Impact of the Implementation of the Deposit Refund System on Coastal Littering in Latvia

Abstract

This paper provides a comprehensive evaluation of the environmental impact of implementing the beverage container deposit refund system on marine and coastal litter along the Latvian coastline. It incorporates data and insights from the assessment of deposit fractions littered in coastal areas during the post-season autumn period (weeks 3–4 in October and week 1 in November) in three monitoring sessions from 2021 (before the introduction of the DRS in Latvia) to 2023 (post-introduction). In 2022, a 43% overall decrease in selected public coastal areas was observed, with significant reductions at 11 out of 17 sites. This positive trend continued in 2023, showcasing a further 22% decrease compared to 2022 and a substantial 56% decrease compared to 2021. This study delves into the specific impact on different material types of beverage containers, reporting significant decreases in plastic and aluminium litter fractions. While glass beverage container litter showed a smaller decrease, overall positive trends continued in 2023. However, the situation with aluminium cans remained challenging, especially in border areas with Lithuania and Estonia. This study emphasizes that beverage containers with identifiable deposit system labels constitute a minority of the total litter pressure, underscoring the need for ongoing efforts to address containers without deposit labels, particularly in specific border areas. The findings provide valuable insights into the effectiveness of the deposit system in mitigating coastal litter, contributing to sustainable waste management practices in Latvia.

1. Introduction

A Deposit Return System (DRS) is a beverage container collection method used by many countries with the objective of improving collection rates and circularity of beverage packaging (mostly plastic, metal, and glass) and reducing littering. Rooted in economic and behavioural theories, the DRS leverages financial incentives and nudges to promote recycling. The DRS incentivizes consumers to return packaging materials by refunding a deposit initially charged at the purchase of the beverage, aligning economic behaviour with environmental benefits [1]. Its environmental impact aligns with circular economy principles, reducing waste and conserving resources.

The DRS has been used for decades by manufacturers of beverages and beer in order to maximise the collection of reusable glass bottles. This collection method based on a deposit was adopted for single-use containers for the first time in Canada, in British Columbia (1970). The first European country which imposed a deposit on non-refillable beverage packaging was Sweden, and the nationwide deposit system started operating there in 1984 [2]. The recent Global Deposit Book [3] suggests that in 2022 the system was introduced in 50 jurisdictions, including several states of the USA, Australia, and European countries. As of the 1st of February 2024, 16 European states have implemented a deposit scheme as a collection method for recyclable containers (Sweden, Norway, Denmark, Iceland, Finland, Germany, Netherlands, Croatia, Estonia, Latvia, Lithuania, Slovakia, Romania, Malta, Hungary, and Ireland).

Many studies [4,5] have demonstrated the positive economic outcomes of implementing a DRS and identified several “best practices” to enhance its effectiveness. For instance, an evaluation of the Latvian DRS [6] indicates that implementing the system demands significant financial and organizational resources. This burden could be mitigated by introducing a DRS after establishing separate waste collection systems first. Moreover, other studies [7,8] have emphasised the importance of ensuring that the economic costs associated with a DRS do not outweigh its environmental benefits.

In addition to boosting beverage container recycling rates, a significant advantage of the DRS—unattainable without its implementation—is a reduction in litter [6,9,10]. Litter remains an ongoing environmental concern [11], with a notable negative impact on the environment and wildlife [12,13], and it also incurs significant costs to people and the economy [14,15].

Economic incentives can shape consumer behaviour by adjusting the relative costs and benefits associated with various actions [16], including littering. The DRS serves as an economic tool known for its cost-efficiency and capability to address market failures, thereby promoting litter reduction [1]. In the realm of environmental economics, market failures related to a public bad like littering occur due to missing markets and negative externalities [17,18]. A missing market for litter indicates undefined property rights, leaving no party accountable for its management [19]. Negative externalities arise when there is a discrepancy between private and social costs [20], meaning that the environmental impacts of littering are not borne by the polluters, resulting in excessive litter production. Furthermore, littering exemplifies the common-pool resource dilemma, where individual actions might seem trivial, but collectively they diminish overall welfare [21]. The DRS addresses these market failures by increasing the relative financial costs of activities leading to littering, thus motivating individuals to alter their behaviour and reduce littering, while also creating market value for used packaging to encourage its collection.

