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Recibido: 2025-09-19 Aceptado: 2025-11-20
Página 207
Ecological responses of Holothuria sanctori to metal
contamination at La Punta del Hidalgo, Tenerife Island:
two-year monitoring and analysis
DOI: https://doi.org/10.5281/zenodo.18479107
Lozano-Bilbao, Enrique
1
Correo: elozanob@ull.edu.es
Orcid: https://orcid.org/0000-0001-6971-1845
University of La Laguna. San Cristóbal de La Laguna, Canary Islands, Spain.
González-Weller, Dailos
2
Correo: dgonzal@ull.edu.es
Orcid: https://orcid.org/0000-0001-7702-4404
Canary Health Service, S/C de Tenerife, Canary Island, Spain
Gutiérrez, Ángel
3
Correo: ajguti@ull.edu.es
Orcid: https://orcid.org/0000-0003-1581-0850
University of La Laguna. San Cristóbal de La Laguna, Canary Islands, Spain.
Abstract
This study investigates the variations in metal and trace element concentrations
within the Holothuria sanctori species over two years, between 2021 and 2022,
with a specific focus on differences between the "Cold" and "Warm" stations. A
total of 80 specimens were collected during four sampling periods, each
comprising 20 individuals in the months of January and August. The selection of
Punta del Hidalgo as the sampling area was based on the presence of this species
in the intertidal zone and the observation of a higher number of specimens in the
vicinity of an underwater outfall. The analysis of metal contents (Zn, Cd, Pb, Cu,
Ni, Cr, and Fe in mg/kg) revealed significant differences in concentrations
between the "Cold" and "Warm" stations across the study years. The warm station
consistently displayed higher metal levels, with notable increments observed in
zinc (Zn), cadmium (Cd), lead (Pb), copper (Cu), nickel (Ni), chromium (Cr), and
iron (Fe). Variations in metal concentrations within H. sanctori during the summer
months at the warm station can be attributed to seasonal weather conditions,
increased tourist activities, and ocean currents transporting contaminants. The
1
PhD in Biodiversity Conservation. University of La Laguna. San Cristóbal de La Laguna, Canary Islands,
Spain.
2
Health Inspecttion and laboratory Service, Canary Health Service, S/C de Tenerife, Canary Island, Spain.
3
University of La Laguna. San Cristóbal de La Laguna, Canary Islands, Spain
Sección: Artículo científico 2026, enero-junio, año 1, núm. 1, 207-228
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 208
study underscores the importance of monitoring and controlling exposure to toxic
metals. Limits established for cadmium, lead, and nickel exposure provide crucial
data for public health policies and environmental regulations, safeguarding against
adverse effects of chronic metal exposure.
Keywords: metal; trace element; underwater outfall; bioindicator; environmental
monitoring,
Respuestas ecológicas de Holothuria sanctori a la contaminación
por metales en La Punta del Hidalgo, Isla de Tenerife: dos años de
monitoreo y análisis
Resumen
En esta investigación se estudian las variaciones en las concentraciones de metales
y oligoelementos dentro de la especie Holothuria sanctori durante dos años, entre
2021 y 2022, con un enfoque específico en las diferencias entre las estaciones
"Frías" y "Cálidas". Se colectaron un total de 80 ejemplares durante cuatro
períodos de muestreo, comprendiendo cada uno 20 individuos en los meses de
enero y agosto. La selección de Punta del Hidalgo como área de muestreo se basó
en la presencia de esta especie en la zona intermareal y la observación de un mayor
número de ejemplares en las cercanías de un emisario submarino. El análisis de
los contenidos de metales (Zn, Cd, Pb, Cu, Ni, Cr y Fe en mg/kg) reveló
diferencias significativas en las concentraciones entre las estaciones "Frías" y
"Cálidas" a lo largo de los años de estudio. La estación caliente mostró
consistentemente niveles de metales más altos, con incrementos notables
observados en zinc (Zn), cadmio (Cd), plomo (Pb), cobre (Cu), níquel (Ni), cromo
(Cr) y hierro (Fe). Las variaciones en las concentraciones de metales dentro de H.
sanctori durante los meses de verano en la estación cálida pueden atribuirse a las
condiciones climáticas estacionales, el aumento de las actividades turísticas y las
corrientes oceánicas que transportan contaminantes. El estudio subraya la
importancia de monitorear y controlar la exposición a metales tóxicos. Los límites
establecidos para la exposición al cadmio, el plomo y el níquel proporcionan datos
cruciales para las políticas de salud pública y las regulaciones ambientales,
salvaguardando contra los efectos adversos de la exposición crónica a metales.
