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Article

Unseen Threats at Sea: Awareness of Plastic Pellets Pollution Among Maritime Professionals and Students

by
Špiro Grgurević
,
Zaloa Sanchez Varela
,
Merica Slišković
* and
Helena Ukić Boljat
Faculty of Maritime Studies, University of Split, Ruđera Boškovića 37, 21000 Split, Croatia
*
Author to whom correspondence should be addressed.
Sustainability 2025, 17(15), 6875; https://doi.org/10.3390/su17156875
Submission received: 16 June 2025 / Revised: 17 July 2025 / Accepted: 25 July 2025 / Published: 29 July 2025
(This article belongs to the Special Issue Water Environmental Control of Pollutants and Environmental Sustainability)
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Abstract

Marine pollution from plastic pellets, small granules used as a raw material for plastic production, is a growing environmental problem with grave consequences for marine ecosystems, biodiversity, and human health. This form of primary microplastic is increasingly becoming the focus of environmental policies, owing to its frequent release into the marine environment during handling, storage, and marine transportation, all of which play a crucial role in global trade. The aim of this paper is to contribute to the ongoing discussions by highlighting the environmental risks associated with plastic pellets, which are recognized as a significant source of microplastics in the marine environment. It will also explore how targeted education and awareness-raising within the maritime sector can serve as key tools to address this environmental challenge. The study is based on a survey conducted among seafarers and maritime students to raise their awareness and assess their knowledge of the issue. Given their operational role in ensuring safe and responsible shipping, seafarers and maritime students are in a key position to prevent the release of plastic pellets into the marine environment through increased awareness and initiative-taking practices. The results show that awareness is moderate, but there is a significant lack of knowledge, particularly in relation to the environmental impact and regulatory aspects of plastic pellet pollution. These results underline the need for improved education and training in this area, especially among future and active maritime professionals.

1. Introduction

Maritime transport enables the movement of goods across continents and serves a key role in global trade. It is globally regarded as the most cost-effective and efficient way to transport goods, supporting large-scale commerce and economic connections. However, despite its economic advantages, maritime shipping is one of the primary causes of marine pollution, exacerbating the global problem of marine litter. The accumulation of litter and harmful substances in the ocean has become a serious environmental issue, garnering increasing attention from researchers and international organisations.
According to the United Nations Environment Programme (UNEP), marine litter is any persistent, manufactured or processed solid material that is discarded, disposed of, or abandoned in the marine environment [1]. Marine litter poses a significant threat to the marine environment [2], with debris commonly found in the sea, on the seabed, and along coastlines [3]. A particularly serious issue is the widespread production and excessive accumulation of plastics, which have costly, immeasurable, and irreversible consequences for humans and the marine environment due to their persistence, the formation of toxic substances, and the transfer of various pollutants [2]. Plastic is the most common marine litter and, in some areas, the only type of marine litter [4,5]. Some researchers have argued that in 25 years, the amount of plastic in the ocean could outweigh the mass of fish [6,7].