Various studies have conducted assessments of the efficiency of the DRS in changing human behaviour and compared littering rates between jurisdictions with and without a DRS [22,23]. However, comprehensive longitudinal studies examining the changes in littering following the introduction of a DRS are lacking. Such studies could provide valuable insights into the effectiveness of the DRS in promoting behavioural change and reducing littering.

This paper contributes to the field of environmental and behavioural economics by exploring how financial incentives can drive changes in individual behaviour and minimize littering. Additionally, it provides insights relevant to environmental policy, waste management, and sustainability studies by examining the effectiveness of the DRS in reducing litter and promoting recycling behaviours. With this background, this article attempts to assess what are the changes in littering trends for different types of beverage containers following the implementation of the DRS and how effective is the DRS in reducing the quantity of beverage container litter along coastal areas. It systematically compares changes in littering in Latvia before, shortly after the implementation, and 1.5 years after the introduction of the DRS in February 2022. By focusing on Latvia’s experience, this study seeks to provide valuable insights for policymakers and stakeholders involved in waste management and environmental protection.

2. Materials and Methods

The Cabinet regulation nr. 519, “Regulations Regarding the Operation of the Deposit System”, outlines the starting point and functioning of the DRS in Latvia [24]. After nearly two decades of deliberation, it commenced operations in February 2022, beginning with a 6-month transition period during which both labelled and un-labelled beverage packaging was available on the market. The eligible container types include carbonated and non-carbonated non-alcoholic beverages (such as drinking water, mineral water, lemonade, energy drinks, iced teas, juices, and nectars), beer, and other fermented products with an alcohol content of up to 6% (e.g., cider, alcohol cocktails with an alcohol content ranging from 0.5% to 6%). The system excludes wine (including sparkling wine and fruit wine), hard liquor, milk, dairy products, and aseptic containers due to their unique recycling requirements and hygiene concerns. The accepted material types comprise plastic (mainly PET), metal (aluminium and steel), and glass.

Latvia has adopted the return-to-retail method within the DRS framework, mandating retailers with a floor space of ≥60 m² in rural areas and ≥300 m² in larger cities to establish a collection point. These points must accept all types of deposit packaging either at the point of sale, on the retailer’s premises, or in close proximity to the sales point, with a distance not exceeding 150 m from the point of sale. At the launch of the system, there are approximately 1350 return locations in Latvia [25]. The first years of implementation have demonstrated high return rates—during the first months of 2024, 86% of DRS-labelled packages were returned, including 92% of glass packaging, 87% of PET bottles, and 79% of aluminium cans [26].

The implementation of a DRS represents a proactive measure aimed at mitigating littering. By incentivising the return of beverage containers for recycling through a refundable deposit, the DRS encourages proper disposal and recycling practices among consumers. Consequently, the introduction of a DRS seeks to reduce littering, particularly of items like glass bottles, plastic bottles, and aluminium beverage cans, thereby contributing to the preservation of coastal and marine environments.

An assessment of the snapshot situation concerning the presence of coastal and marine litter from deposit fractions in Latvia before and after the introduction of the DRS was conducted using point-based monitoring in two distinct types of coastal sites during the post-season autumn period across three monitoring sessions spanning from 2021 to 2023 (weeks 3–4 in October and week 1 in November). The assessment was conducted during the post-summer-season period rather than the high season to capture a more accurate representation of residual litter. This period reflects the lasting impact of littering behaviours over the peak summer months and provides a clearer picture of the litter that persists after the peak tourist season has ended. Monitoring during this time allows for a better assessment of the effectiveness of the DRS in reducing litter that accumulates during the high-activity summer months.

