Assessment of the quality of the
drinking water source (well 1)
Evaluación de la calidad de la fuente de captación (pozo 1) de agua
potable
Andres
Marcel Villamar Cárdenas
Universidad de Guayaquil andres.villamarc@ug.edu.ec,
https://orcid.org/0009-0006-7853-2033
Judith Aracely Chalen Medina
Universidad de Guayaquil judith.chalenm@ug.edu.ec https://orcid.org/0009-0009-4330-1229
Mario Marquez Gallegos
Universidad de Guayaquil mario.marquezg@ug.edu.ec
https://orcid.org/0009-0002-2559-9083.
Franklin Almagro Parra Ortega
Universidad de Guayaquil franklin.parrao@ug.edu.ec
https://orcid.org/0009-0008-2366-6741
In
Ecuador, there are many places that do not have drinking water, which is why
citizens have to find ways to obtain this element that is so essential for
living beings. To do so, they
have to look for sources of water, whether underground or surface sources.
However, in order to use or consume it, they first have to undergo a series of
tests to determine whether the water from the source is fit for human
consumption. For our study, we will focus on the rural area of the Marcelino
Maridueña Canton, since part of this population obtains its water supply from
underground wells. We will therefore conduct tests to analyze whether the water
consumed by this population contains elements that could be harmful to their
health, since the presence of certain elements such as heavy metals or
agrochemicals in the water can be very harmful to the health of those who
consume it consume it. If the water contains these harmful elements, we will
identify them in order to propose a solution and thus comply with the
parameters established in current regulations, achieving a better quality of
life for the inhabitants of the sector and serving as a warning to the
sectional authorities to implement the necessary controls so that the water
source is not contaminated.
Keywords Standards, water, human consumption
Resumen
En Ecuador existen muchos lugares
que no cuentan con agua potable por este motivo los ciudadanos tienen que buscar
la manera de obtener este elemento que es tan esencial para los seres vivos, para
ello tienen que buscar fuentes de captación ya sean estas fuentes subterráneas
o superficiales, sin embargo para poder utilizarla o consumirla primero tienen que
pasar por una serie de análisis que permita conocer si el agua de la fuente de
captación es apta para el consumo humano, para nuestro estudio nos centraremos en
la zona rural del Cantón Marcelino Maridueña ya que una parte de esta población
se abastece de agua mediante pozos subterráneos por ende analizaremos mediante
ensayos si el agua que está consumiendo esta población no contiene elementos
que produzcan daños a su salud ya que la presencia de ciertos elementos como metales
pesados o agroquímicos en el agua puede llegar a ser muy perjudicial para la
salud de quien la llegase a consumirla y si el agua presenta estos elementos dañinos
identificarlos para poder proponer una solución y de esta manera cumplir con
los parámetros establecidos en las normativas vigentes, logrando una mejorar
calidad de vida para los habitantes del sector y sirviendo de alerta para las
autoridades seccionales e implementar los controles necesarios para que no se
contamine la fuente de captación.
Palabras clave Normas, agua, consumo humano
Introduction
In the Marcelino Maridueña district, the population obtains water from
underground sources, as for rural areas such as this one, it may seem more
convenient to use this type of source because it has less turbidity and fewer
solids than surface sources, which is why they built groundwater wells.
However, citizens are often unaware of the
risks involved in consuming water from this type of source without carrying out
the necessary analyses, as groundwater may contain minerals or heavy metals
and/or agrochemicals, which, when consumed by the population, can result in
various types of diseases, including cancer, which is one of the most serious.
For this reason, certain laboratory tests will be carried out to assess the
quality of the water that these inhabitants are consuming and thus prevent or mitigate
risks to their health. Once the results of these analyses have been obtained
and compared with the parameters set in the current regulations, if substances
are found whose concentration levels represent a latent danger, the optimal
treatment to remedy the problem will be proposed, thus improving the quality of
the water from the collection source and providing the right to a water
resource with the necessary conditions to ensure the well-being of all
inhabitants.
This will be further
expanded upon in the chapters that will be detailed in the thesis and its
execution.