Palabras clave: metal; oligoelemento; emisario submarino; bioindicador;
monitoreo ambiental.
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 209
Introduction
The marine environment exhibits a high degree of sensitivity to
anthropization, characterized by the human-induced influence and alteration of the
marine ecosystem. This phenomenon encompasses a broad spectrum of impacts,
including the contamination of oceans with plastic waste, chemicals, and oil spills,
the depletion of commercial fish populations due to overfishing, and the
degradation of coastal habitats like mangroves and coral reefs resulting from
urbanization and coastal development (Pacyna et al. 2006; Durrieu de Madron et
al. 2011; Wang et al. 2018; Morrison et al. 2019; Yuan et al. 2019; Corrias et al.
2020). The marine ecosystem reacts to these impacts in diverse ways.
To begin with, pollution and habitat alterations directly affect many marine
species, leading to population declines, localized extinctions, and shifts in the
composition of marine communities. Furthermore, ecological imbalances can
occur within marine ecosystems, exemplified by harmful algal blooms and the
proliferation of invasive species that exploit the modified conditions (Penha-
Lopes et al. 2011; Kravchenko et al. 2014; Auger et al. 2015; Li et al. 2017; Ali et
al. 2019; Zheng et al. 2022). These factors can exert a global-scale influence on
marine ecosystems, potentially leading to catastrophic outcomes. In summary, the
marine ecosystem plays a vital role in the overall health of our planet, supporting
a substantial portion of Earth's biodiversity. Nevertheless, anthropization poses a
grave threat to these ecosystems, underscoring the urgency of taking measures to
mitigate its impacts and safeguard the diversity and resilience of marine
ecosystems for future generations (Howarth et al. 2005; Pezzullo 2009; Dolenec
et al. 2011; Verma and Dwivedi 2013; Zavodny et al. 2017).
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 210
Human impact on the marine environment encompasses a range of activities
that markedly augment the presence of metals and trace elements in seas and
oceans. These trace elements encompass metals like lead, mercury, cadmium, and
other metallic compounds that are crucial in minuscule quantities for the proper
functioning of marine ecosystems but pose challenges when their concentrations
increase due to human activities (Clark et al. 2001; Harrison 2001; Temsch et al.
2010; Vikas and Dwarakish 2015; Ardeshir et al. 2017).
Industrial pollution stands out as a principal contributor to the accrual of
metals and trace elements in oceanic expanses. Factories and power plants emit a
diverse array of metals and noxious chemicals, which eventually make their way
to the sea through rivers and currents. Furthermore, deep-sea mining and mineral
extraction can directly release metals and trace elements into the marine ecosystem
(Barros et al. 2007; Gaudry et al. 2007; Shekhar et al. 2008; Karantininis et al.
2010). Agricultural practices also wield significant influence in introducing trace
elements into marine domains. Runoff from rainfall carries fertilizers and
pesticides from agricultural lands to rivers, which subsequently flow into the sea.
These chemical agents may harbor metals and trace elements, and their release can
disrupt the natural equilibriums within marine ecosystems (Jiang et al. 2006;
Tomas et al. 2013; Ritchie and Roser 2018; Hossain et al. 2019; Kerfahi et al.
2020).
Holothurians, commonly known as sea cucumbers, have gained recognition
as highly effective bioindicators of marine pollution owing to their capacity to
accumulate and react to a diverse range of contaminants present in oceanic
environments. A fundamental factor contributing to their efficacy as bioindicators
is their filter-feeding behavior, which classifies them as detritivores and makes
them susceptible to the accumulation of environmental contaminants (Tuwo and
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 211
Conand 1992; Xing and Chia 1997; Hamel et al. 2001; Parra-Luna et al. 2020).