The monitored site types include dune areas, referred to as type 1, and access points to the beach used as parking places and pathways, referred to as type 2. This sampling strategy was chosen to enhance the potential detection of littered objects. These areas are renowned for their tendency to accumulate litter and serve as valuable sources of information about littering habits. To ensure data comparability and eliminate any unknown periods of accumulation, only publicly managed sites accessible to the public all year round were selectively chosen. Latvia has a relatively long coastline (504 km), and in total, 17 sites were selected for monitoring, strategically located along the entire Latvian coastline (see Figure 1). Specifics of the sites and sampling transects are available on request.

This methodology is appropriate due to its focus on areas with high litter accumulation, which improves the likelihood of detecting litter and provides a comprehensive understanding of littering habits. Previous studies [27,28,29] have demonstrated the effectiveness of such targeted monitoring in coastal environments, allowing for accurate assessments of litter distribution and composition. By selecting publicly accessible and managed sites, consistent monitoring conditions were ensured and variables that could affect litter accumulation rates, thus enhancing the reliability of data, were eliminated.

The specific location and length of the transects varied depending on the site and the available access routes, resulting in transect lengths ranging from 266 m to 1.11 km. However, for the purposes of this study, the focus lies not on the length of the transects but on the comparison between the years. Each transect was divided into several quadrats, each measuring 2 m by 2 m, systematically positioned along the transect line for sampling purposes. The method involved manually collecting litter within these quadrats by trained volunteers. The precise locations were documented using GPS. This approach allowed for accurate mapping and identification of the study sites, ensuring that data collection and analysis were conducted with precision. To ensure consistency in the sampling methodology, the same quadrats were utilized for sampling across three consecutive years.

Beach litter was categorized into three groups according to the DRS classification: glass bottles, plastic bottles, and aluminium beverage cans. During the survey, all items visible to the naked eye were identified and recorded on provided survey forms. By meticulously cataloguing each item, researchers could gather detailed data regarding the types, quantities, and distributions of litter present in the study areas. For each deposit fraction examined, their sizes were assessed, providing additional data for potential further analysis of littering habits. Other forms of DRS-related litter such as cups were excluded. Starting from the year 2022, the monitoring protocol was enhanced to include the identification of the presence of the deposit system label for each litter item.

The collected data reflect the post-summer-season situation and the rate of litter accumulation in conditions where daily site waste maintenance activities are absent. During the data collection process, the type of waste management infrastructure in place was also identified, recognizing its potential impact on littering habits. This involved documenting the presence of waste bins and containers on-site, specifying the types of containers, and noting whether there were waste containers for recyclable waste categories. It should be noted that, according to available information, off-season maintenance varied from 2 days to 1 week in most sites, with only 2 to 3 exceptions where it was not possible to reliably ascertain waste management routines.

3. Results

Table 1. Summary of the findings with regards to the impact of deposit system implementation litter fractions in selected coastal sites (Oct–Nov 2021 vs. Oct–Nov 2022 and Oct–Nov 2023).

No.	Site	Type	Waste Management	2021	2022	2023	Change 22 vs. 21	Change 23 vs. 21	Change 22/23 vs. 21
1	Užava	2	no	25	4	11	−84%	−56%	−70%
2	Pavilosta	2	mix, recyclables	5	3	1	−40%	−80%	−60%
3	Pape	2	closed, recyclables	9	5	3	−44%	−67%	−56%
4	Karosta	1 and 2	closed, recyclables	12	6	6	−50%	−50%	−50%
5	Zvejniekciems	1 and 2	open	22	23	16	5%	−27%	−11%
6	Salacgriva	1 and 2	no	44	17	19	−61%	−57%	−59%
7	Lilaste	2	closed, recyclables	6	2	2	−67%	−67%	−67%
8	Daugavgriva	2	open	71	36	12	−49%	−83%	−66%
9	Vakarbulli	2	closed, recyclables	5	2	2	−60%	−60%	−60%
10	Vitrupe1	1 and 2	closed	19	22	19	16%	0%	8%
11	Vitrupe2	1 and 2	closed	7	10	11	43%	57%	50%
12	Vitrupe3	1 and 2	closed, recyclables	6	12	9	100%	50%	75%
13	Kolka	2	no	14	2	3	−86%	−79%	−82%
14	Roja	2	closed	0	0	0	0%	0%	0%
15	Mersrags	2	closed, recyclables	0	0	0	0%	0%	0%
16	Abragciems	2	no	10	1	0	−90%	−100%	−95%
17	Lielupe	2	closed, recyclables	2	1	0	−50%	−100%	−75%
Total				257	146	114	−43%	−56%	−49%