Plastic breaks down into microplastics, i.e., plastic parts that are smaller than 5 mm in diameter [8]. Microplastics can enter the marine environment via various non-point sources and can be present in significant quantities in the water column and sediments [9]. Researchers estimate that in 2019, there was an average of 171 trillion pieces of plastic, mainly microplastics, in the world’s marine environment [10]. The Mediterranean Sea is an example of an area with significant microplastic pollution [11,12], and the presence of plastic pellets on its beaches is well documented [12,13,14,15,16]. The sheer quantity of plastic, along with its impact on the health of organisms, biodiversity, and ecosystems, makes it a critical environmental concern [17,18,19]. The EU Zero Pollution Action Plan aims to create a pollution-free environment by 2050 by drastically reducing air, water, and soil pollution. The targets for 2030 include, for example, reducing plastic waste in the sea by 50% and the release of microplastics by 30% [20].
One of the key international tools addressing marine pollution is the International Convention for the Prevention of Pollution from Ships (MARPOL), adopted in 1973 and supplemented by a protocol in 1978. This treaty is considered the most important global framework for preventing marine pollution from both operational and accidental causes, comprising six technical annexes that cover oil (Annex I), noxious liquids substances (Annex II), harmful substances (Annex III), sewage (Annex VI), garbage (Annex V), and air emissions (Annex VI). These annexes set standards for discharge procedures, emission limits, packaging, crew training, and designated “special areas” to ensure that ships manage these various pollutants in compliance with strict environmental regulations [21].
Plastic pellets, also known as nurdles, are categorised as primary microplastics [9,22,23,24] and are considered a significant source of pollution in the marine environment due to their widespread distribution [23,25]. They are used as raw material for the large-scale production of plastic products [26,27] and usually have a uniform shape with diameters of 2 to 5 mm [28,29]. These solid and durable particles do not dissolve, emulsify, disperse, evaporate, biodegrade, or adhere to surfaces and are generally buoyant in water [30]. The OSPAR Commission has defined plastic pellets as a mass of pre-formed moulding material, having relatively uniform dimensions, used as feedstock in plastic product manufacturing operations [31]. Apart from pre-expanded pellets, which are classified as “miscellaneous dangerous substances” (Class 9) under the International Maritime Dangerous Goods Code (they can release pentane, a substance that can create a flammable atmosphere), plastic pellets are classified as non-hazardous substances under shipping regulations [32]. They can enter the marine environment at any stage of the supply chain, continuously or in large quantities [28,33], and have various negative effects [28].
In 2023, the EU laid the groundwork for the adoption of a regulation to prevent plastic pellet loss and reduce microplastic pollution through a set of requirements for handling plastic pellets at all stages of the supply chain [34]. In 2022, around 38% of all pellets were transported to and within the EU by sea [35]. In 2024, the Marine Environment Protection Committee (MEPC) of the International Maritime Organisation (IMO) endorsed Recommendations for the transport of plastic pellets in containers by sea to minimize and mitigate the problem of plastic pellets emitted from ships [36].
Lack of awareness and inadequate training have been identified as reasons for pellet losses in the supply chain [37]. Education and raising awareness are accepted as effective measures for tackling environmental issues [38]. Historically, major environmental incidents have prompted the adoption and enforcement of international regulations, leading to significant progress in preventing maritime pollution. Recent maritime accidents involving large-scale losses of plastic pellets at sea [37,39,40,41,42,43,44,45,46,47,48,49,50] have drawn growing attention, stressing the need to address this specific pollutant, whose physical properties, transport pathways, and environmental impacts distinguish it from other sources of microplastics. This paper aims to highlight the issue of plastic pellets, assess the level of awareness among seafarers and maritime students regarding marine pollution from plastic pellets, identify knowledge gaps, and raise awareness about this specific form of pollution.