Since ancient times, humanity has sought to
settle near freshwater sources, generally rivers, such as the Mesopotamian
civilization that settled near the Tigris and Euphrates rivers (2350 BC) or the
Egyptian civilization that settled near the Nile River (1580 BC). Many other
civilizations that developed in ancient times have this in common. In Ecuador,
there are also cases of this. Guayaquil settled near the Guayas River, to
highlight the most important ones. However, since not all cities or cantons can
be located near a river, inhabitants must find ways to obtain this important
element, water, and to reduce the deficit, they choose to build water wells to
obtain water from this underground source. Generally, an extensive analysis of
all the agents or substances that could be present in raw water is not carried
out. However, these studies are necessary to safeguard the health of the
inhabitants who consume it.
While it is true that institutions such as
COOTAD (Organic Code of Territorial Organization, Autonomy, and
Decentralization) or the GADS (Decentralized Autonomous Government) request
that those in charge of the water supply project carry out laboratory tests,
they do not generally specify the total parameters that must be met in order to
consider that source of water suitable for use. The current standard “Norma NTE
INEN 1108:2014” shows us the maximum permitted limits for a considerable number
of parameters, but it does not establish or require that the respective
laboratory analyses be carried out for all of them, leaving this evaluation to
the discretion of the project owner. This means that certain parameters that
may be extremely important in terms of their influence on the water body under
study are omitted, either due to ignorance or to reduce costs.
Using data and records from the latest
census, it can be seen that the coverage levels of drinking water services at
the national level increased by 6.0% in 2010 to 80.4% and 8.6% in 2014 to
86.4%, and sanitation services from 64.5% to 73.1%, respectively.
According to this same data and treatment,
the access gap between cantonal capitals and the rest of the territory was
drastically reduced, from 24.3% to 15.9% for drinking water and from 24.3% to
15.9% for sanitation.
According to this same data
and treatment, the access gap between cantonal capitals and the rest of the
territory was drastically reduced, from 24.3% to 15.9% for drinking water and
from 17.9% to 3.3% for sanitation.
However, when we analyze the ECV coverage
data, we note that the gap between dispersed rural areas (less than 2,000
inhabitants) and the rest of the country's localities is still very
significant: 19% and 13% for water and sanitation, respectively.
This suggests that municipal GADs' investment efforts in water and sanitation are
concentrated in parish capitals and concentrated rural areas (Senagua, 2014).
In the canton of Coronel
Marcelino Maridueña, we can see that the supply
available to residents does not guarantee the quality of the water they are
consuming, since institutions such as COOTAD (Organic Code of Territorial
Planning, Autonomy, and Decentralization) or GADS (Decentralized Autonomous
Government) do not specify the total number of tests that should be carried out
in order to guarantee the quality of the water consumed by the inhabitants of
the canton, as required by the current standard “Norma INEN 1108:2014.”
Once the parameters and the location where
the assessment will be carried out and the source of collection (well 1 and
well 2) are clear, the respective analysis will be carried out to determine
whether it contains lead (heavy metal) and organochlorine pesticides
(agrochemicals), generating a report that will be presented to the authorities
in charge. Depending on the results, actions will be taken to improve water
quality, thus positively changing the quality of life of the
inhabitants of the area, mitigating the
future risk of disease caused by the consumption of contaminated water.
The Marcelino Maridueña
Canton belongs to the province of Guayas, in the Republic of Ecuador. Its
capital is Marcelino Maridueña, located 65 km from
the city of Guayaquil. It is located in the east of the province, at an
altitude of 80 meters above sea level, with an average temperature of 24 °C and
an average annual rainfall of 1700 mm (Municipal GAD of the Canton of Coronel
Marcelino Maridueña, 2014).
The Marcelino Maridueña
canton is where samples are taken for testing to assess whether the water
analyzed from well 1 and well 2 is within the maximum permissible limits set by
INEN 1108:2014.
· Well 1 is located at the following coordinates: E: 673381; N: 9755480.