demonstrates summarized littering data for all 17 coastal monitoring sites between 2021 and 2023. The results show considerable improvements as the deposit system-linked litter numbers have decreased considerably since the introduction of the DRS in February of 2022.

As of 2022, there was a significant overall reduction of 43% in monitored coastal sites when compared to 2021 (average amounts of selected litter types across 17 chosen coastal locations). Among the surveyed sites, 11 experienced substantial decreases both in terms of quantity and percentage, while only four sites showed a deterioration in the situation, and two sites had no DRS-related littering in any of the years monitored (see Table 1).

The positive trends persisted in 2023, with a further 22% decrease when comparing data from 2022 and 2023, and an overall reduction of 56% compared to 2021, the year preceding the introduction of the DRS (Table 1). Sites such as Lielupe, Daugavgriva, Pavilosta, and Abragciems showed the most significant reductions, exceeding 80% from 2021 to 2023. Conversely, only two sites (Vitrupe2 and Vitrupe3) showed increases in litter over the same period. Overall, there was a 49% decrease in deposit system-related litter across the selected coastal sites in 2022 and 2023 following the DRS implementation.

Sites with mixed and open waste management practices generally showed less reduction in litter, suggesting that enhancing waste management practices in these areas could further improve outcomes. In contrast, sites with closed waste management practices showed varied results. However, there is no strong correlation between the waste management practices and the amount of litter at the site (R²—0.00075), indicating that factors beyond waste management practices influence litter levels.

The subsequent analysis of survey data focuses on developments related to specific material beverage containers, with

Table 2. Hotspot survey summary data comparison 2021 vs. 2022/2023—total by type/average by the material of the beverage containers.

Type of Container	Plastic Bottles			Aluminium Cans			Glass Bottles
Size of container	0.5	>0.5	Other (0.2/0.33)	0.5	≥Pint	Other (<0.5)	<0.5	0.5 and Pint	≥0.7
Total by type 2021	29	62	8	47	25	16	19	41	10
Average by material 2021	5.8			5.2			4.1
Total by type 2022	16	27	2	19	11	7	15	33	16
Average by material 2022	2.6			2.2			3.8
Total by type 2023	1	13	17	13	13	21	9	17	10
Average by material 2023	1.8			2.8			2.1
Change 22 vs. 21	−54%			−58%			−8%
Change 23 vs. 21	−69%			−47%			−48%
Change 22/23 vs. 21	−61%			−52%			−28%

providing a summary of the observed situation and trends for different material beverage containers collected during litter monitoring.

In 2022, data revealed a substantial reduction in selected litter fractions for two materials, with a 54% decrease for plastic beverage containers and a 58% decrease for aluminium cans. Meanwhile, the decrease in glass beverage containers, though present, was smaller at 8% (Table 2). Various factors, such as the inclusion of container types in the deposit system, overall circulation, and public perceptions and habits, may contribute to these differences.

In 2023, positive trends persisted for plastic and glass beverage containers, showing respective decreases of 69% and 48% compared to the situation in 2021 (see Table 2). However, the situation regarding aluminium cans did not improve further and stayed at −47% compared to pre-DRS time. It is noteworthy that in 2023, larger quantities of identified beverage cans without Latvian deposit system labels were observed in sites near the border areas with Lithuania and Estonia (Pape, Vitrupe 1, Vitrupe 2, and Vitrupe 3).

