Environmental Education as a Fundamental Tool for Preventing the Ingestion of Chemical Contaminants in Spain

Abstract

This study examines the environmental science curricula in secondary- and high-school education, as well as the prior knowledge of first-year university students regarding environmental pollution and sustainability. To this end, an inquiry-based methodology was implemented, focusing on the assessment of agricultural pollutants, with particular emphasis on the use of herbicides and pesticides. Through field studies, students developed analytical skills to evaluate crop conditions and understand the impact of agrochemicals on ecosystems. This study carried out in Spain, but may be transposable to other countries with similar characteristics. The results reveal significant variability in students’ prior knowledge, allowing for the identification of two distinct groups: those with no prior knowledge (G1) and those with a partial understanding of sustainability concepts (G2). This heterogeneity highlights the need for educational strategies that integrate scientific knowledge with environmental action, thereby strengthening ecological literacy. In this regard, this study underscores the importance of awareness programs that bridge theoretical concepts with practical applications in chemical risk management within agricultural production. Based on these findings, measures are proposed to mitigate the impact of pollutants on human health and the environment, including phytosanitary control strategies and the promotion of sustainable agricultural practices. In conclusion, this educational approach plays a key role in shaping citizens committed to sustainability and the transition toward responsible production and consumption models.

1. Introduction

Antecedents of the current contamination.

Since the 1970s, a new agricultural paradigm emerged with the primary aim of increasing production. This shift relied on new cultivation technologies, including the use of chemical products for pest control, spurred by advances in the research on plant diseases caused by microbial, fungal, and viral pathogens. Consequently, a wide range of chemical products was developed to combat these diseases. Simultaneously, rural areas adopted the notion that weeds compete with crops for water and nutrients, leading to an aggressive chemical approach against herbaceous plants native to agricultural fields (herbicides). However, the application of these chemical products has not been accompanied by adequate education about the dangers of their handling, posing a significant risk to food safety.

In the face of environmental degradation that exacerbates climate change and pollution due to the loss of plant communities, schools must act as centers for reflection on these issues. They should address societal denial of climate change and the hazards of pollutants to life by integrating these topics into the educational curriculum. As García-Viñuesa et al. [1] emphasize, topics such as climate change and environmental contamination should be mandatory, not optional. This necessitates training future educators on the value of vegetative cover as CO₂ sinks and the various types of herbicides used in agriculture [2,3].

Among the herbicides that pose a risk to human health are paraquat, Agent Orange, glyphosate, and organophosphates. The different types of herbicides result in various clinical manifestations with varying levels of toxicity. Paraquat ingestion, for instance, causes multi-organ damage within hours and is lethal in large doses. Organophosphates are widely used as pesticides [4].

Agent Orange, a highly potent herbicide, has been used in wartime and is classified as a human carcinogen [5]. Glyphosate, on the other hand, is considered highly toxic by some and benign by others. It affects native flora but spares transgenic plants resistant to the compound. Bulbous and tuberous species may experience aerial desiccation due to herbicide application, but their subterranean parts can become contaminated. These contaminated crops are later consumed by the population, leading to food insecurity [6].

A similar issue arises with pesticides and fungicides, which are heavily used on fruit and vegetable crops. The International Code of Conduct on the Distribution and Use of Pesticides, established by the Food and Agriculture Organization (FAO) of the United Nations, defines a pesticide as “a substance or mixture of substances intended to prevent, destroy, or control pests, including vectors of human or animal disease”.

According to their chemical structure, pesticides can vary in their level of danger to humans. The most commonly used types are organochlorines, organophosphates, carbamates, thiocarbamates, and pyrethroids. Among these, organochlorines and organophosphates are the most hazardous. These compounds often have a long persistence in the environment, frequently exceeding three years [7]. Highly hazardous products, characterized by a lethal dose 50 (LD50) threshold, include organochlorine and organophosphate pesticides.

Human exposure to the three major contaminant types—herbicides, pesticides, and fungicides—is constant. The current control mechanisms are insufficient, and ingestion through contaminated food or inhalation results in widespread cases of poisoning. Agricultural contamination enters the food chain, as noted by Arroyare et al. [8] and Castillo et al. [9], who list 32 banned pesticides due to their high toxicity. Among these are the restricted-use herbicide Paraquat and the pesticide Metamidofos.