2. Issue of Plastic Pellets in the Marine Environment

2.1. Pathways of Introduction in the Marine Environment

The loss of plastic pellets in the environment is considered the second [23] and third largest contributor to accidental microplastic pollution [37]. In 2019, between 52,140 and 184,290 tons were lost to the environment in the EU [35], while 445,970 tons were lost to the environment worldwide [23]. Continuous studies have confirmed plastic pellets in the marine environment in Europe [37], and Jiang et al. [51] have identified the accidental spillage of plastic pellets as a significant source of plastic pollution in the marine environment. Environmental leakage (Figure 1), i.e., unintentional loss of plastic pellets, is caused by improper handling during production, manipulation, and transportation and significantly increases the pollution caused by plastic pellets [16,28,52]. Recent studies have shown that the plastic pellets found in the sediments of the Mediterranean are qualitatively similar to the types of polymers produced in the neighbouring industry [12,16,53,54]. Plastic pellets can enter the marine environment directly or enter the sea through rivers and wastewater [24]. Direct and rapid pollution from plastic pellets occurs when pellets are spilled in ports during operations, and significant accidental pollution of the marine environment from pellets can also occur during transportation [25,55]. In addition, pellet losses can be divided into chronic (occurring during routine operations) and acute (resulting from accidents during transportation) (Figure 1) [37,56]. Chronic losses refer to the continuous leakage of small quantities of plastic pellets, while acute losses result in the release of large quantities of plastic pellets into the environment at a single location within a short period [32,57].
Chronic pellet losses have a more significant impact on the environment than acute losses due to their frequency [32,57]. Between 2005 and 2023, 37 sites with chronic pellet loss, comprising more than 1000 pieces, were registered, as well as six direct releases into the marine environment [57]. Lack of awareness, inappropriate training, poor handling, and a lack of prevention and containment measures can be identified as the main causes of chronic pellet loss (Figure 2) [37].
Acute losses are usually the result of accidents combined with a lack of preventative measures [37]. On a major shipping route linking Europe, Saudi Arabia, and China, acute incidents have already occurred, threatening the environment and economies dependent on tourism [57]. Between 1995 and 2023, most acute pellet losses occurred during transportation (including land transportation), with 15 direct losses at sea. In many cases, the causes remain unidentified [57]. The number of acute and chronic pellet losses cannot be considered accurate, as there is no mandatory reporting; however, the number of reports has increased since 2005 [57].
To date, the following accidents have caused considerable acute pollution in maritime traffic:
2025: On 10 March 2025, a collision occurred in the North Sea between the container ship Solong and the oil tanker Stena Immaculate, approximately 13 miles off the coast of Yorkshire. In addition to the fuel spilled from the tanker, 15 containers filled with plastic pellets fell from the Solong into the sea, resulting in a serious environmental hazard [39]. According to local authorities, approximately 11 tons of plastic pellets washed ashore following this collision, which have been removed from beaches in Lincolnshire [40].
2023: On 8 December 2023, the ship Toconao lost six containers in Portuguese territorial waters 80 km west of Viana do Castelo. One of the lost containers contained over 1000 bags of plastic nurdles, each weighing more than 25 kg. The leak has polluted the Galician coast with 25 tons of plastic nurdles, with most of the material remaining in the environment (as of January 2024, 18.5 tons remain unrecovered) [41].
2021: On 20 May 2021, a chemical vapour outbreak occurred on the container ship MV X-Press Pearl while at anchor in Sri Lankan waters. On May 25, a fierce fire broke out, resulting in explosions and the loss of an unknown number of containers, a number of which contained hazardous chemicals and plastic pellets. On board the vessel were 87 containers filled with various types of plastic pellets, with a total estimated quantity of 1680 tons [42].
2020: In February 2020, the ro-ro ship Trans Carrier ran into heavy weather off the Danish coast, which damaged a container. 13 tons of plastic pellets were deposited into the sea, carried by the wind and sea currents, accumulating in the Oslo Fjord [43].
2020: On 2 August 2020, the container ship CMA CGM Bianca was loading cargo in New Orleans when a sudden storm broke the mooring lines. As a result, containers collided with the ship during loading operations. A damaged container fell into the water and released 25 tons of plastic pellets into the environment [37,44].
2020: On 18 August 2020, the ship CSAV Trancura lost a container at Plettenberg Bay. The ship’s P&I club stated that 174.5 tons of plastic pellets had entered the sea. By June 2021, approximately 30,183 tons of plastic pellets had been recovered [45].
2019: In early January 2019, the vessel MSC ZOE lost 342 containers in the North Sea due to the severe weather [46]. The accident, which led to widespread pollution and the washing up of plastic waste, occurred near the Wadden Sea, which is protected under national and European law, classified as Natura 2000, and recognized by the United Nations as a World Heritage Site [46,47]. The lost cargo included a container with 22.5 tons of polymer beads (UN2211, expandable polymer beads that develop flammable vapours) [46,47]. Over 11 metric tons of plastic pellets were lost [46].
2017: On 10 October 2017, a storm in Durban, South Africa, caused at least two 12-m-long shipping containers from the MSC Susanna to fall overboard. The containers remained submerged for days before their contents were discovered. Locals first noticed plastic nurdles washing ashore, and almost a month later, the scale of the pollution prompted a large-scale cleanup operation along 200 km of coastline. Two billion nurdles, or 49 tons of plastic pellets, were released in this accident [48].
2012: On 23 July 2012, Hong Kong was hit by a typhoon, causing a container ship to lose seven 40-foot containers. Six containers containing plastic pellets were damaged, resulting in the spill of approximately 150 tons of plastic pellets into the sea, which later washed up on nearby beaches [49].
2011: In October 2011, the container ship MV Rena ran aground on a reef near Tauranga, New Zealand. The incident resulted in the loss of containers and a significant oil spill. The spilt cargo included approximately 150 tons of plastic pellets, which ended up in the sea [50].
The distribution of plastic pellets in the marine environment is dependent on their properties and marine environment conditions [60]. They can be transported far by wind, surface currents, and tides or accumulate on beaches [61]. Pellets from the marine environment eventually end up on beaches, sometimes near harbours, but they can also accumulate and travel far from their point of origin [25], as seen in the case of South Africa, where plastic pellets were found over 2000 km away [62].