Overall, when comparing data from before the deposit system launch (2021) to average data from 2022 and 2023, the decreases were as follows: 61% for plastic bottles, 52% for aluminium cans, and 28% for glass bottles.

From the 2022 surveys conducted after the deposit system was fully functional, the monitoring protocols included an additional parameter—the identification of whether beverage containers had deposit labels. While providing an additional perspective on the survey data, this parameter has limitations, especially concerning glass bottles, where labels are more prone to weather-related wear and tear.

As indicated in

Table 3. Coastal litter on survey sites by label type in 2022 and 2023 monitoring sessions (deposit label/no deposit label/unclear alignment).

Year	2022			2023
Label	Deposit Label	No Label	Unclear	Deposit Label	No Label	Unclear
Plastic bottles	7%	40%	53%	16%	35%	48%
Aluminium cans	32%	54%	14%	43%	40%	17%
Glass bottles	17%	53%	30%	8%	56%	36%
Average	18%	49%	33%	25%	44%	32%

, beverage containers with identifiable deposit system labels constitute a minority of the total litter pressure for their respective waste fractions—18% in 2022 and 25% in 2023. The increase in the share of labelled items in 2023 aligns with the significant circulation growth of these fractions. However, it is essential to highlight that a considerable share of beverage containers without deposit system labels persists (49% in 2022 and 44% in 2023), where a concentration of such containers was identified on monitoring sites near the Latvian–Estonian and Latvian–Lithuanian borders. Approximately one-third of containers still could not have the presence of the label identified, mostly for plastic and glass bottles where labels tend to wear off with the weather.

4. Discussion and Conclusions

The DRS is not only an economically [30,31,32] and organizationally [2] feasible tool to improve recycling but also offers the most environmentally sustainable solution for managing beverage packaging at the end of its use [2,33]. This study is based on the observed changes in the quantity of beverage container litter before and after the implementation of the DRS. By systematically comparing the litter amounts over time and across different sites, the impact of the DRS on reducing coastal and marine litter was assessed. This study focuses on specific types of litter, such as plastic, glass, and aluminium beverage containers, to directly measure the effectiveness of the DRS in mitigating litter from these sources. This approach allows for a concrete evaluation of the environmental benefits of the DRS in reducing litter along the Latvian coastline.

Comparing the results from 2021 to 2023 in selected coastal sites, this study indicates a discernible positive impact following the introduction of the beverage container DRS in Latvia. In 2022, there was a 43% overall decrease in DRS-related beverage packaging litter in selected public coastal areas, with significant reductions observed at 11 out of 17 sites. This positive trend continued in 2023, with a further 22% decrease compared to 2022 and a substantial 56% decrease compared to 2021 when the DRS was not yet implemented. The overall reduction in deposit system-related litter items across the 17 coastal sites in 2022 and 2023 was 49%. This reduction in litter contributes to the overall health of ecosystems, reduces harm to wildlife, and supports environmental sustainability by ensuring that materials are recycled and reused rather than discarded.

Although the observed change in littering trends could potentially be attributed to various factors such as improvements in waste management practices, heightened environmental awareness, or other external influences, the findings of this study are supported by long-term data. Specifically, beach litter monitoring in Latvia from 2012 to 2023 has shown a significant decrease in DRS-related litter over the same period [34]. Moreover, while it is plausible that other factors have contributed to the reduction in litter, the consistency and specificity of the decline in DRS-related beverage packaging litter suggest that the introduction and promotion of the DRS system have played a pivotal role.