· Well 2 is located at the following coordinates: E: 673333; N: 9754440.
According to data obtained
in the 2001 census, the population of the Marcelino Maridueña
Canton represents 0.3% of the total population of the Province of Guayas. It
has grown in the last period between the 1990-2001 censuses at an average
annual rate of 0.02%. Thirty-nine point two percent of its population resides
in rural areas. It is characterized by a young population, as 41.0% of the
population is under 20 years of age, as can be seen in the population pyramid
by age and sex (Municipal GAD of the Coronel Marcelino Maridueña
Canton, 2014).
According to data from the
2010 INEC census, the canton of Marcelino Maridueña
has a total population of 12,033 inhabitants in urban and rural areas. In the
urban area, the population is 7,163 inhabitants, of whom 3,674 are men and
3,489 are women; in the rural area, the population is 4,870 inhabitants, of
whom 2,591 are men and 2,279 are women (Municipal GAD of the Canton of Coronel
Marcelino Maridueña, 2014).
According to INEC data (2010 Census), the
most representative age group of the total population, and the one that defines
certain characteristics of the demography of the Marcelino Maridueña
canton, is between 30 and 64 years old (adults); then we have the group of
children and adolescents.
Next are young people, who make up 20.58% of
the total population. The group referred to as older adults (over 65 years of
age) accounts for 12.61% (Municipal GAD of the Canton of Coronel Marcelino Maridueña, 2014).
When describing the composition of the
population according to the number of men and women in each age group, we find
that:
· Among those aged 0-11, which includes children, and those aged 12-17,
which includes adolescents, 56.86% are men and 49.45% are women.
· Young people are between 18 and 29 years old, with 26.60% being women
and 29.58% being men.
· Adults are between 30 and 64 years old, with 35.19% being women and
36.33% being men.
· Older adults, who are those over 65 years of age, 23.64% are women and
29.88% are men.
In the Marcelino Maridueña
canton, 35% of the population is supplied by the public network. According to
the data, 52% is urban area, while 9% is rural area.
The canton has a piped water system that
supplies the entire urban population, but this is not the case in the
surrounding areas, where water is supplied by extracting groundwater from
wells, for example, to an elevated tank and then distributing it through pipes
and hoses to homes. The system will not present any problems if the population
does not increase and, therefore, neither does demand, but this situation is
already developing.
The system has drawbacks due to the lack of
maintenance that has been given to the towers and storage tanks, which is
determined to be a problem for water distribution. There is also a need to
increase the flow of the pipes.
In conclusion, we determined that the
installation of water distribution networks has 90% coverage, with 10% still to
be operated.
Therefore, we can say that the canton has a
drinking water network that supplies homes through pipes with a length of
26,906 linear meters, leaving 2,932 linear meters to be served (Municipal GAD
of the Canton of Coronel Marcelino Maridueña, 2014).
Since the wells do not require deep drilling
and provide easy access to fresh water, this water is used in homes and is
supplied by these wells, reaching homes through pipes.
According to data from the 2010 Census, 2,268
homes have water connections inside the home, 542 homes have pipes outside the
home, and 269 homes receive water by other means (Municipal GAD of the Canton
of Coronel Marcelino Maridueña, 2014).
Sewerage coverage in the canton is 55.2%,
which is relatively higher than the national coverage percentage (53.6%) and
slightly higher than the provincial coverage (46.7%). These values have
remained stable between the 2001 and 2010 censuses, meaning that, although the
population has increased considerably, adequate measures have been taken to
ensure that residents have an acceptable quality of life. We must consider that
the level is still not high, but it is not critical either (Municipal GAD of
the Coronel Marcelino Maridueña Canton, 2014).
Ninety-four percent of homes have electricity, which is almost on par with the
national percentage and slightly above the provincial percentage. Depending on
the geographical location, the gaps are smaller than in the previous
indicators. However, differences can still be seen between urban areas, where
the coverage percentage is 99.3%, and rural areas, where it barely reaches
87.9% (Municipal GAD of the Canton of Coronel Marcelino Maridueña,
2014).