In Spain’s woody crops, two types of herbicides are commonly employed: pre-emergent and post-emergent. Notable pre-emergent herbicides include Diflufenican, Flazasulfuron, and Oxifluorfen. Simazine and Diuron were also frequently used but are now banned by public authorities. Common post-emergent herbicides in agriculture include Glyphosate, MCPA, Propaquizafop, and Fluroxypyr. Regarding their mode of action, translocation herbicides, such as Aminotriazole, MCPA, and Glyphosate, are more commonly used than contact herbicides [10].

In terms of toxicity, agricultural chemicals are generally classified as highly toxic (A) or moderately toxic (B). Group (A) includes herbicides such as Simazine, Diuron, Sodium Trichloroacetate, and Terbuthylazine. Group (B) includes compounds like Cyanazine, Carbamates, MCPA, and Glyphosate.

While some of these compounds have been banned, others remain in use and continue to enter the food chain. The excessive application of the three main contaminants—herbicides, pesticides, and fungicides—causes varying degrees of food chain contamination. Even when the levels of these contaminants fall within the WHO guidelines, their bioaccumulative nature or slow elimination from the body significantly increases the likelihood of developing tumors.

To provide the theoretical foundation for this research, two complementary conceptual frameworks are incorporated: the Theoretical Framework of Environmental Education and the Health Belief Model. Both frameworks offer a comprehensive approach to understanding the factors that influence decision-making and the development of attitudes toward environmental and health-related challenges in diverse educational contexts.

Environmental education (EE) is understood as an educational process committed to sustainability, aimed at equipping individuals with the capacity to comprehend the interrelationships among natural, social, and cultural systems. It is an interdisciplinary approach that fosters reflection and action in response to environmental issues from both local and global perspectives [11].

The core objective of EE goes beyond the mere transmission of knowledge; it also seeks to foster the development of values, attitudes, and competencies that facilitate active participation and informed decision-making. In this regard, Vega Marcote and Álvarez Suárez [12] propose a theoretical framework in which environmental education serves as a fundamental pillar for sustainable development, emphasizing the need to integrate multiple dimensions into educational processes.

The Health Belief Model (HBM), developed in the 1950s, enables the analysis of individual perceptions that influence human behaviors related to environmental risks and healthy practices. This model helps individuals adopt protective behaviors in response to environmental risk situations by allowing them to assess the severity of the issue, identify potential barriers, and recognize the benefits of adopting protective actions [13].

Incorporating the HBM into educational contexts facilitates a better understanding of how students perceive environmental or health risks, as well as their willingness to adopt preventive behaviors. This perspective is particularly valuable when addressing topics such as responsible consumption, waste management, or the health impacts of climate change.

The integration of these theoretical frameworks provides a solid foundation for the design of didactic proposals that, in addition to promoting the acquisition of scientific knowledge, foster critical awareness and transformative action in response to socio-environmental challenges. From this perspective, science education becomes a tool for student empowerment and the development of an active and responsible citizenship.

Irresponsible soil, water, and biota contamination by chemical agents, particularly organochlorine pesticides, introduces these substances into the food chain. This issue has been documented through blood and breast milk analyses in pregnant women, where malformations have also been observed. Torres and Capote [14] highlight the critical need for greater involvement of the educational system to address these challenges.

The United Nations Environment Programme (UNEP) [15], in response to pollution issues in Latin America and the Caribbean, advocates for the inclusion of botanical content in educational institutions. In light of the scientific evidence concerning the chemical contamination of food, this organization emphasizes the need to incorporate environmental content on pollutants within education. The World Health Organization (WHO) [16] estimates that approximately 1.6 million deaths worldwide each year are attributable to exposure to hazardous chemicals. This figure clearly reflects the magnitude of this public health issue; however, it remains underestimated in educational policies, as evidenced by an analysis of the curriculum in Spain. A recent United Nations report [17] warns that pollution is responsible for approximately nine million deaths annually—twice the number of deaths caused by COVID-19. This underscores the urgent need to integrate these issues into educational processes from an early age.

