016.04.012
.
Truu
J.
Truu
M.
Espenberg
M.
Nõlvak
H.
Juhanson
J.
2015
Phytoremediation and plant-assisted bioremediation in soil and treatment wetlands: a review
.
The Open Biotechnology Journal
9
(
1
).
doi:10.2174/1874070701509010085
.
Veras
T. B.
de Paiva
A. L. R.
Duarte
M. M. M. B.
Napoleão
D. C.
Cabral
J. J. D. S. P.
2019
Analysis of the presence of anti-inflammatories drugs in surface water: a case study in Beberibe river - PE, Brazil
.
Chemosphere
222
,
961
969
.
https://doi.org/10.1016/j.chemosphere.2019.01.167
.
Verlicchi
P.
Al Aukidy
M.
Zambello
E.
2012
Occurrence of pharmaceutical compounds in urban wastewater: removal, mass load and environmental risk after a secondary treatment – a review
.
Science of the Total Environment
429
,
123
155
.
https://doi.org/10.1016/j.scitotenv.2012.04.028
.
Villaseñor
J. L.
2016
Checklist of the native vascular plants of Mexico
.
Revista Mexicana de Biodiversidad
87
(
3
),
559
902
.
ISSN 1870-3453, https://doi.org/10.1016/j.rmb.2016.06.017
.
Zamora
S.
Sandoval
L.
Marín-Muñíz
J. L.
Fernández-Lambert
G.
Hernández-Orduña
M. G.
2019
Impact of ornamental vegetation type and different substrate layers on pollutant removal in constructed wetland mesocosms treating rural community wastewater
.
Processes
7
(
8
),
531
.
https://doi.org/10.3390/pr7080531
.
Zhang
L.
Lv
T.
Zhang
Y.
Stein
O. R.
Arias
C. A.
Brix
H.
Carvalho
P. N.
2017
Effects of constructed wetland design on ibuprofen removal–A mesocosm scale study
.
Science of the Total Environment
609
,
38
45
.
https://doi.org/10.1016/j.scitotenv.2017.07.130
.
Zhang
X.
Jing
R.
Feng
X.
Dai
Y.
Tao
R.
Vymazal
J.
Cai
N.
Yang
Y.
2018
Removal of acidic pharmaceuticals by small-scale constructed wetlands using different design configurations
.
Science of the Total Environment
639
,
640
647
.
https://doi.org/10.1016/j.ecoleng.2016.05.077
.
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