These remarkable organisms can amass various substances, including heavy
metals, hydrocarbons, toxic chemicals, and microplastics within their tissues.
Their role as non-predators, with their primary exposure to contaminants
occurring through water filtration, allows their contaminant concentrations to
serve as a direct reflection of water quality. Additionally, holothurians possess a
biological defense mechanism that empowers them to detoxify and eliminate toxic
substances.
This mechanism encompasses the capability to sequester harmful
compounds in their tissues and subsequently expel them. Consequently, they
function as authentic indicators of exposure, with their presence and contaminant
levels offering insights into both current and historical pollution within a specific
area (Warnau et al. 2006; Turk Culha et al. 2016; Boluda-Botella et al. 2023;
González-Delgado et al. 2024). This study's primary goal is to evaluate the
ecological condition of La Punta del Hidalgo on Tenerife Island in the Canary
Islands, Spain. It entails a comprehensive two-year monitoring program to analyze
metals and trace elements across both the warm and cold seasons in Holothuria
sanctori.
Material and methods
A total of 80 specimens of Holothuria sanctori were collected in a study
conducted during four periods between 2021 and 2022. In each of these periods,
20 specimens were gathered in the months of January and August each year. Punta
del Hidalgo was chosen as the sampling area because this species is found in the
intertidal zone, and a higher number of specimens are observed in the vicinity of
an underwater outfall (Fig. 1).
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 212
Figure 1. Map of the sampling areas in the Punta del Hidalgo of the Canary archipelago
Sample preparation
The analytical samples comprised a segment of tissue, 5-8 grams for
organisms. These samples were deposited in porcelain crucibles and subjected to
a 24-hour drying process in an oven at 70°C. Subsequently, they were incinerated
in a muffle oven for 48 hours at 450°C ± 25°C until they transformed into white
ashes. Once the white ashes were obtained, they were filtered using a 1.5% HNO3
solution, diluted to 25 mL for the subsequent determination of metal content via
Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). This
method was employed to assess the concentration of toxic metals and trace
elements. To ensure the accuracy of the determinations, a quality control solution
was applied every ten samples. Additionally, certified reference materials
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 213
(DORM-1 and DOLT 2) were utilized to validate the results. All data are presented
in milligrams per kilogram of wet weight (mg/kg w.w.). The analysis included
blanks and standard reference materials, and the following metals and trace
elements were sampled: Cd, Pb, Cr, Cu, Fe, Ni, and Zn. By employing these
reference materials, a recovery rate exceeding 97% was achieved. Both blanks and
standard reference materials were analyzed concurrently with the samples
(Lozano-Bilbao et al. 2023a, b; Thorne-Bazarra et al. 2023).
Statistical analysis
In order to examine possible differences in the content and relative
composition of heavy and trace metals in the analyzed samples, a permutational
multivariate analysis of variance (PERMANOVA) was performed using
Euclidean distances. A two-way design was used, where the factor "year" was
considered as a fixed factor with two levels of variation (2021 - 2022) and the
factor "season" was considered as a fixed factor with two levels of variation (cold
- warm). The variables included in the analysis were Cd, Cr, Cu, Fe, Ni, Pb and
Zn. In order to conduct the statistical tests, 9999 permutations of interchangeable
units were performed and post-hoc comparisons between pairs were carried out to
verify the differences between the levels of the significant factors (p value < 0.05).
Clusters were determined using principal coordinate analysis (PCoA) in which
elements were represented as vectors (Anderson and Braak 2003; Anderson 2004).
The statistical packages PRIMER 7 and PERMANOVA þ v.1.0.1 were used to
perform these statistical analyses.
