Human activities have increasingly shaped coastal ecosystems across the globe, leading to a variety of environmental changes that rival natural geological processes. [30] describe how rapid urbanization, industrialization, and agricultural expansion have significantly altered the natural landscapes and sedimentary processes of coastal regions. These anthropogenic pressures result in the degradation of coastal ecosystems, with consequences for biodiversity, water quality, and the sustainability of marine resources. Coastal vegetation and dune habitats are particularly sensitive to land-cover modification because changes in vegetation structure can weaken ecological stability and accelerate coastal degradation ([1]). The conservation of different coastal habitat types is also important because some dune habitats make disproportionately important contributions to coastal plant-species diversity ([2]). The erosion of coastal land, habitat destruction, and pollution are direct results of human activities, often exacerbated by the increased demand for resources driven by population growth and economic development. For example, industrial discharge and untreated wastewater are common sources of pollution, carrying heavy metals, chemicals, and organic pollutants into marine environments, thus disrupting marine life and endangering public health.

Globally, the issues faced by coastal regions are multifaceted, affecting not only environmental conditions but also social and economic dynamics. Overfishing, pollution from industrial and agricultural runoff, and unsustainable tourism practices have become major contributors to the degradation of coastal ecosystems. [8] highlight the cumulative impact of these activities, including increased sedimentation, habitat loss, and the alteration of nutrient cycles in coastal waters. These effects are not limited to developed nations but are increasingly evident in developing countries, where regulatory frameworks are often weaker, and enforcement of environmental protections is limited. This global perspective underscores the need for comprehensive management strategies that address the environmental, social, and economic dimensions of coastal sustainability.

In Tanzania, the impacts of global environmental issues are particularly pronounced in its coastal areas, which are crucial to both local livelihoods and the national economy. Tanzanian coastal regions, including Dar es Salaam and Bagamoyo, are facing severe pollution challenges due to the discharge of untreated wastewater and industrial effluents directly into the ocean. [13] conducted a study on the levels of microbial contamination and heavy metals in coastal waters in Dar es Salaam and found alarming results, highlighting the direct threat these pollutants pose to marine ecosystems and human health. The study pointed out that these contaminants not only degrade water quality but also accumulate in marine organisms, affecting the food chain and putting local communities at risk due to their reliance on seafood.

Furthermore, [16] reviewed water quality and pollution studies in Tanzania, revealing that inadequate waste treatment infrastructure is a significant contributor to coastal pollution. The rapid growth of urban centers along the Tanzanian coastline has led to a surge in domestic and industrial waste, which is often discharged without proper treatment. This pollution jeopardizes marine life, damages coral reefs, and leads to the depletion of fish stocks, which are vital for local communities. Other destructive anthropogenic practices, including illegal and destructive fishing methods, have also historically threatened Tanzania’s marine habitats and fishery resources ([25]). The increasing levels of pollution in Tanzania’s coastal waters, coupled with limited regulatory enforcement, indicate a need for stronger waste management systems and more comprehensive environmental policies to protect these critical ecosystems.

Tourism, a key economic driver in coastal Tanzania, has brought both benefits and significant environmental challenges. As tourism has grown in regions like Zanzibar and Bagamoyo, so too has the problem of plastic pollution. [14] found that the tourism sector is a major contributor to the accumulation of plastic waste along the Tanzanian coastline, particularly in popular tourist destinations. Beaches once known for their pristine conditions are now littered with plastic bottles, bags, and other debris left by visitors. The lack of effective waste management systems exacerbates this problem, as local authorities are often ill-equipped to handle the volume of waste generated by both tourists and local residents.

This issue of plastic pollution has far-reaching consequences. The plastic waste not only affects the aesthetic value of these beaches, which are a major attraction for tourists, but also poses a threat to marine life. Marine animals often mistake plastic debris for food, which can lead to ingestion, entanglement, and death. Furthermore, plastic breaks down into microplastics, which are difficult to remove from the environment and can accumulate in marine food chains, ultimately affecting human health. [17] argued that Tanzania’s marine environmental protection laws need to be strengthened to address these growing challenges, particularly in high-tourism areas. Despite the existence of environmental regulations, enforcement remains weak, and the legal framework does not fully account for the specific pressures that tourism places on coastal ecosystems.

Mangrove forests are a critical component of coastal ecosystems in Tanzania, providing natural barriers against coastal erosion and supporting marine biodiversity. However, human activities such as deforestation, agriculture, and urban development have led to the degradation of mangrove forests along Tanzania’s coast ([26]). These forests play an essential role in protecting coastlines from the effects of storms and rising sea levels, while also serving as nurseries for many marine species. The destruction of mangroves, therefore, not only increases the vulnerability of coastal areas to environmental threats but also disrupts the ecological balance necessary for the sustainability of local fisheries.