Lead occurs naturally in
the Earth's crust and is a toxic metal. It is a cation-charged element that has
caused serious problems of environmental pollution and human health.
Lead is a heavy metal that has been used for
many years due to its resistance to corrosion, ductility, malleability, and
ease of forming alloys. Among the main sources of environmental pollution are
mining, metallurgy, manufacturing and recycling activities, and, in some
countries, the persistent use of leaded paints and gasoline. More than
three-quarters of global lead consumption is for the manufacture of lead-acid
batteries for motor vehicles. However, this metal is also used in many other
products, such as pigments, paints, soldering material, stained glass, glass
tableware, ammunition, ceramic glazes, jewelry, and toys, as well as in some
cosmetics and traditional medicines. Drinking water piped through lead pipes or
soldered with this metal may also contain lead. Currently, much of the lead
traded on world markets is obtained through recycling (WHO, 2018).
Ingestion of this type of substance can occur
through inhalation of dust containing lead, contaminated water, or contaminated
food. Lead is generally distributed throughout different parts of the body,
such as organs, tissues, bones, and teeth, where it accumulates over time. Lead
poisoning can vary depending on the level of exposure and the age of the person
(Reyes, Vergara, Torres, Díaz Lagos, & Gónzales,
2016).
Absorbing or ingesting lead
is a serious public health risk, as its ingestion leads to problems such as
delayed mental and intellectual development in children and causes hypertension
and cardiovascular disease in adults. Poisoning can occur through accidental
consumption, such as eating contaminated food. Oral absorption of lead occurs
in 10% of adults and can increase to 50% in children. Absorbed lead can be
distributed in the kidneys, liver, brain, and bones due to its similarity to
calcium. The largest deposit of lead is in the bones for up to 20 years; it
interferes with calcium function, inhibits hemoglobin synthesis, and causes
neurological damage (Londoño Franco & Londoño Muñoz, 2016).
The effects can be severe on the central
nervous system, consisting of paresthesia, muscle pain and weakness, hemolytic
crisis, severe anemia, and hemoglobinuria. It also affects the kidneys, causing
oliguria and albuminuria. Although acute poisoning can cause death, it is more
common for the patient to recover and present with chronic poisoning with
gastrointestinal, neuromuscular, nervous, hematological, renal, and
reproductive damage. At the gastrointestinal level, there is anorexia,
headache, constipation, intestinal spasm, and abdominal pain. Neuromuscular
symptoms include muscle weakness and fatigue followed by paralysis of the
forearm, wrist, and fingers, and sometimes the feet. These symptoms were
characteristic of painters' disease, but today the replacement of lead pigments
and improvements in industrial safety and hygiene conditions are leading to the
disappearance of this type of poisoning (Londoño Franco & Londoño Muñoz,
2016).
The first symptoms of
encephalopathy in children are lethargy, vomiting, irritability, loss of
appetite, and dizziness, which progress to ataxia, reduced consciousness, and
ultimately coma and death.
The mortality rate from lead encephalopathy
is high, approximately 25%, and many of the patients who recover are left with
sequelae, including mental retardation, seizures, and optic atrophy. Lead
exposure has been associated with infertility and neonatal death in humans. In
animals, it has been shown to have a toxic effect on gametes and to increase
the concentration of lead in maternal blood, which reduces the duration of
gestation and the birth weight of offspring. Lead can trigger teratogenic
effects in the fetal nervous system and interfere with normal development. Lead
and its compounds are classified in group 2B, probably carcinogenic to humans
(IARC) (Londoño Franco & Londoño Muñoz, 2016).
The chemical composition of well water in
this case can vary depending on a number of factors, including the region where
it is located, its geological formation, and the environmental pollution to
which the area may be subject. Some of the toxic substances that can
contaminate water are attributed to the type of soil that may contain this
contaminant and to agricultural or industrial areas in the vicinity of the
source.
Lead can also contaminate well water in the
following circumstances:
1. Lead can exist naturally in soil and rocks and can seep into
groundwater.
2.