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 214
Results
Table 1 displays the metal contents (Zn, Cd, Pb, Cu, Ni, Cr, and Fe in mg/kg)
at the "Cold" and "Warm" stations during the years 2021 and 2022, revealing
significant differences in the levels of these metals (Table 2), the PERMANOVA
statistical analysis revealed significant differences in the levels of metals (Zn, Cd,
Pb, Cu, Ni, Cr, and Fe) between the "Cold" and "Warm" stations over the two
years of the study, but no significant differences were observed within the same
stations over the two years. At the "Warm" station, higher concentrations were
recorded in comparison to the "Cold" station for many of the analyzed metals in
both years. Zinc (Zn) exhibited an increase from 51.3±4.6 mg/kg in 2021 at the
"Cold" station to 64.9±7.7 mg/kg in 2021 at the "Warm" station, while in 2022, it
varied from 50.8±3.9 mg/kg to 67.4±6.0 mg/kg (Fig. 2). Cadmium (Cd), lead (Pb),
copper (Cu), nickel (Ni), chromium (Cr), and iron (Fe) also experienced similar
increments in their concentrations at the "Warm" station compared to the "Cold"
station. These findings suggest a greater accumulation of these metals at the
"Warm" station over the years 2021 and 2022.
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 215
Table 1. Mean concentrations of metal muscle sample (mg/Kg) with their standard
deviation, according to the study area according to the study area
2021
2022
Warm
Cold
Warm
Zn
64.9±7.7 (54.0-
79.5)
50.8±3.9 (44.4-
55.7)
67.4±6.0
(59.1-79.6)
Cd
0.691±0.089
(0.604-0.868)
0.532±0.073
(0.406-0.699)
0.716±0.08
(0.611-0.878)
Pb
1.98±0.23
(1.37-2.24)
1.59±0.098
(1.47-1.80)
2.05±0.18
(1.81-2.38)
Cu
8.05±0.918
(7.20-9.73)
6.07±0.35
(5.48-6.58)
8.30±0.83
(7.34-9.75)
Ni
3.64±0.47
(3.11-4.50)
2.78±0.19
(2.55-3.10)
3.87±0.52
(3.15-4.62)
Cr
2.39±0.50
(1.74-3.25)
1.46±0.38
(1.17-2.47)
2.51±0.46
(1.96-3.26)
Fe
169.1±16.3
(148.5-194.1)
134.7±12.2
(118.7-152.1)
173.2±15.1
(151.3-194.5)
Table 2. PERMANOVA analysis of year versus the factor "season" and
the studied metals
2021 vs. 2022
Cold vs. warm
Cold
Warm
2021
2022
Zn
0.833
0.403
0.001*
0.001*
Cd
0.826
0.474
0.002*
0.001*
Pb
0.697
0.262
0.001*
0.001*
Cu
0.986
0.511
0.001*
0.001*
Ni
0.83
0.295
0.001*
0.001*
Cr
0.884
0.549
0.001*
0.001*
Fe
0.859
0.569
0.001*
0.001*
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 216
Figure 2. Line graph of each metal in years and seasons
Table 3. Results of the mean metal concentrations in mg/kg and the maximum
daily intake in grams that a 70 kg adult person could ingest during his/her lifetime
without adverse effects
-
-
2021
2022
Cd
2.5 μg /kg /week
Mean
0.611
0.624
Grams
40.10
39.26
Pb 0.5 μg /kg/
day
Mean
1.795
1.82
Grams
19.78
19.51
Ni 2.8 μg/kg/ day
Mean
3.225
3.323
Grams
60.78
58.98
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 217
Discussion and conclusions
The variation in the concentration of metals and trace elements in the
Holothuria sanctori species within the same year, with an increase during the
summer months at the warm station, can be attributed to a series of interconnected
factors. Firstly, seasonal weather conditions play a fundamental role, as the
summer months are typically associated with higher temperatures and increased
solar radiation, influencing the metabolic activity and behavior of the species
(Tuwo and Conand 1992; Morgan 2001; Sicuro et al. 2012b). Additionally, ocean
currents and circulation patterns can transport contaminants and metals from
various sources to the warm station, thereby increasing the concentrations in the
water and, ultimately, in filter-feeding organisms like holothurians. Moreover, it's
important to consider that during the summer months, there is often a higher influx
of tourists and recreational activities in coastal areas, which can lead to the release
of contaminants and metals through various human activities.
