Factsheet: the effect of deposit return schemes on litter

In addition to older measurements from the United States (1970s and 1980s) and Denmark (2017), recent monitoring results from the Netherlands (2018–2022) now also show that the introduction of deposit return schemes sharply reduces the number of beverage containers in litter. Litter data United States (1970s and 1980s) In the 1970s and 1980s, the states of New York, Iowa, Maine, Michigan, Oregon and Vermont in the United States conducted, or commissioned, studies mapping the impact of deposit systems on litter by counting the number of cans and bottles at the same locations before and after the introduction of deposits. A federal analysis by the U.S. Government Accountability Office concluded that these studies were conducted independently and rigorously by the various states and are collectively useful for assessing the effect of deposit systems on litter. The methodologies of the studies are not entirely identical, but are comparable. These studies showed that the introduction of deposits on beverage containers led to a reduction of approximately 70-84% (in numbers) of the relevant beverage containers in roadside litter. The total amount of litter decreased by 30 to 45% as a result. Research agency CE Delft used these results in their study Costs and effects of deposits on small bottles and cans (2017) to estimate the effects of deposits on the volume of bottles and cans in litter. CE Delft summarised the results of the American studies (see table below). Litter data Denmark (2008-2017) Data has also been collected in Denmark showing that deposit return schemes have a significant reducing effect on the presence of deposit packaging in litter. CE Delft (2017) concluded that in Denmark deposits led to a 70-90% reduction of deposit cans in litter. It refers to three different Danish sources that provide insight into the ratio of cans in litter with and without deposits. These reduction percentages are in line with the American results from the 1970s and 1980s. Explanation of the presence of cans without deposits in Denmark Despite the fact that Denmark has had deposits on cans since 2002, there were (mainly) cans without deposits in the litter. This primarily concerned cans from shops just across the border with Germany, which sell packaging with special labels that do not carry German (or Danish) deposits. According to data, the ratio between cans with and without deposits in Denmark is therefore 50/50. According to a press release from the Law Office, the number of German containers (without deposits) placed on the market is around 600 to 700 million. This number is roughly equal to the number of deposit cans reported by Dansk Retursystem (650 million units). Annual clean-up and counting campaign by volunteers (2016) In Denmark, a large group of volunteers annually collects and counts cans from litter. They distinguish between cans with and without deposits. CE Delft (2017) refers to the then most recent count from 2016. That year, a total of more than 100,000 cans were collected, of which 23% were cans with deposits and 77% were cans without deposits. CE Delft (2017) calculated that with the same consumption volumes of Danish and German cans, the chance of Danish cans ending up in litter is a factor of 3.3 smaller than German cans without deposits (77%/23%). This would correspond to a reduction rate of approximately 70%. Calculation: suppose 77 cans initially end up in litter, then after the introduction of deposits, only 23 cans remain. This is a reduction of 54 cans. This corresponds to a reduction rate of approximately 70% (54/77 is 70%). Data from Dansk Retursystem (2014) Dansk Retursystem, system operator of the Danish deposit system, presented to CE Delft that in the year 2014, 80% of the number of cans in litter were cans without deposits. CE Delft concluded that according to this data, the chance of a can without a deposit becoming litter is 4 times higher. This corresponds to a reduction rate of 75%. Calculation: suppose 80 cans initially end up in litter, then with this ratio after introduction, there would be 20. This is a reduction of 60 units (80 minus 20) or 75% (60/80 is 75%). Measurements by Danmarks Naturfredningsforening (2008-2017) CE Delft received measurement data for the years 2008-2018 from Danmarks Naturfredningsforening, the organisation that guides the annual counts. During this period, a total of 1,520,781 cans were collected, of which 162,995 had deposits (and thus 1,357,786 without deposits). This means that, rounded off, 90% of the cans in litter are cans without deposits. According to this data, the chance of a can becoming litter is 9 times higher when there is no deposit on it. CE Delft calculated that this corresponds to a reduction rate of approximately 90%.

In addition to older measurements from the United States (1970s and 1980s) and Denmark (2017), recent monitoring results from the Netherlands (2018–2022) now also show that the introduction of deposit return schemes sharply reduces the number of beverage containers in litter.