2.2. Plastic Pellets Environmental Impact

Several impacts of plastic pellets on the environment have been identified, including environmental, climate, human health, and economic impacts [37]. Due to their properties, such as their small size, which allows them to be easily dispersed, leading to widespread global distribution, plastics, especially microplastics, can pose an unseen threat from diverse and often distant sources [33,63]. Plastic pellets can affect sensitive habitats and compromise services such as decarbonization and shoreline protection [12].
Due to their physicochemical properties, surface characteristics, small particle size, large specific surface area, and hydrophobic nature, microplastics can effectively absorb and desorb substances from the environment, accumulating organic molecules, heavy metals, and other toxic elements in concentrations many times higher than those found in the environment [64,65,66,67,68,69,70]. Various chemical and persistent contaminants from the surrounding water can accumulate on plastic pellets over time, spread to another location, be eaten by marine organisms, and be introduced into the food chain [22,26,71,72,73,74,75,76]. The area in which they are located and the time they are exposed to a particular pollutant affect the amount of pollutant on the plastic pellets [24,77]. Through the ingestion of plastic pellets by marine organisms, environmental pollutants can bioaccumulate and subsequently transfer through the food chain, ultimately posing a risk to the ecosystem and human health [78,79,80,81,82]. Some authors highlight the role of plastics as vectors for the transfer of pollutants to marine organisms and ultimately to humans, as plastics can enhance the environmental persistence of these substances, which are bioaccumulative and toxic, thereby posing a threat to both marine ecosystems and human health [66,67,71,72,83,84].
Due to its persistence, microplastics in the marine environment have become a habitat for microorganisms and invertebrates [85,86], and [87] used the term “plastisphere” to describe the microbial community that colonizes plastic particles [88]. The movement of microorganisms contaminating plastic particles poses a threat to the environment and human health, as they can spread over long distances, expand their natural range and become non-native, invasive species or even transmit diseases [85,87,88,89,90]. Moreover, recent studies have highlighted the importance of the atmosphere as an additional long-distance transport pathway for microplastics, particularly microplastic fibres, enabling their dispersal even to remote and pristine environments [91].
The small size of microplastics contributes to their misuse and uptake by marine organisms, allowing plastic to enter the food web and affect the marine ecosystem [12,92,93,94]. Organisms can ingest microplastics in several ways, e.g., accidentally when filtering or eating deposits, through confusion with food, or indirectly through trophic transfer by eating prey that has already ingested microplastics [95,96]. More than 100 species, such as zooplankton, molluscs, crustaceans, fish, planktivorous sharks, cetaceans, marine reptiles, and seabirds, have been documented to ingest microplastics [96], and plastic ingestion has been detected in the Mediterranean Sea in numerous species, including commercial species [12,97,98,99,100]. The effects of microplastic ingestion are manifested at the population level in the form of reduced species numbers or biomass [101,102], and at the individual level through effects on survival [102,103,104,105], reproduction [84,103,105,106,107,108,109,110,111], growth [102,106,109,112,113,114,115,116,117], and nutrition [107,118,119,120,121,122,123], with physical damage from microplastics or reduced food intake being possible mechanisms [102,103,104,105,106,107,108,110,112,113,114,116,118,121,124,125,126].
The impact of microplastics on wildlife depends on the characteristics, concentration, and duration of exposure [126], so understanding the extent and type of exposure is key to evaluating their ecological impact [95].

3. Survey on Awareness of the Environmental Impact of Plastic Pellets

3.1. Structure of the Survey and Research Methodology

This study was conducted through an online survey aimed at evaluating awareness of marine pollution caused by plastic pellets. The survey was available from July 2024 to March 2025 and was distributed digitally via online platforms and email to the professional associations, alumni, and other maritime faculties.
Seafarers and maritime students were chosen as a target group, due to their unique position within the maritime sector. Both groups operate (or are being trained to operate) within the closed system of a vessel, where they are effectively the first line of defence in the event of an incident or environmental threat. Their knowledge, understanding, and awareness of the potential environmental risks associated with substances such as plastic pellets are critical, not only for recognising potential hazards but also for making timely and informed decisions that can prevent or mitigate environmental impact. It is desirable to assess the level of awareness among those directly responsible for onboard operations and environmental safety.
Participation in the survey was entirely voluntary and anonymous, with no restrictions other than professional status (i.e., being a maritime student or an active seafarer).
The questionnaire was developed within the framework of a master’s thesis at the Faculty of Maritime Studies, University of Split, under the supervision of two mentors: one with professional seafaring experience and the other an expert in marine environmental protection. The design of the questionnaire was informed by a review of relevant scientific literature, applicable maritime regulations, and the combined practical expertise of the student and mentors to ensure the clarity, relevance, and appropriateness of the instrument for the intended study population.
The questionnaire comprised nine questions, categorized into three thematic sections (Table 1):
Section 1: Basic demographic and background information (e.g., occupation, prior awareness of the term “plastic pellets”). This section includes questions 1 through 4.
Section 2: Knowledge-based questions concerning the environmental impacts of plastic pellets and their classification under international conventions such as MARPOL. This section comprises questions 5 through 6.
Section 3: Opinion-based questions addressing the perceived frequency of pollution incidents and the adequacy of existing international regulations. This section includes questions 7 through 9.
All questions were closed-ended, with response formats including multiple choice, yes/no, and Likert-type scales (1–5, where 1 represents ‘strongly disagree’ and 5 represents ‘strongly agree’). An additional follow-up question regarding sources of information was shown to respondents who indicated prior awareness of plastic pellets.
The survey was completed by 206 respondents, representing a sufficient sample size for a preliminary exploratory analysis. Descriptive statistics were used to analyse the frequency distribution of responses to each question, enabling the determination of the most frequently selected answers. The IBM SPSS Statistics 26.0 was used to perform the analysis. The data were then stratified by key variables: target group (seafarer or student), source of information, knowledge rate, and questions from Section 3 regarding opinions about the frequency of pollution incidents. To deepen the analysis, cross-tabulations were created, focusing on the relationships between target groups, sources of information, and response patterns. This approach enabled the identification of notable trends and associations between different target groups.