Food contamination through the ingestion of chemical substances has been highlighted by various authors. In our case, and as a result of our previous research in the Dominican Republic, we have already reported the misuse of translocated herbicides in potato crop production, which leads to the entry of these chemical compounds into the food chain [5].

Furthermore, air pollution is one of the most significant factors affecting human health. According to the WHO [18], 99% of the global population breathes air that exceeds recommended quality standards, which significantly increases the risk of respiratory, cardiovascular, and cerebrovascular diseases. This situation, in addition to being a serious global health problem, must be addressed through an educational approach capable of mobilizing knowledge and values related to prevention, mitigation, and responsible action.

Taken together, this body of evidence strongly supports the need to incorporate environmental and health-related content into educational curricula. It also reinforces the focus of the present study by positioning environmental education as an essential cross-cutting axis for the comprehensive development of students and the improvement of collective health.

This contamination is exacerbated by a lack of education among rural populations and educators. Authors such as Lara Calderón [19] highlight the need to involve the educational system in understanding pesticides. Calderón conducted a study with secondary-school students addressing the use of agrochemicals, encouraging critical questioning of their application, reflecting on the environmental contamination in rural societies, and promoting teaching through flipped classroom methodologies and action-research learning. These methods align with those proposed by Köpeczi-Bócz [20] and Caraballo Vidal et al. [21], who report success with both the flipped classroom approach, which is inherently practical, and project-based learning [22].

Educational inequalities between urban and rural teaching further compound the issue, as Graham [23] observes, with rural schools suffering from a lack of economic incentives, teacher demotivation [24], and insufficient training in environmental topics. Practical environmental education must be emphasized for teachers, enabling them to use their surroundings as experimental laboratories [25,26].

Rural depopulation, driven by a lack of economic development that supports sustainable livelihoods, leads to migration to urban centers. However, a new socioeconomic development model with educational system involvement could promote rural survival. This would be achievable through an understanding of ecosystem services that can increase the per capita income in rural areas [27,28,29,30]. To this end, urgent training is needed for teachers who can convey environmental knowledge to students in rural environments [31], using natural surroundings [25] or school gardens [32].

Environmental education constitutes a fundamental pillar for fostering a conscious, critical, and sustainability-oriented citizenship. In this regard, the United Nations Environment Programme (UNEP) [15] has developed a specific guide for Latin America and the Caribbean aimed at integrating environmental content into both formal and non-formal educational settings. This guide emphasizes various environmental issues, such as climate change, biodiversity loss, and, in particular, pollution—not only from a theoretical knowledge standpoint, but also through the promotion of responsible attitudes and actions. This approach underscores the central role of environmental education in shaping a culture of environmental stewardship, with tangible impacts on the transformation of individual and collective behaviors at the international level.

The current agrochemical regulations and controls are inadequate [33,34,35,36]. Based on this premise, it is necessary to teach about pests, weeds, and their control using chemical agents versus mechanical methods through active methodologies [19,37]. The scientific language related to botany, ecology, agronomy, and health sciences is often beyond the scope of teachers. Therefore, integrating literacy techniques into the training of university graduates (future educators) is essential, as proposed by Guerrero et al. [38]. Moreover, the content of educational curricula must be revised to reflect social realities, as the current framework [35] is inadequate.

Given the lack of content related to environmental pollution in student curricula, and in light of the severe pollution that currently causes thousands of deaths, as reported by the WHO, it is essential to raise awareness and provide health education aimed at preventing the ingestion of harmful chemical agents and, when necessary, mitigating their effects.

The primary objective of this work is to demonstrate agricultural contamination and raise awareness among teachers, students, and society regarding the health hazards of using chemical contaminants without adequate knowledge or awareness. Thus, the involvement of the educational system is crucial for disseminating knowledge and fostering social consciousness. This work proposes strategies to mitigate contamination phenomena and establish measures to ensure food security [39].

2. Materials and Methods

This study diagnoses the environmental contamination of crops and its relationship with the current educational system. The legal curriculum contents from the Official State Bulletins (BOE) were reviewed, and surveys were conducted with a group of undergraduate students (future teachers). With knowledge of the curriculum from the educational system and the survey conducted during the teaching process, an initial bibliographic inquiry was carried out to obtain information on agrochemicals used in crops, as well as their potential impact on health. This study combined project-based learning and flipped classroom methodologies, using the agricultural environment as an experimental laboratory.