[11] highlighted the need for better implementation of environmental policies aimed at protecting mangrove ecosystems. Although national policies in Tanzania recognize the importance of mangroves, enforcement remains inconsistent, with many areas continuing to face illegal logging and land conversion. The degradation of mangroves has a direct impact on the livelihoods of coastal communities, particularly those dependent on fishing and tourism. Without the protection offered by mangroves, coastal erosion intensifies, further threatening the integrity of coastal ecosystems and the economic activities they support. This calls for more robust conservation efforts, including community-based initiatives and stricter enforcement of existing environmental laws to ensure the long-term sustainability of Tanzania’s coastal regions.

Qualitative methods were used to gather detailed and nuanced information from the respondents. Data collection involved three primary techniques: interviews, questionnaires, and observations.

Interviews: Semi-structured interviews were conducted with 34 respondents to explore their perceptions of coastal pollution and how their daily activities might contribute to it. Semi-structured interviews allowed flexibility in questioning, encouraging participants to provide detailed insights while also enabling the interviewer to probe further based on the respondents’ answers. These interviews were recorded (with the participants’ consent) and later transcribed for analysis.

Questionnaires: A set of structured questionnaires was administered to 42 additional respondents, with a focus on gathering data about the frequency of beach use, types of human activities observed, and awareness of coastal pollution. The questionnaires contained both closed and open-ended questions to capture quantitative data, such as the number of times respondents visit the beach each week, and qualitative data, such as personal experiences with pollution.

Observations: Direct observation was used to document visible pollution on the beaches and note the types of human activities that might be contributing to it. A checklist was used to guide observations, ensuring consistency across the five beaches. Photographs were taken to visually capture the extent and types of pollution (e.g., plastic debris, iron waste, plant debris), and these were later used to complement the data collected from interviews and questionnaires.

To examine how anthropogenic activities, affect coastal pollution, the conceptual framework was developed and used in this study (Figure 1). Seven key elements were established in this study, namely: the trading activities, scraping activities, boat maintenance, Boat construction, recreational activities, agricultural activities and industrial activities.

Figure 1. Conceptual framework.

For consistency across the study, anthropogenic activities were grouped into five operational categories. Fishing-related activities refer to fish harvesting, landing-site operations, handling of fishing gear, disposal of nets, and other activities directly connected with fishing livelihoods. Tourism and recreational activities include beach visits, tour guiding, food consumption, recreation, and tourism-related commercial services. Boat construction and repair activities include boat building, scraping, painting, maintenance, and disposal of metal, wood, and other repair-related residues. Coastal trade and food-vending activities refer to small-scale beach-based selling of food, drinks, and other goods that may generate packaging and food waste. Coastal construction and settlement-related activities include building, maintenance, informal settlement use, and disposal of construction-related materials along or near the beach. These categories were used consistently in the analysis to link observed pollution types with the human activities most commonly reported by respondents and observed at the study sites. Fishing methods and the types of gear employed can influence the quantity and characteristics of fishing-related materials entering the coastal environment ([7]).

The data gathered from interviews, questionnaires, and observations were analyzed using thematic analysis, a method well-suited for identifying patterns and themes in qualitative data. Thematic analysis involves a systematic process of coding and categorizing the data into key themes that reflect the research questions and objectives.

Data Familiarization: The first step involved transcribing the interview recordings and thoroughly reading the questionnaire responses and observation notes. This process allowed for a deep understanding of the data and helped in identifying initial codes.

Coding: The data was then coded using a combination of inductive and deductive coding approaches. Deductive codes were based on the research objectives, such as “sources of pollution” and “types of human activities”, while inductive codes emerged from the data itself, capturing new insights that were not anticipated, such as the role of informal waste management practices. Each code was systematically applied to sections of the data that represented similar themes.

Theme Development: Once coding was completed; similar codes were grouped together to form broader themes. For instance, codes related to “plastic waste”, “tourism-related pollution”, and “iron remnants” were grouped under the theme “Human-induced pollution”. Themes such as “economic dependency on the coast” and “perceptions of environmental responsibility” also emerged from the data, offering deeper insights into how local communities view and interact with their coastal environment.

Data Triangulation: To enhance the credibility of the findings, data from interviews, questionnaires, and observations were triangulated. This involved cross-checking the themes identified in one data set with those found in another. For example, observations of plastic waste accumulation were cross-referenced with respondents’ reports of improper waste disposal practices from the interviews and questionnaires.