3.2. Plastic Pellet Pollution: Insights from Seafarers and Maritime Students

  • Section 1: Basic demographic and background information
The participants were evenly distributed between the two target groups, with 51.5% being students and 48.5% being seafarers. A very high percentage (57.3%) of respondents had never heard of the term “plastic pellets” (Figure 3), of which 51.7% were seafarers and 48.3% were students.
The next question related to the source from which the respondents had heard about plastic pellets. Of the 118 positive responses, 43.2% learned about it from the media, while 39.8% learned about it from educational programs or lectures. Seafarers were familiar with the term plastic pellets from educational programs or lectures (21%) or from the media (18%) (Figure 4). Students, on the other hand, heard the term mainly through the media (25%) or from educational programs or lectures (19%) (Figure 4).
  • Section 2: Knowledge-based questions related to the environmental impact of plastic pellets and their classification under international conventions such as MARPOL.
Regarding the level of knowledge of the environmental impact of plastic pellets, 57.3% of respondents state that their knowledge is fair or poor, while only 12.1% have very good or excellent knowledge. Stratified by the target group, seafarers report having mostly good knowledge (37%), while students report having mostly fair knowledge (37.7%).
In terms of MARPOL classification, 67% of respondents believe that plastic pellets fall into the MARPOL Annex V category, while 10% of respondents do not know which category plastic pellets fall into. When stratified by target groups, the percentage of respondents who do not know how to classify plastic pellets is 12.3% among students and 7% among seafarers. A cross-tabulation of these responses with the level of knowledge about plastic pellets reveals that 83% of the responses with excellent knowledge about the environmental impact of plastic pellets classify them in Annex V. In contrast, the answers with poor knowledge classify plastic pellets in Annex V (57.4%) or indicate that they do not know (20.4%). The distribution stratified by source of information shows that 13% of respondents who have heard about plastic pellets in educational programs or lectures are unsure of their classification. Seafarers believe (45%) that plastic pellets should be classified as hazardous cargo, while 48% of students’ responses classify them as hazardous cargo. Among those who have learned about plastic pellets in educational programs, 61.7% believe that plastic pellets should be classified as hazardous cargo. Among those who have learned about plastic pellets in the media, 45.1% believe that plastic pellets should be classified as hazardous cargo.
  • Section 3: Opinion-based questions addressing the perceived frequency of pollution incidents and the adequacy of existing international regulations.
Both students and seafarers believe that plastic pellets enter the marine environment through improper handling and storage, as shown in Figure 5.
Respondents believe that plastic pellets end up in the ocean due to accidents or inadequate handling during transportation occasionally (46.1%), while 33% believe this happens frequently. Seafarers and students have a similar distribution of answers to this question, as shown in Figure 6.
Table 2 analyses the distribution of responses to the questions “How do plastic pellets most commonly end up in the marine environment?” and “How often do you think plastic pellets end up in the sea due to accidents or inadequate handling during transportation?”. The cross tabulation between the perceived causes and the perceived frequency of occurrence shows that respondents who identified improper handling and storage as the main cause also tended to perceive the loss of pellets as occasional or frequent.
Only the group that has never heard of plastic pellets consider pollution very rare. Most of these participants answered that it occurs occasionally (45.5%). If we stratify by knowledge, we see that those with less knowledge about plastic pellets (poor or fair knowledge) most often believe that pollution from plastic pellets occurs occasionally (55.6% and 39.1%, respectively), while those with excellent knowledge more often perceive it as frequent (50%) or very frequent (16.7%).The group that responded that plastic pellets should not be classified as hazardous cargo (60.4%) believes that pollution occurs occasionally.
A significant 52.4% believe that current international regulations and measures do not sufficiently protect the marine environment from plastic pellet pollution, while 37.4% are unsure. Seafarers believe that current international regulations are insufficient (61%) to protect the marine environment from plastic pellet pollution, or they are unsure (27%). Students are mostly unsure (47.2%) or consider them insufficient (44.3%).
The group that has never heard of plastic pellets considers the current regulations to be inadequate (44.3%) or is not sure (44.3%). Those who have heard about plastic pellets through conversations with friends and colleagues overwhelmingly consider the current regulations to be inadequate (66.7%). In contrast, those who have informed themselves through educational programs or lectures consider them to be inadequate (53.2%) or are unsure (38.3%). The group that obtained information from the media also considers the current legislation to be inadequate (56.9%) or uncertain (33.3%).
The group that believes that pollution is very rare is predominantly (50%) of the opinion that current international legislation sufficiently protects the marine environment from pollution by plastic pellets. The group, which states that pollution from plastic pellets occurs very frequently, believes that current international legislation does not sufficiently protect the marine environment from plastic pellet pollution, with a percentage of 84.6%.