Once the students agreed to participate, they were first informed both verbally and in writing that the data collected would be confidential and used exclusively for a scientific study conducted by the researchers from the university of Madrid. Participants were required to complete an informed consent form prior to the survey, which was provided digitally. To avoid any possible coercion, the survey administrators emphasized that participation was voluntary and that participants could withdraw at any time.

The responsible investigator’s (author’s) email address was provided to participants who wished to receive the study results or had any questions that might arise. All of this was documented in the survey form. Before starting the survey, participants were asked if they had any questions or doubts. Both before and after completing the survey, the researchers were available to address any concerns related to the process.

The study participants took part voluntarily. Upon agreeing to participate, they were provided with a hard copy of an “informed consent” document prior to completing the survey. This document informed them that all collected data would remain confidential and be used exclusively for a scientific study conducted by the researchers from the Complutense University of Madrid (Spain). To eliminate any potential coercion, the survey administrators emphasized that participation was voluntary and that participants could withdraw at any time. These instructions, along with the email address of the principal investigator (Author), were made available to participants who wished to receive the study results or had additional questions. This information was included in the “informed con-sent” document provided in paper format. Prior to starting the survey, participants were again encouraged to ask any questions they might have regarding the process. Similarly, during and after the survey, the researchers were available to address any questions or concerns that arose during its completion. This research was submitted for approval to the Ethics Committee of the Complutense University of Madrid, and was approved with the reference code: 115_CE20241212_17_SOC.

2.1. Study Limitations

The actual sample size of the study was 180 students; however, in order to apply Cronbach’s alpha coefficient and assess the degree of internal consistency and reliability, a smaller subsample of 37 students was used, as this coefficient is not suitable for application to large samples. Regarding the absence of a control group, it is important to note that the didactic approach adopted, based on the resolution of real-world problems through fieldwork and school-based research activities, follows an interpretative logic rather than a comparative one. As noted by Hodson [40] and Furtak et al. [41], methodologies that foster active student participation in scientific inquiry processes are difficult to evaluate using classical experimental designs without distorting the formative nature of the educational experience.

Moreover, from a methodological standpoint, the science education research, such as that conducted by Perochena González et al. [42], supports the notion that it is possible to obtain valid information in real educational settings without the use of a control group, provided that there is an adequate characterization of the participant group and a rigorous interpretation of the results.

In conclusion, the methodological choice is grounded in a conception of educational research aimed not only at measuring effects, but also at understanding and improving teaching practices that promote meaningful learning and engagement with the socio-environmental realities of the local context.

From the methodological perspective adopted in this study, the decision to administer the survey to secondary and upper-secondary students, and subsequently direct this article’s analysis and discussion toward the teaching staff, was based on a didactic rationale. This rationale emphasizes the need to understand learning from the students’ perspective in order to improve teaching practice. In science education, it is widely acknowledged that the starting point for any effective educational intervention must be the diagnosis of students’ level of understanding, their prior conceptions, and the difficulties they face when engaging with the scientific content—one of the main limitations being the complexity of the scientific language [43].

Evidently, the methodological strategy aligns with the concept of the “real curriculum”, understood as what students actually learn in the classroom, as opposed to the official curriculum. Therefore, exploring students’ knowledge and perceptions regarding environmental and health risks associated with the use of chemical products serves as a valuable tool for teachers to reflect on the effectiveness of their practices, identify training needs, and guide their pedagogical decision-making.

Some authors, such as Hodson [44], emphasize the need for teachers to develop a deep understanding of their students’ prior conceptions in order to design strategies that foster meaningful conceptual change. From this perspective, the data collected from students are not an end in themselves, but rather a means to support teachers’ professional development and to promote a more contextualized, critical, and socially engaged science education, one that is responsive to contemporary environmental challenges.

2.2. Survey

The survey design began with a bibliographic review. Subsequently, two independent experts reviewed a draft of the survey and suggested which questions should be removed, added, or modified. A pre-test was then conducted with a small group of students (N = 12).

Based on the pre-test results, the researchers made minor adjustments to clarify the wording of some questions and ensure the survey was as accessible as possible. The final version of the survey was reviewed by an expert with over 20 years of research experience in teaching experimental sciences, who introduced small modifications to the phrasing of the questions, and advise on sample size.