Interpretation and Synthesis: Finally, the themes were interpreted in the context of the research questions, focusing on how different human activities contribute to pollution and the socio-economic implications of this pollution on coastal communities. The findings were then synthesized to provide a comprehensive understanding of the impact of anthropogenic activities on Bagamoyo’s coastal areas.

Although the study adopted a qualitative case study design, questionnaire data were incorporated to support and triangulate the qualitative findings. The questionnaire was not used for statistical hypothesis testing, but rather to organize respondents’ perceptions into descriptive categories that could complement interview narratives and direct observations. The percentages reported in the results therefore represent descriptive summaries of respondent reports and should be interpreted as indicative patterns rather than inferential quantitative findings. These descriptive results were integrated with interview themes and field observations during thematic analysis to strengthen interpretation and provide a clearer picture of recurring pollution types, human activities, and perceived socio-economic impacts across the selected beaches.

No statistical comparison was conducted across demographic subgroups such as age, gender, or occupation. Any demographic patterns discussed in the results are therefore presented as descriptive qualitative tendencies emerging from respondents’ narratives and questionnaire comments, rather than as inferential quantitative relationships.

The study area refers to the geographical location selected for conducting the investigation. This study was carried out in Bagamoyo, situated at 6.4456˚S and 38.8989˚E. Data were collected by the researchers from five selected beaches: Kaole, Mbegani, Badeko, Msalabani, and Mwaroni, as illustrated in Figure 2 below.

Figure 2.Study area boundary map.

The study adhered to ethical research guidelines, ensuring that participants were fully informed about the purpose of the study and how the data would be used. Informed consent was obtained from all participants, and their anonymity was guaranteed. Sensitive data were securely stored, and respondents were given the opportunity to withdraw from the study at any time without any consequences.

The study identified several types of pollution prevalent across the five coastal beaches. Plastic debris, iron remnants, plant waste, and food waste were the most commonly reported pollutants.

Table 1.Multiple-response summary of pollution types observed or reported at Bagamoyo beaches.

Table 1 is interpreted as a multiple-response summary rather than a mutually exclusive distribution of respondents. For example, one respondent could report observing both plastic debris and food waste, while another could report plastic debris, plant debris, and iron remnants. This explains why the total frequency of reported pollution types exceeds the total number of respondents.

The most frequently observed pollutant was plastic debris, reported by 62% of respondents. This included plastic bottles, packaging materials, and food containers, which were commonly found on all five beaches. The persistence of plastic in the environment, coupled with inadequate waste management systems, contributes significantly to coastal degradation.

Iron remnants were another notable source of pollution, particularly at Mbegani and Msalabani beaches, where ongoing boat construction and repair activities are prevalent. The presence of these iron wastes poses physical hazards and introduces heavy metals into the coastal waters, threatening both marine life and human health.

Plant debris, particularly mangrove leaves and branches, was observed frequently, especially at Kaole Beach. This is linked to the deforestation of mangrove forests in the area, which results in increased amounts of plant waste being washed ashore.

The results of the study reveal that pollution along Bagamoyo’s coastline has significant socio-economic impacts, particularly on industries reliant on fishing and tourism. Several respondents working in tourism and fishing expressed concerns about the long-term sustainability of their livelihoods, given the high levels of pollution in the area.

Table 2.Multiple-response summary of socio-economic impacts reported by respondents.

The results in Table 2 indicate the range of perceived socio-economic impacts associated with coastal pollution rather than separate respondent groups. Since the same respondent could experience or report more than one impact, such as reduced tourism income and declining beach attractiveness, the categories are overlapping. The percentages therefore show the proportion of all respondents who mentioned each impact.

A significant proportion of respondents (37%) reported that the visible pollution along the coastline has made Bagamoyo’s beaches less attractive to both local and international tourists. This has resulted in a noticeable decline in tourism revenue, directly affecting local businesses such as hotels, tour guides, and restaurants. Additionally, 33% of respondents indicated a direct reduction in their income from tourism-related activities.

Fishing communities were also notably impacted, with 29% of respondents reporting a decline in fish stocks due to pollution. Fishermen mentioned that pollution, especially plastic debris and metal waste, is disrupting breeding grounds and contaminating marine habitats. This is consistent with global trends, where marine pollution has been linked to declining fish populations and biodiversity loss.

The environmental consequences of pollution along Bagamoyo’s coastline are not limited to immediate aesthetic degradation but pose long-term threats to marine ecosystems. The presence of plastic debris is particularly concerning due to its persistence and ability to break down into microplastics, which can enter the marine food chain. Marine species such as fish, turtles, and seabirds are at risk of ingesting plastic particles, which can cause internal injuries, blockages, and death.