These results are in line with studies from other countries. For example, before the mandatory DRS was implemented in Germany, approximately one-fifth of the total litter volume was attributed to single-use beverage containers. However, following the introduction of the system, the littering of single-use beverage containers subject to deposits in the country has been reported to be negligible [35]. More recent studies have compared littering between areas where the DRS has been introduced and those where it has not. According to a 2018–2019 report by Keep South Australia Beautiful [22], beverage container litter accounted for only 2.9% of litter items in South Australia, where a DRS has been in place since 1977, in contrast to 14.2% in Western Australia, which lacked a DRS at that time. Another study [23] observed considerably lower overall litter in US states with a functional DRS. On a per capita basis, states with a DRS exhibited 50% less deposit material litter and 30% less non-deposit material litter compared to states without a DRS.

The results of this study demonstrate a significant decline in litter fractions across various materials. The decrease in plastic (54% in 2022 and 69% in 2023), aluminium (58% in 2022 and 52% in 2023), and glass (8% in 2022 and 48% in 2023) beverage container litter demonstrates that the DRS has successfully internalized the external costs of littering, following Pigouvian theory [36] and leading to a reduction in coastal litter. The global problem of littering and related pollution is escalating rapidly, driven by the proliferation of a throw-away culture marked by excessive consumption and the overproduction of disposable items [37]. Thus, this reduction in littering is of paramount importance for environmental conservation demonstrating the possibilities of market instruments to trigger behavioural change.

The consistent decrease over two consecutive years suggests that the DRS in Latvia effectively motivates people to return their beverage containers for recycling, reducing the likelihood of these containers being littered. Even if some DRS packages have been littered, a group of individuals seeking a deposit refund actively collects these containers, thus reducing the amount of littering. This trend suggests that the positive impact of the DRS is sustainable and likely to persist in the future. The DRS also seems to be a more effective policy tool in dealing with market failures, as other economic instruments, like taxing litter, pose significant challenges in monitoring and enforcement [1].

The introduction and promotion of the DRS also likely raised public awareness about the importance of recycling and proper disposal of beverage containers. This increased awareness and motivation can lead to more responsible behaviour among consumers. Also, regular monitoring and reporting of litter data can help identify problem areas and inform targeted interventions, leading to more effective litter reduction strategies. These are significant arguments to be considered by all the countries (e.g., Slovakia, Spain, and Bulgaria) planning to introduce the DRS.

This study demonstrates that a DRS addresses market failures by creating a financial incentive for consumers to return beverage containers. This effectively assigns value to these items, transforming the external cost of litter into a direct economic cost for consumers and incentivizing behaviour that reduces littering while promoting proper disposal and recycling of waste. Additionally, the DRS mitigates the common-pool resource problem by providing a structured system that encourages collective action towards recycling and proper waste management.

However, this study also shows that in some situations a DRS might not be as effective. Even when a DRS existed in both Estonia and Lithuania, a notable trend in 2023 identified a concentration of DRS-related beverage packaging litter near the coastal sites on the Latvian–Estonian and Latvian–Lithuanian borders. Thus, cross-border tourism may be influencing coastal littering and decrease the effectiveness of the DRS in littering reduction. Lack of awareness about the DRS labelling or infrastructure could lead to confusion and increased littering at the borders. Additionally, a potential increase in cross-border tourism in 2023 after the COVID-19 restrictions have been lifted could have contributed to the concentration of DRS-related litter near the borders.

These results underscore the effectiveness of targeted efforts to mitigate littering, highlighting the significance of addressing litter across different material types to achieve comprehensive environmental improvements. The system encourages recycling and effectively reduces the amount of beverage container litter that ends up in coastal and marine environments, especially for plastic and aluminium containers. The more modest reduction in glass bottle litter might be attributed to the existing practices of glass bottle recycling in the absence of the DRS.

However, several limitations in this study and methodology should be considered when interpreting the data:

• The survey of coastal littering hot spots included only three monitoring sessions, making the findings situational in some places;
• Improvements in coastal sites may be interlinked with broader coastal management enhancements in some municipalities;
• Some “unidentified” deposit label presence in 2022 coastal spots may be due to worn-off tags, especially for glass bottles.