The items included in the questionnaire are as follows:

• P1: Should a well-maintained soil have a horizon A rich in plant residues?
• P2: Do you believe a well-maintained soil should have vegetation cover or not?
• P3: Do you think there is competition for water between vegetation cover and cultivated species?
• P4: Do you think this competition for water depends on the type of crop?
• P5: Do you believe that without vegetation cover, insects disappear?
• P6: Do you consider it appropriate to eliminate vegetation from a crop using herbicides?
• P7: Do you believe herbicides are harmful to health?
• P8: Could herbicides reach groundwater?
• P9: Could herbicides reach the fruits or vegetables we eat?
• P10: Do you know of any diseases caused by food contamination?
• P11: Do you know how agrochemical products should be used and in what concentrations?
• P12: Do you think you have received sufficient knowledge about agriculture and sustainability in school?
• P13: Do you consider sustainability a relevant topic for you?
• P14: Would you propose to include their study in initial levels in education?

The responses were rated using a 1–5 Likert scale.

A survey was conducted among 180 secondary- and upper-secondary-education students from both rural and urban settings. From the total sample, 37 individuals were randomly selected for the application of Cronbach’s alpha coefficient. The information obtained from these secondary- and upper-secondary students was used to inform and guide the instruction of future teachers.

Using the responses from the 37 students, an Excel table was generated and subjected to statistical analysis using the Past.exe program (PAST4.03, UCM, Madrid, Spain). Linear correlation was calculated for each item, and the average correlation was used to apply the Cronbach’s alpha coefficient to determine internal consistency and assess reliability [45]. The following formula was used:

This methodology ensures the robustness and reliability of the survey for subsequent analysis and interpretation.

a = n × p/1 + p (n − 1)

(1)

where:

• a = Cronbach’s alpha coefficient;
• n = number of items;
• p = average of all item correlations.

Following the survey, students reviewed grassland communities, commonly known as crop weeds, their removal using herbicides, and the use of pesticides and fungicides for pest control, along with the potential contamination of agricultural products. After conducting the environmental diagnosis, the impact of this contamination on society was analyzed, and strategies to reduce the entry of these pollutants into the human body were evaluated.

The project-based learning (PBL) method used follows the principle of construction of significant knowledge, as an instructional strategy supported by various studies [46,47,48]. This method promotes the gradual development of critical thinking skills, as confirmed by Katz and Chard [49] in their studies on the long-term effects of incorporating project work at various ages.

This approach is complemented by action-based tools, such as the Teaching–Learning Strategy for Reasoned Action (EADR). Using the PBL method, which retains its original student-centered characteristics, students build knowledge from their immediate environment, mediated by core questions that generate learning. This methodology fosters critical thinking responses based both on information and the exercise of thinking through cognitively appropriate tasks for the students’ age, thus achieving maximum student development (

Table 1. Schematic diagram of the methodological structure used.

Method	Objective	Data Source	Conclusion
Assessment of students’ knowledge.	Measure the level of understanding regarding chemical and environmental risks.	Questionnaires, response analysis.	Identification of knowledge gaps and areas for improvement.
Effectiveness of teaching methods (PBL, IBL, flipped classroom).	Evaluate the effectiveness of pedagogical methods in promoting students’ critical understanding.	Classroom observation, interviews, grade analysis.	Significant improvement in critical understanding and knowledge application.
Analysis of educational curricula.	Assess the inclusion of environmental and health topics in curricula.	Curriculum documents, teacher interviews.	Need to integrate more content related to sustainability and health.
Environmental and health impacts of chemical risks in agriculture.	Evaluate the effects of chemical pollution on health and the environment.	International reports, expert interviews.	Chemical pollution in agriculture poses a serious risk to human health.

).

In any case, the learning process is innovative in addressing, through these methodologies and within an educational context, the current and future social challenges. It fosters reflection on teaching practices among educators, driving a paradigm shift in the institution’s educational approach. The project’s central theme of sustainable agriculture serves as a generator of knowledge.