Litter data United States (1970s and 1980s)

In the 1970s and 1980s, the states of New York, Iowa, Maine, Michigan, Oregon and Vermont in the United States conducted, or commissioned, studies mapping the impact of deposits on litter by counting the number of cans and bottles at the same locations before and after the introduction of deposits.

A federal analysis by the U.S. Government Accountability Office concluded that these studies were conducted independently and rigorously by the various states and are collectively useful for assessing the effect of deposit systems on litter. The methodologies of the studies are not entirely identical, but are comparable.

These studies showed that the introduction of deposits on beverage containers led to a reduction of approximately 70-84% (in numbers) of the relevant beverage containers in roadside litter. The total amount of litter decreased by 30 to 45% as a result.

Research agency CE Delft used these results in their study Costs and effects of deposits on small bottles and cans (2017) to estimate the effects of deposits on the volume of bottles and cans in litter. CE Delft summarised the results of the American studies (see table below).

Litter data Denmark (2008-2017)

Data has also been collected in Denmark showing that deposit return schemes have a significant reducing effect on the presence of deposit packaging in litter.

CE Delft (2017) concluded that in Denmark deposits led to a reduction of 70-90% of deposit cans in litter. It refers to three different Danish sources that provide insight into the ratio of cans in litter with and without deposits. These reduction percentages are in line with the American results from the 1970s and 1980s.

Explanation of the presence of cans without deposits in Denmark

Despite the fact that Denmark has had deposits on cans since 2002, there were (mainly) cans without deposits in the litter. This primarily concerned cans from shops just across the border with Germany, which sell packaging with special labels that do not carry German (or Danish) deposits. According to data, the ratio between cans with and without deposits in Denmark is therefore 50/50. The number of German containers (without deposits) placed on the market is, according to a press release from the Law Office, around 600 to 700 million. This number is roughly equal to the number of deposit cans reported by Dansk Retursystem (650 million units).

Annual clean-up and counting campaign by volunteers (2016)

In Denmark, a large group of volunteers annually collects and counts cans from litter. They distinguish between cans with and without deposits. CE Delft (2017) refers to the then most recent count from 2016. That year, a total of more than 100,000 cans were collected, of which 23% were cans with deposits and 77% were cans without deposits. CE Delft (2017) calculated that with the same consumption volumes of Danish and German cans, the chance of Danish cans ending up in litter is a factor of 3.3 smaller than German cans without deposits (77%/23%). This would correspond to a reduction rate of approximately 70%.

Calculation: suppose 77 cans initially end up in litter, then after the introduction of deposits, only 23 cans remain. This is a reduction of 54 cans. This corresponds to a reduction rate of approximately 70% (54/77 is 70%).

Data from Dansk Retursystem (2014)

Dansk Retursystem, system operator of the Danish deposit system, presented to CE Delft that in the year 2014, 80% of the number of cans in litter were cans without deposits. CE Delft concluded that according to this data, the chance of a can without a deposit becoming litter is 4 times higher. This corresponds to a reduction rate of 75%.

Calculation: suppose 80 cans initially end up in litter, then with this ratio after introduction, there would be 20. This is a reduction of 60 units (80 minus 20) or 75% (60/80 is 75%).

Measurements by Danmarks Naturfredningsforening (2008-2017)

CE Delft received measurement data for the years 2008-2018 from Danmarks Naturfredningsforening, the organisation that guides the annual counts. During this period, there

were a total of 1,520,781 cans collected, of which 162,995 had deposits (and thus 1,357,786 without deposits). This means that, rounded off, 90% of the cans in litter are cans without deposits. According to this data, the chance of a can becoming litter is 9 times higher when there is no deposit on it. CE Delft calculated that this corresponds to a reduction rate of approximately 90%.

Calculation: Before introduction, 90 cans end up in litter, after introduction, this drops to 10 at this ratio. The decrease is 80/90 or (rounded off) 90%.