These pollutants can reach the marine environment and accumulate in
marine organisms, including holothurians. The bioavailability of metals can also
change due to biogeochemical factors such as water salinity and acidity,
influencing the organisms' ability to absorb and accumulate these elements. H.
sanctori, a species of holothurian, has emerged as a valuable bioindicator of heavy
metal and trace element contamination in areas near underwater outfalls due to its
detritivorous nature and its position in the marine food chain(Sicuro et al. 2012a;
Navarro et al. 2013; Ahmed et al. 2017; Sroyraya et al. 2017).
These organisms primarily feed on decomposing organic matter that
accumulates on the seabed, making them excellent accumulators of particles and
contaminants present in the sediment. By inhabiting areas near underwater
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 218
outfalls, where wastewater is often released into the ocean, holothurians can
concentrate and accumulate heavy metals and trace elements found in this
wastewater. By monitoring the concentrations of these pollutants in holothurians,
scientists can assess the health of the marine ecosystem and the impact of pollutant
release through underwater outfalls. The capacity of H. sanctori to reflect water
quality and the presence of contaminants in its environment makes it a valuable
tool for environmental management and monitoring in coastal and underwater
regions (Warnau et al. 2006; Magdy et al. 2021). In the area, several studies have
been conducted on contamination by heavy metals and trace elements in water and
different organisms (Lozano-Bilbao et al. 2018, 2021, 2024; Lozano-Bilbao and
Alcázar-Treviño 2023). This leads us to suggest that the species used in our study,
H. sanctori, could be a good bioindicator of environmental contamination by
heavy metals and trace elements in this specific zone.
Previous studies on contamination in water and organisms have revealed the
presence of these pollutants, and H. sanctori, being a marine organism capable of
accumulating and responding to the presence of heavy metals and trace elements
in its environment, could reflect the environmental quality and extent of pollution
in the study area. This capacity for accumulation and response to pollutants makes
it a potential useful biological indicator for monitoring and evaluating the
environmental health of this marine ecosystem concerning the presence of specific
contaminants.
Mohammadizadeh et al. 2016, studied the concentrations of holothuria in
the Persian Gulf, obtaining Cd values of 0.91-1.15 mg/kg, Zn 44.28 mg/kg and Pb
15.78. These are very high values compared to those found in our study, this may
be due to the fact that the Persian Gulf is an area very frequented by commercial
sea routes and in the neighboring countries there are no regulations and legislation
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 219
as rigorous as in Spain. Turk Culha et al. 2016 studied the concentrations of
holothuria in the Persian Gulf, obtaining Cd values of 1.19 mg/kg, Zn 56.73
mg/kg, Pb 4.31 mg/kg and Ni 11.06 mg/kg. These values are very high compared
to those found in our study, this may be due to the fact that, like the Persian Gulf,
the Bosphorus is an area frequented by commercial marine routes with high levels
of pollutants.