In a secondary approach, we proposed the use of strategies such as “flipped classrooms” within inquiry-based university teaching methodology. This approach shifts learning models outside the classroom, leveraging class time and the instructor’s expertise to facilitate and promote advanced knowledge acquisition and practical application processes. Through this methodology, teaching extends beyond the classroom to the field. Students gain hands-on experience not only in identifying crop weeds, pests, and diseases but also in learning to control them using herbicides, pesticides, fungicides, and non-polluting systems. With prior knowledge as a foundation, students actively applied these insights in real-world settings [50]. This approach integrates knowledge expressed in various items both inside and outside the classroom [51,52].

The flipped classroom model is recognized as an alternative for achieving competencies—defined as the combination of knowledge, attitudes, and skills students are expected to acquire. This methodological approach enhances the attainment of competencies and introduces students to real-world problems, such as the contamination of agricultural products by chemical agents. In the field, students address issues like the loss of floristic diversity and the growing chemical usage among populations.

To gain knowledge and, consequently, skills in sustainable development while preventing environmental contamination, students analyze research conducted in the same experimental plots with a 13-year temporal gap [10,53]. These plots, previously treated with herbicides [54,55], are revisited years later [51] to conduct comparative analyses of biodiversity. Each studied point is precisely located in the same UTM coordinates as in the 2005 study. Students document the coverage, abundance, and dominance values of the species present in these areas, enabling longitudinal assessments of environmental and ecological changes (Figure 1).

3. Results and Discussion

3.1. Results Analysis

The linear correlation analysis r yields a value of 0.1562. When applying the Cronbach’s alpha coefficient, α = 37 × 0.1562 / [1 + 0.1562(37 − 1)] = 0.87. Regarding the data distribution analysis, when applying the boxplot, although some outliers appear in a few items, there are few abnormal values with a similar interquartile range, suggesting that the data are approximately normally distributed. This is confirmed by the Shapiro–Wilk test with a value of 0.9301 and p (normal) > 0.05, indicating a parametric distribution (Figure 2 and Figure 3).

In the cluster analysis, two groups were identified, comprising 18 and 19 students. G1 was composed of 18 students, demonstrating two distinct levels of responses. G1 showed a higher number of negative responses to items P12 and P13 compared to G2 (Figure 4). This analysis was further complemented by a Principal Component Analysis (PCA), which revealed that G2 influenced a greater number of responses across the remaining 12 items (Figure 5).

The reliability measure of the scale used, through the Cronbach’s alpha coefficient, presents a value of 0.87, which is close to 0.8. Since this value falls between 0.8 and 0.9, it is evident that there is strong internal consistency in the scale used.

According to the cluster analysis, G1 consists of 18 students who responded on the Likert scale with values closer to 1 on items P12 and P13, while G2 comprises 19 students who rated the remaining items more positively, showing some heterogeneity in the students’ prior knowledge. This is due to the fact that G1 starts their university studies with less knowledge of sustainability than G2. This is logical, since Spanish law does not specifically address sustainability education for students in secondary education and high school.

3.2. Discussion Analysis

While the lack of prior knowledge contributes to the group’s diversity, the students’ backgrounds whether rural or urban are the reason for the division into two subgroups: G1 and G2. This creates certain challenges in teaching, which are further compounded by the students’ limited scientific vocabulary. Students from rural areas gained more knowledge about pollutants through informal family experiences. This is reflected in their responses to questions about herbicides and their impact on health (see Figure 6).

On the other hand, the grouping of students into two groups (G1 and G2) was not artificially imposed, but rather emerged naturally based on the levels of prior knowledge identified at the beginning of the intervention. This differentiation allowed for the analysis of the impact of the didactic proposal without excluding part of the student body from an educational experience considered relevant to their scientific and environmental literacy. In this regard, several authors have highlighted the ethical implications of forming control groups that do not receive the educational intervention, particularly when it holds significant formative value [56,57].

With the diagnosis of students’ knowledge level regarding plant cover, herbicides, and pesticides, the appropriate teaching methodology was selected, considering the interdisciplinary nature of this study [58], as it intersects with various disciplines, such as Botany, Chemistry, and Health. In light of this need, we consider the inquiry-based learning method as the most suitable, as described by Díaz Linares [59].

