Of the 1,342 pieces of litter caught, 816 pieces were plastic

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Countdown New Zealand

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There are growing concerns regarding plastic pollution that is entering the oceans. Studies are finding evidence that commercial areas, such as those with supermarkets are “hotspot” sites that generate high litter loadings into the stormwater drains.These sites tend to have large amounts of pedestrians, as well as busy loading zones generating high amounts of litter. These drains often discharge with no treatment to stormwater drains contributing to the pollution in the oceans.  

In order to address pollution generated at supermarket carparks and service centres, Stormwater 360 has conducted a trial at two Countdown locations: one being a supermarket located in Takapuna, and the other is a warehouse in Favona that supplies Countdowns all over the North Island and some in the South Island.

Countdown Takapuna

There were two sites that were assessed in this supermarket.

The first pit is located directly outside the main entrance leading up to the carparks.

This site saw high amounts of cigarette butts (56) and food packaging (38). As can be seen from the picture below, there is litter in the vegetated area directly by the storm drain which will enter the stormwater network in the presence of rainfall.

Litter in vegetated garden

The second pit is located downstream from two loading bays.

This site caught the most amount of soft plastic pieces (176). This is largely from the plastic wrap that is pulled off pallet shipments that come in. These smaller pieces are easily carried away by light breezes. This pit also had a very high loading of paper(64) and cardboard (92). Directly next to the pit, there were pallets with bound cardboard that is due to be recycled as well as various trash cans and dumpsters. All of these are directly upstream from the pit.

Countdown Warehouse in Favona

 In this site, the LittaTraps were installed in two catch pits next to each other. The pits were next to a staging and loading area. Both pits had very high plastic loading. In the event of spilled pallets, even though we expect great care is taken to avoid incidents, all debris unable to be cleaned up enter the stormwater system.

Summary of Results

The two sites (supermarket and processing area) had similar loading of debris. In the 134 days that the LittaTraps were installed, 1,342 pieces of litter were caught from the two sites combined, and of these, 816 pieces were plastic, refer to Figure 1 below for more details. The dominant source of pollution overall was soft plastic.This type of pollutant is easily broken down to smaller pieces and is easily carried away by wind and rain. Soft plastics also create serious problems within the ocean environment by trapping, choking, or filling the stomachs of marine life.

Figure1. Litter composition
Figure 2. Plastic composition