4. Discussion and Conclusions

The environmental impact of plastic pellets is rather deceptive and sustainable due to their endurance and extensive spreading [23]. As cited by Sabatino et al. [12], the widespread accumulation and distribution of plastic pellets has been documented worldwide. Although numerous studies have addressed the topic of microplastics and plastic pellets, knowledge of the main sources and pathways can be improved through continuous long-term monitoring data to understand their origin and distribution in the marine environment [12].
The results of the exploratory survey show that awareness and understanding of plastic pellet pollution are very low among both seafarers and students. Although both groups were relatively equally represented in the survey, more than half of the respondents (57.3%) stated that they had never encountered the term “plastic pellets” in relation to marine pollution. This underlines the lack of awareness regarding a major source of primary microplastic pollution and underscores the importance of educational initiatives and multi-stakeholder engagement to enhance public understanding of the issue. Greater environmental awareness and knowledge among the public lead to increased environmental protection [127]. Various research suggests that younger generations are more aware of environmental issues and are committed to restoring the environment by adopting positive and proactive environmental practices and behaviour [128].
Among respondents aware of the problem of marine pollution from plastic pellets, the primary sources of information are the media and educational programs. There are clear differences between the target groups: students are primarily informed through the media, while seafarers are more likely to be educated through structured, job-specific training and educational programs. The media have an opportunity to sensitize the public about critical environmental issues and the accompanying measures [129].
A worrying trend emerged from the respondents’ self-assessment of their knowledge of plastic pellet pollution. Only a small proportion (12.1%) rated their knowledge as very good or excellent, while the majority (57.3%) rated their knowledge as fair or poor. Seafarers (37%) rated their knowledge about plastic pellets as good, while students (37.7%) rated their knowledge as fair. This difference is evident in the context of different levels of education and experience. Equally, the results show that both target groups lack knowledge about the classification of plastic pellets, as well as their impact on the marine environment. Considering the growing demand for sustainable maritime transport, it is essential to foster collaboration between the maritime industry and educational institutions to develop targeted educational programs [130]. The IMO supports this in its document Review of Action Plan and other sources of microplastics from ships by setting key objectives such as reducing plastic waste on ships and in ports, increasing public awareness, educating and training seafarers, and strengthening international cooperation and understanding of legislation [131].
According to MARPOL Annex V, garbage includes food waste, domestic and operational waste, all plastics, cargo residues, incinerator ash, cooking oil, fishing gear, and animal carcasses generated during normal ship operations, except natural material such as fresh fish caught at sea. The Annex prohibits the discharge of waste into the sea except in certain circumstances (e.g., comminuted food waste or harmless cargo residues under strict distance restrictions) and mandates Garbage Management Plans and Record Books for monitoring and compliance on board [132,133].
In terms of classification according to international regulations, particularly MARPOL Annex V, the majority (67%) correctly identify plastic pellets under this category. However, classification accuracy correlates strongly with the level of knowledge; those with very good knowledge were most likely to classify correctly (83%), while those with poor knowledge showed a higher level of uncertainty or incorrect answers. Interestingly, even among those who had received information through educational programs, a remarkable 13% were uncertain about the MARPOL classification, suggesting that the educational content should be improved. The perception of plastic pellets as hazardous cargo also varies among target groups. There is more uncertainty among students: 34% are unsure how to classify them, while seafarers and those trained through formal programs are more likely to support classification as hazardous cargo (45% and 61.7%, respectively). This reflects a discrepancy between practical experience in the field and the acquisition of theoretical or passive information.
According to the results of the perceived pathways of plastic pellet entry into the marine environment, 70% of respondents identified improper handling and transportation as the primary causes of plastic pellet release into the environment. Additionally, when asked to estimate the frequency of pellet pollution due to transport-related incidents, 46.1% of participants stated it occurs occasionally, while 33% believe it happens frequently. A key point to highlight here is the correlation between the level of knowledge about plastic pellets and the perceived risk of marine pollution. The findings clearly show that individuals with limited knowledge (rated as poor or fair) tend to believe that such pollution occurs occasionally. One of the fundamental leads in dealing with this challenge is to constantly raise ocean literacy, not only in educational institutions but also in society in general [134]. The raising of the level of knowledge and awareness of the importance of the ocean [135] is a crucial preservation for coping and ultimately a decrease in the impact on the marine environment. We all share a common goal—the preservation of the ocean—and we can only achieve it if we are an ocean-literate society.