The inquiry method was chosen because it enables personalized learning, meaning that the student is in control of their own learning process. This allows them to acquire a holistic, comprehensive education, as emphasized by several authors [60,61,62]. Through this question-and-answer approach, the student gains knowledge and skills related to environmental contamination, enabling them to avoid consuming contaminated food.

After the preliminary bibliographic study of the experimental plots, the students and the teacher visited the plots to verify that there was indeed damage to the flora. This damage is reflected in the increased abundance of herbicide-resistant species, in contrast to the sensitive species that have been diminished or have disappeared.

In the phase following the fieldwork, the analysis phase begins. Due to the heterogeneity of the student body, which is divided into two groups, G1 and G2, the teacher applies the open inquiry approach proposed by Reyes-Cárdenas and Padilla [63], in which the teacher guides the learning process. In this regard, two options are applied: For the less-advanced group, G1, the criterion of Hong Thu Thi Nguyen [64] is used, involving feedforward feedback, applying personalized teaching as recommended by González-Peilteado [65]. For the more advanced group, G2, feedback is applied to correct the errors made, which requires analyzing which learning styles best suit the students, as stated by Perlado et al. [66].

The learning for both groups, G1 and G2, is based on observation and experimentation, involving an inquiry-based methodology in which flipped classroom, blended learning, STEN learning, and project-based learning (PBL) are utilized. Regarding the PBL method, Campos Bernal [67] notes that it has not been implemented in primary education, highlighting the need to incorporate this methodology into classrooms, with group learning so that students can learn from each other. In our view, this approach can be either positive or negative, as students may reach an understanding that is not aligned with the natural and social reality if there is no feedback mechanism from the teacher.

Inquiry-based teaching involves certain complexities in environmental studies due to its interdisciplinary nature [68], requiring a very specific scientific vocabulary [69]. Therefore, to prevent students from becoming lost in the intricate terminology, feedback mechanisms have been used to advance scientific literacy, which can be one of the goals of education at different educational levels [70], making scientific education beyond the classroom feasible [71]. All of this has allowed students to achieve the proposed objective: detecting contamination from chemical agents in situ and reflecting on how such contaminants enter the food chain.

Finally, to mitigate the potential ingestion of contaminants, the students propose an education that involves contact with nature to inspire a passion for knowledge and to understand the harms and benefits of education through green spaces, as advocated by Gutiérrez-Pérez et al. [72]. These authors highlight the positive effects on emotional development and social behavior of children, who achieve healthy personal development through their connection with nature. Therefore, it is necessary to promote contact with nature from an early age. We agree with this approach, as it gradually introduces children to the scientific paradigm, enabling the construction of their own thinking [73].

The existence of natural areas not exposed to chemical pollutants, alongside agricultural zones that are subject to contamination [10], as well as the proximity of these spaces to rural educational centers, enables their use as learning laboratories [25]. Consequently, students can carry out comparative analyses between both types of environments, which contributes to the construction of knowledge and enhances their motivation to advocate for sustainability. Based on students’ responses regarding the use of herbicides in agriculture and their potential ingestion, a certain level of awareness about herbicides is evident; however, there is a lack of understanding regarding their consequences. This finding supports the United Nations’ recommendation to incorporate botanical and environmental content into student curricula.

4. Conclusions

This research on environmental education has identified an excessive use of chemical agents harmful to health, such as herbicides, fungicides, and pesticides, in rural environments, with little knowledge of the dangers associated with their use. This was confirmed through an analysis of the existing flora in crops in 2005, which had been eliminated or significantly reduced 13 years later due to the application of chemical products. However, despite the hazardous nature of the compounds used to eliminate flora, there is a lack of training within the population regarding their proper handling, possibly due to a flaw in the educational system. This is evident, as undergraduate students, when interviewed, reported limited knowledge of these compounds. Nevertheless, after conducting the fieldwork, they acknowledged the need to modify school curricula, emphasizing the study of environmental pollution and ways to prevent its effects on health.

This is evident, as undergraduate students enter higher education with a limited understanding of these compounds. Consequently, the education system must serve as a fundamental pillar to prevent environmental pollution and improve public health. Accordingly, after conducting fieldwork, students acknowledged the need to revise school curricula, emphasizing the study of environmental pollution and strategies for preventing its effects on human health.