Iron remnants from construction activities contribute to the introduction of heavy metals, such as lead and copper, into the coastal waters. These metals are toxic to marine organisms and can disrupt growth, reproduction, and overall ecosystem health. Over time, the bioaccumulation of these metals in marine organisms can also affect human populations through the consumption of contaminated seafood (Table 3).

Table 3. Environmental impacts of pollution on marine ecosystems.

The demographic analysis of the respondents reveals interesting patterns in how pollution is perceived and experienced based on factors such as age, occupation, and frequency of beach visits (Table 4).

Table 4. Demographic distribution of respondents and pollution awareness.

The demographic responses also suggested some variation in how different age groups perceived the impacts of coastal pollution. However, because the study adopted a qualitative case study design and did not conduct statistical subgroup testing, these differences should be interpreted as descriptive patterns rather than conclusive age-based comparisons. Younger respondents, particularly those within the 25 - 34 age range, tended to express concern about the long-term implications of pollution for tourism, environmental sustainability, and future coastal livelihoods. In contrast, older respondents, particularly those within the 45 - 54 age range, more frequently emphasized immediate livelihood concerns, including declining fish catches, reduced income, and the day-to-day economic effects of pollution. These observations provide useful qualitative insight into how pollution is experienced differently across respondent groups, but they should not be interpreted as statistically significant differences.

Occupation-based trends: Fishermen and other frequent beach users were more acutely aware of specific pollution sources, such as construction waste and plastic debris, which directly affect their livelihoods. In contrast, tourists and occasional beachgoers reported pollution in more general terms, such as litter or dirty water, without necessarily identifying specific causes (Table 5).

Beach-specific trends: The variation in the types of pollution across different beaches suggests that different human activities are contributing to pollution in different ways. For example, Kaole Beach suffers primarily from plant debris due to deforestation, whereas Mbegani is heavily affected by iron remnants from boat construction. These insights can help local authorities target specific activities and sectors when formulating pollution control measures.

Table 5.Beach-specific pollution trends.

Plastic debris was identified as the most pervasive pollutant across the five coastal areas studied. This is consistent with global patterns, where plastic pollution has become one of the most significant environmental challenges of the 21st century ([6]). Plastics are non-biodegradable and break down into microplastics, which persist in marine environments for centuries, posing risks to both marine life and human health. In Bagamoyo, plastic waste, including bottles, packaging, and containers, was frequently (Figure 3, Figure 4).

Figure 3.Plant debris observed along the shoreline.

Figure 4.Accumulation of mixed coastal waste at the study site.

Observed along the shoreline, particularly in areas with high tourist activity. Respondents noted that the unsightly accumulation of plastic has reduced the aesthetic appeal of the beaches, which in turn has negatively affected tourism a key economic sector in the region.

The economic impact of this pollution is profound. As highlighted by [19], the attractiveness of coastal areas is crucial for sustaining tourism. Beaches are therefore important tourism assets whose environmental quality requires active and continuous management ([20]). The decline in beach cleanliness has led to fewer tourists visiting Bagamoyo, directly affecting local businesses such as hotels, restaurants, and tour guides. This is a common issue in coastal regions globally, where the economic benefits of tourism are often offset by the environmental degradation caused by poor waste management ([5]). Furthermore, the respondents’ concerns about the impact of plastic pollution on marine species reflect broader environmental issues. Marine animals, including fish, turtles, and seabirds, often ingest plastic, mistaking it for food. This can lead to digestive blockages, malnutrition, and death, as noted by studies like [12], which emphasize the fatal consequences of plastic ingestion for marine species.

In addition, microplastics present in the water can accumulate in the food chain, potentially affecting human health when contaminated seafood is consumed ([31]). The presence of microplastics in marine organisms not only threatens biodiversity but also poses risks to local communities that rely heavily on fishing for their livelihoods. This aligns with findings by [13], who reported a significant decline in fish stocks in polluted coastal areas of Tanzania, further exacerbating the economic vulnerability of local fishermen.

Iron remnants from boat repair and coastal construction activities were another major pollutant, particularly at Mbegani and Msalabani beaches. These remnants introduce heavy metals such as iron, lead, and copper into the marine ecosystem, which are toxic to marine organisms and can have long-term ecological impacts. The toxicity of heavy metals has been well-documented in studies such as those by [15], which describe how these metals disrupt the physiological processes of marine life, inhibit growth, and affect reproductive success.

