Urban Rivers

Urban rivers serve as conduits for the influx of plastic pollution into the oceans. An analysis of waste from five urban rivers flowing into the Oslo Fjord reveals that consumer waste is the primary source of plastic pollution. 

There is limited knowledge about the quantities and composition of waste from Norwegian rivers. In collaboration with Hold Norge Rent (HNR) and Mepex, the Oslo Fjord Outdoor Council (OF) sought to gain more insights into plastic waste along rivers flowing into the Oslo Fjord. 

To identify the sources of pollution, we analysed waste from five rivers: Lysakerelva, Sandvikselva, Askerelva, Åroselva, and Lierelva. 

The project’s objective is to identify key sources and propose concrete measures to prevent pollution. The target audience for project information includes pollution authorities, residents, and local businesses. 

Based on quantity, unidentified plastic products are the most found items. Unidentified metal products top the list based on weight. 

Personal consumption source of half the waste 

We identified the source of pollution in more than half of the analysed waste. The results show that 49 percent originates from personal consumption. Additionally, there may be additional consumer-related waste in the “Unknown source” category, which ranks second on the list. 

Plastic in LDPE and PP tops the list 

Plastic constitutes 76.3 percent of all waste from the five rivers, with metal as the second most common material. The majority of plastic material is LDPE and PP plastic. Based on quantity, LDPE and PP plastics make up nearly 80 percent of the plastic. These plastic types are primarily used in food/snack packaging (LDPE) and carry bags (PP). 

Most of the waste is less than 5 years old 

For a little over 13 percent of the waste, it was possible to record the production date or year. Of this waste, 82 percent is less than five years old, 10 percent is between five and fifteen years old, and 8 percent is fifteen years or older. The prevalence of recent waste (under five years) is a natural consequence of frequent cleanup efforts by both the municipality and volunteers along stretches of the rivers. 

Origin Identified in Less Than a Third of Waste 

We were able to identify the country of origin for 24 percent of the waste from the rivers. Of this, a substantial 91 percent originates from Norwegian producers. 

Clean-Up Initiative for a Cleaner Oslo Fjord 

“Plastic Pollution Along Urban Rivers” is a subproject within the Oslo Fjord Outdoor Council’s main initiative “Clean-Up Initiative for a Cleaner Oslo Fjord,” financed by the Norwegian Environment Agency. 

Similar analyses were conducted in 2022, encompassing the same five rivers, in addition to the Neselva river. 

Mepex played a pivotal role in river clean-up efforts, took the lead in waste analysis, and compiled the project reports.