Significant quantities of plastic pellets enter the marine environment through container losses but are not considered as a source in the assessment of seashore litter, as the data situation is uncertain and controversial [136,137]. Furthermore, there are no binding regulations for the packaging of pellets in containers or for the stowage of these containers on ships [62]. In order to minimize the environmental risks of plastic pellets, the MEPC has drawn up Recommendations for the carriage of plastic pellets by sea in freight containers, which apply from February 2024 [36]. However, the lack of a central database with comprehensive statistics on container losses poses a major challenge, as damage and loss reports are rarely exchanged between interested parties [137,138]. It is essential to develop a management system tailored to the specific context of each country based on a thorough study of the link between lost containers and marine plastic pollution, especially due to the presence of plastic pellets in some of these containers [50].
Considering that plastic pellets can be lost at every step from production to final use, future regulations should consider all these steps together and be supported by best management practices in all steps where plastic pellets are handled in order to achieve greater success [139]. As of January 2026, the reporting requirements for containers lost at sea, as laid down by the IMO, will come into force. These regulations require the timely and comprehensive reporting of lost or drifting containers and obligate the master to notify nearby ships, the nearest coastal state, and the flag state to mitigate potential environmental risks, among other threats [6].
The research findings regarding the attitudes and opinions of seafarers related to the international regulation of plastic pellets indicate that more than half of the respondents (52.4%) hold the attitude that the current legislation is inadequate. In comparison, 37.4% are uncertain about this issue. Seafarers are more critical (61% of them), likely due to their first-hand experience of regulatory gaps. If we link this question to the question related to the source of information on plastic pellets, it is essential to discuss the following: more than half of the respondents (53.2%) who learned about the above issue through educational programs or lectures believe that the international legal regulation is inadequate. Scepticism extends across all sources of information, particularly among those informed through peer discussion (66.7%) and the media (56.9%).
Despite growing concerns about marine plastic pollution, there are currently no international or EU-level legal frameworks focusing on plastic pollution resulting from industrial spills, while national regulations specifically targeting pellet spills remain uncommon [28]. In the United States, the Environmental Protection Agency (EPA) first recognized the issue of plastic spills in 1990 [140]. Shipping regulations generally take a broad approach, prioritizing safety at sea, the protection of human life, the protection of goods, and the marine environment [141,142].
Although plastic pellets are not currently classified as dangerous goods under international maritime regulations, recent large-scale spills and scientific findings have raised doubts as to whether this classification adequately reflects the environmental risks. A reclassification could lead to stricter packaging, handling, and transport requirements and more robust accident response measures. Even without a formal reclassification, improved industry guidelines, crew training, and increased regulatory oversight could play an important role in mitigating the environmental risks associated with plastic pellet pollution.
The maritime industry is in a constant process of growth and change. To achieve and maintain sustainability, all key components must operate sustainably—a goal that the exchange of information and continuous co-operation between shipping companies and maritime educational institutions can support [143]. The IMO plays a significant role in the sustainability of the maritime industry through harmonization of standards, regulatory compliance, and introducing innovation to reduce the sector’s environmental footprint [142].
Combating pollution from plastic pellets requires coordinated efforts by all stakeholders involved in the production, transport, and regulation of plastics. Plastic producers and manufacturers are responsible for minimizing the loss of plastic pellets at source through improved packaging, storage, and handling, while shipping companies and logistics service providers ensure safe transport, implement containment measures, and train crews in spill prevention and response. Seafarers play a crucial role as they are the first line of defense in the event of incidents at sea, and their knowledge and awareness are key to identifying hazards and making timely decisions. Regulatory bodies (IMO) and national maritime administrations are essential for setting and enforcing regulations, strengthening monitoring, and promoting international cooperation. Environmental Non-Governmental Organizations and academia contribute by conducting research, raising public awareness, and advocating for better environmental protection, while the public and consumers indirectly support change by demanding sustainable practices and holding companies accountable.
Raising awareness among these groups is critical to promoting a culture of environmental responsibility and improving the overall prevention and management of plastic pellet pollution. Specific strategies to raise awareness include incorporating the topic of microplastic and pellet pollution in maritime education curricula, organizing training programmes for seafarers and port workers, developing best practice guidelines for industry, and conducting public information campaigns in collaboration with NGOs and international organizations. Such combined efforts can contribute significantly to reducing the environmental impact of plastic pellet pollution.
The results of this study further highlight the importance of strengthening educational initiatives, especially those aimed at maritime students and active seafarers. The responses to the survey indicate that educational programmes should place more emphasis on the environmental impact of plastic pellet pollution, the relevant legal framework, and practical measures to prevent and combat marine pollution. Incorporating these focus areas into maritime education and vocational training can improve environmental awareness and preparedness among key stakeholders in the maritime sector.
The problem of plastic pellets can only be solved through the active cooperation and involvement of all stakeholders, with targeted education, improved industrial practices, and a strong regulatory framework. These three pillars are the foundations that must be firmly established in order to respond to the challenge set before us.