The Table 3 provides significant data on exposure to different metals during
the years 2021 and 2022, with limits established in micrograms per kilogram of
body weight per week or day for cadmium (Cd), lead (Pb), and nickel (Ni). These
limits are used to calculate the maximum amount in grams that an adult weighing
70 kg could ingest over their entire life without experiencing adverse effects. This
type of analysis is crucial for assessing and mitigating potential risks associated
with chronic exposure to toxic metals. The weekly exposure limit for cadmium in
2021 was 2.5 micrograms per kilogram of body weight per week (μg/kg/week),
and it remained the same in 2022 at 2.5 μg/kg/week. The average exposure levels
in the population were 0.611 μg/kg/week in 2021 and slightly increased to 0.624
μg/kg/week in 2022. These levels translate into cumulative exposure, and if we
consider an adult weighing 70 kg, the calculated safety limit in grams that could
be ingested without risks over a lifetime was 40.10 grams in 2021 and 39.26 grams
in 2022. Regarding lead (Pb), the daily exposure limit was 0.5 μg/kg/day in both
2021 and 2022. The average exposure levels were recorded at 1.795 μg/kg/day in
2021 and slightly increased to 1.82 μg/kg/day in 2022. Although this difference
may not seem significant, when considering the maximum amount in grams that a
70 kg person could ingest over their entire life without risks, it would be 19.78
grams in 2021 and 19.51 grams in 2022. Finally, let's examine nickel (Ni). The
daily exposure limit was 2.8 μg/kg/day for both years. The average exposure levels
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 220
were 3.225 μg/kg/day in 2021 and increased to 3.323 μg/kg/day in 2022. This
indicates an increase in the population's average exposure over these two years. In
terms of the maximum amount of nickel that a 70 kg person could ingest over their
entire life without risks, this translates to 60.78 grams in 2021 and 58.98 grams in
2022. These calculations underscore the importance of monitoring and controlling
exposure to toxic metals such as cadmium, lead, and nickel in the population. The
established limits help define safe levels of ingestion over time, providing crucial
data for public health policies and environmental regulations aimed at protecting
people's health against the adverse effects of chronic exposure to heavy metals
(Reglamento (CE) No 1881/2006 2006; Reglamento (CE) No 420/2011 2011;
Reglamento (UE) No 488/2014 2014; Reglamento (UE)2015/1005 2015).
Credit authorship contribution statement
Sampling data and analysis were performed by all authors. Int ELB, AJG,
SP; MM: ELB, CR, AH, DGW; Res: ELB, AJG, AH; CD: ELB, AH, CR, SP,
DGW, AJG.
Declaration of competing interest
The authors declare that they have no known competing financial interests
or personal relationships that could have appeared to influence the work reported
in this paper.
Data availability
Data will be made available on request
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 221
Declarations
Ethics approval all authors declare that the use of animals for this research
complies with the requirements of the European legislation on the use of animals
for experimentation. All the f samples collected were provided by the fishermen
in the fish markets, so these organisms were not slaughtered by the authors of this
manuscript; therefore, we faithfully comply with the Code of Practice for Housing
and Care of Animals Used in Scientific Procedures.
Consent to participate for the study, no animals had to be killed, so it is not
applicable.
Consent for publication The authors consent the publication of this study.
Competing interests The authors declare no competing interests.
Funding
Study carried out thanks to the project: Study on tuna and small pelagics
caught by the coastal fleet of the Canary Islands (2021BDE057)
Acknowledgments
Enrique Lozano-Bilbao would like to thank the University of La Laguna
(ULL) and the Spanish Ministry of Universities for the Margarita Salas
postdoctoral fellowship, granted by the UNI/551/2021 Order and funded by Next
Generation EU Fund.
Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
Tenerife Island: two-year monitoring and analysis
Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
ISSN: 3101-4895 / Vigo, Provincia de Pontevedra – España
Año 1, Núm. 1, enero-junio, 2026
Página 222
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Ecological responses of Holothuria sanctori to metal contamination at La Punta del Hidalgo,
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Lozano, Enrique; González, Dailos and Gutiérrez, Ángel.
Ceres. Revista de Ingeniería, Tecnología, Ciencias Agropecuarias y Desarrollo Sostenible
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Conflict of interest and originality declaration
As stipulated in the Code of Ethics and Best Practices published in Ceres Journal,
the authors, Lozano-Bilbao, Enrique; González-Weller, Dailos and Gutiérrez,
Ángel declare that they have no real, potential or evident conflicts of interest, of
an academic, financial, intellectual or intellectual property nature, related to the
content of the article: Ecological responses of Holothuria sanctori to metal
contamination at La Punta del Hidalgo, Tenerife Island: two-year monitoring and
analysis, in relation to its publication. Likewise, they declare that the work is
original, has not been published partially or totally in another medium of
dissemination, no ideas, formulations, citations or illustrations were used,
extracted from different sources, without clearly and strictly mentioning their
origin and without being duly referenced in the corresponding bibliography. They
consent to the Editorial Board applying any plagiarism detection system to verify
their originality. The authors declare that in preparing this manuscript they did not
use generative artificial intelligence tools for text writing or data interpretation.