From hazardous waste
deposits, refineries, recycling centers, battery crushing, or industrial
sources of lead.
3. However, lead usually enters the water through the system's pipes, brass
faucets, or solder.
Lead can usually seep into drinking water
when lead service pipes corrode, especially where the water has high acidity or
low mineral content, which facilitates corrosion of the pipes and fixed
elements of the system. The most common problem is caused by brass or
chrome-plated brass faucets and fixed elements with lead solder, which can
result in concerning amounts of lead in the water. Lead can infiltrate the
water, especially hot water (EPA, 2017).
Producing clear water
without fine solids is a prerequisite for providing the population with
low-turbidity water, which is why the filtration process is essential.
Filters are generally thought of as a sieve
or micro-screen that traps suspended material between the grains of the filter
medium. However, the action of straining, screening, or sieving the water is
the least important part of the filtration process, since most suspended
particles can easily pass through the spaces between the grains of the filter
medium (Romero Rojas, 1999).
Filtration is a combination of physical and
chemical mechanisms. It can be said that absorption is essential for drinking
water, since as the water passes through the filter bed, particles are retained
upon contact (Romero Rojas, 1999).
Filter beds must have certain
characteristics, such as:
·
Grain size.
· Grain size distribution.
· Density, shape, and composition of the grain.
· With these three parameters, we can evaluate the efficiency of particle
removal.
· Porosity of the filter bed; this determines the amount of solids that
the filter can store.
· Filtration rate; this affects the quality of the effluent and determines
the area required.
Characteristics of the
influent or catchment source; this determines the removal capacity of the
filter.
There are different types of filters,
including:
Slow sand filters.
These have the following characteristics: a
filtration rate of 2-5 (<12 m/d), a sand stratum, no wash water, a depth of
0.6-1.0 m, a gravel depth of 0.30 m, and drainage through perforated pipe.
Rapid sand filters.
These have the following characteristics: a
filtration rate of 120 m/d, a sand stratum, backwash water present at 2–4% of
the filtered water, a depth of 0.6–0.75 m, a gravel depth of 0.30–0.45 m, and
drainage through perforated pipe false bottoms.
High-rate filters.
It has the following characteristics: a
filtration rate of 180–480 m/d, a sand and anthracite stratum, wash water
present is 6% of the filtered water, the depth of the anthracite is 0.4–0.6 m
and of the sand 0.15–0.30 m, the depth of the gravel is 0.30-0.45 m, and
drainage is provided by perforated pipe false bottoms.
Cellulose acetate (and its
derivatives) is one of the most widely used materials, as are aromatic
polyamides.
Methodology
We will use an analytical
methodology, as tests will be carried out for the presence of agrochemicals and
a heavy metal has been chosen to assess their presence in this case. We will
determine whether lead (Pb) is present in the catchment source and analyze
whether the quantities generated by the tests are within the ranges permitted
by both the regulatory body and the current legal framework.
It is necessary to determine the nature of
the sampling, i.e., where the samples will be taken. If the source of the
catchment is an estuary, stream, river, reservoir, well, lagoon, or lake, the
type of soil in the vicinity must be considered, as well as whether it may
contain crops or any external contaminants that could affect the type of source
to be evaluated.
We must know the types of samples that can be
used:
If it is known that the
source where the sample is to be collected has a constant composition in time
or space, a simple survey can be considered, but if it is known that the source
has variations of any kind, more samples must be taken at different times in
the same place.
Composite samples are those collected at
different times in the same place. For analysis purposes, composite samples can
be taken over a period of 24 hours.
These samples are collected at different
locations, but at the same time, this type of sampling is most commonly used in
rivers, lakes, reservoirs, or places that undergo changes in composition due to
the presence of currents. The use of special equipment is recommended.
In order to obtain optimal results and ensure
that the sampling does not influence them, the following steps should be
followed:
· Samples should be labeled with the name of the person or entity taking
the sample, the sample number, the time, the date, and the location where it
was taken.
· The sample should be properly sealed.
· It is recommended to record field data such as the location, the number
of samples taken and their volume, a description of the location, and any other
information that may be useful.