Dutch deposit study CE Delft (2017)

In the study Costs and effects of deposits on small bottles and cans (2017), research consultancy CE Delft investigated the effect of deposits on the volume of bottles and cans in litter. They analysed the aforementioned data from the United States and Denmark. Based on these figures (and calculations based on a 2001 survey by CE Delft), CE Delft based its expectation that “deposits would reduce the number of cans and bottles in litter by 70 to 90%”.

Litter data Netherlands (2016–2022)

Litter monitoring as part of policy agreement

On 10 March 2018, then-State Secretary Stientje van Veldhoven announced that she would introduce deposits on small plastic bottles containing water and soft drinks, unless the business community succeeded by autumn 2020 in (a) recycling 90% of small plastic bottles and (b) reducing the share of plastic bottles in litter by 70-90%. The 70-90% reduction in litter was based on expected deposit results from the CE Delft (2017) report and thus measurements from the United States and Denmark.

In light of the performance agreement regarding litter reduction, monitoring was set up. Rijkswaterstaat reports every six months on the number of plastic bottles in litter. They started with the first half of 2018. From the second measurement (covering the second half of 2018), RWS also counted the number of cans in litter and included this in the report. From the report on the first half of 2019, Rijkswaterstaat also includes the measurements of Zwerfinator Dirk Groot in their reporting. Rijkswaterstaat and Dirk Groot each use their own methodology.

Deposits are introduced, monitoring continues

When the Rijkswaterstaat report in April 2020 showed that the industry would not succeed in reducing the share of plastic bottles in litter by at least 70% before autumn 2020 (the number of plastic bottles in the environment had increased by 7%), then-State Secretary Van Veldhoven made an early decision on 24 April 2020 to introduce deposits on small plastic bottles containing water and soft drinks as of 1 July 2021.

Recycling Netwerk Benelux urged at the time that Rijkswaterstaat's monitoring of the number of bottles should continue after the introduction of deposits on these beverage containers. This would provide new figures to show the effect of deposits on the volume of beverage packaging in litter. This was agreed.

First results after the introduction of deposits (second half of 2021)

The first results after the introduction of deposits on 1 July 2021 covered the monitoring for the second half of 2021. On 3 January 2022, Zwerfinator Dirk Groot communicated that his research showed that the share of small plastic bottles in litter had decreased since the introduction of deposits. In the final quarter of 2021, he registered 70.2% fewer plastic bottles per kilometre than the average of the final quarters of 2017, 2018, 2019 and 2020.

The report on the second half of 2021 from Rijkswaterstaat (dated 15 February 2022) was shared on 5 April 2022. This report shows that in the second half of 2021, Rijkswaterstaat counted 41% fewer small plastic bottles in litter than in the second half of 2020.

Please note: deposits were introduced on small plastic bottles containing soft drinks and water. As a result, some other categories of small plastic bottles fall outside the deposit scheme, such as dairy and juices. In both measurements above, the reduction percentage relates to all small plastic bottles.

The 70.2% reduction measured by Groot covers the fourth quarter, and the 41% reduction measured by Rijkswaterstaat covers the third and fourth quarters of 2021. The difference in results can be explained, among other things, by the fact that in the third quarter there were still many bottles without deposits in the litter, and (old) bottles without deposits were still being sold. Indeed, producers are given time to sell off their old stock without deposits. Additionally, Groot removes the counted beverage containers from the litter during his measurements, preventing them from being counted multiple times. Rijkswaterstaat only counts them and leaves the beverage containers behind. As a result, 'old' bottles, still without deposits, can reappear in counts multiple times. This flattens the reduction rate somewhat.

Results one year after the introduction of deposits (first half of 2022)

On 12 September 2022, Zwerfinator Dirk Groot published his report with monitoring results up to and including the first half of 2022—one year after the introduction of deposits. In this report, Groot calculates the reduction percentage for plastic bottles within the category on which deposits are levied: soft drinks and waters. His measurements show that 76% fewer plastic bottles containing water and soft drinks had ended up in litter.

This percentage from Groot is already focused on the water and soft drinks category. However, the measurement is still 'polluted' by bottles without deposits. Consider, for example:

old bottles of water and soft drinks that ended up in litter before deposits were introduced and are still there;

bottles of water and soft drinks purchased abroad without deposits;