Author Contributions

Conceptualization, Š.G., M.S. and Z.S.V.; methodology, Š.G., M.S. and Z.S.V.; software, Z.S.V.; formal analysis, Š.G., M.S., H.U.B. and Z.S.V.; resources, Š.G., M.S., H.U.B. and Z.S.V.; writing—original draft preparation, Š.G., M.S., H.U.B. and Z.S.V.; writing—review and editing, Š.G., M.S., H.U.B. and Z.S.V.; visualization, Š.G. and Z.S.V. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

The data presented in this study are available at reasonable request from the corresponding author.

Acknowledgments

We sincerely thank all participants who took part in the survey for their valuable input. A special thanks goes to Lucy Boko for her careful proofreading.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Sources and pathways of plastic pellets pollution adopted from [50,58,59].
Figure 1. Sources and pathways of plastic pellets pollution adopted from [50,58,59].
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Figure 2. Causes of chronic pellet losses during production, transportation, and processing [37].
Figure 2. Causes of chronic pellet losses during production, transportation, and processing [37].
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Figure 3. Proportion of respondents familiar with the term “plastic pellets” in the context of marine pollution, by target group.
Figure 3. Proportion of respondents familiar with the term “plastic pellets” in the context of marine pollution, by target group.
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Figure 4. Reported sources of information among respondents familiar with the term ‘plastic pellets’ in the context of marine pollution.
Figure 4. Reported sources of information among respondents familiar with the term ‘plastic pellets’ in the context of marine pollution.
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Figure 5. Perceived pathways of plastic pellet entry into the marine environment, with responses categorized by target group.
Figure 5. Perceived pathways of plastic pellet entry into the marine environment, with responses categorized by target group.
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Figure 6. Target group-specific responses regarding the estimated frequency of plastic pellet pollution caused by transportation accidents or mishandling.
Figure 6. Target group-specific responses regarding the estimated frequency of plastic pellet pollution caused by transportation accidents or mishandling.
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Table 1. Survey Questions and Response Types.
Table 1. Survey Questions and Response Types.
QuestionType of Response
1Occupation?Student/Seafarer
2Have you ever heard of the term “plastic pellets” (nurdles) in the context of marine pollution?Yes/No
3If yes, where did you hear about this term?Multiple choice
4How would you rate your knowledge of the environmental impact of plastic pellets?Scale (1–5)
5According to the International Convention MARPOL, which type of waste do you think plastic pellets belong to?Multiple choice
6Do you think plastic pellets should be classified as hazardous cargo?Yes/No
7In your opinion, how do plastic pellets most commonly end up in the marine environment?Multiple choice
8How often do you think plastic pellets end up in the sea due to accidents or improper handling during transport?Scale (1–5)
9Do you think current international regulations and measures sufficiently protect the marine environment from plastic pellet pollution?Yes/No
Table 2. Cross tabulation of questions 7 and 8.
Table 2. Cross tabulation of questions 7 and 8.
8. How Often Do You Think Plastic Pellets End Up in the Sea Due to Accidents or Inadequate Handling During Transportation?
Very RarelyRarelyOccasionallyFrequentlyVery Frequently
7. In your opinion, how do plastic pellets most commonly end up in the marine environment?During production0.0%2.4%3.9%4.9%0.5%
From ships during accidents0.0%1.5%3.9%2.9%1.0%
Improper handling and storage1.5%7.3%33.0%23.3%4.9%
Other1.5%0.5%5.3%1.9%0.0%
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Grgurević, Š.; Sanchez Varela, Z.; Slišković, M.; Ukić Boljat, H. Unseen Threats at Sea: Awareness of Plastic Pellets Pollution Among Maritime Professionals and Students. Sustainability 2025, 17, 6875. https://doi.org/10.3390/su17156875

AMA Style

Grgurević Š, Sanchez Varela Z, Slišković M, Ukić Boljat H. Unseen Threats at Sea: Awareness of Plastic Pellets Pollution Among Maritime Professionals and Students. Sustainability. 2025; 17(15):6875. https://doi.org/10.3390/su17156875

Chicago/Turabian Style

Grgurević, Špiro, Zaloa Sanchez Varela, Merica Slišković, and Helena Ukić Boljat. 2025. "Unseen Threats at Sea: Awareness of Plastic Pellets Pollution Among Maritime Professionals and Students" Sustainability 17, no. 15: 6875. https://doi.org/10.3390/su17156875

APA Style

Grgurević, Š., Sanchez Varela, Z., Slišković, M., & Ukić Boljat, H. (2025). Unseen Threats at Sea: Awareness of Plastic Pellets Pollution Among Maritime Professionals and Students. Sustainability, 17(15), 6875. https://doi.org/10.3390/su17156875

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