In Bagamoyo, the presence of iron waste poses direct threats to both marine biodiversity and human safety. Iron remnants not only contribute to the contamination of coastal waters but also disrupt important breeding grounds for fish and other marine species. Coral reefs, which are already under threat from climate change and ocean acidification, are particularly vulnerable to heavy metal contamination, which can weaken their structures and reduce biodiversity ([22]). Fishermen who participated in this study reported that fish populations in areas near construction sites had significantly declined, a finding supported by similar studies in other developing coastal regions ([9]).

The socio-economic consequences of this pollution are severe. As fish stocks diminish, local fishermen face reduced catches, which directly affects their income and food security. This reflects the broader challenge of balancing economic development, such as coastal construction, with environmental sustainability. Without proper regulation and management of construction waste, the long-term viability of Bagamoyo’s fishing industry is at risk. This underscores the importance of stronger enforcement of environmental regulations, such as Tanzania’s National Environmental Management Policy (NEP, 1997), which calls for sustainable practices in industrial and construction activities (Figure 5).

Figure 5.Iron remains.

Mangrove deforestation is another critical issue identified in this study, contributing to both environmental degradation and increased pollution levels. Mangroves are essential for protecting coastlines from erosion, filtering pollutants, and providing habitat for a wide range of marine species ([26]). However, the deforestation of mangroves in Bagamoyo has led to significant environmental consequences, including the accumulation of plant debris along the beaches and increased vulnerability to coastal erosion.

The loss of mangroves exacerbates coastal erosion, leaving the shoreline more susceptible to the impacts of storms and rising sea levels. Assessing shoreline susceptibility is therefore important for identifying sections of the coast that require priority protection and erosion-control interventions ([28]). This finding is consistent with studies by [5], who emphasized the role of mangroves in stabilizing shorelines and preventing land degradation. In Bagamoyo, the destruction of these vital ecosystems has resulted in more plant debris being washed ashore, which, while seemingly natural, contributes to the overall pollution problem. As mangrove roots are removed, the ability of the coastline to retain sediment and prevent further erosion is weakened, leading to more debris being introduced into the coastal waters. Furthermore, mangrove deforestation disrupts the breeding habitats of many marine species, leading to a decline in biodiversity. This is particularly problematic for fish species that rely on mangroves as nursery grounds. The decline in fish populations, as reported by local fishermen, not only threatens marine biodiversity but also has direct economic consequences for the fishing industry. The destruction of mangrove ecosystems also increases the vulnerability of coastal communities to natural disasters, such as storm surges and floods, as the protective buffer provided by these forests is lost ([26]). This highlights the need for reforestation efforts and stricter enforcement of conservation laws to protect these critical ecosystems.

Food waste, particularly from restaurants and beach vendors, was identified as another significant pollutant. Respondents noted that leftover food and packaging from local eateries are often discarded irresponsibly, contributing to the degradation of the coastal environment. This problem is especially prevalent in tourist-heavy areas like Badeko Beach, where the influx of visitors exacerbates the strain on local waste management systems. Food waste, particularly from restaurants and beach vendors, was identified as another significant pollutant. Respondents noted that leftover food and packaging materials from local eateries were often discarded irresponsibly, contributing to the degradation of the coastal environment. This problem was especially prevalent in tourism-intensive areas such as Badeko Beach, where the influx of visitors placed additional pressure on local waste-management systems. Evidence of food debris observed along the shoreline is presented inFigure 6.

Figure 6.Food debris.

Tourism, while economically beneficial, often leads to environmental challenges if not properly managed. Beach tourism depends heavily on the environmental quality, accessibility, cleanliness, and recreational appeal of coastal destinations ([21]). Rapid tourism growth can also place additional pressure on local infrastructure and communities when waste-management capacity does not expand at a similar rate ([24]). As seen in other tourist destinations worldwide, such as Portugal and Chile, unmanaged tourism leads to littering, pollution, and habitat destruction ([23]). The findings of this study align with [14], who also identified tourism as a significant contributor to coastal pollution in Zanzibar and Bagamoyo. The improper disposal of food waste not only impacts the cleanliness of the beaches but also attracts scavenging animals, which can further spread the waste and disrupt the local ecosystem.

The long-term consequences of tourism-related pollution are severe. As beach cleanliness deteriorates, tourist numbers may decline, leading to reduced revenue for local businesses. Additionally, the accumulation of organic waste contributes to water pollution, as decomposing food releases nutrients that can lead to algal blooms, further degrading water quality and harming marine life. This reinforces the need for more sustainable tourism practices and improved waste management systems to mitigate the environmental impact of tourism on Bagamoyo’s coastline.