Containers can be made of glass or plastic,
but because some substances, such as cations including cadmium, lead, iron,
aluminum, copper, zinc, and manganese, can be absorbed by the walls of glass
containers, they are not recommended as they alter the nature of the sample.
Samples should be taken in plastic containers.
If the samples cannot be analyzed
immediately, they must be stored at 5°C from the time they are collected until
they are taken to the laboratory and the respective analyses are performed.
The containers used must be able to hold a
minimum of 250 ml, but if the analytical technique requires it, a larger
capacity container must be provided.
Results
The first samples taken
from wells 1 and 2 were delivered to the Marcos Chemical Group laboratory,
which is accredited by the SAE (Ecuadorian Accreditation Service). The entity
provided the results on December 11, 2018.
The first samples were analyzed for
organochlorine pesticides (agrochemicals) and lead (heavy metals).
The results showed that organochlorines are
present, some in higher proportions than others, but due to the analysis
method, it cannot be verified whether they are within the maximum permissible
limit of INEN 1108:2014. A comparison table of the results with the different
standards is provided below:
In the case of lead (heavy metal), it was
chosen as an indicator of the presence of heavy metals in the catchment source,
with the results showing that this element is present in well 1, but above the
maximum permissible limit according to INEN 1108:2014. Well 2 also contains
this element within the maximum permissible limit of INEN 1108:2014. A table
comparing the results with the different standards for the two wells is
provided below:
After analyzing the results of the first
sampling and observing that the presence of organochlorines is within the
permissible limits, but that of lead in well 1 is above the maximum permissible
limit according to the standard, it was decided to take a new sample only for
this element from the well in question and take it to three different
laboratories to verify that the results of the first sample were not erroneous.
The samples were delivered to the PSI (Productos y Servicios Industriales C. LTDA.), SGS del Ecuador S.A., and
Bureau Veritas laboratories, noting that these laboratories are accredited by
the SAE (Servicio Acreditación Ecuatoriano).
Once the results were obtained, we found that
lead is present in the water source and exceeds the permissible limits. A
comparison table of the results with the different standards and the different
results from the laboratories that tested the samples is provided.
With the results, a suitable treatment method
for water containing lead will be proposed. We propose that the treatment
method be reverse osmosis, since according to the filtration spectrum, this is
an appropriate method for this type of contaminant. The method in question will
be detailed below. In order to carry out the reverse osmosis treatment, we
first propose a pretreatment with filtration, followed by the reverse osmosis
process and, finally, a disinfection process.
Filtration will remove
turbidity and possible microorganisms, followed by reverse osmosis to reduce
the lead content, which is the problem at hand. Finally, disinfection is
proposed to reduce or eliminate microorganisms, mainly pathogens, present in
the well water. The aim of this system is to make the collected water suitable
for human consumption and compliant with current standards such as "INEN
1108:2014 ," and that the costs are not too high, as methods such as
aeration, coagulation, flocculation, and sedimentation are not considered
because the characteristics of the water do not warrant them, and the areas of
operation of the proposed system would be much smaller than that of a complete
system.
Conclusions
Although the results
obtained show that the levels are below the established limits, the importance
of monitoring and regulation studies to ensure the safety of citizens is
highlighted (Reyes, Vergara, Torres, Díaz Lagos, & Gónzales,
2016).
This assessment seeks to raise awareness
among local governments about the importance of conducting preliminary
evaluations to ensure optimal quality of water collection sources.
Laboratory tests determined that the lead
content exceeded the maximum limits allowed by regulatory bodies; therefore, a
three-stage system has been proposed to reduce this concentration and bring it
within the permissible range. These stages consist of pre-treatment
(filtration) + treatment (reverse osmosis) + disinfection (chlorination).
·A visual inspection revealed a lack of
maintenance of the pipes that transport the vital liquid, which is likely to be
one of the sources of contamination.
The wells (well #1 and well #2) lack a
treatment system (filters or disinfection) prior to distribution to the
community, which is contributing to the deterioration of the health of its
inhabitants.
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